from flask import Flask, render_template_string, request, redirect, url_for, jsonify, flash, abort, Response, session
import json
import os
import logging
import threading
import time
from datetime import datetime, timedelta
import pytz
from huggingface_hub import HfApi, hf_hub_download
from huggingface_hub.utils import RepositoryNotFoundError, HfHubHTTPError
import uuid
from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
import functools
from functools import wraps
from collections import defaultdict
from urllib.parse import quote

app = Flask(__name__)
app.secret_key = os.urandom(24)
app.permanent_session_lifetime = timedelta(days=7)

ADMIN_PASS = os.getenv("ADMIN_PASS", "admin")

DATA_DIR = 'pos_data'
os.makedirs(DATA_DIR, exist_ok=True)

INVENTORY_FILE = os.path.join(DATA_DIR, 'inventory.json')
TRANSACTIONS_FILE = os.path.join(DATA_DIR, 'transactions.json')
USERS_FILE = os.path.join(DATA_DIR, 'users.json')
KASSAS_FILE = os.path.join(DATA_DIR, 'kassas.json')
EXPENSES_FILE = os.path.join(DATA_DIR, 'expenses.json')

DATA_FILES = {
    'inventory': (INVENTORY_FILE, threading.Lock()),
    'transactions': (TRANSACTIONS_FILE, threading.Lock()),
    'users': (USERS_FILE, threading.Lock()),
    'kassas': (KASSAS_FILE, threading.Lock()),
    'expenses': (EXPENSES_FILE, threading.Lock()),
}

HF_TOKEN_WRITE = os.getenv("HF_TOKEN_WRITE", "YOUR_WRITE_TOKEN_HERE")
HF_TOKEN_READ = os.getenv("HF_TOKEN_READ", "YOUR_READ_TOKEN_HERE")
REPO_ID = "Kgshop/morshenbasekz"

BISHKEK_TZ = pytz.timezone('Asia/Almaty')

logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

def get_current_time():
    return datetime.now(BISHKEK_TZ)

class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, Decimal):
            return str(obj)
        return json.JSONEncoder.default(self, obj)

def to_decimal(value_str, default='0.00'):
    if value_str is None or value_str == '':
        return Decimal(default)
    try:
        return Decimal(str(value_str).replace(',', '.'))
    except InvalidOperation:
        logging.warning(f"Could not convert '{value_str}' to Decimal. Returned {default}.")
        return Decimal(default)
        
def load_json_data(file_key):
    filepath, lock = DATA_FILES[file_key]
    filename = os.path.basename(filepath)
    with lock:
        try:
            hf_hub_download(
                repo_id=REPO_ID, filename=filename, repo_type="dataset", token=HF_TOKEN_READ,
                local_dir=DATA_DIR, local_dir_use_symlinks=False, force_download=True,
            )
        except HfHubHTTPError as e:
            if e.response.status_code != 404:
                logging.error(f"HTTP error downloading {filename}: {e}")
        except Exception as e:
            logging.error(f"Unknown error downloading {filename}: {e}")

        try:
            with open(filepath, 'r', encoding='utf-8') as f:
                return json.load(f)
        except (FileNotFoundError, json.JSONDecodeError):
            return []

def save_json_data(file_key, data):
    filepath, lock = DATA_FILES[file_key]
    with lock:
        try:
            temp_file = filepath + ".tmp"
            with open(temp_file, 'w', encoding='utf-8') as f:
                json.dump(data, f, ensure_ascii=False, indent=4, cls=DecimalEncoder)
            os.replace(temp_file, filepath)
        except Exception as e:
            logging.error(f"Critical error saving {filepath}: {e}", exc_info=True)

@functools.lru_cache(maxsize=1)
def get_hf_api():
    if not HF_TOKEN_WRITE or HF_TOKEN_WRITE == "YOUR_WRITE_TOKEN_HERE":
        return None
    try:
        return HfApi()
    except Exception as e:
        logging.error(f"Error initializing HfApi: {e}")
        return None

def upload_db_to_hf(file_key):
    api = get_hf_api()
    if not api:
        return
    filepath, _ = DATA_FILES[file_key]
    if not os.path.exists(filepath):
        return
    try:
        filename = os.path.basename(filepath)
        commit_time = get_current_time().strftime('%Y-%m-%d %H:%M:%S %Z%z')
        api.upload_file(
            path_or_fileobj=filepath, path_in_repo=filename, repo_id=REPO_ID, repo_type="dataset",
            token=HF_TOKEN_WRITE, commit_message=f"Automated backup {filename} {commit_time}",
            run_as_future=True
        )
    except Exception as e:
        logging.error(f"Error initiating upload of {filepath}: {e}")

def periodic_backup():
    while True:
        time.sleep(1800)
        try:
            for key in DATA_FILES.keys():
                upload_db_to_hf(key)
        except Exception as e:
            logging.error(f"Error during scheduled backup: {e}", exc_info=True)
            
def find_item_by_field(data, field, value):
    for item in data:
        if isinstance(item, dict) and item.get(field) == value:
            return item
    return None

def find_user_by_pin(pin):
    users = load_json_data('users')
    return find_item_by_field(users, 'pin', pin)

def format_currency_py(value):
    try:
        number = to_decimal(value)
        return f"{number:,.2f}".replace(",", " ").replace(".", ",")
    except (InvalidOperation, TypeError, ValueError):
        return "0,00"

def generate_receipt_html(transaction):
    items_html = ""
    for item in transaction['items']:
        items_html += f"""
        <tr>
            <td>{item['name']}</td>
            <td style="text-align: right;">{item['quantity']}</td>
            <td style="text-align: right;">{format_currency_py(item['price_at_sale'])}</td>
            <td style="text-align: right;">{format_currency_py(item['total'])}</td>
        </tr>
        """
    return f"""
    <!DOCTYPE html>
    <html lang="ru">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Чек {transaction['id'][:8]}</title>
        <style>
            body {{ font-family: 'Courier New', monospace; margin: 0; padding: 20px; background-color: #f4f4f4; }}
            .receipt {{ max-width: 350px; margin: auto; background: white; padding: 20px; box-shadow: 0 0 10px rgba(0,0,0,0.1); }}
            h2, p {{ text-align: center; margin: 5px 0; }}
            table {{ width: 100%; border-collapse: collapse; margin: 15px 0; }}
            th, td {{ padding: 5px; border-bottom: 1px dashed #ccc; }}
            .total {{ font-weight: bold; font-size: 1.2em; }}
        </style>
    </head>
    <body>
        <div class="receipt">
            <h2>Компания Morshen Group</h2>
            <p>--------------------------------</p>
            <p>Чек №: {transaction['id'][:8]}</p>
            <p>Дата: {datetime.fromisoformat(transaction['timestamp']).strftime('%d.%m.%Y %H:%M')}</p>
            <p>Кассир: {transaction['user_name']}</p>
            <p>--------------------------------</p>
            <table>
                <thead>
                    <tr>
                        <th style="text-align: left;">Товар</th>
                        <th style="text-align: right;">Кол.</th>
                        <th style="text-align: right;">Цена</th>
                        <th style="text-align: right;">Сумма</th>
                    </tr>
                </thead>
                <tbody>{items_html}</tbody>
            </table>
            <p>--------------------------------</p>
            <p class="total">Итого: {format_currency_py(transaction['total_amount'])} ₸</p>
            <p>Способ оплаты: {'Наличные' if transaction['payment_method'] == 'cash' else 'Карта'}</p>
            <p>--------------------------------</p>
            <p>Спасибо за покупку!</p>
        </div>
    </body>
    </html>
    """

def admin_required(f):
    @wraps(f)
    def decorated_function(*args, **kwargs):
        if 'admin_logged_in' not in session:
            flash("Для доступа к этой странице требуется аутентификация.", "warning")
            return redirect(url_for('admin_login', next=request.url))
        return f(*args, **kwargs)
    return decorated_function

@app.context_processor
def inject_utils():
    return {'format_currency_py': format_currency_py, 'get_current_time': get_current_time, 'quote': quote}

@app.route('/')
def sales_screen():
    inventory = load_json_data('inventory')
    users = load_json_data('users')
    kassas = load_json_data('kassas')
    
    active_inventory = []
    for p in inventory:
        if isinstance(p, dict) and any(v.get('stock', 0) > 0 for v in p.get('variants', [])):
            active_inventory.append(p)

    active_inventory.sort(key=lambda x: x.get('name', '').lower())
    html = BASE_TEMPLATE.replace('__TITLE__', "Касса").replace('__CONTENT__', SALES_SCREEN_CONTENT).replace('__SCRIPTS__', SALES_SCREEN_SCRIPTS)
    return render_template_string(html, inventory=active_inventory, users=users, kassas=kassas)

@app.route('/inventory', methods=['GET', 'POST'])
@admin_required
def inventory_management():
    if request.method == 'POST':
        try:
            name = request.form.get('name', '').strip()
            barcode = request.form.get('barcode', '').strip()
            
            if not name or not barcode:
                flash("Название и штрих-код - обязательные поля.", "danger")
                return redirect(url_for('inventory_management'))

            inventory = load_json_data('inventory')
            if find_item_by_field(inventory, 'barcode', barcode):
                flash(f"Товар со штрих-кодом {barcode} уже существует.", "warning")
                return redirect(url_for('inventory_management'))

            variants = []
            variant_names = request.form.getlist('variant_name[]')
            variant_prices = request.form.getlist('variant_price[]')
            variant_cost_prices = request.form.getlist('variant_cost_price[]')
            variant_stocks = request.form.getlist('variant_stock[]')

            for i in range(len(variant_names)):
                v_name = variant_names[i].strip()
                if not v_name: continue
                variants.append({
                    'id': uuid.uuid4().hex,
                    'option_name': "Вариант",
                    'option_value': v_name,
                    'price': str(to_decimal(variant_prices[i])),
                    'cost_price': str(to_decimal(variant_cost_prices[i])),
                    'stock': int(to_decimal(variant_stocks[i], '0')),
                })
            
            if not variants:
                flash("Нужно добавить хотя бы один вариант товара.", "danger")
                return redirect(url_for('inventory_management'))

            new_product = {
                'id': uuid.uuid4().hex,
                'name': name,
                'barcode': barcode,
                'variants': variants,
                'timestamp_added': get_current_time().isoformat(),
                'timestamp_updated': get_current_time().isoformat()
            }
            inventory.append(new_product)
            save_json_data('inventory', inventory)
            upload_db_to_hf('inventory')
            flash(f"Товар '{name}' успешно добавлен.", "success")
        except Exception as e:
            logging.error(f"Error adding product: {e}", exc_info=True)
            flash(f"Ошибка при добавлении товара: {e}", "danger")
        return redirect(url_for('inventory_management'))
    
    inventory_list = load_json_data('inventory')
    inventory_list.sort(key=lambda x: x.get('name', '').lower())
    html = BASE_TEMPLATE.replace('__TITLE__', "Склад").replace('__CONTENT__', INVENTORY_CONTENT).replace('__SCRIPTS__', INVENTORY_SCRIPTS)
    return render_template_string(html, inventory=inventory_list)

@app.route('/inventory/edit/<product_id>', methods=['POST'])
@admin_required
def edit_product(product_id):
    inventory = load_json_data('inventory')
    product_found = False
    for i, product in enumerate(inventory):
        if isinstance(product, dict) and product.get('id') == product_id:
            try:
                name = request.form.get('name', '').strip()
                barcode = request.form.get('barcode', '').strip()

                if not name or not barcode:
                    flash("Название и штрих-код обязательны.", "danger")
                    return redirect(url_for('inventory_management'))

                existing_barcode = find_item_by_field(inventory, 'barcode', barcode)
                if existing_barcode and existing_barcode.get('id') != product_id:
                    flash(f"Штрих-код {barcode} уже используется другим товаром.", "warning")
                    return redirect(url_for('inventory_management'))

                inventory[i]['name'] = name
                inventory[i]['barcode'] = barcode
                
                new_variants = []
                variant_ids = request.form.getlist('variant_id[]')
                variant_names = request.form.getlist('variant_name[]')
                variant_prices = request.form.getlist('variant_price[]')
                variant_cost_prices = request.form.getlist('variant_cost_price[]')
                variant_stocks = request.form.getlist('variant_stock[]')

                for j in range(len(variant_ids)):
                    v_name = variant_names[j].strip()
                    if not v_name: continue
                    new_variants.append({
                        'id': variant_ids[j] or uuid.uuid4().hex,
                        'option_name': "Вариант",
                        'option_value': v_name,
                        'price': str(to_decimal(variant_prices[j])),
                        'cost_price': str(to_decimal(variant_cost_prices[j])),
                        'stock': int(to_decimal(variant_stocks[j], '0')),
                    })
                
                inventory[i]['variants'] = new_variants
                inventory[i]['timestamp_updated'] = get_current_time().isoformat()
                product_found = True
                break
            except Exception as e:
                logging.error(f"Error updating product: {e}", exc_info=True)
                flash(f"Ошибка при обновлении товара: {e}", "danger")
                return redirect(url_for('inventory_management'))
    
    if product_found:
        save_json_data('inventory', inventory)
        upload_db_to_hf('inventory')
        flash("Товар успешно обновлен.", "success")
    else:
        flash("Товар не найден.", "danger")
    return redirect(url_for('inventory_management'))

@app.route('/inventory/delete/<product_id>', methods=['POST'])
@admin_required
def delete_product(product_id):
    inventory = load_json_data('inventory')
    initial_len = len(inventory)
    inventory = [p for p in inventory if not (isinstance(p, dict) and p.get('id') == product_id)]
    if len(inventory) < initial_len:
        save_json_data('inventory', inventory)
        upload_db_to_hf('inventory')
        flash("Товар удален.", "success")
    else:
        flash("Товар не найден.", "warning")
    return redirect(url_for('inventory_management'))

@app.route('/inventory/stock_in', methods=['POST'])
@admin_required
def stock_in():
    try:
        product_id = request.form.get('product_id')
        variant_id = request.form.get('variant_id')
        quantity = int(request.form.get('quantity', 0))
        cost_price_str = request.form.get('cost_price')
        
        if not product_id or not variant_id or quantity <= 0:
            flash("Неверные данные для оприходования.", "danger")
            return redirect(url_for('inventory_management'))

        inventory = load_json_data('inventory')
        product = find_item_by_field(inventory, 'id', product_id)
        if not product:
            flash("Товар не найден.", "danger")
            return redirect(url_for('inventory_management'))

        variant_found = False
        for i, variant in enumerate(product.get('variants', [])):
            if variant.get('id') == variant_id:
                variant['stock'] = variant.get('stock', 0) + quantity
                if cost_price_str:
                    new_cost = to_decimal(cost_price_str)
                    old_stock = variant.get('stock', 0) - quantity
                    old_cost = to_decimal(variant.get('cost_price', '0'))
                    if old_stock + quantity > 0:
                        avg_cost = ((old_cost * old_stock) + (new_cost * quantity)) / (old_stock + quantity)
                        variant['cost_price'] = str(avg_cost.quantize(Decimal('0.01'), rounding=ROUND_HALF_UP))
                
                variant_found = True
                break

        if not variant_found:
            flash("Вариант товара не найден.", "danger")
            return redirect(url_for('inventory_management'))

        product['timestamp_updated'] = get_current_time().isoformat()
        save_json_data('inventory', inventory)
        upload_db_to_hf('inventory')
        flash(f"Остаток товара '{product['name']} ({variant['option_value']})' увеличен на {quantity}.", "success")

    except Exception as e:
        logging.error(f"Error stocking in: {e}", exc_info=True)
        flash(f"Ошибка при оприходовании: {e}", "danger")

    return redirect(url_for('inventory_management'))

@app.route('/api/product_by_barcode/<barcode>')
def get_product_by_barcode(barcode):
    inventory = load_json_data('inventory')
    product = find_item_by_field(inventory, 'barcode', barcode)
    if product:
        active_variants = [v for v in product.get('variants', []) if v.get('stock', 0) > 0]
        if active_variants:
            product_copy = product.copy()
            product_copy['variants'] = active_variants
            return jsonify({'success': True, 'product': product_copy})
        else:
            return jsonify({'success': False, 'message': 'Товар закончился на складе'}), 404
    return jsonify({'success': False, 'message': 'Товар не найден'}), 404

@app.route('/api/complete_sale', methods=['POST'])
def complete_sale():
    try:
        data = request.get_json()
        cart = data.get('cart', [])
        user_id = data.get('userId')
        kassa_id = data.get('kassaId')
        payment_method = data.get('paymentMethod', 'cash')

        if not cart or not user_id or not kassa_id:
            return jsonify({'success': False, 'message': 'Неполные данные для продажи.'}), 400

        inventory = load_json_data('inventory')
        users = load_json_data('users')
        kassas = load_json_data('kassas')
        
        user = find_item_by_field(users, 'id', user_id)
        kassa = find_item_by_field(kassas, 'id', kassa_id)

        if not user or not kassa:
            return jsonify({'success': False, 'message': 'Кассир или касса не найдены.'}), 404

        sale_items = []
        total_amount = Decimal('0.00')
        inventory_updates = {}

        for variant_id, cart_item in cart.items():
            product = find_item_by_field(inventory, 'id', cart_item['productId'])
            if not product:
                return jsonify({'success': False, 'message': f"Товар с ID {cart_item['productId']} не найден."}), 404
            
            variant = find_item_by_field(product.get('variants', []), 'id', variant_id)
            if not variant:
                 return jsonify({'success': False, 'message': f"Вариант товара с ID {variant_id} не найден."}), 404
            
            quantity_sold = cart_item['quantity']
            current_stock = variant.get('stock', 0)

            if quantity_sold > current_stock:
                return jsonify({'success': False, 'message': f"Недостаточно товара '{product['name']} ({variant['option_value']})'. В наличии: {current_stock}"}), 400

            price_at_sale = to_decimal(variant.get('price', '0'))
            cost_price_at_sale = to_decimal(variant.get('cost_price', '0'))
            item_total = price_at_sale * Decimal(quantity_sold)
            total_amount += item_total

            sale_items.append({
                'product_id': product['id'],
                'variant_id': variant_id,
                'name': f"{product['name']} ({variant['option_value']})",
                'barcode': product.get('barcode'),
                'quantity': quantity_sold,
                'price_at_sale': str(price_at_sale),
                'cost_price_at_sale': str(cost_price_at_sale),
                'total': str(item_total)
            })
            inventory_updates[variant_id] = {'product_id': product['id'], 'new_stock': current_stock - quantity_sold}

        now_iso = get_current_time().isoformat()
        
        new_transaction = {
            'id': uuid.uuid4().hex,
            'timestamp': now_iso,
            'type': 'sale',
            'status': 'completed',
            'original_transaction_id': None,
            'user_id': user_id,
            'user_name': user.get('name', 'N/A'),
            'kassa_id': kassa_id,
            'kassa_name': kassa.get('name', 'N/A'),
            'items': sale_items,
            'total_amount': str(total_amount),
            'payment_method': payment_method
        }
        
        new_transaction['receipt_html'] = generate_receipt_html(new_transaction)
        transactions = load_json_data('transactions')
        transactions.append(new_transaction)

        for variant_id, update_info in inventory_updates.items():
            for p in inventory:
                if p.get('id') == update_info['product_id']:
                    for v in p.get('variants', []):
                        if v.get('id') == variant_id:
                            v['stock'] = update_info['new_stock']
                            p['timestamp_updated'] = now_iso
                            break
                    break

        if payment_method == 'cash':
            for i, k in enumerate(kassas):
                if k.get('id') == kassa_id:
                    current_balance = to_decimal(k.get('balance', '0'))
                    kassas[i]['balance'] = str(current_balance + total_amount)
                    if 'history' not in kassas[i] or not isinstance(kassas[i]['history'], list):
                        kassas[i]['history'] = []
                    kassas[i]['history'].append({
                        'type': 'sale',
                        'amount': str(total_amount),
                        'timestamp': now_iso,
                        'transaction_id': new_transaction['id']
                    })
                    break

        save_json_data('transactions', transactions)
        save_json_data('inventory', inventory)
        save_json_data('kassas', kassas)
        
        upload_db_to_hf('transactions')
        upload_db_to_hf('inventory')
        upload_db_to_hf('kassas')

        receipt_url = url_for('view_receipt', transaction_id=new_transaction['id'], _external=True)
        return jsonify({
            'success': True, 
            'message': 'Продажа успешно зарегистрирована.', 
            'transactionId': new_transaction['id'],
            'receiptUrl': receipt_url
        })

    except Exception as e:
        logging.error(f"Error completing sale: {e}", exc_info=True)
        return jsonify({'success': False, 'message': f'Внутренняя ошибка сервера: {e}'}), 500

@app.route('/receipt/<transaction_id>')
def view_receipt(transaction_id):
    transactions = load_json_data('transactions')
    transaction = find_item_by_field(transactions, 'id', transaction_id)
    if transaction and 'receipt_html' in transaction:
        return Response(transaction['receipt_html'], mimetype='text/html')
    abort(404, description="Чек не найден")

@app.route('/transactions')
def transaction_history():
    transactions = load_json_data('transactions')
    transactions.sort(key=lambda x: x.get('timestamp', ''), reverse=True)
    html = BASE_TEMPLATE.replace('__TITLE__', "История транзакций").replace('__CONTENT__', TRANSACTIONS_CONTENT).replace('__SCRIPTS__', TRANSACTIONS_SCRIPTS)
    return render_template_string(html, transactions=transactions)

@app.route('/reports')
@admin_required
def reports():
    today = get_current_time().date()
    start_date_str = request.args.get('start_date', (today.replace(day=1)).strftime('%Y-%m-%d'))
    end_date_str = request.args.get('end_date', (today).strftime('%Y-%m-%d'))

    start_date = datetime.strptime(start_date_str, '%Y-%m-%d').replace(tzinfo=BISHKEK_TZ)
    end_date = (datetime.strptime(end_date_str, '%Y-%m-%d') + timedelta(days=1)).replace(tzinfo=BISHKEK_TZ)
    num_days = (end_date - start_date).days

    transactions = load_json_data('transactions')
    expenses = load_json_data('expenses')
    users = load_json_data('users')

    filtered_transactions = [
        t for t in transactions 
        if start_date <= datetime.fromisoformat(t['timestamp']) < end_date
    ]
    filtered_expenses = [
        e for e in expenses 
        if start_date <= datetime.fromisoformat(e['timestamp']) < end_date
    ]
    
    total_revenue = sum(to_decimal(t['total_amount']) for t in filtered_transactions)
    total_cogs = sum(
        to_decimal(item.get('cost_price_at_sale', '0')) * to_decimal(str(item['quantity']))
        for t in filtered_transactions for item in t['items']
    )
    gross_profit = total_revenue - total_cogs
    total_expenses = sum(to_decimal(e['amount']) for e in filtered_expenses)
    
    sales_by_cashier = defaultdict(lambda: {'count': 0, 'total': Decimal(0)})
    for t in filtered_transactions:
        if t.get('type') == 'sale':
            cashier_name = t.get('user_name', 'Неизвестный')
            sales_by_cashier[cashier_name]['count'] += 1
            sales_by_cashier[cashier_name]['total'] += to_decimal(t['total_amount'])
        elif t.get('type') == 'return':
            cashier_name = t.get('user_name', 'Неизвестный')
            sales_by_cashier[cashier_name]['count'] -= 1
            sales_by_cashier[cashier_name]['total'] += to_decimal(t['total_amount'])

    cashier_payouts = defaultdict(Decimal)
    for t in filtered_transactions:
        user = find_item_by_field(users, 'id', t.get('user_id'))
        if user:
            payment_type = user.get('payment_type')
            payment_value = to_decimal(user.get('payment_value', '0'))
            if payment_type == 'percentage' and payment_value > 0:
                payout = to_decimal(t['total_amount']) * (payment_value / Decimal(100))
                cashier_payouts[user['name']] += payout

    for user in users:
        if user.get('payment_type') == 'salary':
            monthly_salary = to_decimal(user.get('payment_value', '0'))
            if monthly_salary > 0:
                daily_salary = monthly_salary / Decimal(30) 
                period_salary = daily_salary * Decimal(num_days)
                cashier_payouts[user['name']] += period_salary

    total_salary_expenses = sum(cashier_payouts.values())
    net_profit = gross_profit - total_expenses - total_salary_expenses
    
    stats = {
        'total_revenue': total_revenue,
        'total_cogs': total_cogs,
        'gross_profit': gross_profit,
        'total_expenses': total_expenses,
        'total_salary_expenses': total_salary_expenses,
        'net_profit': net_profit,
        'sales_by_cashier': sorted(sales_by_cashier.items(), key=lambda item: item[1]['total'], reverse=True),
        'cashier_payouts': sorted(cashier_payouts.items(), key=lambda item: item[1], reverse=True)
    }

    filtered_expenses.sort(key=lambda x: x['timestamp'], reverse=True)

    html = BASE_TEMPLATE.replace('__TITLE__', "Отчеты").replace('__CONTENT__', REPORTS_CONTENT).replace('__SCRIPTS__', REPORTS_SCRIPTS)
    return render_template_string(html, stats=stats, start_date=start_date_str, end_date=end_date_str, expenses=filtered_expenses)

@app.route('/reports/product_roi')
@admin_required
def product_roi_report():
    inventory = load_json_data('inventory')
    transactions = load_json_data('transactions')

    product_stats = []

    for product in inventory:
        for variant in product.get('variants', []):
            total_revenue = Decimal('0.00')
            total_cogs = Decimal('0.00')
            total_qty_sold = 0

            for t in transactions:
                if t['type'] in ['sale', 'return']:
                    for item in t['items']:
                        if item.get('variant_id') == variant['id']:
                            total_revenue += to_decimal(item['total'])
                            total_cogs += to_decimal(item.get('cost_price_at_sale', '0')) * to_decimal(str(item['quantity']))
                            if t['type'] == 'sale':
                                total_qty_sold += item['quantity']
                            elif t['type'] == 'return':
                                total_qty_sold += item['quantity']

            current_stock = to_decimal(str(variant.get('stock', 0)))
            cost_price = to_decimal(variant.get('cost_price', '0'))
            
            inventory_value = current_stock * cost_price
            total_investment = total_cogs + inventory_value
            payback = total_revenue - total_investment

            product_stats.append({
                'name': product['name'],
                'variant_name': variant['option_value'],
                'total_qty_sold': total_qty_sold,
                'total_revenue': total_revenue,
                'total_investment': total_investment,
                'inventory_value': inventory_value,
                'payback': payback
            })

    product_stats.sort(key=lambda x: x['payback'], reverse=True)
    html = BASE_TEMPLATE.replace('__TITLE__', "Отчет по окупаемости товаров").replace('__CONTENT__', PRODUCT_ROI_CONTENT).replace('__SCRIPTS__', '')
    return render_template_string(html, stats=product_stats)

@app.route('/admin', methods=['GET'])
@admin_required
def admin_panel():
    users = load_json_data('users')
    kassas = load_json_data('kassas')
    expenses = load_json_data('expenses')
    expenses.sort(key=lambda x: x.get('timestamp', ''), reverse=True)
    html = BASE_TEMPLATE.replace('__TITLE__', "Админ-панель").replace('__CONTENT__', ADMIN_CONTENT).replace('__SCRIPTS__', ADMIN_SCRIPTS)
    return render_template_string(html, users=users, kassas=kassas, expenses=expenses[:10])

@app.route('/admin/user', methods=['POST'])
@admin_required
def manage_user():
    action = request.form.get('action')
    users = load_json_data('users')
    
    if action == 'add':
        name = request.form.get('name', '').strip()
        pin = request.form.get('pin', '').strip()
        payment_type = request.form.get('payment_type')
        payment_value = to_decimal(request.form.get('payment_value', '0'))
        if name and pin and pin.isdigit() and payment_type:
            new_user = {
                'id': uuid.uuid4().hex, 'name': name, 'pin': pin,
                'payment_type': payment_type, 'payment_value': str(payment_value)
            }
            users.append(new_user)
            flash(f"Кассир '{name}' добавлен.", "success")
        else:
            flash("Все поля обязательны.", "danger")
    
    elif action == 'edit':
        user_id = request.form.get('id')
        user = find_item_by_field(users, 'id', user_id)
        if user:
            user['name'] = request.form.get('name', '').strip()
            user['pin'] = request.form.get('pin', '').strip()
            user['payment_type'] = request.form.get('payment_type')
            user['payment_value'] = str(to_decimal(request.form.get('payment_value', '0')))
            flash(f"Данные кассира '{user['name']}' обновлены.", "success")
        else:
            flash("Кассир не найден.", "warning")

    elif action == 'delete':
        user_id = request.form.get('id')
        initial_len = len(users)
        users = [u for u in users if u.get('id') != user_id]
        if len(users) < initial_len:
            flash("Кассир удален.", "success")
        else:
            flash("Кассир не найден.", "warning")

    save_json_data('users', users)
    upload_db_to_hf('users')
    return redirect(url_for('admin_panel'))

@app.route('/admin/kassa', methods=['POST'])
@admin_required
def manage_kassa():
    action = request.form.get('action')
    kassas = load_json_data('kassas')
    
    if action == 'add':
        name = request.form.get('name', '').strip()
        balance = to_decimal(request.form.get('balance', '0'))
        if name:
            new_kassa = {
                'id': uuid.uuid4().hex,
                'name': name,
                'balance': str(balance),
                'history': []
            }
            if balance > 0:
                new_kassa['history'].append({
                    'type': 'deposit',
                    'amount': str(balance),
                    'timestamp': get_current_time().isoformat(),
                    'description': 'Начальный баланс'
                })
            kassas.append(new_kassa)
            flash(f"Касса '{name}' добавлена.", "success")
        else:
            flash("Название кассы обязательно.", "danger")

    elif action == 'delete':
        kassa_id = request.form.get('id')
        initial_len = len(kassas)
        kassas = [k for k in kassas if k.get('id') != kassa_id]
        if len(kassas) < initial_len:
            flash("Касса удалена.", "success")
        else:
            flash("Касса не найдена.", "warning")
            
    save_json_data('kassas', kassas)
    upload_db_to_hf('kassas')
    return redirect(url_for('admin_panel'))

@app.route('/admin/kassa_op', methods=['POST'])
@admin_required
def kassa_operation():
    kassa_id = request.form.get('kassa_id')
    op_type = request.form.get('op_type')
    amount = to_decimal(request.form.get('amount', '0'))
    description = request.form.get('description', '').strip()
    
    if not kassa_id or not op_type or amount <= 0:
        flash("Выберите кассу, тип операции и укажите положительную сумму.", "danger")
        return redirect(url_for('admin_panel'))
    
    kassas = load_json_data('kassas')
    kassa_found = False
    for i, kassa in enumerate(kassas):
        if kassa.get('id') == kassa_id:
            current_balance = to_decimal(kassa.get('balance', '0'))
            new_balance = current_balance
            
            if op_type == 'deposit':
                new_balance += amount
            elif op_type == 'withdrawal':
                if amount > current_balance:
                    flash("Сумма изъятия превышает баланс кассы.", "danger")
                    return redirect(url_for('admin_panel'))
                new_balance -= amount
            
            kassas[i]['balance'] = str(new_balance)
            if 'history' not in kassas[i]: kassas[i]['history'] = []
            kassas[i]['history'].append({
                'type': op_type,
                'amount': str(amount),
                'timestamp': get_current_time().isoformat(),
                'description': description or f"{'Внесение' if op_type == 'deposit' else 'Изъятие'} средств"
            })
            kassa_found = True
            break
            
    if kassa_found:
        save_json_data('kassas', kassas)
        upload_db_to_hf('kassas')
        flash("Операция по кассе успешно проведена.", "success")
    else:
        flash("Касса не найдена.", "danger")
        
    return redirect(url_for('admin_panel'))
    
@app.route('/admin/expense', methods=['POST'])
@admin_required
def manage_expense():
    amount = to_decimal(request.form.get('amount', '0'))
    description = request.form.get('description', '').strip()

    if amount <= 0 or not description:
        flash("Укажите положительную сумму и описание расхода.", "danger")
        return redirect(url_for('admin_panel'))

    new_expense = {
        'id': uuid.uuid4().hex,
        'timestamp': get_current_time().isoformat(),
        'amount': str(amount),
        'description': description
    }
    expenses = load_json_data('expenses')
    expenses.append(new_expense)
    save_json_data('expenses', expenses)
    upload_db_to_hf('expenses')
    flash("Расход успешно добавлен.", "success")
    return redirect(url_for('admin_panel'))

@app.route('/cashier_login', methods=['GET', 'POST'])
def cashier_login():
    if request.method == 'POST':
        pin = request.form.get('pin')
        user = find_user_by_pin(pin)
        if user:
            return redirect(url_for('cashier_dashboard', user_id=user['id']))
        else:
            flash("Неверный ПИН-код.", "danger")
    html = BASE_TEMPLATE.replace('__TITLE__', "Вход для кассира").replace('__CONTENT__', CASHIER_LOGIN_CONTENT).replace('__SCRIPTS__', '')
    return render_template_string(html)

@app.route('/cashier_dashboard/<user_id>')
def cashier_dashboard(user_id):
    users = load_json_data('users')
    user = find_item_by_field(users, 'id', user_id)
    if not user:
        abort(404, "Кассир не найден")
    
    transactions = load_json_data('transactions')
    user_transactions = [t for t in transactions if t.get('user_id') == user_id]
    user_transactions.sort(key=lambda x: x['timestamp'], reverse=True)
    
    html = BASE_TEMPLATE.replace('__TITLE__', f"Продажи кассира: {user['name']}").replace('__CONTENT__', CASHIER_DASHBOARD_CONTENT).replace('__SCRIPTS__', '')
    return render_template_string(html, user=user, transactions=user_transactions)

@app.route('/return_transaction/<transaction_id>', methods=['POST'])
def return_transaction(transaction_id):
    cashier_id = request.form.get('cashier_id')
    if not cashier_id:
        flash("Не удалось определить кассира для оформления возврата.", "danger")
        return redirect(url_for('cashier_login'))

    transactions = load_json_data('transactions')
    inventory = load_json_data('inventory')
    kassas = load_json_data('kassas')
    
    original_transaction = find_item_by_field(transactions, 'id', transaction_id)

    if not original_transaction:
        flash("Оригинальная транзакция не найдена.", "danger")
        return redirect(url_for('cashier_dashboard', user_id=cashier_id))
    if original_transaction.get('status') == 'returned':
        flash("Эта продажа уже была возвращена.", "warning")
        return redirect(url_for('cashier_dashboard', user_id=cashier_id))

    total_amount = to_decimal(original_transaction['total_amount'])
    
    return_items = []
    inventory_updates = {}
    for item in original_transaction['items']:
        return_items.append({**item, 'quantity': -item['quantity'], 'total': str(-to_decimal(item['total']))})
        product = find_item_by_field(inventory, 'id', item['product_id'])
        if product:
            variant = find_item_by_field(product.get('variants', []), 'id', item['variant_id'])
            if variant:
                 inventory_updates[item['variant_id']] = {'product_id': item['product_id'], 'new_stock': variant.get('stock', 0) + item['quantity']}


    now_iso = get_current_time().isoformat()
    return_transaction = {
        'id': uuid.uuid4().hex,
        'timestamp': now_iso,
        'type': 'return',
        'status': 'completed',
        'original_transaction_id': transaction_id,
        'user_id': original_transaction['user_id'],
        'user_name': original_transaction['user_name'],
        'kassa_id': original_transaction['kassa_id'],
        'kassa_name': original_transaction['kassa_name'],
        'items': return_items,
        'total_amount': str(-total_amount),
        'payment_method': original_transaction['payment_method']
    }
    transactions.append(return_transaction)

    for i, t in enumerate(transactions):
        if t['id'] == transaction_id:
            transactions[i]['status'] = 'returned'
            break

    for variant_id, update_info in inventory_updates.items():
        for p in inventory:
            if p.get('id') == update_info['product_id']:
                for v in p.get('variants', []):
                    if v.get('id') == variant_id:
                        v['stock'] = update_info['new_stock']
                        p['timestamp_updated'] = now_iso
                        break
                break
    
    if original_transaction['payment_method'] == 'cash':
        for i, k in enumerate(kassas):
            if k['id'] == original_transaction['kassa_id']:
                current_balance = to_decimal(k.get('balance', '0'))
                kassas[i]['balance'] = str(current_balance - total_amount)
                kassas[i].setdefault('history', []).append({
                    'type': 'return', 'amount': str(-total_amount), 'timestamp': now_iso,
                    'transaction_id': return_transaction['id']
                })
                break
                
    save_json_data('transactions', transactions)
    save_json_data('inventory', inventory)
    save_json_data('kassas', kassas)
    upload_db_to_hf('transactions')
    upload_db_to_hf('inventory')
    upload_db_to_hf('kassas')
    
    flash("Возврат успешно оформлен.", "success")
    return redirect(url_for('cashier_dashboard', user_id=cashier_id))

@app.route('/backup', methods=['POST'])
@admin_required
def backup_hf():
    try:
        for key in DATA_FILES.keys():
            upload_db_to_hf(key)
        flash(f"Резервное копирование {len(DATA_FILES)} файлов инициировано.", "success")
    except Exception as e:
        flash(f"Ошибка при резервном копировании: {e}", "danger")
    return redirect(url_for('admin_panel'))

@app.route('/download', methods=['GET'])
@admin_required
def download_hf():
    errors = []
    success_count = 0
    for key in DATA_FILES.keys():
        filepath, _ = DATA_FILES[key]
        filename = os.path.basename(filepath)
        try:
            hf_hub_download(
                repo_id=REPO_ID, filename=filename, repo_type="dataset", token=HF_TOKEN_READ,
                local_dir=DATA_DIR, local_dir_use_symlinks=False, force_download=True,
            )
            success_count += 1
        except Exception as e:
            errors.append(f"Ошибка загрузки {filename}: {e}")
    if success_count > 0:
        flash(f"Успешно загружено {success_count} файлов. Данные перезаписаны.", "success")
    if errors:
        flash("Произошли ошибки: " + "; ".join(errors), "danger")
    return redirect(url_for('admin_panel'))

@app.route('/admin_login', methods=['GET', 'POST'])
def admin_login():
    if request.method == 'POST':
        password = request.form.get('password')
        if password == ADMIN_PASS:
            session['admin_logged_in'] = True
            session.permanent = True
            next_url = request.args.get('next')
            flash("Вы успешно вошли в систему.", "success")
            return redirect(next_url or url_for('admin_panel'))
        else:
            flash("Неверный пароль.", "danger")
    html = BASE_TEMPLATE.replace('__TITLE__', "Вход для администратора").replace('__CONTENT__', ADMIN_LOGIN_CONTENT).replace('__SCRIPTS__', '')
    return render_template_string(html)

@app.route('/admin_logout')
def admin_logout():
    session.pop('admin_logged_in', None)
    flash("Вы вышли из системы.", "info")
    return redirect(url_for('sales_screen'))

BASE_TEMPLATE = """
<!DOCTYPE html>
<html lang="ru" data-bs-theme="light">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>__TITLE__ - POS</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css">
    <style>
        :root { --sidebar-width: 250px; }
        body { background-color: #f8f9fa; }
        .sidebar { position: fixed; top: 0; left: 0; width: var(--sidebar-width); height: 100vh; background-color: #343a40; padding-top: 1rem; }
        .sidebar .nav-link { color: rgba(255,255,255,.75); }
        .sidebar .nav-link:hover, .sidebar .nav-link.active { color: #fff; }
        .main-content { margin-left: var(--sidebar-width); padding: 1.5rem; }
        @media (max-width: 992px) {
            .sidebar { transform: translateX(calc(-1 * var(--sidebar-width))); transition: transform 0.3s ease-in-out; z-index: 1040; }
            .sidebar.active { transform: translateX(0); }
            .main-content { margin-left: 0; }
        }
        [data-bs-theme="dark"] body { background-color: #212529; color: #dee2e6; }
        [data-bs-theme="dark"] .card, [data-bs-theme="dark"] .modal-content, [data-bs-theme="dark"] .list-group-item, [data-bs-theme="dark"] .table, [data-bs-theme="dark"] .accordion-item { background-color: #343a40; }
        [data-bs-theme="dark"] .accordion-button { background-color: #3e444a; color: #fff; }
        [data-bs-theme="dark"] .accordion-button:not(.collapsed) { background-color: #495057;}
        [data-bs-theme="dark"] .accordion-button::after { filter: invert(1) grayscale(100) brightness(200%); }
        [data-bs-theme="dark"] .table-hover>tbody>tr:hover>* { color: var(--bs-table-hover-color); background-color: rgba(255, 255, 255, 0.075); }
        .product-card { cursor: pointer; }
        .product-card:hover { border-color: var(--bs-primary); }
        .payback-positive { color: var(--bs-success); }
        .payback-negative { color: var(--bs-danger); }
        .payback-zero { color: var(--bs-secondary); }
    </style>
</head>
<body>
<nav class="sidebar">
    <div class="p-3 text-white">
        <a href="/" class="text-white text-decoration-none"><h4 class="fw-bold"><i class="fas fa-cash-register me-2"></i>POS System</h4></a>
    </div>
    <ul class="nav flex-column">
        <li class="nav-item"><a class="nav-link {% if request.endpoint == 'sales_screen' %}active{% endif %}" href="{{ url_for('sales_screen') }}"><i class="fas fa-fw fa-dollar-sign me-2"></i>Касса</a></li>
        <li class="nav-item"><a class="nav-link {% if request.endpoint == 'inventory_management' %}active{% endif %}" href="{{ url_for('inventory_management') }}"><i class="fas fa-fw fa-boxes me-2"></i>Склад</a></li>
        <li class="nav-item"><a class="nav-link {% if request.endpoint == 'transaction_history' %}active{% endif %}" href="{{ url_for('transaction_history') }}"><i class="fas fa-fw fa-history me-2"></i>Транзакции</a></li>
        <li class="nav-item dropdown">
            <a class="nav-link dropdown-toggle {% if request.endpoint in ['reports', 'product_roi_report'] %}active{% endif %}" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
                <i class="fas fa-fw fa-chart-line me-2"></i>Отчеты
            </a>
            <ul class="dropdown-menu dropdown-menu-dark">
                <li><a class="dropdown-item" href="{{ url_for('reports') }}">Сводный отчет</a></li>
                <li><a class="dropdown-item" href="{{ url_for('product_roi_report') }}">Окупаемость товаров</a></li>
            </ul>
        </li>
        <li class="nav-item"><a class="nav-link {% if request.endpoint in ['cashier_login', 'cashier_dashboard'] %}active{% endif %}" href="{{ url_for('cashier_login') }}"><i class="fas fa-fw fa-user-circle me-2"></i>Кабинет кассира</a></li>
        <li class="nav-item"><a class="nav-link {% if request.endpoint == 'admin_panel' %}active{% endif %}" href="{{ url_for('admin_panel') }}"><i class="fas fa-fw fa-cogs me-2"></i>Админка</a></li>
        {% if session.admin_logged_in %}
        <li class="nav-item"><a class="nav-link" href="{{ url_for('admin_logout') }}"><i class="fas fa-fw fa-sign-out-alt me-2"></i>Выйти (Админ)</a></li>
        {% endif %}
    </ul>
    <div class="mt-auto p-3 text-secondary small">
        &copy; {{ get_current_time().year }}<br>{{ get_current_time().strftime('%Y-%m-%d %H:%M') }}
    </div>
</nav>

<div class="main-content">
    <header class="d-flex justify-content-between align-items-center mb-4">
        <button class="btn btn-dark d-lg-none" id="sidebar-toggle"><i class="fas fa-bars"></i></button>
        <h2 class="h3 mb-0">__TITLE__</h2>
        <div id="theme-toggle" style="cursor: pointer;"><i class="fas fa-sun fa-lg"></i></div>
    </header>
    <main>
        {% with messages = get_flashed_messages(with_categories=true) %}
          {% if messages %}
            {% for category, message in messages %}
              <div class="alert alert-{{ category }} alert-dismissible fade show" role="alert">
                {{ message }}
                <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
              </div>
            {% endfor %}
          {% endif %}
        {% endwith %}
        __CONTENT__
    </main>
</div>

<div class="modal fade" id="receiptModal" tabindex="-1" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">Продажа завершена</h5>
        <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
      </div>
      <div class="modal-body">
        <p>Чек успешно создан.</p>
        <div class="mb-3">
            <label for="whatsapp-phone" class="form-label">Отправить чек на WhatsApp</label>
            <input type="tel" class="form-control" id="whatsapp-phone" placeholder="996555123456">
            <div class="form-text">Введите полный номер с кодом страны (без +).</div>
        </div>
        <input type="hidden" id="receipt-url">
      </div>
      <div class="modal-footer">
        <a id="view-receipt-btn" href="#" target="_blank" class="btn btn-secondary">Посмотреть чек</a>
        <button type="button" id="send-whatsapp-btn" class="btn btn-success"><i class="fab fa-whatsapp"></i> Отправить</button>
      </div>
    </div>
  </div>
</div>

<div class="modal fade" id="variantSelectModal" tabindex="-1" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="variantSelectModalTitle">Выберите вариант</h5>
        <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
      </div>
      <div class="modal-body">
        <div id="variant-list" class="list-group"></div>
      </div>
    </div>
  </div>
</div>

<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script>
<script src="https://unpkg.com/html5-qrcode@2.3.8/html5-qrcode.min.js"></script>
<script>
    document.addEventListener('DOMContentLoaded', () => {
        document.getElementById('sidebar-toggle')?.addEventListener('click', () => document.querySelector('.sidebar').classList.toggle('active'));
        const themeToggle = document.getElementById('theme-toggle');
        const getStoredTheme = () => localStorage.getItem('theme');
        const setStoredTheme = theme => localStorage.setItem('theme', theme);
        const getPreferredTheme = () => getStoredTheme() || (window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light');
        const setTheme = theme => {
            document.documentElement.setAttribute('data-bs-theme', theme);
            themeToggle.innerHTML = theme === 'dark' ? '<i class="fas fa-moon fa-lg"></i>' : '<i class="fas fa-sun fa-lg"></i>';
        };
        setTheme(getPreferredTheme());
        themeToggle.addEventListener('click', () => {
            const newTheme = getPreferredTheme() === 'light' ? 'dark' : 'light';
            setStoredTheme(newTheme);
            setTheme(newTheme);
        });
    });
</script>
__SCRIPTS__
</body>
</html>
"""

SALES_SCREEN_CONTENT = """
<div class="row">
    <div class="col-lg-7 mb-4">
        <div class="card">
            <div class="card-header d-flex justify-content-between align-items-center">
                <h5 class="mb-0">Товары</h5>
                <button id="scan-btn" class="btn btn-primary btn-sm"><i class="fas fa-barcode me-2"></i>Сканировать</button>
            </div>
            <div class="card-body">
                <div id="scanner-container" class="mb-3" style="display: none; position: relative;">
                    <div id="reader" style="width: 100%;"></div>
                    <div id="scanner-status" style="position: absolute; top: 10px; left: 10px; background: rgba(0,0,0,0.5); color: white; padding: 5px; border-radius: 5px; display: none;"></div>
                    <button id="stop-scan-btn" class="btn btn-danger btn-sm mt-2">Остановить</button>
                </div>
                <input type="text" id="product-search" class="form-control mb-3" placeholder="Поиск по названию или штрих-коду...">
                <div id="product-grid" class="d-grid gap-2" style="grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));">
                    {% for p in inventory %}
                    <div class="card text-center product-card" data-barcode="{{ p.barcode }}">
                        <div class="card-body p-2">
                            <h6 class="card-title small mb-1">{{ p.name }}</h6>
                            <p class="card-text fw-bold mb-0">
                                {% if p.variants|length > 1 %}
                                    от {{ format_currency_py(p.variants|map(attribute='price')|min) }} ₸
                                {% elif p.variants|length == 1 %}
                                    {{ format_currency_py(p.variants[0].price) }} ₸
                                {% else %}
                                    Нет в наличии
                                {% endif %}
                            </p>
                        </div>
                    </div>
                    {% endfor %}
                </div>
            </div>
        </div>
    </div>
    <div class="col-lg-5">
        <div class="card">
            <div class="card-header"><h5 class="mb-0">Чек</h5></div>
            <div class="card-body">
                <div class="row g-2 mb-3">
                    <div class="col-6"><select id="user-select" class="form-select"><option value="">-- Кассир --</option>{% for u in users %}<option value="{{ u.id }}">{{ u.name }}</option>{% endfor %}</select></div>
                    <div class="col-6"><select id="kassa-select" class="form-select"><option value="">-- Касса --</option>{% for k in kassas %}<option value="{{ k.id }}">{{ k.name }}</option>{% endfor %}</select></div>
                </div>
                <div id="cart-items" class="list-group mb-3"></div>
                <div class="d-flex justify-content-between align-items-center mb-3">
                    <h4 class="mb-0">Итого:</h4>
                    <h4 class="mb-0" id="cart-total">0,00 ₸</h4>
                </div>
                <div class="d-grid gap-2">
                    <div class="btn-group"><button class="btn btn-success flex-grow-1" id="pay-cash-btn"><i class="fas fa-money-bill-wave me-2"></i>Наличные</button><button class="btn btn-info flex-grow-1" id="pay-card-btn"><i class="far fa-credit-card me-2"></i>Карта</button></div>
                    <button class="btn btn-danger" id="clear-cart-btn">Очистить</button>
                </div>
            </div>
        </div>
    </div>
</div>
"""

SALES_SCREEN_SCRIPTS = """
<script>
document.addEventListener('DOMContentLoaded', () => {
    const cart = {};
    const productGrid = document.getElementById('product-grid');
    const cartItemsEl = document.getElementById('cart-items');
    const cartTotalEl = document.getElementById('cart-total');
    let audioCtx;
    let isScannerPaused = false;
    const receiptModal = new bootstrap.Modal(document.getElementById('receiptModal'));
    const variantSelectModal = new bootstrap.Modal(document.getElementById('variantSelectModal'));

    function playBeep() {
        if (!audioCtx) {
            try { audioCtx = new (window.AudioContext || window.webkitAudioContext)(); } 
            catch (e) { console.error("Web Audio API is not supported"); return; }
        }
        const oscillator = audioCtx.createOscillator();
        const gainNode = audioCtx.createGain();
        oscillator.connect(gainNode);
        gainNode.connect(audioCtx.destination);
        oscillator.type = 'sine';
        oscillator.frequency.setValueAtTime(880, audioCtx.currentTime);
        gainNode.gain.setValueAtTime(0.5, audioCtx.currentTime);
        gainNode.gain.exponentialRampToValueAtTime(0.0001, audioCtx.currentTime + 0.15);
        oscillator.start(audioCtx.currentTime);
        oscillator.stop(audioCtx.currentTime + 0.15);
    }

    const updateCartView = () => {
        cartItemsEl.innerHTML = '';
        let total = 0;
        if (Object.keys(cart).length === 0) {
            cartItemsEl.innerHTML = '<p class="text-center text-muted">Корзина пуста</p>';
        }
        for (const id in cart) {
            const item = cart[id];
            total += parseFloat(item.price.replace(',', '.')) * item.quantity;
            cartItemsEl.innerHTML += `
                <div class="list-group-item d-flex justify-content-between align-items-center">
                    <div>
                        <h6 class="mb-0 small">${item.productName} (${item.variantName})</h6>
                        <small>${item.price} ₸</small>
                    </div>
                    <div class="d-flex align-items-center">
                        <button class="btn btn-sm btn-outline-secondary cart-qty-btn" data-id="${id}" data-op="-1">-</button>
                        <input type="number" class="form-control form-control-sm text-center mx-1 cart-qty-input" data-id="${id}" value="${item.quantity}" style="width: 60px;" min="1">
                        <button class="btn btn-sm btn-outline-secondary cart-qty-btn" data-id="${id}" data-op="1">+</button>
                    </div>
                </div>`;
        }
        cartTotalEl.textContent = total.toLocaleString('ru-RU', {minimumFractionDigits: 2, maximumFractionDigits: 2}) + ' ₸';
    };

    const addToCart = (product, variant) => {
        if (cart[variant.id]) {
            cart[variant.id].quantity++;
        } else {
            cart[variant.id] = {
                productId: product.id,
                productName: product.name,
                variantName: variant.option_value,
                price: String(variant.price).replace('.',','),
                quantity: 1
            };
        }
        playBeep();
        updateCartView();
    };
    
    const handleProductSelection = (product) => {
        if (!product.variants || product.variants.length === 0) {
            alert("У этого товара нет доступных вариантов.");
            return;
        }
        if (product.variants.length === 1) {
            addToCart(product, product.variants[0]);
        } else {
            document.getElementById('variantSelectModalTitle').textContent = `Выберите вариант для "${product.name}"`;
            const variantList = document.getElementById('variant-list');
            variantList.innerHTML = '';
            product.variants.forEach(variant => {
                const btn = document.createElement('button');
                btn.type = 'button';
                btn.className = 'list-group-item list-group-item-action';
                btn.innerHTML = `${variant.option_value} - <strong>${parseFloat(variant.price).toLocaleString('ru-RU', {minimumFractionDigits: 2})} ₸</strong> <span class="badge bg-secondary float-end">Остаток: ${variant.stock}</span>`;
                btn.addEventListener('click', () => {
                    addToCart(product, variant);
                    variantSelectModal.hide();
                });
                variantList.appendChild(btn);
            });
            variantSelectModal.show();
        }
    };
    
    const fetchAndHandleProduct = (barcode) => {
        fetch(`/api/product_by_barcode/${barcode}`)
            .then(res => res.json())
            .then(data => {
                if (data.success) handleProductSelection(data.product);
                else alert(data.message);
            });
    }

    productGrid.addEventListener('click', e => {
        const card = e.target.closest('.product-card');
        if (card) {
            fetchAndHandleProduct(card.dataset.barcode);
        }
    });

    const updateCartItemQuantity = (id, newQuantity) => {
        if (cart[id]) {
            const qty = parseInt(newQuantity, 10);
            if (!isNaN(qty) && qty > 0) {
                cart[id].quantity = qty;
            } else {
                delete cart[id];
            }
            updateCartView();
        }
    };

    cartItemsEl.addEventListener('click', e => {
        if (e.target.classList.contains('cart-qty-btn')) {
            const id = e.target.dataset.id;
            const op = parseInt(e.target.dataset.op);
            if (cart[id]) {
                const newQuantity = cart[id].quantity + op;
                updateCartItemQuantity(id, newQuantity);
            }
        }
    });

    cartItemsEl.addEventListener('change', e => {
        if (e.target.classList.contains('cart-qty-input')) {
            const id = e.target.dataset.id;
            updateCartItemQuantity(id, e.target.value);
        }
    });
    
    document.getElementById('clear-cart-btn').addEventListener('click', () => {
        for(const id in cart) delete cart[id];
        updateCartView();
    });

    document.getElementById('product-search').addEventListener('input', e => {
        const term = e.target.value.toLowerCase();
        document.querySelectorAll('.product-card').forEach(card => {
            const productName = card.querySelector('.card-title').textContent.toLowerCase();
            const show = productName.includes(term) || card.dataset.barcode.includes(term);
            card.style.display = show ? '' : 'none';
        });
    });

    const completeSale = (paymentMethod) => {
        const userId = document.getElementById('user-select').value;
        const kassaId = document.getElementById('kassa-select').value;
        if (!userId || !kassaId) {
            alert('Выберите кассира и кассу!');
            return;
        }
        if (Object.keys(cart).length === 0) {
            alert('Корзина пуста!');
            return;
        }
        fetch('/api/complete_sale', {
            method: 'POST',
            headers: {'Content-Type': 'application/json'},
            body: JSON.stringify({ cart, userId, kassaId, paymentMethod })
        })
        .then(res => res.json())
        .then(data => {
            if (data.success) {
                for(const id in cart) delete cart[id];
                updateCartView();
                document.getElementById('receipt-url').value = data.receiptUrl;
                document.getElementById('view-receipt-btn').href = data.receiptUrl;
                receiptModal.show();
            } else {
                alert(`Ошибка: ${data.message}`);
            }
        })
        .catch(err => alert(`Сетевая ошибка: ${err}`));
    };
    
    document.getElementById('pay-cash-btn').addEventListener('click', () => completeSale('cash'));
    document.getElementById('pay-card-btn').addEventListener('click', () => completeSale('card'));
    
    document.getElementById('send-whatsapp-btn').addEventListener('click', () => {
        const phone = document.getElementById('whatsapp-phone').value.replace(/\\D/g, '');
        const receiptUrl = document.getElementById('receipt-url').value;
        if (phone && receiptUrl) {
            const fullPhone = phone;
            const message = encodeURIComponent(`Ваш чек: ${receiptUrl}`);
            window.open(`https://wa.me/${fullPhone}?text=${message}`, '_blank');
        } else {
            alert('Введите номер телефона.');
        }
    });

    const html5QrCode = new Html5Qrcode("reader");
    const scannerStatusEl = document.getElementById('scanner-status');
    
    const onScanSuccess = (decodedText, decodedResult) => {
        if (isScannerPaused) return;
        isScannerPaused = true;
        scannerStatusEl.textContent = 'Пауза...';
        scannerStatusEl.style.display = 'block';
        if (html5QrCode.getState() === 2) html5QrCode.pause();

        fetchAndHandleProduct(decodedText);

        setTimeout(() => {
            isScannerPaused = false;
            scannerStatusEl.style.display = 'none';
            if (html5QrCode.getState() === 2) html5QrCode.resume();
        }, 1500);
    };

    const startScanner = () => {
        document.getElementById('scanner-container').style.display = 'block';
        const config = { fps: 10, qrbox: { width: 250, height: 250 } };
        html5QrCode.start({ facingMode: "environment" }, config, onScanSuccess)
            .catch(err => console.error("Scanner start error:", err));
    };
    
    const stopScanner = () => {
        if (html5QrCode.isScanning) {
            html5QrCode.stop().then(() => {
                document.getElementById('scanner-container').style.display = 'none';
            }).catch(err => console.error("Failed to stop scanner", err));
        } else {
            document.getElementById('scanner-container').style.display = 'none';
        }
    };

    document.getElementById('scan-btn').addEventListener('click', startScanner);
    document.getElementById('stop-scan-btn').addEventListener('click', stopScanner);
    
    updateCartView();
});
</script>
"""

INVENTORY_CONTENT = """
<div class="d-flex justify-content-between mb-3">
    <button class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#addProductModal"><i class="fas fa-plus me-2"></i>Добавить товар</button>
    <button class="btn btn-success" data-bs-toggle="modal" data-bs-target="#stockInModal"><i class="fas fa-truck-loading me-2"></i>Оприходовать</button>
</div>

<div class="accordion" id="inventoryAccordion">
  {% for p in inventory %}
  <div class="accordion-item">
    <h2 class="accordion-header" id="heading-{{ p.id }}">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapse-{{ p.id }}">
        <strong>{{ p.name }}</strong>&nbsp;<small class="text-muted"> ({{ p.barcode }})</small>
      </button>
    </h2>
    <div id="collapse-{{ p.id }}" class="accordion-collapse collapse" data-bs-parent="#inventoryAccordion">
      <div class="accordion-body">
        <div class="d-flex justify-content-end mb-2">
            <button class="btn btn-sm btn-outline-primary" data-bs-toggle="modal" data-bs-target="#editProductModal-{{ p.id }}"><i class="fas fa-edit me-1"></i>Редактировать товар</button>
            <form action="{{ url_for('delete_product', product_id=p.id) }}" method="POST" class="d-inline ms-2" onsubmit="return confirm('Удалить товар?');">
                <button type="submit" class="btn btn-sm btn-outline-danger"><i class="fas fa-trash"></i></button>
            </form>
        </div>
        <table class="table table-sm table-bordered">
            <thead><tr><th>Вариант</th><th>Цена</th><th>Себест.</th><th>Остаток</th></tr></thead>
            <tbody>
                {% for v in p.variants %}
                <tr>
                    <td>{{ v.option_value }}</td>
                    <td>{{ format_currency_py(v.price) }} ₸</td>
                    <td>{{ format_currency_py(v.cost_price) }} ₸</td>
                    <td>{{ v.stock }}</td>
                </tr>
                {% else %}
                <tr><td colspan="4" class="text-center text-muted">Нет вариантов</td></tr>
                {% endfor %}
            </tbody>
        </table>
      </div>
    </div>
  </div>
  {% endfor %}
</div>

<div class="modal fade" id="addProductModal" tabindex="-1">
  <div class="modal-dialog modal-lg">
    <div class="modal-content">
      <div class="modal-header"><h5 class="modal-title">Новый товар</h5><button type="button" class="btn-close" data-bs-dismiss="modal"></button></div>
      <form action="{{ url_for('inventory_management') }}" method="POST">
        <div class="modal-body">
          <div class="row">
              <div class="col-md-6 mb-3"><label class="form-label">Название</label><input type="text" name="name" class="form-control" required></div>
              <div class="col-md-6 mb-3"><label class="form-label">Штрих-код</label>
                <div class="input-group"><input type="text" name="barcode" class="form-control barcode-input" required><button type="button" class="btn btn-outline-secondary scan-modal-btn"><i class="fas fa-barcode"></i></button></div>
              </div>
          </div>
          <div id="modal-scanner-add" class="mb-2" style="display:none;"></div>
          <hr>
          <h6>Варианты товара</h6>
          <div id="variants-container-add">
          </div>
          <button type="button" class="btn btn-sm btn-outline-success mt-2" id="add-variant-btn-add">Добавить вариант</button>
        </div>
        <div class="modal-footer"><button type="submit" class="btn btn-primary">Сохранить</button></div>
      </form>
    </div>
  </div>
</div>

{% for p in inventory %}
<div class="modal fade" id="editProductModal-{{ p.id }}" tabindex="-1">
  <div class="modal-dialog modal-lg">
    <div class="modal-content">
      <div class="modal-header"><h5 class="modal-title">Редактировать товар</h5><button type="button" class="btn-close" data-bs-dismiss="modal"></button></div>
      <form action="{{ url_for('edit_product', product_id=p.id) }}" method="POST">
        <div class="modal-body">
          <div class="row">
              <div class="col-md-6 mb-3"><label class="form-label">Название</label><input type="text" name="name" class="form-control" value="{{ p.name }}" required></div>
              <div class="col-md-6 mb-3"><label class="form-label">Штрих-код</label><input type="text" name="barcode" class="form-control" value="{{ p.barcode }}" required></div>
          </div>
          <hr>
          <h6>Варианты товара</h6>
          <div id="variants-container-edit-{{ p.id }}">
            {% for v in p.variants %}
            <div class="row g-2 mb-2 align-items-center variant-row">
                <input type="hidden" name="variant_id[]" value="{{ v.id }}">
                <div class="col-3"><input type="text" name="variant_name[]" class="form-control" placeholder="Название варианта" value="{{ v.option_value }}" required></div>
                <div class="col"><input type="text" name="variant_price[]" class="form-control" placeholder="Цена" value="{{ v.price|string|replace('.', ',') }}" inputmode="decimal"></div>
                <div class="col"><input type="text" name="variant_cost_price[]" class="form-control" placeholder="Себестоимость" value="{{ v.cost_price|string|replace('.', ',') }}" inputmode="decimal"></div>
                <div class="col"><input type="number" name="variant_stock[]" class="form-control" placeholder="Остаток" value="{{ v.stock }}"></div>
                <div class="col-auto"><button type="button" class="btn btn-sm btn-danger remove-variant-btn"><i class="fas fa-times"></i></button></div>
            </div>
            {% endfor %}
          </div>
          <button type="button" class="btn btn-sm btn-outline-success mt-2 add-variant-btn-edit" data-target-container="variants-container-edit-{{ p.id }}">Добавить вариант</button>
        </div>
        <div class="modal-footer"><button type="submit" class="btn btn-primary">Сохранить</button></div>
      </form>
    </div>
  </div>
</div>
{% endfor %}

<div class="modal fade" id="stockInModal" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header"><h5 class="modal-title">Оприходование товара</h5><button type="button" class="btn-close" data-bs-dismiss="modal"></button></div>
      <form action="{{ url_for('stock_in') }}" method="POST">
        <div class="modal-body">
            <div class="mb-3">
                <label for="stockin-product" class="form-label">Товар</label>
                <select id="stockin-product" name="product_id" class="form-select" required>
                    <option value="">-- Выберите товар --</option>
                    {% for p in inventory %}
                    <option value="{{ p.id }}">{{ p.name }}</option>
                    {% endfor %}
                </select>
            </div>
            <div class="mb-3">
                <label for="stockin-variant" class="form-label">Вариант</label>
                <select id="stockin-variant" name="variant_id" class="form-select" required disabled>
                    <option value="">-- Сначала выберите товар --</option>
                </select>
            </div>
            <div class="row">
                <div class="col-6 mb-3">
                    <label for="stockin-quantity" class="form-label">Количество</label>
                    <input type="number" id="stockin-quantity" name="quantity" class="form-control" required min="1">
                </div>
                <div class="col-6 mb-3">
                    <label for="stockin-cost" class="form-label">Себестоимость (за ед.)</label>
                    <input type="text" id="stockin-cost" name="cost_price" class="form-control" inputmode="decimal" placeholder="Необязательно">
                </div>
            </div>
        </div>
        <div class="modal-footer"><button type="submit" class="btn btn-primary">Оприходовать</button></div>
      </form>
    </div>
  </div>
</div>
"""

INVENTORY_SCRIPTS = """
<script>
document.addEventListener('DOMContentLoaded', () => {
    let currentScanner = null;
    let currentScannerContainer = null;
    document.querySelectorAll('.scan-modal-btn').forEach(btn => {
        btn.addEventListener('click', e => {
            const form = e.target.closest('form');
            const scannerContainer = form.querySelector('[id^="modal-scanner-"]');
            const barcodeInput = form.querySelector('.barcode-input');
            
            if (currentScanner) {
                try { currentScanner.stop(); } catch(e) {}
                currentScanner = null;
                if(currentScannerContainer) currentScannerContainer.style.display = 'none';
                return;
            }
            scannerContainer.style.display = 'block';
            currentScannerContainer = scannerContainer;
            const scannerId = scannerContainer.id + '-reader';
            if(!document.getElementById(scannerId)) scannerContainer.innerHTML = `<div id="${scannerId}" style="width: 100%;"></div>`;

            const html5QrCode = new Html5Qrcode(scannerId);
            currentScanner = html5QrCode;
            const onScanSuccess = (decodedText, decodedResult) => {
                barcodeInput.value = decodedText;
                try { html5QrCode.stop(); } catch(e) {}
                currentScanner = null;
                scannerContainer.style.display = 'none';
            };
            html5QrCode.start({ facingMode: "environment" }, { fps: 10, qrbox: { width: 250, height: 250 } }, onScanSuccess);
        });
    });
    
    document.querySelectorAll('.modal').forEach(modal => {
        modal.addEventListener('hidden.bs.modal', () => {
             if (currentScanner) {
                try { currentScanner.stop(); } catch(e) {}
                currentScanner = null;
             }
             if(currentScannerContainer) {
                 currentScannerContainer.style.display = 'none';
                 currentScannerContainer.innerHTML = '';
             }
        });
    });
    
    const createVariantRow = () => {
        const div = document.createElement('div');
        div.className = 'row g-2 mb-2 align-items-center variant-row';
        div.innerHTML = `
            <input type="hidden" name="variant_id[]" value="">
            <div class="col-3"><input type="text" name="variant_name[]" class="form-control" placeholder="Название варианта" required></div>
            <div class="col"><input type="text" name="variant_price[]" class="form-control" placeholder="Цена" inputmode="decimal"></div>
            <div class="col"><input type="text" name="variant_cost_price[]" class="form-control" placeholder="Себестоимость" inputmode="decimal"></div>
            <div class="col"><input type="number" name="variant_stock[]" class="form-control" placeholder="Остаток" value="0"></div>
            <div class="col-auto"><button type="button" class="btn btn-sm btn-danger remove-variant-btn"><i class="fas fa-times"></i></button></div>
        `;
        div.querySelector('.remove-variant-btn').addEventListener('click', () => div.remove());
        return div;
    };

    document.getElementById('add-variant-btn-add').addEventListener('click', () => {
        document.getElementById('variants-container-add').appendChild(createVariantRow());
    });
    
    document.querySelectorAll('.add-variant-btn-edit').forEach(btn => {
        btn.addEventListener('click', (e) => {
            const containerId = e.target.dataset.targetContainer;
            document.getElementById(containerId).appendChild(createVariantRow());
        });
    });
    
    document.querySelectorAll('.remove-variant-btn').forEach(btn => {
        btn.addEventListener('click', e => e.target.closest('.variant-row').remove());
    });
    
    const addProductModal = document.getElementById('addProductModal');
    addProductModal.addEventListener('shown.bs.modal', () => {
        const container = document.getElementById('variants-container-add');
        if (container.children.length === 0) {
            container.appendChild(createVariantRow());
        }
    });

    const inventoryData = JSON.parse('{{ inventory|tojson|safe }}');
    const productSelect = document.getElementById('stockin-product');
    const variantSelect = document.getElementById('stockin-variant');

    productSelect.addEventListener('change', () => {
        const productId = productSelect.value;
        variantSelect.innerHTML = '<option value="">-- Выберите вариант --</option>';
        variantSelect.disabled = true;

        if (productId) {
            const product = inventoryData.find(p => p.id === productId);
            if (product && product.variants) {
                product.variants.forEach(v => {
                    const option = document.createElement('option');
                    option.value = v.id;
                    option.textContent = v.option_value;
                    variantSelect.appendChild(option);
                });
                variantSelect.disabled = false;
            }
        }
    });
});
</script>
"""

TRANSACTIONS_CONTENT = """
<div class="card">
    <div class="card-body">
        <div class="table-responsive">
            <table class="table table-sm table-hover">
                <thead><tr><th>ID</th><th>Дата</th><th>Тип</th><th>Кассир</th><th>Касса</th><th>Сумма</th><th>Статус</th><th>Позиции</th></tr></thead>
                <tbody>
                {% for t in transactions %}
                <tr class="{% if t.type == 'return' %}table-danger{% endif %}">
                    <td><a href="{{ url_for('view_receipt', transaction_id=t.id) if t.type == 'sale' else '#' }}" target="_blank"><small class="text-muted">{{ t.id[:8] }}</small></a></td>
                    <td>{{ t.timestamp[:16]|replace('T', ' ') }}</td>
                    <td><span class="badge bg-{{'primary' if t.type == 'sale' else 'warning'}}">{{'Продажа' if t.type == 'sale' else 'Возврат'}}</span></td>
                    <td>{{ t.user_name }}</td><td>{{ t.kassa_name }}</td>
                    <td class="fw-bold">{{ format_currency_py(t.total_amount) }} ₸</td>
                    <td><span class="badge bg-{{'success' if t.status == 'completed' else 'secondary'}}">{{t.status}}</span></td>
                    <td>
                        <ul class="list-unstyled mb-0 small">
                        {% for item in t['items'] %}<li>{{ item.name }} ({{ item.quantity }}x{{ format_currency_py(item.price_at_sale) }})</li>{% endfor %}
                        </ul>
                    </td>
                </tr>
                {% endfor %}
                </tbody>
            </table>
        </div>
    </div>
</div>
"""

TRANSACTIONS_SCRIPTS = ""

REPORTS_CONTENT = """
<div class="card mb-4">
    <div class="card-body">
        <form method="GET" action="{{ url_for('reports') }}">
            <div class="row g-2 align-items-end">
                <div class="col-md-4"><label for="start_date" class="form-label">Начало периода</label><input type="date" id="start_date" name="start_date" value="{{ start_date }}" class="form-control"></div>
                <div class="col-md-4"><label for="end_date" class="form-label">Конец периода</label><input type="date" id="end_date" name="end_date" value="{{ end_date }}" class="form-control"></div>
                <div class="col-md-4"><button type="submit" class="btn btn-primary w-100">Сформировать отчет</button></div>
            </div>
        </form>
    </div>
</div>

<div class="row">
    <div class="col-lg-7">
        <div class="card mb-4">
            <div class="card-header"><h5 class="mb-0">Сводный отчет за период</h5></div>
            <div class="card-body">
                <ul class="list-group list-group-flush">
                    <li class="list-group-item d-flex justify-content-between"><span><i class="fas fa-chart-bar me-2 text-primary"></i>Выручка (за вычетом возвратов)</span> <strong>{{ format_currency_py(stats.total_revenue) }} ₸</strong></li>
                    <li class="list-group-item d-flex justify-content-between"><span><i class="fas fa-cogs me-2 text-secondary"></i>Себестоимость проданных товаров</span> <strong>{{ format_currency_py(stats.total_cogs) }} ₸</strong></li>
                    <li class="list-group-item d-flex justify-content-between"><span><i class="fas fa-piggy-bank me-2 text-info"></i>Валовая прибыль</span> <strong class="text-info">{{ format_currency_py(stats.gross_profit) }} ₸</strong></li>
                    <li class="list-group-item d-flex justify-content-between"><span><i class="fas fa-receipt me-2 text-warning"></i>Расходы (операционные)</span> <strong class="text-warning">-{{ format_currency_py(stats.total_expenses) }} ₸</strong></li>
                    <li class="list-group-item d-flex justify-content-between"><span><i class="fas fa-users-cog me-2 text-danger"></i>Расходы (зарплаты)</span> <strong class="text-danger">-{{ format_currency_py(stats.total_salary_expenses) }} ₸</strong></li>
                    <li class="list-group-item d-flex justify-content-between fs-5"><span><i class="fas fa-check-circle me-2 text-success"></i>Чистая прибыль</span> <strong class="text-success">{{ format_currency_py(stats.net_profit) }} ₸</strong></li>
                </ul>
            </div>
        </div>
        <div class="card mb-4">
            <div class="card-header"><h5 class="mb-0">Расчеты с кассирами за период</h5></div>
            <div class="card-body p-0">
                <div class="table-responsive"><table class="table table-sm mb-0">
                    <thead><tr><th>Кассир</th><th class="text-end">К выплате</th></tr></thead>
                    <tbody>
                    {% for name, payout in stats.cashier_payouts %}
                    <tr><td>{{ name }}</td><td class="text-end">{{ format_currency_py(payout) }} ₸</td></tr>
                    {% else %}<tr><td colspan="2" class="text-center text-muted">Нет данных для расчета.</td></tr>
                    {% endfor %}
                    </tbody>
                </table></div>
            </div>
        </div>
    </div>
    <div class="col-lg-5">
        <div class="card mb-4">
            <div class="card-header"><h5 class="mb-0">Продажи по кассирам</h5></div>
            <div class="card-body p-0">
                <div class="table-responsive"><table class="table table-hover mb-0">
                    <thead><tr><th>Кассир</th><th>Чеков</th><th class="text-end">Сумма</th></tr></thead>
                    <tbody>
                    {% for name, data in stats.sales_by_cashier %}
                    <tr><td>{{ name }}</td><td>{{ data.count }}</td><td class="text-end">{{ format_currency_py(data.total) }} ₸</td></tr>
                    {% else %}<tr><td colspan="3" class="text-center text-muted">Нет продаж за выбранный период.</td></tr>
                    {% endfor %}
                    </tbody>
                </table></div>
            </div>
        </div>
        <div class="card mb-4">
            <div class="card-header"><h5 class="mb-0">Операционные расходы за период</h5></div>
            <div class="card-body p-0">
                <div class="table-responsive"><table class="table table-sm mb-0">
                    <thead><tr><th>Дата</th><th>Описание</th><th class="text-end">Сумма</th></tr></thead>
                    <tbody>
                    {% for expense in expenses %}
                    <tr>
                        <td><small>{{ expense.timestamp[:10] }}</small></td>
                        <td>{{ expense.description }}</td>
                        <td class="text-end">{{ format_currency_py(expense.amount) }} ₸</td>
                    </tr>
                    {% else %}<tr><td colspan="3" class="text-center text-muted">Нет расходов за выбранный период.</td></tr>
                    {% endfor %}
                    </tbody>
                </table></div>
            </div>
        </div>
    </div>
</div>
"""

REPORTS_SCRIPTS = ""

PRODUCT_ROI_CONTENT = """
<div class="card">
    <div class="card-header"><h5 class="mb-0">Окупаемость по товарам</h5></div>
    <div class="card-body p-0">
        <div class="table-responsive">
            <table class="table table-hover table-sm mb-0">
                <thead class="table-light">
                    <tr>
                        <th>Товар (вариант)</th>
                        <th class="text-end">Продано, шт</th>
                        <th class="text-end">Выручка</th>
                        <th class="text-end">Стоимость на складе</th>
                        <th class="text-end">Общие вложения</th>
                        <th class="text-end">Результат (Окупаемость)</th>
                    </tr>
                </thead>
                <tbody>
                {% for item in stats %}
                    <tr>
                        <td><strong>{{ item.name }}</strong><br><small class="text-muted">{{ item.variant_name }}</small></td>
                        <td class="text-end">{{ item.total_qty_sold }}</td>
                        <td class="text-end">{{ format_currency_py(item.total_revenue) }} ₸</td>
                        <td class="text-end">{{ format_currency_py(item.inventory_value) }} ₸</td>
                        <td class="text-end text-secondary">{{ format_currency_py(item.total_investment) }} ₸</td>
                        <td class="text-end fw-bold 
                            {% if item.payback > 0 %}payback-positive
                            {% elif item.payback < 0 %}payback-negative
                            {% else %}payback-zero{% endif %}">
                            {{ format_currency_py(item.payback) }} ₸
                        </td>
                    </tr>
                {% else %}
                    <tr><td colspan="6" class="text-center">Нет данных для анализа.</td></tr>
                {% endfor %}
                </tbody>
            </table>
        </div>
    </div>
    <div class="card-footer small text-muted">
        <i class="fas fa-info-circle me-1"></i>
        <strong>Общие вложения</strong> = Себестоимость проданных товаров + Стоимость текущих остатков на складе.
        <strong>Результат</strong> = Выручка - Общие вложения.
    </div>
</div>
"""

ADMIN_CONTENT = """
<div class="row">
    <div class="col-md-6 mb-4">
        <div class="card h-100">
            <div class="card-header d-flex justify-content-between align-items-center"><h5 class="mb-0">Кассиры</h5><button class="btn btn-primary btn-sm" data-bs-toggle="modal" data-bs-target="#addUserModal"><i class="fas fa-plus"></i></button></div>
            <div class="card-body">
                <ul class="list-group">
                    {% for u in users %}
                    <li class="list-group-item d-flex justify-content-between align-items-center">
                        <div>{{ u.name }} <br>
                        <small class="text-muted">
                        {% if u.payment_type == 'salary' %}Зарплата: {{ format_currency_py(u.payment_value) }} ₸/мес.
                        {% elif u.payment_type == 'percentage' %}Процент: {{ u.payment_value }}%
                        {% endif %}
                        </small>
                        </div>
                        <div>
                            <button class="btn btn-sm btn-outline-primary" data-bs-toggle="modal" data-bs-target="#editUserModal-{{ u.id }}"><i class="fas fa-edit"></i></button>
                            <form action="{{ url_for('manage_user') }}" method="POST" class="d-inline" onsubmit="return confirm('Удалить кассира?');"><input type="hidden" name="action" value="delete"><input type="hidden" name="id" value="{{ u.id }}"><button type="submit" class="btn btn-sm btn-outline-danger"><i class="fas fa-trash"></i></button></form>
                        </div>
                    </li>
                    {% endfor %}
                </ul>
            </div>
        </div>
    </div>
    <div class="col-md-6 mb-4">
        <div class="card h-100">
            <div class="card-header"><h5 class="mb-0">Кассы</h5></div>
            <div class="card-body">
                <form action="{{ url_for('manage_kassa') }}" method="POST" class="mb-3">
                    <input type="hidden" name="action" value="add">
                    <div class="input-group">
                        <input type="text" name="name" class="form-control" placeholder="Название кассы" required>
                        <input type="text" name="balance" class="form-control" placeholder="Начальный баланс" value="0" inputmode="decimal">
                        <button type="submit" class="btn btn-primary">Добавить</button>
                    </div>
                </form>
                <ul class="list-group">
                    {% for k in kassas %}
                    <li class="list-group-item d-flex justify-content-between align-items-center">
                        <div>{{ k.name }} <br><small class="fw-bold">{{ format_currency_py(k.balance) }} ₸</small></div>
                        <form action="{{ url_for('manage_kassa') }}" method="POST" onsubmit="return confirm('Удалить кассу?');"><input type="hidden" name="action" value="delete"><input type="hidden" name="id" value="{{ k.id }}"><button type="submit" class="btn btn-sm btn-danger"><i class="fas fa-trash"></i></button></form>
                    </li>
                    {% endfor %}
                </ul>
            </div>
        </div>
    </div>
    <div class="col-12 mb-4">
        <div class="card">
            <div class="card-header"><h5 class="mb-0">Операции по кассе (Внесение/Изъятие)</h5></div>
            <div class="card-body">
                <form action="{{ url_for('kassa_operation') }}" method="POST">
                    <div class="row g-2 align-items-end">
                        <div class="col-md-3"><label class="form-label">Касса</label><select name="kassa_id" class="form-select" required><option value="">-- Выберите --</option>{% for k in kassas %}<option value="{{k.id}}">{{k.name}}</option>{% endfor %}</select></div>
                        <div class="col-md-2"><label class="form-label">Операция</label><select name="op_type" class="form-select" required><option value="deposit">Внесение</option><option value="withdrawal">Изъятие</option></select></div>
                        <div class="col-md-2"><label class="form-label">Сумма</label><input type="text" name="amount" class="form-control" required inputmode="decimal"></div>
                        <div class="col-md-3"><label class="form-label">Описание</label><input type="text" name="description" class="form-control"></div>
                        <div class="col-md-2"><button type="submit" class="btn btn-success w-100">Выполнить</button></div>
                    </div>
                </form>
            </div>
        </div>
    </div>
     <div class="col-12 mb-4">
        <div class="card">
            <div class="card-header"><h5 class="mb-0">Учет расходов</h5></div>
            <div class="card-body">
                <form action="{{ url_for('manage_expense') }}" method="POST" class="mb-4">
                    <div class="row g-2 align-items-end">
                        <div class="col-md-3"><label class="form-label">Сумма</label><input type="text" name="amount" class="form-control" required inputmode="decimal"></div>
                        <div class="col-md-7"><label class="form-label">Описание</label><input type="text" name="description" class="form-control" required placeholder="Напр: Аренда за май"></div>
                        <div class="col-md-2"><button type="submit" class="btn btn-warning w-100">Добавить расход</button></div>
                    </div>
                </form>
                <h6>Последние 10 расходов:</h6>
                <div class="table-responsive">
                    <table class="table table-sm table-striped">
                        <tbody>
                        {% for e in expenses %}
                        <tr>
                            <td><small>{{ e.timestamp[:16]|replace('T', ' ') }}</small></td>
                            <td>{{ e.description }}</td>
                            <td class="text-end fw-bold">{{ format_currency_py(e.amount) }} ₸</td>
                        </tr>
                        {% else %}
                        <tr><td colspan="3" class="text-center">Расходов пока нет</td></tr>
                        {% endfor %}
                        </tbody>
                    </table>
                </div>
            </div>
        </div>
    </div>
    <div class="col-12">
        <div class="card">
            <div class="card-header"><h5 class="mb-0">Резервное копирование</h5></div>
            <div class="card-body">
                <p>Данные периодически сохраняются в облако. Можно сделать это вручную.</p>
                <form method="POST" action="{{ url_for('backup_hf') }}" class="d-inline-block me-2">
                    <button type="submit" class="btn btn-outline-primary"><i class="fas fa-cloud-upload-alt me-2"></i>Сохранить в облако</button>
                </form>
                <form method="GET" action="{{ url_for('download_hf') }}" class="d-inline-block" onsubmit="return confirm('ВНИМАНИЕ! Это действие заменит все локальные данные данными из облака. Продолжить?');">
                    <button type="submit" class="btn btn-outline-danger"><i class="fas fa-cloud-download-alt me-2"></i>Загрузить из облака</button>
                </form>
            </div>
        </div>
    </div>
</div>

<div class="modal fade" id="addUserModal" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header"><h5 class="modal-title">Новый кассир</h5><button type="button" class="btn-close" data-bs-dismiss="modal"></button></div>
      <form action="{{ url_for('manage_user') }}" method="POST">
        <input type="hidden" name="action" value="add">
        <div class="modal-body">
          <div class="mb-3"><label class="form-label">Имя</label><input type="text" name="name" class="form-control" required></div>
          <div class="mb-3"><label class="form-label">ПИН-код</label><input type="password" name="pin" class="form-control" required></div>
          <div class="mb-3"><label class="form-label">Тип оплаты</label><select name="payment_type" class="form-select"><option value="percentage">Процент от продаж</option><option value="salary">Фиксированная зарплата</option></select></div>
          <div class="mb-3"><label class="form-label">Значение</label><input type="text" name="payment_value" class="form-control" inputmode="decimal" value="0" required><small class="form-text text-muted">Для процентов - число (напр. 5), для зарплаты - сумма в тенге.</small></div>
        </div>
        <div class="modal-footer"><button type="submit" class="btn btn-primary">Сохранить</button></div>
      </form>
    </div>
  </div>
</div>
{% for u in users %}
<div class="modal fade" id="editUserModal-{{ u.id }}" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header"><h5 class="modal-title">Редактировать кассира</h5><button type="button" class="btn-close" data-bs-dismiss="modal"></button></div>
      <form action="{{ url_for('manage_user') }}" method="POST">
        <input type="hidden" name="action" value="edit">
        <input type="hidden" name="id" value="{{ u.id }}">
        <div class="modal-body">
          <div class="mb-3"><label class="form-label">Имя</label><input type="text" name="name" value="{{ u.name }}" class="form-control" required></div>
          <div class="mb-3"><label class="form-label">ПИН-код</label><input type="password" name="pin" value="{{ u.pin }}" class="form-control" required></div>
          <div class="mb-3"><label class="form-label">Тип оплаты</label><select name="payment_type" class="form-select">
            <option value="percentage" {% if u.payment_type == 'percentage' %}selected{% endif %}>Процент от продаж</option>
            <option value="salary" {% if u.payment_type == 'salary' %}selected{% endif %}>Фиксированная зарплата</option></select>
          </div>
          <div class="mb-3"><label class="form-label">Значение</label><input type="text" name="payment_value" class="form-control" value="{{ u.payment_value }}" inputmode="decimal" required></div>
        </div>
        <div class="modal-footer"><button type="submit" class="btn btn-primary">Сохранить</button></div>
      </form>
    </div>
  </div>
</div>
{% endfor %}
"""

ADMIN_SCRIPTS = ""

ADMIN_LOGIN_CONTENT = """
<div class="row justify-content-center mt-5">
    <div class="col-md-6 col-lg-4">
        <div class="card">
            <div class="card-body">
                <h4 class="card-title text-center">Вход для администратора</h4>
                <form method="POST">
                    <div class="mb-3">
                        <label for="password" class="form-label">Пароль</label>
                        <input type="password" name="password" id="password" class="form-control" required autofocus>
                    </div>
                    <div class="d-grid">
                        <button type="submit" class="btn btn-primary">Войти</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
</div>
"""

CASHIER_LOGIN_CONTENT = """
<div class="row justify-content-center">
    <div class="col-md-6 col-lg-4">
        <div class="card">
            <div class="card-body">
                <h4 class="card-title text-center">Вход для кассира</h4>
                <form method="POST" action="{{ url_for('cashier_login') }}">
                    <div class="mb-3">
                        <label for="pin" class="form-label">Введите ваш ПИН-код</label>
                        <input type="password" name="pin" id="pin" class="form-control form-control-lg text-center" required autofocus>
                    </div>
                    <div class="d-grid">
                        <button type="submit" class="btn btn-primary btn-lg">Войти</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
</div>
"""

CASHIER_DASHBOARD_CONTENT = """
<div class="card">
    <div class="card-body">
        <div class="table-responsive">
            <table class="table table-sm table-hover">
                <thead><tr><th>ID</th><th>Дата</th><th>Тип</th><th>Сумма</th><th>Статус</th><th>Действие</th></tr></thead>
                <tbody>
                {% for t in transactions %}
                <tr class="{% if t.type == 'return' %}table-danger{% endif %}">
                    <td><small class="text-muted">{{ t.id[:8] }}</small></td>
                    <td>{{ t.timestamp[:16]|replace('T', ' ') }}</td>
                    <td><span class="badge bg-{{'primary' if t.type == 'sale' else 'warning'}}">{{'Продажа' if t.type == 'sale' else 'Возврат'}}</span></td>
                    <td class="fw-bold">{{ format_currency_py(t.total_amount) }} ₸</td>
                    <td><span class="badge bg-{{'success' if t.status == 'completed' else 'secondary'}}">{{t.status}}</span></td>
                    <td>
                        {% if t.type == 'sale' and t.status == 'completed' %}
                        <form action="{{ url_for('return_transaction', transaction_id=t.id) }}" method="POST" onsubmit="return confirm('Оформить возврат по этому чеку?');">
                            <input type="hidden" name="cashier_id" value="{{ user.id }}">
                            <button type="submit" class="btn btn-sm btn-warning">Возврат</button>
                        </form>
                        {% endif %}
                    </td>
                </tr>
                {% endfor %}
                </tbody>
            </table>
        </div>
    </div>
</div>
"""

if __name__ == '__main__':
    backup_thread = threading.Thread(target=periodic_backup, daemon=True)
    backup_thread.start()
    for key in DATA_FILES.keys():
        load_json_data(key)
    app.run(debug=False, host='0.0.0.0', port=7860, use_reloader=False)