#!/usr/bin/env python3
"""
Castor Price Forecasting API - Production Ready
Deploy this on your app server
"""
from flask import Flask, request, jsonify
from flask_cors import CORS
import pandas as pd
import numpy as np
import json
import os
from datetime import datetime, timedelta
import uuid

app = Flask(__name__)
CORS(app)

# ============= CONFIGURATION =============
API_KEYS_FILE = 'api_keys.json'
DATA_FILE = 'daily_oilseeds_full_ml_dataset_2015_01_01_2025_12_02.csv'

# ============= API KEY MANAGEMENT =============

def load_api_keys():
    """Load existing API keys"""
    if os.path.exists(API_KEYS_FILE):
        with open(API_KEYS_FILE, 'r') as f:
            return json.load(f)
    return {}

def save_api_keys(keys):
    """Save API keys to file"""
    with open(API_KEYS_FILE, 'w') as f:
        json.dump(keys, f, indent=2)

def generate_api_key(name):
    """Generate a new API key"""
    api_key = f"castor_{uuid.uuid4().hex[:32]}"
    
    api_keys = load_api_keys()
    api_keys[api_key] = {
        'name': name,
        'created_at': datetime.now().isoformat(),
        'last_used': None,
        'requests_count': 0,
        'active': True
    }
    save_api_keys(api_keys)
    
    return api_key, api_keys[api_key]

def verify_api_key(key):
    """Verify API key is valid and active"""
    api_keys = load_api_keys()
    if key in api_keys and api_keys[key].get('active', False):
        # Update last used
        api_keys[key]['last_used'] = datetime.now().isoformat()
        api_keys[key]['requests_count'] = api_keys[key].get('requests_count', 0) + 1
        save_api_keys(api_keys)
        return True
    return False

# ============= DATA LOADING =============

def load_data():
    """Load CSV data"""
    try:
        df = pd.read_csv(DATA_FILE)
        return df
    except FileNotFoundError:
        return None

# ============= ENDPOINTS =============

@app.route('/', methods=['GET'])
def index():
    """API Documentation"""
    return jsonify({
        'service': 'Castor Price Forecasting API v1.0',
        'status': 'active',
        'endpoints': {
            'GET /': 'API Documentation',
            'GET /api/health': 'Health check',
            'POST /api/generate-key': 'Generate new API key',
            'POST /api/forecast': 'Get price forecast',
            'POST /api/forecast/arima': 'Get ARIMA forecast',
            'POST /api/forecast/lstm': 'Get LSTM forecast'
        },
        'usage': 'Include X-API-Key header in all forecast requests'
    }), 200

@app.route('/api/health', methods=['GET'])
def health():
    """Health check endpoint"""
    return jsonify({
        'status': 'healthy',
        'timestamp': datetime.now().isoformat(),
        'service': 'Castor Price Forecasting API'
    }), 200

@app.route('/api/generate-key', methods=['POST'])
def generate_key():
    """Generate new API key"""
    try:
        data = request.json or {}
        name = data.get('name', 'default_app')
        
        api_key, key_info = generate_api_key(name)
        
        return jsonify({
            'status': 'success',
            'api_key': api_key,
            'name': name,
            'created_at': key_info['created_at'],
            'message': 'Use this API key in X-API-Key header for all requests'
        }), 200
    except Exception as e:
        return jsonify({
            'status': 'error',
            'message': str(e)
        }), 500

@app.route('/api/forecast', methods=['GET', 'POST'])
def forecast():
    """Get price forecast (both ARIMA and LSTM)"""
    
    # Verify API key - accept from header or query param
    api_key = request.headers.get('X-API-Key') or request.args.get('api_key')
    if not api_key or not verify_api_key(api_key):
        return jsonify({
            'status': 'error',
            'message': 'Invalid or missing API key. Generate one using /api/generate-key'
        }), 401
    
    try:
        # Support both JSON body (POST) and query params (GET)
        if request.method == 'POST':
            data = request.json or {}
        else:
            data = request.args.to_dict()
        
        product = data.get('product', 'Castor')
        start_date = data.get('start_date', '2025-12-01')
        end_date = data.get('end_date', '2026-01-31')
        
        # Load data
        df = load_data()
        if df is None:
            return jsonify({
                'status': 'error',
                'message': 'Data file not found'
            }), 500
        
        # Filter by product if available
        if 'Product' in df.columns:
            df_product = df[df['Product'] == product].copy()
        else:
            df_product = df.copy()
        
        if len(df_product) == 0:
            return jsonify({
                'status': 'error',
                'message': f'Product {product} not found in database'
            }), 404
        
        # Get date and price columns
        date_col = 'Expiry_Date' if 'Expiry_Date' in df_product.columns else 'Date'
        if date_col not in df_product.columns and date_col.replace('_', ' ') in df_product.columns:
            date_col = date_col.replace('_', ' ')
        
        price_col = 'Close' if 'Close' in df_product.columns else 'Price'
        if price_col not in df_product.columns:
            price_col = df_product.columns[-1]
        
        # Parse dates
        df_product[date_col] = pd.to_datetime(df_product[date_col])
        df_product = df_product.sort_values(date_col)
        
        # Get historical data (last 60 days before forecast start)
        hist_start = pd.to_datetime(start_date) - pd.Timedelta(days=60)
        historical_data = df_product[df_product[date_col] >= hist_start].copy()
        
        last_price = float(df_product[price_col].iloc[-1])
        
        # Generate forecast date range
        forecast_dates = pd.date_range(start=start_date, end=end_date, freq='D')
        
        # Placeholder forecasts
        arima_forecast = [last_price] * len(forecast_dates)
        lstm_forecast = [last_price * (1 + 0.0001 * i) for i in range(len(forecast_dates))]
        
        # Format historical data
        historical_data_list = []
        for _, row in historical_data.iterrows():
            historical_data_list.append({
                'date': row[date_col].strftime('%Y-%m-%d'),
                'actual_price': round(float(row[price_col]), 2),
                'type': 'historical'
            })
        
        # Format forecast data
        forecast_data = []
        for i, date in enumerate(forecast_dates):
            forecast_data.append({
                'date': date.strftime('%Y-%m-%d'),
                'arima_price': round(arima_forecast[i], 2),
                'lstm_price': round(lstm_forecast[i], 2),
                'average_price': round((arima_forecast[i] + lstm_forecast[i]) / 2, 2),
                'type': 'forecast'
            })
        
        return jsonify({
            'status': 'success',
            'product': product,
            'last_known_price': round(last_price, 2),
            'historical': historical_data_list,
            'forecast_period': {
                'start': start_date,
                'end': end_date,
                'days': len(forecast_dates)
            },
            'forecast': forecast_data,
            'timestamp': datetime.now().isoformat()
        }), 200
        
    except ValueError as e:
        return jsonify({
            'status': 'error',
            'message': f'Invalid date format: {str(e)}'
        }), 400
    except Exception as e:
        return jsonify({
            'status': 'error',
            'message': str(e)
        }), 500

@app.route('/api/forecast/arima', methods=['GET', 'POST'])
def forecast_arima():
    """Get ARIMA forecast only"""
    
    api_key = request.headers.get('X-API-Key') or request.args.get('api_key')
    if not api_key or not verify_api_key(api_key):
        return jsonify({'status': 'error', 'message': 'Invalid API key'}), 401
    
    try:
        if request.method == 'POST':
            data = request.json or {}
        else:
            data = request.args.to_dict()
        
        product = data.get('product', 'Castor')
        start_date = data.get('start_date', '2025-12-01')
        end_date = data.get('end_date', '2026-01-31')
        
        df = load_data()
        if df is None:
            return jsonify({'status': 'error', 'message': 'Data not found'}), 500
        
        if 'Product' in df.columns:
            df_product = df[df['Product'] == product].copy()
        else:
            df_product = df.copy()
        
        if len(df_product) == 0:
            return jsonify({'status': 'error', 'message': f'Product {product} not found'}), 404
        
        price_col = 'Close' if 'Close' in df_product.columns else 'Price'
        if price_col not in df_product.columns:
            price_col = df_product.columns[-1]
        
        last_price = float(df_product[price_col].iloc[-1])
        
        forecast_dates = pd.date_range(start=start_date, end=end_date, freq='D')
        arima_forecast = [last_price] * len(forecast_dates)
        
        labels = [date.strftime('%Y-%m-%d') for date in forecast_dates]
        values = [round(price, 2) for price in arima_forecast]
        
        return jsonify({
            'status': 'success',
            'model': 'ARIMA',
            'product': product,
            'labels': labels,
            'values': values,
            'forecast': [{'date': label, 'price': value} for label, value in zip(labels, values)]
        }), 200
        
    except Exception as e:
        return jsonify({'status': 'error', 'message': str(e)}), 500

@app.route('/api/forecast/lstm', methods=['GET', 'POST'])
def forecast_lstm():
    """Get LSTM forecast only"""
    
    api_key = request.headers.get('X-API-Key') or request.args.get('api_key')
    if not api_key or not verify_api_key(api_key):
        return jsonify({'status': 'error', 'message': 'Invalid API key'}), 401
    
    try:
        if request.method == 'POST':
            data = request.json or {}
        else:
            data = request.args.to_dict()
        
        product = data.get('product', 'Castor')
        start_date = data.get('start_date', '2025-12-01')
        end_date = data.get('end_date', '2026-01-31')
        
        df = load_data()
        if df is None:
            return jsonify({'status': 'error', 'message': 'Data not found'}), 500
        
        if 'Product' in df.columns:
            df_product = df[df['Product'] == product].copy()
        else:
            df_product = df.copy()
        
        if len(df_product) == 0:
            return jsonify({'status': 'error', 'message': f'Product {product} not found'}), 404
        
        price_col = 'Close' if 'Close' in df_product.columns else 'Price'
        if price_col not in df_product.columns:
            price_col = df_product.columns[-1]
        
        last_price = float(df_product[price_col].iloc[-1])
        
        forecast_dates = pd.date_range(start=start_date, end=end_date, freq='D')
        lstm_forecast = [last_price * (1 + 0.0001 * i) for i in range(len(forecast_dates))]
        
        labels = [date.strftime('%Y-%m-%d') for date in forecast_dates]
        values = [round(price, 2) for price in lstm_forecast]
        
        return jsonify({
            'status': 'success',
            'model': 'LSTM',
            'product': product,
            'labels': labels,
            'values': values,
            'forecast': [{'date': label, 'price': value} for label, value in zip(labels, values)]
        }), 200
        
    except Exception as e:
        return jsonify({'status': 'error', 'message': str(e)}), 500

if __name__ == '__main__':
    # Create initial API key
    if not os.path.exists(API_KEYS_FILE):
        api_key, info = generate_api_key("demo")
        print(f"\n{'='*60}")
        print(f"Initial API Key Generated: {api_key}")
        print(f"{'='*60}\n")
    
    port = int(os.environ.get('PORT', 7860))
    app.run(debug=False, port=port, host='0.0.0.0', threaded=True)