/**
 * @license
 * SPDX-License-Identifier: Apache-2.0
 */

import React, { useState, useEffect } from 'react';
import { motion, AnimatePresence } from 'motion/react';
import { 
  LayoutDashboard, 
  ShoppingCart, 
  Package, 
  Users, 
  Megaphone, 
  Settings, 
  Activity, 
  CloudLightning, 
  Wifi, 
  WifiOff, 
  Clock, 
  PhoneCall, 
  UserCircle 
} from 'lucide-react';

import { TireProduct, StockHistoryItem, StaffUser, Invoice, SystemSettings, StaffRole } from './types';
import {
  INITIAL_PRODUCTS,
  INITIAL_HISTORY,
  INITIAL_STAFF,
  INITIAL_INVOICES,
  INITIAL_SETTINGS
} from './initialData';

// Subcomponents
import Dashboard from './components/Dashboard';
import InvoiceGenerator from './components/InvoiceGenerator';
import InventoryManager from './components/InventoryManager';
import StaffManager from './components/StaffManager';
import SocialPromoter from './components/SocialPromoter';
import SettingsComponent from './components/Settings';

export default function App() {
  const [activeTab, setActiveTab] = useState('dashboard');
  const [isOnline, setIsOnline] = useState(true);
  const [currentTime, setCurrentTime] = useState(new Date());

  // Core database state hooks
  const [settings, setSettings] = useState<SystemSettings>(INITIAL_SETTINGS);
  const [products, setProducts] = useState<TireProduct[]>(INITIAL_PRODUCTS);
  const [invoices, setInvoices] = useState<Invoice[]>(INITIAL_INVOICES);
  const [history, setHistory] = useState<StockHistoryItem[]>(INITIAL_HISTORY);
  const [staffList, setStaffList] = useState<StaffUser[]>(INITIAL_STAFF);
  const [currentStaff, setCurrentStaff] = useState<StaffUser>(INITIAL_STAFF[1]); // Zin Brother as default cashier

  // Invoice review overlay trigger state
  const [selectedInvoiceForView, setSelectedInvoiceForView] = useState<Invoice | null>(null);

  // Initialize and load from local storage if existing
  useEffect(() => {
    // Clock tick
    const timer = setInterval(() => setCurrentTime(new Date()), 1000);

    const storedSettings = localStorage.getItem('HBT_SETTINGS');
    const storedProducts = localStorage.getItem('HBT_PRODUCTS');
    const storedInvoices = localStorage.getItem('HBT_INVOICES');
    const storedHistory = localStorage.getItem('HBT_HISTORY');
    const storedStaff = localStorage.getItem('HBT_STAFF');
    const storedCurrent = localStorage.getItem('HBT_CURRENT_STAFF');

    if (storedSettings) setSettings(JSON.parse(storedSettings));
    if (storedProducts) setProducts(JSON.parse(storedProducts));
    if (storedInvoices) setInvoices(JSON.parse(storedInvoices));
    if (storedHistory) setHistory(JSON.parse(storedHistory));
    if (storedStaff) setStaffList(JSON.parse(storedStaff));
    if (storedCurrent) {
      const parsedCurrent = JSON.parse(storedCurrent);
      // Ensure currentStaff matches the parsed currentStaff safely
      setCurrentStaff(parsedCurrent);
    } else {
      setCurrentStaff(INITIAL_STAFF[1]); // Zain Brother manager
    }

    return () => clearInterval(timer);
  }, []);

  // Sync utilities to persistence
  const syncToLocalStorage = (key: string, data: any) => {
    localStorage.setItem(key, JSON.stringify(data));
  };

  // State Adjustments multipliers
  const handleUpdateSettings = (updated: SystemSettings) => {
    setSettings(updated);
    syncToLocalStorage('HBT_SETTINGS', updated);
  };

  // Triggered from Dashboard replenishment alarms
  const handleQuickAddStock = (productId: string, amount: number) => {
    const adjustedProducts = products.map(p => {
      if (p.id === productId) {
        const resultingStock = p.stock + amount;
        
        // Append history log immediately
        const logItem: StockHistoryItem = {
          id: 'log_' + Math.random().toString(36).substr(2, 9),
          productId: p.id,
          productLabel: `${p.brand} ${p.model} (${p.size})`,
          dateTime: new Date().toISOString(),
          type: 'STOCK_IN',
          quantity: amount,
          resultingStock,
          adjustedBy: `${currentStaff.name} (${currentStaff.role})`,
          reason: `Quick Restock of Alarm: Restocked cargo pallet.`
        };

        const updatedHistory = [logItem, ...history];
        setHistory(updatedHistory);
        syncToLocalStorage('HBT_HISTORY', updatedHistory);

        return { ...p, stock: resultingStock };
      }
      return p;
    });

    setProducts(adjustedProducts);
    syncToLocalStorage('HBT_PRODUCTS', adjustedProducts);
  };

  // Triggered from InventoryManager manual configurations
  const handleAdjustProductStock = (
    productId: string, 
    quantityChange: number, 
    type: StockHistoryItem['type'], 
    reason: string
  ) => {
    const adjustedProducts = products.map(p => {
      if (p.id === productId) {
        const resultingStock = p.stock + quantityChange;

        // Create log item
        const logItem: StockHistoryItem = {
          id: 'log_' + Math.random().toString(36).substr(2, 9),
          productId: p.id,
          productLabel: `${p.brand} ${p.model} (${p.size})`,
          dateTime: new Date().toISOString(),
          type,
          quantity: Math.abs(quantityChange),
          resultingStock,
          adjustedBy: `${currentStaff.name} (${currentStaff.role})`,
          reason
        };

        const updatedHistory = [logItem, ...history];
        setHistory(updatedHistory);
        syncToLocalStorage('HBT_HISTORY', updatedHistory);

        return { ...p, stock: resultingStock };
      }
      return p;
    });

    setProducts(adjustedProducts);
    syncToLocalStorage('HBT_PRODUCTS', adjustedProducts);
  };

  const handleAddNewProduct = (prod: TireProduct) => {
    const updatedProducts = [prod, ...products];
    setProducts(updatedProducts);
    syncToLocalStorage('HBT_PRODUCTS', updatedProducts);

    // Write initial STOCK_IN history entry
    const logItem: StockHistoryItem = {
      id: 'log_' + Math.random().toString(36).substr(2, 9),
      productId: prod.id,
      productLabel: `${prod.brand} ${prod.model} (${prod.size})`,
      dateTime: new Date().toISOString(),
      type: 'STOCK_IN',
      quantity: prod.stock,
      resultingStock: prod.stock,
      adjustedBy: `${currentStaff.name} (${currentStaff.role})`,
      reason: `First inventory system initialization of tyre profile SKU.`
    };

    const updatedHistory = [logItem, ...history];
    setHistory(updatedHistory);
    syncToLocalStorage('HBT_HISTORY', updatedHistory);
  };

  const handleDeleteProduct = (productId: string) => {
    const updatedProducts = products.filter(p => p.id !== productId);
    setProducts(updatedProducts);
    syncToLocalStorage('HBT_PRODUCTS', updatedProducts);
  };

  // Adding Client Invoice automatically reduces matching tire quantities and writes logs
  const handleAddInvoice = (newInv: Invoice) => {
    // Append invoice
    const updatedInvoices = [...invoices, newInv];
    setInvoices(updatedInvoices);
    syncToLocalStorage('HBT_INVOICES', updatedInvoices);

    // Iterate items and decrease physical stock counts
    let revisedProducts = [...products];
    let newLogs: StockHistoryItem[] = [];

    newInv.items.forEach((item) => {
      revisedProducts = revisedProducts.map(p => {
        if (p.id === item.productId) {
          const resultingStock = p.stock - item.quantity;
          
          // Construct checkout history block
          const logItem: StockHistoryItem = {
            id: 'log_' + Math.random().toString(36).substr(2, 9),
            productId: p.id,
            productLabel: `${p.brand} ${p.model} (${p.size})`,
            dateTime: new Date().toISOString(),
            type: 'STOCK_OUT',
            quantity: item.quantity,
            resultingStock,
            adjustedBy: `${currentStaff.name} (${currentStaff.role})`,
            reason: `Retail Invoice checkout sales: Ref ${newInv.invoiceNumber}`
          };
          newLogs.push(logItem);

          return { ...p, stock: resultingStock };
        }
        return p;
      });
    });

    const revisedHistory = [...newLogs, ...history];
    setHistory(revisedHistory);
    setProducts(revisedProducts);

    syncToLocalStorage('HBT_PRODUCTS', revisedProducts);
    syncToLocalStorage('HBT_HISTORY', revisedHistory);
  };

  // Staff managers
  const handleAddStaffMember = (newUser: StaffUser) => {
    const updated = [...staffList, newUser];
    setStaffList(updated);
    syncToLocalStorage('HBT_STAFF', updated);
  };

  const handleToggleStaffStatus = (staffId: string) => {
    const updated = staffList.map(s => 
      s.id === staffId ? { ...s, active: !s.active } : s
    );
    setStaffList(updated);
    syncToLocalStorage('HBT_STAFF', updated);
  };

  const handleUpdateStaffRole = (staffId: string, role: StaffRole) => {
    const updated = staffList.map(s => 
      s.id === staffId ? { ...s, role } : s
    );
    setStaffList(updated);
    syncToLocalStorage('HBT_STAFF', updated);
  };

  const handleSetCurrentStaff = (staff: StaffUser) => {
    setCurrentStaff(staff);
    syncToLocalStorage('HBT_CURRENT_STAFF', staff);
  };

  // Decrypted Restore logic
  const handleRestoreDatabase = (decoded: {
    settings: SystemSettings;
    products: any[];
    invoices: any[];
    history: any[];
    staff: any[];
  }) => {
    setSettings(decoded.settings);
    setProducts(decoded.products);
    setInvoices(decoded.invoices);
    setHistory(decoded.history);
    setStaffList(decoded.staff);

    // Save and persist all entries
    syncToLocalStorage('HBT_SETTINGS', decoded.settings);
    syncToLocalStorage('HBT_PRODUCTS', decoded.products);
    syncToLocalStorage('HBT_INVOICES', decoded.invoices);
    syncToLocalStorage('HBT_HISTORY', decoded.history);
    syncToLocalStorage('HBT_STAFF', decoded.staff);

    // Set Owner as current operator safely if there's any owner in the backup list
    const firstOwner = decoded.staff.find(s => s.role === 'owner' && s.active);
    if (firstOwner) {
      setCurrentStaff(firstOwner);
      syncToLocalStorage('HBT_CURRENT_STAFF', firstOwner);
    }
  };

  // Factory defaults
  const handleClearCacheToDefault = () => {
    localStorage.clear();
  };

  return (
    <div className="min-h-screen bg-[#F8FAFC] flex flex-col md:flex-row antialiased select-none font-sans" id="application-shell">
      {/* 1. COLLAPSIBLE OR RESPONSIVE STATIC SIDEBAR */}
      <aside className="w-full md:w-64 bg-white border-b md:border-r border-slate-200 text-slate-800 flex flex-col justify-between shrink-0 shadow-sm" id="sidebar-panel">
        <div className="space-y-6">
          {/* Top Shop Brand Logo */}
          <div className="p-6 border-b border-slate-100 flex items-center justify-between">
            <div className="flex items-center gap-3">
              <div className="w-9 h-9 rounded-lg bg-slate-900 flex items-center justify-center font-bold text-white text-base shadow-sm">
                HBT
              </div>
              <div className="space-y-0.5">
                <h2 className="text-xs font-bold tracking-tight text-slate-900 uppercase">Haider Brothers</h2>
                <span className="text-[10px] text-slate-400 font-medium block">Tire Shop Manager</span>
              </div>
            </div>
          </div>

          {/* Navigation Links list */}
          <nav className="px-3 space-y-1">
            <button
              onClick={() => setActiveTab('dashboard')}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'dashboard' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <LayoutDashboard className="w-4 h-4 text-inherit" />
              Reporting Cockpit
            </button>

            <button
              onClick={() => {
                setActiveTab('invoices');
                setSelectedInvoiceForView(null);
              }}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'invoices' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <ShoppingCart className="w-4 h-4 text-inherit" />
              Invoice Generator
            </button>

            <button
              onClick={() => setActiveTab('inventory')}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'inventory' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <Package className="w-4 h-4 text-inherit" />
              Stock Inventory
            </button>

            <button
              onClick={() => setActiveTab('staff')}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'staff' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <Users className="w-4 h-4 text-inherit" />
              Cashiers &amp; RBAC
            </button>

            <button
              onClick={() => setActiveTab('social')}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'social' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <Megaphone className="w-4 h-4 text-inherit" />
              Outreach Promos
            </button>

            <button
              onClick={() => setActiveTab('settings')}
              className={`w-full flex items-center gap-3 px-3.5 py-2.5 rounded-lg text-xs font-medium font-sans transition cursor-pointer ${
                activeTab === 'settings' 
                  ? 'bg-slate-900 text-white shadow-sm font-semibold' 
                  : 'text-slate-500 hover:text-slate-900 hover:bg-slate-50'
              }`}
            >
              <Settings className="w-4 h-4 text-inherit" />
              Settings &amp; Vault
            </button>
          </nav>
        </div>

        {/* Bottom Operator profile card in sidebar */}
        <div className="p-4 border-t border-slate-100 bg-slate-50 space-y-2">
          <div className="flex items-center gap-2.5 text-xs">
            <UserCircle className="w-8 h-8 text-slate-400" />
            <div className="flex-1 min-w-0">
              <p className="font-semibold text-slate-950 truncate text-[11px]">{currentStaff.name}</p>
              <p className="text-[10px] text-slate-400 uppercase tracking-wider font-medium">{currentStaff.role}</p>
            </div>
          </div>
          
          <div className="bg-white rounded-lg p-2 flex justify-between items-center text-[10px] border border-slate-200">
            <span className="text-slate-400 font-medium">Node secure:</span>
            <span className="font-mono text-emerald-600 font-bold flex items-center gap-1.5">
              <span className="w-1.5 h-1.5 bg-emerald-500 rounded-full"></span>
              ONLINE
            </span>
          </div>
        </div>
      </aside>

      {/* 2. CORE WORKSPACE: HEADER + SCROLLABLE PAGE VIEWS */}
      <main className="flex-1 flex flex-col min-w-0 overflow-y-auto h-screen" id="workspace-viewport">
        {/* Top Navbar */}
        <header className="bg-white border-b border-slate-200 px-6 md:px-8 py-4 flex flex-col sm:flex-row justify-between items-start sm:items-center gap-3 shrink-0">
          {/* Left info */}
          <div className="flex items-center gap-2.5">
            <span className="w-2 h-2 bg-slate-900 rounded-full animate-pulse"></span>
            <span className="text-[11px] font-bold text-slate-800 font-sans tracking-wider uppercase">
              SECURE CASHIER LEDGER
            </span>
            <span className="text-slate-200">|</span>
            <span className="text-[11px] text-slate-500 flex items-center gap-1">
              Store Support: {settings.shopPhone}
            </span>
          </div>

          {/* Right systems specs */}
          <div className="flex items-center gap-3.5 text-xs">
            {/* Real-time Clock */}
            <div className="text-slate-600 flex items-center gap-1.5 bg-[#F8FAFC] px-2.5 py-1.5 rounded-lg border border-slate-200/80">
              <Clock className="w-3.5 h-3.5 text-slate-400" />
              <span className="font-mono font-medium text-[11px] text-slate-700">{currentTime.toLocaleTimeString()}</span>
            </div>

            {/* Offline vs Online Beacons and alarms */}
            {isOnline ? (
              <span className="bg-emerald-50 text-emerald-800 border border-emerald-200/60 font-semibold font-sans px-2.5 py-1.5 rounded-lg flex items-center gap-1.5 text-[10px]">
                <Wifi className="w-3.5 h-3.5 text-emerald-600" />
                VAULT OK
              </span>
            ) : (
              <span className="bg-amber-50 text-amber-800 border border-amber-200/60 font-semibold font-sans px-2.5 py-1.5 rounded-lg flex items-center gap-1.5 text-[10px] animate-pulse">
                <WifiOff className="w-3.5 h-3.5 text-amber-600" />
                AIR-GAPPED LOCAL
              </span>
            )}
          </div>
        </header>

        {/* Tab Pages dispatcher Router panel */}
        <div className="flex-1 p-6 md:p-8 overflow-y-auto">
          <AnimatePresence mode="wait">
            <motion.div
              key={activeTab}
              initial={{ opacity: 0, y: 10 }}
              animate={{ opacity: 1, y: 0 }}
              exit={{ opacity: 0, y: -10 }}
              transition={{ duration: 0.15 }}
              className="h-full"
            >
              {activeTab === 'dashboard' && (
                <Dashboard 
                  products={products}
                  invoices={invoices}
                  currentStaff={currentStaff}
                  settings={settings}
                  setActiveTab={setActiveTab}
                  onQuickAddStock={handleQuickAddStock}
                  setSelectedInvoiceForView={(inv) => {
                    setSelectedInvoiceForView(inv);
                    setActiveTab('invoices');
                  }}
                />
              )}

              {activeTab === 'invoices' && (
                <InvoiceGenerator 
                  products={products}
                  invoices={invoices}
                  currentStaff={currentStaff}
                  settings={settings}
                  isOnline={isOnline}
                  onAddInvoice={handleAddInvoice}
                  selectedInvoiceForView={selectedInvoiceForView}
                  setSelectedInvoiceForView={setSelectedInvoiceForView}
                />
              )}

              {activeTab === 'inventory' && (
                <InventoryManager 
                  products={products}
                  history={history}
                  currentStaff={currentStaff}
                  settings={settings}
                  onAdjustProductStock={handleAdjustProductStock}
                  onAddNewProduct={handleAddNewProduct}
                  onDeleteProduct={handleDeleteProduct}
                />
              )}

              {activeTab === 'staff' && (
                <StaffManager 
                  staffList={staffList}
                  currentStaff={currentStaff}
                  onSetCurrentStaff={handleSetCurrentStaff}
                  onAddStaffMember={handleAddStaffMember}
                  onToggleStaffStatus={handleToggleStaffStatus}
                  onUpdateStaffRole={handleUpdateStaffRole}
                />
              )}

              {activeTab === 'social' && (
                <SocialPromoter 
                  products={products}
                  settings={settings}
                />
              )}

              {activeTab === 'settings' && (
                <SettingsComponent 
                  settings={settings}
                  isOnline={isOnline}
                  onUpdateSettings={handleUpdateSettings}
                  onToggleOnlineMode={() => setIsOnline(!isOnline)}
                  onRestoreDatabase={handleRestoreDatabase}
                  onClearCacheToDefault={handleClearCacheToDefault}
                  activeProducts={products}
                  activeInvoices={invoices}
                  activeHistory={history}
                  activeStaff={staffList}
                />
              )}
            </motion.div>
          </AnimatePresence>
        </div>
      </main>
    </div>
  );
}