import { useMemo, useState } from 'react';
import { Link, useOutletContext } from 'react-router-dom';
import { Search, ChevronRight, Filter } from 'lucide-react';
import type { OrderData } from '../types';
import { parseOrderDate } from '../dataService';

type SortOption = 'recent' | 'spent_desc' | 'spent_asc' | 'items_desc' | 'items_asc';

const Clients = () => {
  const { ordersData } = useOutletContext<{ ordersData: OrderData[] }>();
  const [searchTerm, setSearchTerm] = useState('');
  const [sortBy, setSortBy] = useState<SortOption>('recent');

  const clientsData = useMemo(() => {
    const orders = ordersData;
    const clientMap: Record<string, { totalSpent: number, totalItems: number, uniqueOrders: Set<string>, lastPurchase: number }> = {};

    orders.forEach(order => {
      const clientName = order.Nome_Cliente || `Cliente Desconhecido (Pedido ${order.Valor_Pedido})`;

      if (!clientMap[clientName]) {
        clientMap[clientName] = { totalSpent: 0, totalItems: 0, uniqueOrders: new Set(), lastPurchase: 0 };
      }
      
      // Calculate total spent based on quantity * unit price
      clientMap[clientName].totalSpent += (order.Quantidade * order.Valor_Unitario);
      clientMap[clientName].totalItems += order.Quantidade;
      clientMap[clientName].uniqueOrders.add(`${order.Data_Pedido}_${order.Valor_Pedido}`);
      
      const orderTime = parseOrderDate(order.Data_Pedido).getTime();
      
      if (orderTime > clientMap[clientName].lastPurchase) {
        clientMap[clientName].lastPurchase = orderTime;
      }
    });

    let result = Object.keys(clientMap).map(name => ({
      name,
      totalSpent: clientMap[name].totalSpent,
      totalItems: clientMap[name].totalItems,
      orderCount: clientMap[name].uniqueOrders.size, // Grouped by unique date+value combinations
      lastPurchase: clientMap[name].lastPurchase
    }));

    if (searchTerm) {
      result = result.filter(c => c.name.toLowerCase().includes(searchTerm.toLowerCase()));
    }

    return result.sort((a, b) => {
      switch (sortBy) {
        case 'recent': return b.lastPurchase - a.lastPurchase;
        case 'spent_desc': return b.totalSpent - a.totalSpent;
        case 'spent_asc': return a.totalSpent - b.totalSpent;
        case 'items_desc': return b.totalItems - a.totalItems;
        case 'items_asc': return a.totalItems - b.totalItems;
        default: return 0;
      }
    });
  }, [searchTerm, sortBy, ordersData]);

  const formatCurrency = (value: number) => {
    return new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(value);
  };

  return (
    <div className="space-y-6">
      <div className="flex flex-col md:flex-row md:items-center justify-between gap-4">
        <div>
          <h1 className="text-2xl font-bold mb-2 text-zinc-900 dark:text-dark-text">Clientes</h1>
          <p className="text-zinc-500 dark:text-dark-muted font-medium">Métricas de engajamento e histórico de consumo dos seus clientes.</p>
        </div>
        
        <div className="flex flex-col sm:flex-row gap-3">
          <div className="relative">
            <Filter className="absolute left-3 top-1/2 transform -translate-y-1/2 text-zinc-400 dark:text-dark-muted w-4 h-4" />
            <select 
              value={sortBy}
              onChange={(e) => setSortBy(e.target.value as SortOption)}
              className="appearance-none bg-white dark:bg-dark-input border border-zinc-200 dark:border-dark-border text-zinc-700 dark:text-dark-text text-sm rounded-xl pl-9 pr-8 py-2.5 focus:outline-none focus:border-brand-primary transition-all shadow-sm cursor-pointer"
            >
              <option value="recent">Mais Recentes</option>
              <option value="spent_desc">Maior Gasto</option>
              <option value="spent_asc">Menor Gasto</option>
              <option value="items_desc">Mais Produtos</option>
              <option value="items_asc">Menos Produtos</option>
            </select>
          </div>

          <div className="relative">
            <Search className="absolute left-3 top-1/2 transform -translate-y-1/2 text-zinc-400 dark:text-dark-muted w-5 h-5" />
            <input 
              type="text" 
              placeholder="Buscar cliente..." 
              value={searchTerm}
              onChange={(e) => setSearchTerm(e.target.value)}
              className="w-full md:w-64 bg-white dark:bg-dark-input border border-zinc-200 dark:border-dark-border text-zinc-900 dark:text-dark-text rounded-xl pl-10 pr-4 py-2.5 focus:outline-none focus:border-brand-primary focus:ring-2 focus:ring-brand-primary/20 transition-all shadow-sm"
            />
          </div>
        </div>
      </div>

      <div className="bg-white dark:bg-dark-card border border-zinc-200 dark:border-dark-border rounded-2xl overflow-hidden shadow-sm">
        <div className="overflow-x-auto">
          <table className="w-full text-left text-sm">
            <thead className="bg-zinc-50 dark:bg-dark-header border-b border-zinc-100 dark:border-dark-border text-zinc-500 dark:text-dark-muted">
              <tr>
                <th className="px-6 py-4 font-bold uppercase tracking-wider text-[10px]">Posição</th>
                <th className="px-6 py-4 font-bold uppercase tracking-wider text-[10px]">Nome do Cliente</th>
                <th className="px-6 py-4 font-bold uppercase tracking-wider text-[10px]">Total Gasto</th>
                <th className="px-6 py-4 font-bold uppercase tracking-wider text-[10px]">Produtos Comprados</th>
                <th className="px-6 py-4 font-bold uppercase tracking-wider text-[10px] text-right">Ações</th>
              </tr>
            </thead>
            <tbody className="divide-y divide-zinc-100 dark:divide-dark-border">
              {clientsData.map((client, index) => (
                <tr key={client.name} className="hover:bg-zinc-50/80 dark:hover:bg-dark-input/50 transition-colors group">
                  <td className="px-6 py-2.5">
                    <span className="inline-flex items-center justify-center w-7 h-7 rounded-full text-xs font-bold bg-zinc-100 dark:bg-dark-border text-zinc-500 dark:text-dark-muted">
                      {index + 1}
                    </span>
                  </td>
                  <td className="px-6 py-2.5 font-semibold text-zinc-900 dark:text-dark-text">{client.name}</td>
                  <td className="px-6 py-2.5 text-brand-primary font-bold">{formatCurrency(client.totalSpent)}</td>
                  <td className="px-6 py-2.5 text-zinc-500 dark:text-dark-muted text-xs font-medium">
                    {client.totalItems} un. ({client.orderCount} {client.orderCount === 1 ? 'pedido' : 'pedidos'})
                  </td>
                  <td className="px-6 py-2.5 text-right">
                    <Link 
                      to={`/clients/${encodeURIComponent(client.name)}`}
                      className="inline-flex items-center text-xs font-bold text-brand-primary hover:opacity-80 transition-opacity"
                    >
                      Ver detalhes
                      <ChevronRight className="w-3.5 h-3.5 ml-1" />
                    </Link>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      </div>
    </div>
  );
};

export default Clients;