import { useState, useCallback } from 'react';
import { ChevronLeft, ChevronRight, Calculator } from 'lucide-react';
import { useQuery, useQueryClient } from '@tanstack/react-query';
import { toast } from 'sonner';

import api, { type Transaction } from '@/lib/api';
import { MONTH_NAMES_ES as MONTH_NAMES } from '@/lib/dates';
import { useBudget } from '@/hooks/useBudget';
import { Button } from '@/components/ui/button';
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
import ErrorState from '@/components/ErrorState';
import MonthlyDetail from '@/components/budget/MonthlyDetail';
import RecurringItemsManager from '@/components/budget/RecurringItemsManager';
import TransactionList from '@/components/TransactionList';


const MIN_YEAR = 2026;
const MAX_YEAR = 2030;

export default function Budget() {
  const currentYear = Math.max(MIN_YEAR, new Date().getFullYear());
  const {
    year,
    setYear,
    selectedMonth,
    setSelectedMonth,
    monthDetail,
    recurringItems,
    monthLoading,
    error: budgetError,
    addItem,
    updateItem,
    deleteItem,
    refresh,
  } = useBudget(currentYear);
  const queryClient = useQueryClient();

  const [subTab, setSubTab] = useState<'detail' | 'transactions'>('detail');
  const [txSearch, setTxSearch] = useState('');
  const [txSource, setTxSource] = useState<'CREDIT_CARD' | 'CASH_AND_TRANSFER'>('CREDIT_CARD');

  const txQuery = useQuery({
    queryKey: ['transactions', 'budget', year, selectedMonth, txSource, txSearch],
    queryFn: async ({ signal }) => {
      const params: Record<string, string | number | boolean | undefined> = {
        search: txSearch || undefined,
        limit: 200,
      };
      if (txSource === 'CREDIT_CARD') {
        params.source = 'CREDIT_CARD';
        // Credit card: billing cycle that ends around the 18th of selectedMonth
        const prevMonth = selectedMonth === 1 ? 12 : selectedMonth - 1;
        const prevYear = selectedMonth === 1 ? year - 1 : year;
        params.cycle_year = prevYear;
        params.cycle_month = prevMonth;
      } else {
        // Cash + Transfer merged: calendar month, exclude credit card
        params.exclude_source = 'CREDIT_CARD';
        const startDate = `${year}-${String(selectedMonth).padStart(2, '0')}-01`;
        const endMonth = selectedMonth === 12 ? 1 : selectedMonth + 1;
        const endYear = selectedMonth === 12 ? year + 1 : year;
        const endDate = `${endYear}-${String(endMonth).padStart(2, '0')}-01`;
        params.start_date = startDate;
        params.end_date = endDate;
      }
      const { data } = await api.get<Transaction[]>('/transactions/', { params, signal });
      const INCOME_TYPES = ['DEPOSITO', 'SALARY'];
      return data.filter((tx) => !INCOME_TYPES.includes(tx.transaction_type));
    },
    placeholderData: (prev) => prev,
  });
  const transactions = txQuery.data ?? [];

  const invalidateTransactionsAndBudget = useCallback(() => {
    queryClient.invalidateQueries({ queryKey: ['transactions'] });
    refresh();
  }, [queryClient, refresh]);

  const handleToggleDeferred = useCallback(async (tx: Transaction) => {
    try {
      await api.patch(`/transactions/${tx.id}`, {
        deferred_to_next_cycle: !tx.deferred_to_next_cycle,
      });
      toast.success(
        tx.deferred_to_next_cycle
          ? 'Transacción restaurada a su ciclo original'
          : 'Transacción diferida al siguiente ciclo',
      );
    } catch {
      toast.error('No se pudo actualizar la transacción');
      return;
    }
    invalidateTransactionsAndBudget();
  }, [invalidateTransactionsAndBudget]);

  const handleNavigateToTransactions = useCallback(() => {
    setTxSource('CASH_AND_TRANSFER');
    setSubTab('transactions');
  }, []);

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex items-center justify-between">
        <div className="flex items-center gap-3">
          <Calculator className="w-6 h-6 text-primary" />
          <h1 className="text-2xl font-bold tracking-tight">Presupuesto</h1>
        </div>
        <div className="flex items-center gap-1">
          <Button variant="outline" size="icon" disabled={year <= MIN_YEAR} onClick={() => setYear(year - 1)}>
            <ChevronLeft className="w-4 h-4" />
          </Button>
          <span className="w-16 text-center font-semibold tabular-nums">{year}</span>
          <Button variant="outline" size="icon" disabled={year >= MAX_YEAR} onClick={() => setYear(year + 1)}>
            <ChevronRight className="w-4 h-4" />
          </Button>
        </div>
      </div>

      <Tabs defaultValue="overview">
        <TabsList>
          <TabsTrigger value="overview">Resumen</TabsTrigger>
          <TabsTrigger value="items">Items Recurrentes</TabsTrigger>
        </TabsList>

        <TabsContent value="overview" className="mt-4">
          <Tabs
            value={subTab}
            onValueChange={(v) => setSubTab(v as typeof subTab)}
          >
            <div className="flex items-center justify-between">
              <TabsList variant="line">
                <TabsTrigger value="detail">Detalle</TabsTrigger>
                <TabsTrigger value="transactions">Transacciones</TabsTrigger>
              </TabsList>
              <div className="flex items-center gap-1">
                <Button
                  variant="ghost"
                  size="icon"
                  className="h-7 w-7"
                  disabled={selectedMonth <= 1}
                  onClick={() => setSelectedMonth(selectedMonth - 1)}
                >
                  <ChevronLeft className="w-4 h-4" />
                </Button>
                <span className="text-sm font-medium w-28 text-center">
                  {MONTH_NAMES[selectedMonth]} {year}
                </span>
                <Button
                  variant="ghost"
                  size="icon"
                  className="h-7 w-7"
                  disabled={selectedMonth >= 12}
                  onClick={() => setSelectedMonth(selectedMonth + 1)}
                >
                  <ChevronRight className="w-4 h-4" />
                </Button>
              </div>
            </div>

            <TabsContent value="detail" className="space-y-6 mt-4">
              {budgetError ? (
                <ErrorState onRetry={refresh} />
              ) : (
                <MonthlyDetail
                  detail={monthDetail}
                  loading={monthLoading || !monthDetail}
                  onNavigateToTransactions={handleNavigateToTransactions}
                />
              )}
            </TabsContent>

            <TabsContent value="transactions" className="space-y-3 mt-4">
              <Tabs
                value={txSource}
                onValueChange={(v) => setTxSource(v as typeof txSource)}
              >
                <TabsList>
                  <TabsTrigger value="CREDIT_CARD">Tarjeta</TabsTrigger>
                  <TabsTrigger value="CASH_AND_TRANSFER">Efectivo y Transferencias</TabsTrigger>
                </TabsList>
              </Tabs>
              {txQuery.isError ? (
                <ErrorState
                  message="No se pudieron cargar las transacciones"
                  onRetry={() => txQuery.refetch()}
                />
              ) : (
              <TransactionList
                transactions={transactions}
                loading={txQuery.isPending}
                source={txSource === 'CREDIT_CARD' ? 'CREDIT_CARD' : 'CASH'}
                search={txSearch}
                onSearchChange={setTxSearch}
                onRefresh={invalidateTransactionsAndBudget}
                showCategory={txSource === 'CREDIT_CARD'}
                showSourceIcon={txSource === 'CASH_AND_TRANSFER'}
                emptyMessage={`Sin transacciones de ${txSource === 'CREDIT_CARD' ? 'tarjeta' : 'efectivo o transferencia'} en ${MONTH_NAMES[selectedMonth]}`}
                onToggleDeferred={txSource === 'CREDIT_CARD' ? handleToggleDeferred : undefined}
              />
              )}
            </TabsContent>
          </Tabs>
        </TabsContent>

        <TabsContent value="items" className="mt-4">
          <RecurringItemsManager
            items={recurringItems}
            onAdd={addItem}
            onUpdate={updateItem}
            onDelete={deleteItem}
          />
        </TabsContent>
      </Tabs>
    </div>
  );
}