'use client';

import { useState, useEffect, useCallback } from 'react';
import { CreateAusgabenEntry, AusgabenEntry, ZAHLUNGSARTEN_HAUSHALT, ZAHLUNGSARTEN_PRIVAT, MonthlyStats } from '@/types/ausgaben';

interface AusgabenFormProps {
  onSuccess: () => void;
  selectedEntry?: AusgabenEntry | null;
  typ: number; // 0 = Haushalt, 1 = Privat
}

export default function AusgabenForm({ onSuccess, selectedEntry, typ }: AusgabenFormProps) {
  const zahlungsarten = typ === 0 ? ZAHLUNGSARTEN_HAUSHALT : ZAHLUNGSARTEN_PRIVAT;
  const defaultZahlungsart = typ === 0 ? 'ECR' : 'bar';

  const [formData, setFormData] = useState<CreateAusgabenEntry>({
    Datum: '',
    WochTag: '',
    Wo: '',
    Was: '',
    Wieviel: '',
    Wie: defaultZahlungsart,
    TYP: typ,
    OK: 0,
  });

  const [isSubmitting, setIsSubmitting] = useState(false);
  const [editId, setEditId] = useState<number | null>(null);
  
  // Monthly stats
  const [stats, setStats] = useState<MonthlyStats | null>(null);
  const [month, setMonth] = useState('');
  const [year, setYear] = useState('');
  const [isLoadingStats, setIsLoadingStats] = useState(false);

  const fetchStats = useCallback(async (y: string, m: string) => {
    if (!y || !m) return;
    
    setIsLoadingStats(true);
    try {
      const response = await fetch(`/api/ausgaben/stats?year=${y}&month=${m}&typ=${typ}`);
      const data = await response.json();
      if (data.success) {
        setStats(data.data);
      }
    } catch (error) {
      console.error('Error fetching stats:', error);
    } finally {
      setIsLoadingStats(false);
    }
  }, [typ]);

  // Initialize month/year on first load
  useEffect(() => {
    const now = new Date();
    const currentMonth = String(now.getMonth() + 1).padStart(2, '0');
    const currentYear = String(now.getFullYear());
    setMonth(currentMonth);
    setYear(currentYear);
  }, []);

  // Fetch stats when month, year, or typ changes
  useEffect(() => {
    if (month && year) {
      fetchStats(year, month);
    }
  }, [month, year, typ, fetchStats]);

  const handleMonthChange = (newMonth: string) => {
    setMonth(newMonth);
  };

  const handleYearChange = (newYear: string) => {
    setYear(newYear);
  };

  const formatAmount = (amount: number | null) => {
    if (amount === null || amount === undefined) return '0,00 €';
    return new Intl.NumberFormat('de-DE', {
      style: 'currency',
      currency: 'EUR',
    }).format(amount);
  };

  useEffect(() => {
    if (selectedEntry) {
      // Load selected entry for editing
      const dateStr = selectedEntry.Datum.toString().split('T')[0];
      
      setFormData({
        Datum: dateStr,
        WochTag: selectedEntry.WochTag,
        Wo: selectedEntry.Wo,
        Was: selectedEntry.Was,
        Wieviel: selectedEntry.Wieviel.toString(),
        Wie: selectedEntry.Wie,
        TYP: selectedEntry.TYP,
        OK: selectedEntry.OK || 0,
      });
      
      setEditId(selectedEntry.ID);
    } else {
      // Initialize with current date for new entry
      const now = new Date();
      const dateStr = now.toISOString().split('T')[0];
      const weekday = getWeekday(now);
      
      setFormData(prev => ({
        ...prev,
        Datum: dateStr,
        WochTag: weekday,
        TYP: typ,
      }));
      
      setEditId(null);
    }
  }, [selectedEntry, typ]);

  const getWeekday = (date: Date): string => {
    const weekdays = ['Sonntag', 'Montag', 'Dienstag', 'Mittwoch', 'Donnerstag', 'Freitag', 'Samstag'];
    return weekdays[date.getDay()];
  };

  const handleDateChange = (dateStr: string) => {
    const [year, month, day] = dateStr.split('-');
    const date = new Date(Number(year), Number(month) - 1, Number(day));
    const weekday = getWeekday(date);
    
    setFormData(prev => ({ ...prev, Datum: dateStr, WochTag: weekday }));
  };

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    
    if (!formData.Wo || !formData.Was || !formData.Wieviel) {
      alert('Bitte alle Pflichtfelder ausfüllen!');
      return;
    }
    
    setIsSubmitting(true);

    try {
      const url = editId ? `/api/ausgaben/${editId}` : '/api/ausgaben';
      const method = editId ? 'PUT' : 'POST';
      
      const response = await fetch(url, {
        method: method,
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(formData),
      });

      if (response.ok) {
        handleReset();
        onSuccess();
        // Refresh stats after successful save
        fetchStats(year, month);
      } else {
        alert('Fehler beim Speichern!');
      }
    } catch (error) {
      console.error('Error:', error);
      alert('Fehler beim Speichern!');
    } finally {
      setIsSubmitting(false);
    }
  };

  const handleReset = () => {
    const now = new Date();
    const dateStr = now.toISOString().split('T')[0];
    const weekday = getWeekday(now);
    
    setFormData({
      Datum: dateStr,
      WochTag: weekday,
      Wo: '',
      Was: '',
      Wieviel: '',
      Wie: defaultZahlungsart,
      TYP: typ,
      OK: 0,
    });
    
    setEditId(null);
  };

  return (
    <div className="bg-[#CCCCFF] border border-black p-6 rounded-lg mb-6">
      {editId && (
        <div className="mb-4 p-3 bg-blue-100 border border-blue-400 rounded text-sm text-blue-800">
          ℹ️ <strong>Bearbeitungsmodus:</strong> Sie bearbeiten einen bestehenden Eintrag.
        </div>
      )}
      
      <form onSubmit={handleSubmit}>
        <table className="w-full text-center"> 
          <thead>
            <tr >
              <th className="p-2 w-32">Datum</th>
              <th className="p-2">Wo</th>
              <th className="p-2">Was</th>
              <th className="p-2 w-24">Wieviel</th>
              <th className="p-2 w-4"></th>
              <th className="p-2 w-38 text-left">Wie</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td className="p-2 w-32">
                <input
                  type="date"
                  value={formData.Datum}
                  onChange={(e) => handleDateChange(e.target.value)}
                  className="w-full px-2 py-1 text-base rounded border-2 border-gray-400 bg-white focus:border-blue-500 focus:outline-none"
                  required
                />
              </td>
              <td className="p-2">
                <input
                  type="text"
                  value={formData.Wo}
                  onChange={(e) => setFormData({ ...formData, Wo: e.target.value })}
                  className="w-full px-2 py-1 text-base rounded border-2 border-gray-400 bg-white focus:border-blue-500 focus:outline-none"
                  placeholder="Geschäft/Ort"
                  required
                />
              </td>
              <td className="p-2">
                <input
                  type="text"
                  value={formData.Was}
                  onChange={(e) => setFormData({ ...formData, Was: e.target.value })}
                  className="w-full px-2 py-1 text-base rounded border-2 border-gray-400 bg-white focus:border-blue-500 focus:outline-none"
                  placeholder="Beschreibung"
                  required
                />
              </td>
              <td className="p-2 w-24">
                <input
                  type="number"
                  step="0.01"
                  value={formData.Wieviel}
                  onChange={(e) => setFormData({ ...formData, Wieviel: e.target.value })}
                  className="w-full px-2 py-1 text-base rounded border-2 border-gray-400 bg-white focus:border-blue-500 focus:outline-none [appearance:textfield] [&::-webkit-outer-spin-button]:appearance-none [&::-webkit-inner-spin-button]:appearance-none"
                  placeholder="0.00"
                  required
                />
              </td>
              <td className="p-2 w-4 text-left">€</td>
              <td className="p-2 w-38">
                <select
                  value={formData.Wie}
                  onChange={(e) => setFormData({ ...formData, Wie: e.target.value })}
                  className="w-full px-2 py-1 text-base rounded border-2 border-gray-400 bg-white focus:border-blue-500 focus:outline-none"
                  required
                >
                  {zahlungsarten.map((za) => (
                    <option key={za.value} value={za.value}>
                      {za.label}
                    </option>
                  ))}
                </select>
              </td>
            </tr>
          </tbody>
        </table>

        {/* Wochentag */}
        <div className="mt-3 text-left pl-3">
          <span className="font-semibold">{formData.WochTag}</span>
        </div>

        {/* Buttons */}
        <div className="mb-3 flex gap-10 justify-center">
          <button
            type="submit"
            disabled={isSubmitting}
            className="bg-[#85B7D7] hover:bg-[#6a9fc5] text-black font-medium py-2 px-8 rounded-lg transition-colors disabled:opacity-50"
          >
            {isSubmitting ? 'Speichere...' : editId ? 'Aktualisieren' : 'Speichern'}
          </button>
          <button
            type="button"
            onClick={handleReset}
            className="bg-[#85B7D7] hover:bg-[#6a9fc5] text-black font-medium py-2 px-8 rounded-lg transition-colors"
          >
            Löschen
          </button>
        </div>

        {/* Monatsstatistiken */}
        <div className="mt-6 pt-4 pb-6 -mb-6 border-t border-black -mx-6 px-6 bg-[#E0E0FF]">
          <div className="flex items-center justify-between pt-1">
            <div className="flex gap-4 items-center">
              <label className="font-semibold">Monat:</label>
              <select
                value={month}
                onChange={(e) => handleMonthChange(e.target.value)}
                className="border border-gray-400 rounded px-3 py-1"
              >
                <option value="01">Januar</option>
                <option value="02">Februar</option>
                <option value="03">März</option>
                <option value="04">April</option>
                <option value="05">Mai</option>
                <option value="06">Juni</option>
                <option value="07">Juli</option>
                <option value="08">August</option>
                <option value="09">September</option>
                <option value="10">Oktober</option>
                <option value="11">November</option>
                <option value="12">Dezember</option>
              </select>
              
              <label className="font-semibold">Jahr:</label>
              <input
                type="number"
                value={year}
                onChange={(e) => handleYearChange(e.target.value)}
                className="border border-gray-400 rounded px-3 py-1 w-24"
                min="2013"
                max="2099"
              />
            </div>

            <div>
              {isLoadingStats ? (
                <span>Lade...</span>
              ) : stats ? (
                <span className="font-bold text-lg">
                  Summe: {formatAmount(stats.totalAusgaben)}
                </span>
              ) : null}
            </div>
          </div>
        </div>
      </form>
    </div>
  );
}