'use client'

import { useState, useEffect, useCallback } from 'react'
import { useTheme } from '@/lib/ThemeContext'
import { subjectsApi } from '@/lib/stundenplan/api'
import type { TimetableSubject, CreateTimetableSubject } from '@/app/stundenplan/types'

const initialForm: CreateTimetableSubject = {
  name: '',
  short_code: '',
  color: '#6366f1',
  is_main_subject: false,
  required_room_type: '',
}

export function FaecherManager() {
  const { isDark } = useTheme()
  const [items, setItems] = useState<TimetableSubject[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [showForm, setShowForm] = useState(false)
  const [submitting, setSubmitting] = useState(false)
  const [form, setForm] = useState<CreateTimetableSubject>(initialForm)

  const load = useCallback(async () => {
    setLoading(true); setError(null)
    try {
      const data = await subjectsApi.list()
      setItems(data || [])
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Laden fehlgeschlagen')
    } finally { setLoading(false) }
  }, [])

  useEffect(() => { load() }, [load])

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()
    setSubmitting(true); setError(null)
    try {
      await subjectsApi.create(form)
      setForm(initialForm)
      setShowForm(false)
      await load()
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Anlegen fehlgeschlagen')
    } finally { setSubmitting(false) }
  }

  const handleDelete = async (id: string) => {
    if (!confirm('Fach wirklich loeschen? Verbundene Stundentafel-Eintraege werden mitgeloescht.')) return
    try {
      await subjectsApi.remove(id)
      await load()
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Loeschen fehlgeschlagen')
    }
  }

  const cardClass = isDark ? 'bg-white/10 border-white/20 text-white' : 'bg-white/80 border-black/10 text-slate-900'
  const inputClass = isDark ? 'bg-white/10 border-white/20 text-white placeholder-white/40' : 'bg-white border-slate-300 text-slate-900 placeholder-slate-400'

  return (
    <div className="space-y-4" data-testid="faecher-manager">
      <div className="flex items-center justify-between">
        <h2 className={`text-xl font-semibold ${isDark ? 'text-white' : 'text-slate-900'}`}>Faecher ({items.length})</h2>
        <button onClick={() => setShowForm(s => !s)} className={`px-4 py-2 rounded-xl font-medium transition-colors ${isDark ? 'bg-indigo-500 hover:bg-indigo-600 text-white' : 'bg-indigo-600 hover:bg-indigo-700 text-white'}`}>
          {showForm ? 'Abbrechen' : '+ Neues Fach'}
        </button>
      </div>

      {error && <div className="p-3 rounded-xl bg-red-500/20 border border-red-500/40 text-red-300">{error}</div>}

      {showForm && (
        <form onSubmit={handleSubmit} className={`p-4 rounded-2xl border backdrop-blur-xl ${cardClass}`}>
          <div className="grid grid-cols-1 md:grid-cols-3 gap-3">
            <div>
              <label className="block text-sm mb-1 opacity-70">Name</label>
              <input required value={form.name} onChange={e => setForm({ ...form, name: e.target.value })} placeholder="z.B. Mathematik" className={`w-full px-3 py-2 rounded-lg border ${inputClass}`} />
            </div>
            <div>
              <label className="block text-sm mb-1 opacity-70">Kuerzel</label>
              <input required maxLength={10} value={form.short_code} onChange={e => setForm({ ...form, short_code: e.target.value.toUpperCase() })} placeholder="z.B. M" className={`w-full px-3 py-2 rounded-lg border ${inputClass}`} />
            </div>
            <div>
              <label className="block text-sm mb-1 opacity-70">Farbe</label>
              <input type="color" value={form.color || '#6366f1'} onChange={e => setForm({ ...form, color: e.target.value })} className="w-full h-10 rounded-lg border cursor-pointer" />
            </div>
            <div>
              <label className="block text-sm mb-1 opacity-70">Benoetigter Raumtyp (optional)</label>
              <input value={form.required_room_type || ''} onChange={e => setForm({ ...form, required_room_type: e.target.value })} placeholder="z.B. Sporthalle" className={`w-full px-3 py-2 rounded-lg border ${inputClass}`} />
            </div>
            <div className="flex items-center gap-2">
              <input type="checkbox" id="is_main" checked={!!form.is_main_subject} onChange={e => setForm({ ...form, is_main_subject: e.target.checked })} className="w-5 h-5" />
              <label htmlFor="is_main" className="text-sm">Hauptfach</label>
            </div>
            <div className="flex items-end">
              <button type="submit" disabled={submitting} className="w-full px-4 py-2 rounded-lg bg-emerald-500 hover:bg-emerald-600 text-white font-medium disabled:opacity-50">
                {submitting ? 'Speichert...' : 'Anlegen'}
              </button>
            </div>
          </div>
        </form>
      )}

      {loading ? (
        <div className={`text-center py-8 opacity-60 ${isDark ? 'text-white' : 'text-slate-700'}`}>Laedt…</div>
      ) : items.length === 0 ? (
        <div className={`text-center py-8 opacity-60 ${isDark ? 'text-white' : 'text-slate-700'}`}>Noch keine Faecher angelegt.</div>
      ) : (
        <div className={`rounded-2xl border backdrop-blur-xl overflow-hidden ${cardClass}`}>
          <table className="w-full">
            <thead className={isDark ? 'bg-white/5' : 'bg-slate-100'}>
              <tr>
                <th className="text-left px-4 py-3 text-sm font-medium opacity-70">Farbe</th>
                <th className="text-left px-4 py-3 text-sm font-medium opacity-70">Name</th>
                <th className="text-left px-4 py-3 text-sm font-medium opacity-70">Kuerzel</th>
                <th className="text-left px-4 py-3 text-sm font-medium opacity-70">Hauptfach</th>
                <th className="text-left px-4 py-3 text-sm font-medium opacity-70">Raumtyp</th>
                <th className="px-4 py-3"></th>
              </tr>
            </thead>
            <tbody>
              {items.map(s => (
                <tr key={s.id} className={isDark ? 'border-t border-white/10' : 'border-t border-slate-200'}>
                  <td className="px-4 py-3"><span className="inline-block w-5 h-5 rounded" style={{ backgroundColor: s.color || '#94a3b8' }} /></td>
                  <td className="px-4 py-3 font-medium">{s.name}</td>
                  <td className="px-4 py-3">{s.short_code}</td>
                  <td className="px-4 py-3">{s.is_main_subject ? 'Ja' : '—'}</td>
                  <td className="px-4 py-3 text-sm opacity-70">{s.required_room_type || '—'}</td>
                  <td className="px-4 py-3 text-right">
                    <button onClick={() => handleDelete(s.id)} className="text-red-400 hover:text-red-300 text-sm">Loeschen</button>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      )}
    </div>
  )
}
