'use client'

import { use, useState, useEffect } from 'react'
import { useRouter } from 'next/navigation'
import { trpc } from '@/lib/trpc-client'
import { getTrpcErrorMessage } from '@/lib/trpc-error'
import Link from 'next/link'
import dynamic from 'next/dynamic'

const MDEditor = dynamic(() => import('@uiw/react-md-editor'), { ssr: false })

const KATEGORIEN = [
  { value: 'Wichtig', label: 'Wichtig' },
  { value: 'Pruefung', label: 'Prüfung' },
  { value: 'Foerderung', label: 'Förderung' },
  { value: 'Veranstaltung', label: 'Veranstaltung' },
  { value: 'Allgemein', label: 'Allgemein' },
]

export default function NewsEditPage({ params }: { params: Promise<{ id: string }> }) {
  const { id } = use(params)
  const router = useRouter()

  const { data: news, isLoading } = trpc.news.byId.useQuery({ id })
  const updateMutation = trpc.news.update.useMutation({
    onSuccess: () => router.push('/dashboard/news'),
  })
  const deleteMutation = trpc.news.delete.useMutation({
    onSuccess: () => router.push('/dashboard/news'),
  })

  const [title, setTitle] = useState('')
  const [body, setBody] = useState('')
  const [kategorie, setKategorie] = useState('Allgemein')
  const [uploading, setUploading] = useState(false)
  const [attachments, setAttachments] = useState<
    Array<{ name: string; storagePath: string; sizeBytes: number; mimeType?: string | null }>
  >([])

  useEffect(() => {
    if (news) {
      setTitle(news.title)
      setBody(news.body)
      setKategorie(news.kategorie)
      if (news.attachments) {
        setAttachments(news.attachments.map((a: typeof news.attachments[number]) => ({ ...a, sizeBytes: a.sizeBytes ?? 0 })))
      }
    }
  }, [news])

  if (isLoading) return <div className="text-gray-500 text-sm">Wird geladen...</div>
  if (!news) return <div className="text-gray-500 text-sm">Beitrag nicht gefunden.</div>

  async function handleFileUpload(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0]
    if (!file) return
    setUploading(true)
    const formData = new FormData()
    formData.append('file', file)
    try {
      const res = await fetch('/api/upload', { method: 'POST', body: formData })
      const data = await res.json()
      setAttachments((prev) => [...prev, data])
    } catch {
      alert('Upload fehlgeschlagen')
    } finally {
      setUploading(false)
    }
  }

  function handleSave(publishNow: boolean) {
    if (!title.trim() || !body.trim()) return
    updateMutation.mutate({
      id,
      data: {
        title,
        body,
        kategorie: kategorie as never,
        publishedAt: publishNow ? new Date().toISOString() : undefined,
        attachments: attachments.map((a) => ({
          name: a.name,
          storagePath: a.storagePath,
          sizeBytes: a.sizeBytes,
          mimeType: a.mimeType || 'application/pdf',
        })),
      },
    })
  }

  function handleUnpublish() {
    updateMutation.mutate({ id, data: { publishedAt: null } })
  }

  const isPublished = !!news.publishedAt

  return (
    <div className="max-w-4xl space-y-6">
      <div className="flex items-center gap-3">
        <Link href="/dashboard/news" className="text-xs text-gray-400 hover:text-gray-600 uppercase tracking-wide">
          ← Zurück
        </Link>
        <span className="text-gray-200">/</span>
        <h1 className="text-2xl font-bold text-gray-900">Beitrag bearbeiten</h1>
        {isPublished && (
          <span className="text-[11px] font-medium bg-green-100 text-green-700 px-2 py-0.5 rounded-full">
            Publiziert
          </span>
        )}
        {!isPublished && (
          <span className="text-[11px] font-medium bg-gray-100 text-gray-500 px-2 py-0.5 rounded-full">
            Entwurf
          </span>
        )}
      </div>

      <div className="bg-white rounded-lg border p-6 space-y-4">
        <div className="grid grid-cols-3 gap-4">
          <div className="col-span-2">
            <label className="block text-xs font-medium text-gray-500 uppercase tracking-wide mb-1">Titel</label>
            <input
              value={title}
              onChange={(e) => setTitle(e.target.value)}
              placeholder="Titel..."
              className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-brand-500 focus:border-transparent"
            />
          </div>
          <div>
            <label className="block text-xs font-medium text-gray-500 uppercase tracking-wide mb-1">Kategorie</label>
            <select
              value={kategorie}
              onChange={(e) => setKategorie(e.target.value)}
              className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-brand-500 focus:border-transparent"
            >
              {KATEGORIEN.map((k) => (
                <option key={k.value} value={k.value}>{k.label}</option>
              ))}
            </select>
          </div>
        </div>

        <div>
          <label className="block text-xs font-medium text-gray-500 uppercase tracking-wide mb-1">Inhalt</label>
          <div data-color-mode="light">
            <MDEditor
              value={body}
              onChange={(v) => setBody(v ?? '')}
              height={400}
              preview="live"
            />
          </div>
        </div>

        {/* Attachments */}
        <div>
          <label className="block text-xs font-medium text-gray-500 uppercase tracking-wide mb-1">Anhänge (PDF)</label>
          <label className="cursor-pointer inline-flex items-center gap-2 px-4 py-2 border border-dashed border-gray-300 rounded-lg text-sm text-gray-500 hover:border-brand-500 hover:text-brand-500 transition-colors">
            {uploading ? '⏳ Hochladen...' : '📎 Datei anhängen'}
            <input
              type="file"
              accept=".pdf,image/*"
              onChange={handleFileUpload}
              disabled={uploading}
              className="hidden"
            />
          </label>
          {attachments.length > 0 && (
            <ul className="mt-2 space-y-1">
              {attachments.map((a, i) => (
                <li key={i} className="flex items-center gap-2 text-sm text-gray-600">
                  <span>📄</span>
                  <span>{a.name}</span>
                  {a.sizeBytes != null && (
                    <span className="text-gray-400">({Math.round(a.sizeBytes / 1024)} KB)</span>
                  )}
                  <button
                    onClick={() => setAttachments(prev => prev.filter((_, idx) => idx !== i))}
                    className="text-red-500 hover:text-red-700 ml-2"
                    title="Entfernen"
                  >
                    ×
                  </button>
                </li>
              ))}
            </ul>
          )}
        </div>

        {updateMutation.error && (
          <p className="text-sm text-red-600 bg-red-50 px-4 py-2 rounded-lg">
            {getTrpcErrorMessage(updateMutation.error)}
          </p>
        )}

        <div className="flex items-center justify-between pt-2 border-t">
          <div className="flex gap-3">
            {!isPublished && (
              <button
                onClick={() => handleSave(true)}
                disabled={updateMutation.isPending}
                className="bg-brand-500 text-white px-5 py-2 rounded-lg text-sm font-medium hover:bg-brand-600 disabled:opacity-60 transition-colors"
              >
                Publizieren
              </button>
            )}
            <button
              onClick={() => handleSave(false)}
              disabled={updateMutation.isPending}
              className="px-5 py-2 rounded-lg text-sm font-medium text-gray-700 border border-gray-200 hover:bg-gray-50 transition-colors"
            >
              {updateMutation.isPending ? 'Wird gespeichert...' : 'Speichern'}
            </button>
            {isPublished && (
              <button
                onClick={handleUnpublish}
                disabled={updateMutation.isPending}
                className="px-5 py-2 rounded-lg text-sm font-medium text-gray-500 hover:text-gray-700 hover:bg-gray-50 transition-colors"
              >
                Depublizieren
              </button>
            )}
          </div>
          <button
            onClick={() => {
              if (confirm('Beitrag wirklich löschen?')) deleteMutation.mutate({ id })
            }}
            disabled={deleteMutation.isPending}
            className="text-sm text-red-500 hover:text-red-700 transition-colors"
          >
            Löschen
          </button>
        </div>
      </div>
    </div>
  )
}