'use client';

import { type ChangeEvent, useRef, useState } from 'react';
import { useTranslations } from 'next-intl';
import {
  PICTURE_FRAME_INTERVAL_OPTIONS,
  PICTURE_FRAME_MAX_IMAGES,
  type PictureFrameEntry,
  entryKey,
  isHttpsUrl,
  resolvePictureFrameConfig,
} from '@/components/dashboard/widgets/picture-frame-config';
import {
  dashboardImageSrc,
  deleteDashboardImage,
  uploadDashboardImage,
} from '@/lib/dashboard-images-api';

interface PictureFrameConfigFormProps {
  config: Record<string, unknown>;
  onChange: (partial: Record<string, unknown>) => void;
}

/**
 * Bildverwaltung des Bilderrahmen-Widgets im WidgetSettingsPanel
 * (quick-260921-pi9, Muster ClockConfig/FavoritesConfig).
 *
 * `onChange` bekommt bei Listenaenderungen IMMER das vollstaendige
 * `images`-Array: die API fuehrt Widget-Konfigurationen flach zusammen
 * (`{ ...alt, ...neu }`), ein Teil-Array wuerde die uebrigen Eintraege
 * ueberschreiben. Die drei Auswahlfelder senden dagegen nur ihr eines Feld.
 *
 * Kette Datei -> Server -> Config: Datei waehlen -> `uploadDashboardImage`
 * (POST /dashboard/images, Magic-Byte-Pruefung serverseitig) -> Antwort
 * `{ id }` -> `onChange({ images: [...alt, { kind: 'upload', imageId }] })`.
 * Entfernen eines Upload-Eintrags loescht das Bild auch auf dem Server
 * (best effort, Fehler verschluckt — der Eintrag verschwindet in jedem Fall
 * aus der Config).
 *
 * Webadressen: nur https (`isHttpsUrl`, echter URL-Parser) — dieselbe
 * Pruefung, die das Widget beim Rendern erneut anwendet (T-PI9-07). Die
 * Vorschau laedt der Browser direkt mit `referrerPolicy="no-referrer"`
 * (T-PI9-09); der Server ruft nie eine Adresse ab (T-PI9-05).
 */
export function PictureFrameConfigForm({ config, onChange }: PictureFrameConfigFormProps) {
  const t = useTranslations('widgets');
  const { images, fit, intervalSeconds, order } = resolvePictureFrameConfig(config);

  const fileInputRef = useRef<HTMLInputElement>(null);
  const [uploading, setUploading] = useState(false);
  const [uploadError, setUploadError] = useState<string | null>(null);
  const [urlDraft, setUrlDraft] = useState('');
  const [urlError, setUrlError] = useState(false);
  // Entwuerfe der Unterschriften je Eintragsschluessel; Uebernahme bei
  // Blur/Enter (Muster commitFontSize in ClockConfig).
  const [captionDrafts, setCaptionDrafts] = useState<Record<string, string>>({});
  const [brokenPreviews, setBrokenPreviews] = useState<string[]>([]);

  const limitReached = images.length >= PICTURE_FRAME_MAX_IMAGES;

  function setImages(next: PictureFrameEntry[]) {
    // Entwuerfe verwerfen: nach einer Listenaenderung gelten die Schluessel
    // (Index-Anteil bei URL-Eintraegen) nicht mehr zwingend fuer dieselbe Zeile.
    setCaptionDrafts({});
    onChange({ images: next });
  }

  async function handleFileChange(e: ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    // Auswahl zuruecksetzen, damit dieselbe Datei erneut waehlbar ist.
    e.target.value = '';
    if (!file || limitReached) return;
    setUploading(true);
    setUploadError(null);
    try {
      const meta = await uploadDashboardImage(file);
      setImages([...images, { kind: 'upload', imageId: meta.id }]);
    } catch (error) {
      setUploadError(error instanceof Error ? error.message : t('pictureFrame.uploadFailed'));
    } finally {
      setUploading(false);
    }
  }

  function handleAddUrl() {
    const url = urlDraft.trim();
    if (!isHttpsUrl(url)) {
      setUrlError(true);
      return;
    }
    setUrlError(false);
    setUrlDraft('');
    setImages([...images, { kind: 'url', url }]);
  }

  function handleRemove(index: number) {
    const entry = images[index];
    if (entry.kind === 'upload') {
      // Best effort: das Bild gehoert dem Benutzer, ein Fehler hier aendert
      // nichts daran, dass der Eintrag aus der Config verschwindet.
      deleteDashboardImage(entry.imageId).catch(() => undefined);
    }
    setImages(images.filter((_, i) => i !== index));
  }

  function handleMove(index: number, direction: 'up' | 'down') {
    const target = direction === 'up' ? index - 1 : index + 1;
    if (target < 0 || target >= images.length) return;
    const next = [...images];
    [next[index], next[target]] = [next[target], next[index]];
    setImages(next);
  }

  function commitCaption(index: number, key: string) {
    const draft = captionDrafts[key];
    if (draft === undefined) return;
    const trimmed = draft.trim();
    const current = images[index].caption ?? '';
    if (trimmed === current) return;
    const next = images.map((entry, i) => {
      if (i !== index) return entry;
      const { caption: _dropped, ...rest } = entry;
      return trimmed === '' ? rest : { ...rest, caption: trimmed };
    });
    setImages(next);
  }

  function intervalLabel(seconds: number): string {
    if (seconds === 0) return t('pictureFrame.intervalOff');
    if (seconds < 60) return t('pictureFrame.intervalSeconds', { n: seconds });
    return t('pictureFrame.intervalMinutes', { n: seconds / 60 });
  }

  const fieldClassName =
    'h-9 w-full max-w-xs rounded border border-border bg-background px-3 text-sm text-foreground';
  const iconButtonClassName =
    'rounded p-1 text-muted-foreground transition-colors hover:bg-muted hover:text-foreground disabled:opacity-40';

  return (
    <div className="space-y-4">
      {/* Bildausschnitt */}
      <div>
        <label htmlFor="picture-frame-fit" className="mb-1 block text-sm text-foreground">
          {t('pictureFrame.fitLabel')}
        </label>
        <select
          id="picture-frame-fit"
          className={fieldClassName}
          value={fit}
          onChange={(e) => onChange({ fit: e.target.value })}
        >
          <option value="contain">{t('pictureFrame.fitContain')}</option>
          <option value="cover">{t('pictureFrame.fitCover')}</option>
        </select>
      </div>

      {/* Wechselintervall */}
      <div>
        <label htmlFor="picture-frame-interval" className="mb-1 block text-sm text-foreground">
          {t('pictureFrame.intervalLabel')}
        </label>
        <select
          id="picture-frame-interval"
          className={fieldClassName}
          value={String(intervalSeconds)}
          onChange={(e) => onChange({ intervalSeconds: Number(e.target.value) })}
        >
          {PICTURE_FRAME_INTERVAL_OPTIONS.map((seconds) => (
            <option key={seconds} value={String(seconds)}>
              {intervalLabel(seconds)}
            </option>
          ))}
        </select>
      </div>

      {/* Reihenfolge */}
      <div>
        <label htmlFor="picture-frame-order" className="mb-1 block text-sm text-foreground">
          {t('pictureFrame.orderLabel')}
        </label>
        <select
          id="picture-frame-order"
          className={fieldClassName}
          value={order}
          onChange={(e) => onChange({ order: e.target.value })}
        >
          <option value="sequence">{t('pictureFrame.orderSequence')}</option>
          <option value="random">{t('pictureFrame.orderRandom')}</option>
        </select>
      </div>

      {/* Bilder */}
      <div>
        <p className="mb-1 block text-sm text-foreground">{t('pictureFrame.imagesLabel')}</p>
        {images.length > 0 && (
          <ul className="space-y-2" data-testid="picture-frame-list">
            {images.map((entry, index) => {
              const key = entryKey(entry, index);
              const src = entry.kind === 'upload' ? dashboardImageSrc(entry.imageId) : entry.url;
              const draft = captionDrafts[key] ?? entry.caption ?? '';
              return (
                <li key={key} className="flex items-center gap-2" data-testid="picture-frame-entry">
                  {brokenPreviews.includes(key) ? (
                    <span className="flex h-12 w-12 flex-shrink-0 items-center justify-center rounded bg-muted text-center text-[10px] leading-tight text-muted-foreground">
                      {t('pictureFrame.unavailable')}
                    </span>
                  ) : (
                    <img
                      src={src}
                      alt=""
                      aria-hidden="true"
                      width={48}
                      height={48}
                      loading="lazy"
                      referrerPolicy="no-referrer"
                      className="h-12 w-12 flex-shrink-0 rounded bg-muted object-cover"
                      data-testid="picture-frame-preview"
                      onError={() =>
                        setBrokenPreviews((prev) => (prev.includes(key) ? prev : [...prev, key]))
                      }
                    />
                  )}
                  <input
                    type="text"
                    aria-label={t('pictureFrame.captionPlaceholder')}
                    placeholder={t('pictureFrame.captionPlaceholder')}
                    value={draft}
                    onChange={(e) => setCaptionDrafts((prev) => ({ ...prev, [key]: e.target.value }))}
                    onBlur={() => commitCaption(index, key)}
                    onKeyDown={(e) => {
                      if (e.key === 'Enter') {
                        e.preventDefault();
                        commitCaption(index, key);
                      }
                    }}
                    className="h-9 min-w-0 flex-1 rounded border border-border bg-background px-3 text-sm text-foreground"
                  />
                  <button
                    type="button"
                    aria-label={t('pictureFrame.moveUpButton')}
                    disabled={index === 0}
                    onClick={() => handleMove(index, 'up')}
                    className={iconButtonClassName}
                  >
                    <ArrowIcon direction="up" />
                  </button>
                  <button
                    type="button"
                    aria-label={t('pictureFrame.moveDownButton')}
                    disabled={index === images.length - 1}
                    onClick={() => handleMove(index, 'down')}
                    className={iconButtonClassName}
                  >
                    <ArrowIcon direction="down" />
                  </button>
                  <button
                    type="button"
                    aria-label={t('pictureFrame.removeButton')}
                    onClick={() => handleRemove(index)}
                    className="rounded p-1 text-muted-foreground transition-colors hover:bg-muted hover:text-destructive"
                  >
                    <svg
                      aria-hidden="true"
                      xmlns="http://www.w3.org/2000/svg"
                      width="16"
                      height="16"
                      viewBox="0 0 24 24"
                      fill="none"
                      stroke="currentColor"
                      strokeWidth="2"
                      strokeLinecap="round"
                      strokeLinejoin="round"
                    >
                      <line x1="18" y1="6" x2="6" y2="18" />
                      <line x1="6" y1="6" x2="18" y2="18" />
                    </svg>
                  </button>
                </li>
              );
            })}
          </ul>
        )}

        {/* Hochladen */}
        <div className="mt-3 space-y-1">
          <input
            ref={fileInputRef}
            type="file"
            accept="image/png,image/jpeg,image/gif,image/webp"
            className="hidden"
            aria-label={t('pictureFrame.uploadButton')}
            data-testid="picture-frame-file-input"
            onChange={handleFileChange}
          />
          <button
            type="button"
            disabled={limitReached || uploading}
            onClick={() => fileInputRef.current?.click()}
            className="h-9 rounded border border-border bg-background px-3 text-sm text-foreground transition-colors hover:bg-muted disabled:opacity-50"
          >
            {t('pictureFrame.uploadButton')}
          </button>
          <p className="text-xs text-muted-foreground">{t('pictureFrame.uploadHint')}</p>
          {limitReached && (
            <p className="text-xs text-muted-foreground" data-testid="picture-frame-limit">
              {t('pictureFrame.limitReached')}
            </p>
          )}
          {uploadError && (
            <p role="alert" className="text-xs text-destructive">
              {uploadError}
            </p>
          )}
        </div>

        {/* Webadresse */}
        <div className="mt-3 space-y-1">
          <div className="flex gap-2">
            <input
              type="url"
              aria-label={t('pictureFrame.urlAddButton')}
              placeholder={t('pictureFrame.urlPlaceholder')}
              value={urlDraft}
              onChange={(e) => {
                setUrlDraft(e.target.value);
                setUrlError(false);
              }}
              onKeyDown={(e) => {
                if (e.key === 'Enter') {
                  e.preventDefault();
                  handleAddUrl();
                }
              }}
              disabled={limitReached}
              aria-invalid={urlError || undefined}
              className={fieldClassName}
            />
            <button
              type="button"
              disabled={limitReached}
              onClick={handleAddUrl}
              className="h-9 whitespace-nowrap rounded border border-border bg-background px-3 text-sm text-foreground transition-colors hover:bg-muted disabled:opacity-50"
            >
              {t('pictureFrame.urlAddButton')}
            </button>
          </div>
          {urlError && (
            <p role="alert" className="text-xs text-destructive">
              {t('pictureFrame.urlInvalid')}
            </p>
          )}
        </div>
      </div>
    </div>
  );
}

function ArrowIcon({ direction }: { direction: 'up' | 'down' }) {
  return (
    <svg
      aria-hidden="true"
      xmlns="http://www.w3.org/2000/svg"
      width="16"
      height="16"
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="2"
      strokeLinecap="round"
      strokeLinejoin="round"
    >
      {direction === 'up' ? <polyline points="18 15 12 9 6 15" /> : <polyline points="6 9 12 15 18 9" />}
    </svg>
  );
}