/**
 * PhotoGrid — client component wrapping the masonry grid and lightbox.
 * Handles image click → lightbox open, keyboard nav, and EXIF fetching.
 *
 * Deep-link support: syncs the lightbox with `?photo=<assetId>`, a stable
 * per-photo id rather than a position, so reordering or deleting other
 * photos in the album does not repoint an already-shared link (#588). A
 * legacy `#photo-N` hash is still read on the initial load — those links
 * have been shared for months — but the grid never writes that form again.
 */

'use client';

import { useState, useCallback, useEffect, useMemo } from 'react';
import Image from 'next/image';
import { Lightbox, type LightboxWatermark } from '@/components/Lightbox';
import { FadeIn } from '@/components/FadeIn';
import { ProofingProvider, useProofing } from '@/components/ProofingContext';
import { ProofingModal } from '@/components/ProofingModal';
import { useDictionary } from '@/components/I18nProvider';
import { parsePhotoHash, parsePhotoQuery, buildPhotoQuery } from '@/lib/photoHash';

export interface PhotoItem {
  id: string;
  type: 'image' | 'video';
  thumbUrl: string;
  previewUrl: string;
  videoUrl?: string;
  exifUrl: string;
  blurDataURL?: string;
  dominantColor?: string;
  /** Compact EXIF summary for hover overlay */
  camera?: string;
  lens?: string;
  focalLength?: string;
  /** Natural image aspect ratio (width/height) for masonry layout */
  aspectRatio?: number;
  /** Immich asset description, used as alt text. Absent when captions are off. */
  caption?: string;
  /** Present only when the surrounding album offers its originals (#475). */
  downloadUrl?: string;
}

interface PhotoGridProps {
  assets: PhotoItem[];
  layout?:
    'masonry' | 'uniform' | 'showcase' | 'filmstrip' | 'editorial-flow' | 'essay' | 'justified';
  gridStyle?: React.CSSProperties;
  watermark?: LightboxWatermark;
  /**
   * Offer the lightbox info panel. Off when every EXIF group is switched off,
   * so the `i` key does not open an empty panel (#506).
   */
  showExifPanel?: boolean;
  /**
   * Client proofing — favorite hearts, the selection bar and the send-off
   * modal. Off unless the caller opts in, so a grid rendered outside the
   * album routes never grows a delivery workflow by accident.
   */
  proofing?: boolean;
  /** Offer the "send by email" button in the proofing modal. */
  allowMailto?: boolean;
  /**
   * The ZIP endpoint for this album, when it offers downloads. Lets the
   * proofing modal offer a "download selected" action (#475).
   */
  downloadArchiveUrl?: string;
  /**
   * The album's display name. Scopes the proofing favourites to this album —
   * without it every album shares the provider's default storage key, so a
   * selection made in one album leaks into the next.
   */
  albumName?: string;
}

function PhotoGridInner({
  assets,
  layout = 'masonry',
  gridStyle,
  watermark,
  showExifPanel = true,
}: PhotoGridProps) {
  const t = useDictionary();
  const proofing = useProofing();
  const [lightboxIndex, setLightboxIndex] = useState<number | null>(null);

  const displayedAssets = useMemo(() => {
    if (proofing && proofing.isFilterActive) {
      return assets.filter((a) => proofing.isFavorite(a.id));
    }
    return assets;
  }, [assets, proofing]);

  // ── Initial deep-link check (client-only to avoid hydration mismatch) ──
  // ?photo=<assetId> wins when present; #photo-N is read only as a fallback,
  // for a link shared before this format existed.
  useEffect(() => {
    const token = parsePhotoQuery(window.location.search);
    const byToken = token ? displayedAssets.findIndex((a) => a.id === token) : -1;
    if (byToken >= 0) {
      // eslint-disable-next-line react-hooks/set-state-in-effect
      setLightboxIndex(byToken);
      return;
    }
    const idx = parsePhotoHash(window.location.hash);
    if (idx !== null && idx < displayedAssets.length) {
      setLightboxIndex(idx);
    }
  }, [displayedAssets]);

  // ── Sync the URL's `photo` param when the lightbox state changes ──
  useEffect(() => {
    const assetId =
      lightboxIndex !== null && lightboxIndex < displayedAssets.length
        ? displayedAssets[lightboxIndex].id
        : null;
    if (assetId === null) return;
    const query = buildPhotoQuery(window.location.search, assetId);
    // Building the full URL (not just the search string) drops any leftover
    // #photo-N hash from a legacy link this page was opened with.
    const url = window.location.pathname + query;
    if (window.location.pathname + window.location.search !== url || window.location.hash) {
      window.history.replaceState(null, '', url);
    }
  }, [lightboxIndex, displayedAssets]);

  // ── Listen for browser back/forward ────────────────────────────
  useEffect(() => {
    const handlePopState = () => {
      const token = parsePhotoQuery(window.location.search);
      const byToken = token ? displayedAssets.findIndex((a) => a.id === token) : -1;
      setLightboxIndex(byToken >= 0 ? byToken : null);
    };

    window.addEventListener('popstate', handlePopState);
    return () => window.removeEventListener('popstate', handlePopState);
  }, [displayedAssets]);

  const openLightbox = useCallback(
    (index: number) => {
      setLightboxIndex(index);
      const asset = displayedAssets[index];
      if (asset) {
        window.history.pushState(
          null,
          '',
          window.location.pathname + buildPhotoQuery(window.location.search, asset.id),
        );
      }
    },
    [displayedAssets],
  );

  const closeLightbox = useCallback(() => {
    setLightboxIndex(null);
    window.history.pushState(
      null,
      '',
      window.location.pathname + buildPhotoQuery(window.location.search, null),
    );
  }, []);

  const goNext = useCallback(() => {
    setLightboxIndex((prev) => (prev !== null ? (prev + 1) % displayedAssets.length : null));
  }, [displayedAssets.length]);

  const goPrev = useCallback(() => {
    setLightboxIndex((prev) =>
      prev !== null ? (prev - 1 + displayedAssets.length) % displayedAssets.length : null,
    );
  }, [displayedAssets.length]);

  // Keyboard navigation and the scroll lock live in <Lightbox/>.

  const gridItems = useMemo(() => {
    return displayedAssets.map((asset, index) => {
      const isFav = proofing ? proofing.isFavorite(asset.id) : false;

      // Justified rows: the flex sizing must sit on the outermost grid child,
      // which is the FadeIn wrapper — not the .photo-grid__item inside it.
      // Aspect ratio drives both grow factor and basis; ~3:2 fallback for
      // assets without dimensions (e.g. videos) keeps the row math sane.
      const justifiedAr = asset.aspectRatio || 1.5;
      const justifiedStyle: React.CSSProperties | undefined =
        layout === 'justified'
          ? {
              flexGrow: justifiedAr,
              flexBasis: `calc(var(--grid-row-height, 300px) * ${justifiedAr})`,
            }
          : undefined;

      return (
        <FadeIn key={asset.id} delay={index < 12 ? index * 50 : 0} style={justifiedStyle}>
          <div
            className={`photo-grid__item${
              layout === 'showcase' && index === 0 ? ' photo-grid__featured' : ''
            }`}
            onClick={() => openLightbox(index)}
            onKeyDown={(e) => {
              if (e.key === 'Enter' || e.key === ' ') {
                e.preventDefault();
                openLightbox(index);
              }
            }}
            role="button"
            tabIndex={0}
            aria-label={t.lightbox.openPhoto(index + 1)}
            aria-haspopup="dialog"
            style={{
              ...(asset.dominantColor ? { backgroundColor: asset.dominantColor } : {}),
              ...((layout === 'masonry' || layout === 'showcase') && asset.aspectRatio
                ? { aspectRatio: `${asset.aspectRatio}` }
                : {}),
              position: 'relative',
            }}
          >
            <Image
              src={asset.thumbUrl}
              alt={asset.caption ?? ''}
              fill
              sizes="(max-width: 600px) 50vw, (max-width: 1000px) 33vw, 25vw"
              loading={index < 6 ? 'eager' : 'lazy'}
              {...(asset.blurDataURL
                ? { placeholder: 'blur' as const, blurDataURL: asset.blurDataURL }
                : {})}
            />

            {proofing && (
              <button
                type="button"
                className="photo-grid__fav-btn"
                onClick={(e) => {
                  e.stopPropagation();
                  proofing.toggleFavorite(asset.id);
                }}
                aria-label={isFav ? t.proofing.removeFavorite : t.proofing.addFavorite}
                title={isFav ? t.proofing.removeFavorite : t.proofing.addFavorite}
                style={{
                  position: 'absolute',
                  top: '8px',
                  right: '8px',
                  zIndex: 5,
                  width: '44px',
                  height: '44px',
                  display: 'flex',
                  alignItems: 'center',
                  justifyContent: 'center',
                  background: 'none',
                  border: 'none',
                  cursor: 'pointer',
                  color: isFav ? '#ff4d4f' : 'rgba(255,255,255,0.85)',
                  filter: 'drop-shadow(0 2px 4px rgba(0,0,0,0.6))',
                  padding: 0,
                }}
              >
                <svg
                  viewBox="0 0 24 24"
                  width="24"
                  height="24"
                  fill={isFav ? 'currentColor' : 'none'}
                  stroke="currentColor"
                  strokeWidth="2"
                >
                  <path d="M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z" />
                </svg>
              </button>
            )}

            {asset.type === 'video' && (
              <div className="photo-grid__item-play" aria-hidden="true">
                <svg viewBox="0 0 24 24" fill="currentColor">
                  <circle cx="12" cy="12" r="12" fillOpacity="0.55" />
                  <polygon points="10,8 10,16 17,12" fill="white" />
                </svg>
              </div>
            )}
            {(asset.camera || asset.lens) && (
              <div className="photo-grid__item-exif" aria-hidden="true">
                {[asset.camera, asset.lens, asset.focalLength].filter(Boolean).join(' · ')}
              </div>
            )}
          </div>
        </FadeIn>
      );
    });
  }, [displayedAssets, layout, openLightbox, proofing, t]);

  return (
    <>
      <div className={`photo-grid photo-grid--${layout}`} style={gridStyle}>
        {gridItems}
      </div>

      {proofing && proofing.favorites.size > 0 && (
        <div
          className="proofing-sticky-bar"
          style={{
            position: 'fixed',
            bottom: '24px',
            right: '24px',
            zIndex: 990,
            display: 'flex',
            alignItems: 'center',
            gap: '12px',
            padding: '8px 16px',
            borderRadius: '30px',
            background: 'var(--bg-card, #1e1e1e)',
            color: 'var(--text-primary, #ffffff)',
            border: '1px solid var(--border-subtle, rgba(255,255,255,0.15))',
            boxShadow: '0 8px 24px rgba(0,0,0,0.4)',
            backdropFilter: 'blur(8px)',
          }}
        >
          <button
            type="button"
            onClick={() => proofing.setIsFilterActive((prev) => !prev)}
            style={{
              background: proofing.isFilterActive
                ? 'var(--accent, #e60012)'
                : 'var(--bg-card-hover)',
              color: proofing.isFilterActive ? 'var(--on-accent, #fff)' : 'var(--text-primary)',
              border: 'none',
              padding: '6px 14px',
              borderRadius: '20px',
              fontSize: '0.85rem',
              fontWeight: 500,
              cursor: 'pointer',
            }}
          >
            {proofing.isFilterActive
              ? t.proofing.showAll
              : t.proofing.selected(proofing.favorites.size)}
          </button>
          <button
            type="button"
            onClick={() => proofing.setIsModalOpen(true)}
            style={{
              background: 'none',
              border: 'none',
              color: 'inherit',
              fontSize: '0.85rem',
              fontWeight: 500,
              cursor: 'pointer',
              textDecoration: 'underline',
            }}
          >
            {t.proofing.shareExport}
          </button>
        </div>
      )}

      {proofing && <ProofingModal />}

      {lightboxIndex !== null && (
        <Lightbox
          assets={displayedAssets}
          currentIndex={lightboxIndex}
          onClose={closeLightbox}
          onNext={goNext}
          onPrev={goPrev}
          watermark={watermark}
          showExifToggle={showExifPanel}
        />
      )}
    </>
  );
}

export function PhotoGrid(props: PhotoGridProps) {
  const albumTokens = useMemo(() => props.assets.map((a) => a.id), [props.assets]);

  // Without the provider useProofing() returns null, and every proofing control
  // (hearts in the grid and in the lightbox, selection bar, modal) drops out on
  // its own.
  if (!props.proofing) {
    return <PhotoGridInner {...props} />;
  }

  return (
    <ProofingProvider
      albumTokens={albumTokens}
      albumName={props.albumName}
      allowMailto={props.allowMailto ?? true}
      downloadArchiveUrl={props.downloadArchiveUrl}
    >
      <PhotoGridInner {...props} />
    </ProofingProvider>
  );
}