import React, { useState } from 'react';
import { Icon, Icons, Spinner, Text } from 'folds';
import { MatrixEvent, MsgType } from 'matrix-js-sdk';
import { BlurhashCanvas } from 'react-blurhash';
import { useMatrixClient } from '../../../hooks/useMatrixClient';
import { useMediaAuthentication } from '../../../hooks/useMediaAuthentication';
import { useDecryptedMediaUrl } from '../../../hooks/useDecryptedMediaUrl';
import { getThumbMxc } from '../../../utils/mediaThumb';
import { validBlurHash } from '../../../utils/blurHash';
import { MATRIX_BLUR_HASH_PROPERTY_NAME } from '../../../../types/matrix/common';
import * as css from './MediaGroupGrid.css';

/** Column count for `n` tiles: 2 → 2, 3 → 3, 4 → 2×2, 5–6 → 3, 7+ → 4. */
export const gridColumns = (n: number): number => {
  if (n <= 2) return 2;
  if (n === 3) return 3;
  if (n === 4) return 2;
  if (n <= 6) return 3;
  return 4;
};

/** "5 photos" / "2 videos" / "6 items". */
export const describeGroup = (events: MatrixEvent[]): string => {
  const videos = events.filter((e) => e.getContent().msgtype === MsgType.Video).length;
  const n = events.length;
  if (videos === 0) return `${n} photos`;
  if (videos === n) return `${n} videos`;
  return `${n} items`;
};

function Cell({
  mEvent,
  load,
  onOpen,
}: {
  mEvent: MatrixEvent;
  load: boolean;
  onOpen: (eventId: string) => void;
}) {
  const mx = useMatrixClient();
  const useAuthentication = useMediaAuthentication();
  const content = mEvent.getContent();
  const isVideo = content.msgtype === MsgType.Video;
  const thumbMxc = getThumbMxc(mEvent);
  const info = content.info as Record<string, unknown> | undefined;
  const encInfo = content.file
    ? ((info?.thumbnail_file as typeof content.file | undefined) ?? content.file)
    : undefined;
  const mimeType =
    (info?.thumbnail_info as { mimetype?: string } | undefined)?.mimetype ??
    (info?.mimetype as string | undefined);
  const blurHash = validBlurHash(info?.[MATRIX_BLUR_HASH_PROPERTY_NAME] as string | undefined);
  const media = useDecryptedMediaUrl(mx, thumbMxc, encInfo, useAuthentication, mimeType, load);
  const body = typeof content.body === 'string' ? content.body : '';

  return (
    <button
      type="button"
      className={css.Cell}
      aria-label={body || (isVideo ? 'Video' : 'Image')}
      onClick={() => onOpen(mEvent.getId() ?? '')}
    >
      {blurHash && media.status !== 'ok' && (
        <BlurhashCanvas className={css.CellBlur} hash={blurHash} width={32} height={32} punch={1} />
      )}
      {load && media.status === 'loading' && <Spinner size="200" />}
      {media.status === 'error' && <Icon src={isVideo ? Icons.Play : Icons.Photo} size="300" />}
      {!load && !blurHash && <Icon src={isVideo ? Icons.Play : Icons.Photo} size="300" />}
      {media.status === 'ok' && <img src={media.url} alt="" className={css.CellImg} />}
      {isVideo && (
        <span className={css.PlayBadge}>
          <Icon src={Icons.Play} size="200" filled />
        </span>
      )}
    </button>
  );
}

type MediaGroupGridProps = {
  events: MatrixEvent[];
  mediaAutoLoad: boolean;
  onOpen: (eventId: string) => void;
  onShowSeparately: () => void;
};

/**
 * [Gitea #137] Several consecutive image/video events from one sender shown
 * as one grid. Each tile opens the room's shared lightbox at that event, so
 * ←/→ walk through the group (and beyond). Purely a render-time grouping.
 */
export function MediaGroupGrid({
  events,
  mediaAutoLoad,
  onOpen,
  onShowSeparately,
}: MediaGroupGridProps) {
  const [load, setLoad] = useState(mediaAutoLoad);
  const columns = gridColumns(events.length);

  return (
    <div className={css.Wrap}>
      <div
        className={css.Grid}
        role="group"
        aria-label={describeGroup(events)}
        style={{ gridTemplateColumns: `repeat(${columns}, minmax(0, 1fr))` }}
        onClick={load ? undefined : () => setLoad(true)}
      >
        {events.map((ev) => (
          <Cell
            key={ev.getId()}
            mEvent={ev}
            load={load}
            onOpen={load ? onOpen : () => setLoad(true)}
          />
        ))}
      </div>
      <div className={css.Footer}>
        <Text size="T200" priority="300">
          {describeGroup(events)}
          {!load && ' · tap to load'}
        </Text>
        <Text size="T200" priority="300">
          ·
        </Text>
        <Text
          as="button"
          size="T200"
          priority="300"
          className={css.FooterButton}
          onClick={onShowSeparately}
        >
          Show separately
        </Text>
      </div>
    </div>
  );
}

/** Shown under the last of a gallery the user split up, to put it back together. */
export function RegroupChip({ onClick }: { onClick: () => void }) {
  return (
    <div className={css.Footer}>
      <Text as="button" size="T200" priority="300" className={css.FooterButton} onClick={onClick}>
        Show as gallery
      </Text>
    </div>
  );
}