import React, { useCallback, useRef, useState } from 'react';
import FocusTrap from 'focus-trap-react';
import { useAtom } from 'jotai';
import { Grid, SearchBar, SearchContext, SearchContextManager } from '@giphy/react-components';
import { IGif } from '@giphy/js-types';
import { Box, color, config } from 'folds';
import { TapToSendBar } from './tap-to-send/TapToSendBar';
import { useRecentTouch } from '../hooks/useRecentTouch';
import { useElementSizeObserver } from '../hooks/useElementSizeObserver';
import { useSetting } from '../state/hooks/settings';
import { settingsAtom } from '../state/settings';
import { addRecentGif, RecentGif, recentGifsAtom } from '../state/recentGifs';

const PICKER_WIDTH = 312;
const PICKER_WIDTH_CSS = `min(${PICKER_WIDTH}px, calc(100vw - 16px))`;

type GifPickerInnerProps = {
  onSelect: (url: string, width: number, height: number) => void;
  requestClose: () => void;
  lotusTerminal: boolean;
};

// Small monospace section header matching the picker's `// GIF_SEARCH` treatment
// (lotusTerminal) / a muted label otherwise.
const RECENT_LABEL_ID = 'gif-picker-recent-label';

function SectionLabel({
  text,
  lotusTerminal,
  id,
}: {
  text: string;
  lotusTerminal: boolean;
  id?: string;
}) {
  if (lotusTerminal) {
    return (
      <div
        id={id}
        style={{
          padding: '4px 2px',
          fontFamily: "'JetBrains Mono', 'Cascadia Code', monospace",
          fontSize: '10px',
          fontWeight: 700,
          letterSpacing: '0.1em',
          color: 'var(--lt-accent-orange)',
          userSelect: 'none',
        }}
      >
        {`// ${text.toUpperCase()}`}
      </div>
    );
  }
  return (
    <div
      id={id}
      style={{
        padding: '2px 2px 4px',
        fontSize: '11px',
        fontWeight: 600,
        color: color.Surface.OnContainer,
        opacity: 0.6,
        userSelect: 'none',
      }}
    >
      {text}
    </div>
  );
}

function RecentGifs({
  recents,
  lotusTerminal,
  onPick,
}: {
  recents: RecentGif[];
  lotusTerminal: boolean;
  onPick: (gif: RecentGif) => void;
}) {
  return (
    <div style={{ marginBottom: 8 }}>
      <SectionLabel text="Recent" lotusTerminal={lotusTerminal} id={RECENT_LABEL_ID} />
      <div
        role="group"
        aria-labelledby={RECENT_LABEL_ID}
        style={{ display: 'grid', gridTemplateColumns: 'repeat(3, 1fr)', gap: 4 }}
      >
        {recents.map((g, i) => (
          <button
            key={g.url}
            type="button"
            aria-label={`Send recent GIF ${i + 1} of ${recents.length}`}
            onClick={() => onPick(g)}
            style={{
              padding: 0,
              border: 'none',
              background: 'transparent',
              cursor: 'pointer',
              height: 72,
              borderRadius: lotusTerminal ? '4px' : '8px',
              overflow: 'hidden',
            }}
          >
            {/* A still preview (falls back to the animated url for pre-existing
                recents) so the Recent row doesn't autoplay many GIFs at once. */}
            <img
              src={g.previewUrl ?? g.url}
              alt=""
              loading="lazy"
              style={{ width: '100%', height: '100%', objectFit: 'cover', display: 'block' }}
            />
          </button>
        ))}
      </div>
    </div>
  );
}

function GifPickerInner({ onSelect, requestClose, lotusTerminal }: GifPickerInnerProps) {
  const { fetchGifs, searchKey, term } = React.useContext(SearchContext);
  const [recents, setRecents] = useAtom(recentGifsAtom);

  const sendGif = useCallback(
    (gif: RecentGif) => {
      const { url, width, height, previewUrl } = gif;
      setRecents((prev) => addRecentGif(prev, { url, width, height, previewUrl }));
      onSelect(gif.url, gif.width, gif.height);
      requestClose();
    },
    [onSelect, requestClose, setRecents],
  );

  // [Gitea #147] Touch: first tap parks the GIF in a preview bar, second tap
  // (or Send) sends. Mouse/keyboard/screen reader: one step, as before.
  const containerRef = useRef<HTMLDivElement>(null);
  const { wasTouch } = useRecentTouch(containerRef);
  const [pending, setPending] = useState<(RecentGif & { title?: string }) | undefined>();
  const pick = useCallback(
    (gif: RecentGif & { title?: string }) => {
      if (wasTouch() && pending?.url !== gif.url) {
        setPending(gif);
        return;
      }
      setPending(undefined);
      sendGif(gif);
    },
    [wasTouch, pending, sendGif],
  );

  const handleClick = useCallback(
    (gif: IGif, e: React.SyntheticEvent) => {
      e.preventDefault();
      const r = gif.images.downsized ?? gif.images.original;
      const previewUrl =
        gif.images.fixed_width_small_still?.url ??
        gif.images.downsized_still?.url ??
        gif.images.original_still?.url;
      pick({
        url: r.url,
        width: Number(r.width) || 200,
        height: Number(r.height) || 200,
        previewUrl,
        title: gif.title,
      });
    },
    [pick],
  );

  const showRecents = recents.length > 0 && !(term ?? '').trim();

  // The container is min(312px, 100vw-16); feed the Grid the live pixel width
  // (minus the inner 8px padding on each side) so it doesn't overflow a phone
  // narrower than 312px with a fixed 296px grid.
  const [gridWidth, setGridWidth] = useState(PICKER_WIDTH - 16);
  useElementSizeObserver(
    useCallback(() => containerRef.current, []),
    useCallback((w) => setGridWidth(Math.max(1, Math.floor(w) - 16)), []),
  );

  return (
    <Box direction="Column" style={{ width: PICKER_WIDTH_CSS }} ref={containerRef}>
      {lotusTerminal && (
        <div
          style={{
            padding: '5px 10px 4px',
            borderBottom: '1px solid color-mix(in srgb, var(--lt-accent-orange) 20%, transparent)',
            fontFamily: "'JetBrains Mono', 'Cascadia Code', monospace",
            fontSize: '10px',
            fontWeight: 700,
            letterSpacing: '0.1em',
            color: 'var(--lt-accent-orange)',
            userSelect: 'none',
          }}
        >
          {'// GIF_SEARCH'}
        </div>
      )}
      <Box style={{ padding: '8px 8px 4px' }}>
        <div style={{ width: '100%', borderRadius: lotusTerminal ? '4px' : '8px' }}>
          <SearchBar />
        </div>
      </Box>
      {pending && (
        <TapToSendBar
          previewUrl={pending.previewUrl ?? pending.url}
          label={pending.title || 'GIF'}
          onSend={() => {
            setPending(undefined);
            sendGif(pending);
          }}
          onCancel={() => setPending(undefined)}
        />
      )}
      <div
        style={{ overflowY: 'auto', overflowX: 'hidden', maxHeight: '340px', padding: '0 8px 8px' }}
      >
        {showRecents && (
          <RecentGifs recents={recents} lotusTerminal={lotusTerminal} onPick={pick} />
        )}
        <Grid
          key={searchKey}
          fetchGifs={fetchGifs}
          width={gridWidth}
          columns={2}
          gutter={4}
          onGifClick={handleClick}
          hideAttribution={false}
          noLink
        />
      </div>
    </Box>
  );
}

type GifPickerProps = {
  apiKey: string;
  onSelect: (url: string, width: number, height: number) => void;
  requestClose: () => void;
};

export function GifPicker({ apiKey, onSelect, requestClose }: GifPickerProps) {
  const [lotusTerminal] = useSetting(settingsAtom, 'lotusTerminal');
  const [gifPickerEnabled] = useSetting(settingsAtom, 'gifPickerEnabled');

  // Searches (and every keystroke) go straight to Giphy's API, so the picker
  // is opt-in (Settings → Messages) and must not render or fetch until then.
  if (!gifPickerEnabled) {
    return null;
  }

  const containerStyle = lotusTerminal
    ? {
        background: 'var(--lt-bg-secondary)',
        border: '1px solid color-mix(in srgb, var(--lt-accent-orange) 35%, transparent)',
        borderRadius: '4px',
        overflow: 'hidden',
        boxShadow:
          '0 4px 24px color-mix(in srgb, var(--lt-accent-orange) 10%, transparent), 0 0 0 1px color-mix(in srgb, var(--lt-accent-orange) 8%, transparent)',
        width: PICKER_WIDTH_CSS,
      }
    : {
        background: color.Surface.Container,
        border: `${config.borderWidth.B300} solid ${color.Surface.ContainerLine}`,
        borderRadius: config.radii.R400,
        overflow: 'hidden',
        boxShadow: color.Other.Shadow,
        width: PICKER_WIDTH_CSS,
      };

  return (
    <FocusTrap
      focusTrapOptions={{
        initialFocus: false,
        returnFocusOnDeactivate: true,
        onDeactivate: requestClose,
        clickOutsideDeactivates: true,
        allowOutsideClick: true,
      }}
    >
      <Box
        direction="Column"
        data-gif-terminal={lotusTerminal ? '' : undefined}
        style={containerStyle}
      >
        <SearchContextManager apiKey={apiKey} initialTerm="">
          <GifPickerInner
            onSelect={onSelect}
            requestClose={requestClose}
            lotusTerminal={!!lotusTerminal}
          />
        </SearchContextManager>
      </Box>
    </FocusTrap>
  );
}