import React, { useEffect, useMemo, useRef, useState } from 'react';

import { ipcChannels } from '../../shared/ipc/contracts';
import {
  clampSceneAudioVolume,
  type AssetId,
  type MediaAsset,
  type SceneAudioRef,
} from '../../shared/types';
import { getDndApi } from '../shared/dndApi';
import { useEditorI18n } from './i18n/EditorI18nContext';
import { registerEditorAudioStopper } from '../shared/audio/editorAudioStop';

import styles from './EditorApp.module.css';

const AUDIO_REF_DND = 'application/x-dnd-scene-audio-ref';

function reorderRefs(refs: SceneAudioRef[], draggedId: AssetId, targetId: AssetId): SceneAudioRef[] {
  if (draggedId === targetId) return refs;
  const from = refs.findIndex((r) => r.assetId === draggedId);
  const to = refs.findIndex((r) => r.assetId === targetId);
  if (from < 0 || to < 0) return refs;
  const next = [...refs];
  const [item] = next.splice(from, 1);
  if (!item) return refs;
  next.splice(to, 0, item);
  return next;
}

/** Локальный draft — не пишет в проект на каждый tick ползунка (иначе мигает граф). */
function AudioVolumeSlider({
  assetId,
  volume,
  isPlaying,
  previewElRef,
  label,
  onCommit,
}: {
  assetId: AssetId;
  volume: number;
  isPlaying: boolean;
  previewElRef: React.MutableRefObject<HTMLAudioElement | null>;
  label: string;
  onCommit: (volume: number) => void;
}) {
  const [draft, setDraft] = useState(() => clampSceneAudioVolume(volume));
  const draftRef = useRef(draft);
  draftRef.current = draft;

  useEffect(() => {
    setDraft(clampSceneAudioVolume(volume));
  }, [assetId, volume]);

  const applyLocal = (v: number) => {
    const next = clampSceneAudioVolume(v);
    setDraft(next);
    if (isPlaying && previewElRef.current) previewElRef.current.volume = next;
  };

  const commit = () => {
    const next = clampSceneAudioVolume(draftRef.current);
    if (next === clampSceneAudioVolume(volume)) return;
    onCommit(next);
  };

  return (
    <label className={styles.audioVolumeLabel} title={label}>
      <span className={styles.spanXs}>{label}</span>
      <input
        type="range"
        className={styles.audioVolumeRange}
        min={0}
        max={1}
        step={0.01}
        value={draft}
        aria-label={label}
        onChange={(e) => applyLocal(Number(e.target.value))}
        onPointerUp={commit}
        onBlur={commit}
        onKeyUp={(e) => {
          if (e.key === 'ArrowLeft' || e.key === 'ArrowRight' || e.key === 'Home' || e.key === 'End') {
            commit();
          }
        }}
      />
    </label>
  );
}

export type EditorAudioTrackListProps = {
  audioRefs: SceneAudioRef[];
  mediaAssets: MediaAsset[];
  removeTitle: string;
  onAudioRefsChange: (next: SceneAudioRef[]) => void;
};

export function EditorAudioTrackList({
  audioRefs,
  mediaAssets,
  removeTitle,
  onAudioRefsChange,
}: EditorAudioTrackListProps) {
  const { t } = useEditorI18n();
  const assetById = useMemo(() => new Map(mediaAssets.map((a) => [a.id, a])), [mediaAssets]);
  const [playingId, setPlayingId] = useState<AssetId | null>(null);
  const previewElRef = useRef<HTMLAudioElement | null>(null);

  useEffect(() => {
    return () => {
      const el = previewElRef.current;
      if (el) {
        el.pause();
        el.src = '';
        previewElRef.current = null;
      }
    };
  }, []);

  useEffect(() => {
    return registerEditorAudioStopper(() => {
      const el = previewElRef.current;
      if (el) {
        el.pause();
        el.onended = null;
        el.src = '';
      }
      previewElRef.current = null;
      setPlayingId(null);
    });
  }, []);

  const stopPreview = () => {
    const el = previewElRef.current;
    if (el) {
      el.pause();
      el.onended = null;
      el.src = '';
    }
    previewElRef.current = null;
    setPlayingId(null);
  };

  const togglePreview = async (assetId: AssetId, volume: number) => {
    if (playingId === assetId) {
      stopPreview();
      return;
    }
    stopPreview();
    try {
      const r = await getDndApi().invoke(ipcChannels.project.assetFileUrl, { assetId });
      const url = r.url;
      if (!url) return;
      const el = new Audio(url);
      el.volume = clampSceneAudioVolume(volume);
      el.onended = () => {
        previewElRef.current = null;
        setPlayingId(null);
      };
      previewElRef.current = el;
      setPlayingId(assetId);
      await el.play();
    } catch {
      stopPreview();
    }
  };

  if (audioRefs.length === 0) {
    return (
      <div className={[styles.muted, styles.spanSm].join(' ')}>{t('campaign.noFiles')}</div>
    );
  }

  return (
    <div className={styles.audioList}>
      {audioRefs.map((ref) => {
        const asset = assetById.get(ref.assetId);
        const name = asset?.originalName ?? ref.assetId;
        const volume = clampSceneAudioVolume(ref.volume);
        const isPlaying = playingId === ref.assetId;
        return (
          <div
            key={ref.assetId}
            className={styles.audioRow}
            onDragOver={(e) => {
              if (e.dataTransfer.types.includes(AUDIO_REF_DND)) e.preventDefault();
            }}
            onDrop={(e) => {
              e.preventDefault();
              e.stopPropagation();
              const dragged = e.dataTransfer.getData(AUDIO_REF_DND) as AssetId;
              if (!dragged) return;
              const next = reorderRefs(audioRefs, dragged, ref.assetId);
              if (next !== audioRefs) onAudioRefsChange(next);
            }}
          >
            <div
              className={styles.audioDragHandle}
              draggable
              title={name}
              onDragStart={(e) => {
                e.dataTransfer.setData(AUDIO_REF_DND, ref.assetId);
                e.dataTransfer.effectAllowed = 'move';
              }}
            >
              <span className={styles.audioDragGrip} aria-hidden>
                ⋮⋮
              </span>
              <span className={styles.audioName}>{name}</span>
            </div>
            <span className={styles.audioControls}>
              <label className={styles.checkboxLabelSm}>
                <input
                  type="checkbox"
                  checked={ref.autoplay}
                  onChange={(e) => {
                    const next = audioRefs.map((x) =>
                      x.assetId === ref.assetId ? { ...x, autoplay: e.target.checked } : x,
                    );
                    onAudioRefsChange(next);
                  }}
                />
                <span className={styles.spanXs}>{t('campaign.auto')}</span>
              </label>
              <label className={styles.checkboxLabelSm}>
                <input
                  type="checkbox"
                  checked={ref.loop}
                  onChange={(e) => {
                    const next = audioRefs.map((x) =>
                      x.assetId === ref.assetId ? { ...x, loop: e.target.checked } : x,
                    );
                    onAudioRefsChange(next);
                  }}
                />
                <span className={styles.spanXs}>{t('campaign.loop')}</span>
              </label>
              <AudioVolumeSlider
                assetId={ref.assetId}
                volume={volume}
                isPlaying={isPlaying}
                previewElRef={previewElRef}
                label={t('campaign.volume')}
                onCommit={(v) => {
                  const next = audioRefs.map((x) =>
                    x.assetId === ref.assetId ? { ...x, volume: v } : x,
                  );
                  onAudioRefsChange(next);
                }}
              />
              <button
                type="button"
                className={styles.audioPreviewBtn}
                title={isPlaying ? t('campaign.previewStop') : t('campaign.preview')}
                aria-label={isPlaying ? t('campaign.previewStop') : t('campaign.preview')}
                onClick={() => void togglePreview(ref.assetId, volume)}
              >
                {isPlaying ? '■' : '▶'}
              </button>
              <button
                type="button"
                title={removeTitle}
                className={styles.audioRemove}
                onClick={() => {
                  if (playingId === ref.assetId) stopPreview();
                  onAudioRefsChange(audioRefs.filter((x) => x.assetId !== ref.assetId));
                }}
              >
                <svg
                  className={styles.audioRemoveIcon}
                  viewBox="0 0 24 24"
                  width={16}
                  height={16}
                  aria-hidden
                >
                  <path
                    fill="currentColor"
                    d="M9 3h6a1 1 0 0 1 1 1v1h4v2H4V5h4V4a1 1 0 0 1 1-1zm1 5h2v9h-2V8zm4 0h2v9h-2V8zM7 8h2v9H7V8zm9-3H8v1h8V5zM6 21a2 2 0 0 0 2 2h8a2 2 0 0 0 2-2V8H6v13z"
                  />
                </svg>
              </button>
            </span>
          </div>
        );
      })}
    </div>
  );
}