// Chapter audio playback. The Home page's whole-book player and the Reader's
// chapter player share one <audio> element; audioModeRef tracks which owns it.
import { useEffect, useRef, useState } from 'react';
import { bookOptions, CHAPTER_COUNTS } from '../utils/bibleUtils.jsx';

export function useAudio(readerBookAbbrev, readerChapter, readerTranslation = 'BSB') {
  const [audioBook, setAudioBook] = useState(bookOptions[0].abbrev);
  const [audioNarrator, setAudioNarratorState] = useState(() => {
    try {
      const saved = localStorage.getItem('audio-narrator');
      return ['david', 'hays', 'souer'].includes(saved) ? saved : 'souer';
    } catch { return 'souer'; }
  });
  const setAudioNarrator = (id) => {
    setAudioNarratorState(id);
    try { localStorage.setItem('audio-narrator', id); } catch { /* storage unavailable */ }
  };
  const [audioState, setAudioState] = useState({ status: 'idle', chapter: 0, total: 0 });
  const [readerAudioState, setReaderAudioState] = useState({ status: 'idle', chapter: 0 });
  const [audioProgress, setAudioProgress] = useState({ currentTime: 0, duration: 0 });
  const audioRef = useRef(null);
  const audioModeRef = useRef('book'); // 'book' | 'reader' — which player owns audioRef
  const audioBookRef = useRef(audioBook);
  const audioNarratorRef = useRef(audioNarrator);
  const audioStateRef = useRef(audioState);
  audioBookRef.current = audioBook;
  audioNarratorRef.current = audioNarrator;
  audioStateRef.current = audioState;
  // The Reader's player follows the translation on screen: ESV has its own
  // recording; every other translation falls back to the BSB narrators.
  const readerTranslationRef = useRef(readerTranslation);
  readerTranslationRef.current = readerTranslation;
  const readerAudioSource = () => (readerTranslationRef.current === 'ESV' ? 'ESV' : 'BSB');

  const playAudioChapter = async (abbrev, chapterNum, narrator) => {
    const source = audioModeRef.current === 'reader' ? readerAudioSource() : 'BSB';
    let url;
    let total;
    if (source === 'ESV') {
      const res = await fetch(`/api/bible/ESV/audio/${abbrev}/${chapterNum}`, { credentials: 'include' });
      if (!res.ok) throw new Error('Failed to load ESV audio');
      url = (await res.json()).url;
      total = CHAPTER_COUNTS[abbrev] ?? chapterNum;
    } else {
      const res = await fetch(`https://bible.helloao.org/api/BSB/${abbrev}/${chapterNum}.json`);
      if (!res.ok) throw new Error('Failed to load chapter audio');
      const data = await res.json();
      total = data.book?.numberOfChapters ?? chapterNum;
      url = data.thisChapterAudioLinks?.[narrator];
    }
    if (!url) throw new Error('Audio not available for this narrator');
    if (!audioRef.current) {
      audioRef.current = new Audio();
      audioRef.current.addEventListener('timeupdate', () => {
        setAudioProgress({ currentTime: audioRef.current.currentTime, duration: audioRef.current.duration || 0 });
      });
      audioRef.current.addEventListener('loadedmetadata', () => {
        setAudioProgress((prev) => ({ ...prev, duration: audioRef.current.duration || 0 }));
      });
      audioRef.current.addEventListener('ended', () => {
        if (audioModeRef.current === 'reader') {
          setReaderAudioState({ status: 'idle', chapter: 0 });
          return;
        }
        const nextChapter = audioStateRef.current.chapter + 1;
        if (nextChapter > audioStateRef.current.total) {
          setAudioState({ status: 'idle', chapter: 0, total: 0 });
          return;
        }
        playAudioChapter(audioBookRef.current, nextChapter, audioNarratorRef.current).catch(() =>
          setAudioState({ status: 'error', chapter: 0, total: 0 }),
        );
      });
    }
    const audioEl = audioRef.current;
    audioEl.src = url;
    await audioEl.play();
    if (audioModeRef.current === 'reader') {
      setReaderAudioState({ status: 'playing', chapter: chapterNum, source });
    } else {
      setAudioState({ status: 'playing', chapter: chapterNum, total });
    }
  };

  const handlePlayBookAudio = async () => {
    audioModeRef.current = 'book';
    try {
      await playAudioChapter(audioBook, 1, audioNarrator);
    } catch {
      setAudioState({ status: 'error', chapter: 0, total: 0 });
    }
  };

  // Starts book-mode playback at an arbitrary chapter (e.g. a reading plan's
  // "today" chapter) instead of always chapter 1. Explicit args avoid relying
  // on reader state that may not have re-rendered yet if called right after
  // navigating there in the same event handler.
  const handlePlayBookAudioFrom = async (abbrev, startChapter) => {
    audioModeRef.current = 'book';
    setAudioBook(abbrev);
    try {
      await playAudioChapter(abbrev, startChapter, audioNarrator);
    } catch {
      setAudioState({ status: 'error', chapter: 0, total: 0 });
    }
  };

  const handleStopBookAudio = () => {
    if (audioRef.current) {
      audioRef.current.pause();
      audioRef.current.src = '';
    }
    setAudioState({ status: 'idle', chapter: 0, total: 0 });
    setReaderAudioState({ status: 'idle', chapter: 0 });
    setAudioProgress({ currentTime: 0, duration: 0 });
  };

  const handleToggleBookAudioPause = () => {
    if (!audioRef.current) return;
    if (audioRef.current.paused) {
      audioRef.current.play();
      setAudioState((prev) => ({ ...prev, status: 'playing' }));
    } else {
      audioRef.current.pause();
      setAudioState((prev) => ({ ...prev, status: 'paused' }));
    }
  };

  const handleSeekAudio = (deltaSeconds) => {
    if (!audioRef.current) return;
    const el = audioRef.current;
    const duration = Number.isFinite(el.duration) ? el.duration : Infinity;
    el.currentTime = Math.min(Math.max(el.currentTime + deltaSeconds, 0), duration);
  };

  const handleSeekAudioTo = (seconds) => {
    if (!audioRef.current) return;
    const el = audioRef.current;
    const duration = Number.isFinite(el.duration) ? el.duration : 0;
    el.currentTime = Math.min(Math.max(seconds, 0), duration);
  };

  const handleSkipBookChapter = () => {
    const nextChapter = audioStateRef.current.chapter + 1;
    if (nextChapter > audioStateRef.current.total) return;
    audioModeRef.current = 'book';
    playAudioChapter(audioBookRef.current, nextChapter, audioNarratorRef.current).catch(() =>
      setAudioState({ status: 'error', chapter: 0, total: 0 }),
    );
  };

  const handlePlayReaderAudio = async () => {
    audioModeRef.current = 'reader';
    try {
      await playAudioChapter(readerBookAbbrev, readerChapter, audioNarrator);
    } catch {
      setReaderAudioState({ status: 'error', chapter: 0 });
    }
  };

  const handleToggleReaderAudioPause = () => {
    if (!audioRef.current) return;
    if (audioRef.current.paused) {
      audioRef.current.play();
      setReaderAudioState((prev) => ({ ...prev, status: 'playing' }));
    } else {
      audioRef.current.pause();
      setReaderAudioState((prev) => ({ ...prev, status: 'paused' }));
    }
  };

  // Auto-switch the reader's audio to match the book/chapter currently being read.
  useEffect(() => {
    if (audioModeRef.current !== 'reader') return;
    if (readerAudioState.status !== 'playing' && readerAudioState.status !== 'paused') return;
    if (readerAudioState.chapter === readerChapter && readerAudioState.source === readerAudioSource()) return;
    const wasPaused = readerAudioState.status === 'paused';
    playAudioChapter(readerBookAbbrev, readerChapter, audioNarrator)
      .then(() => {
        if (wasPaused && audioRef.current) {
          audioRef.current.pause();
          setReaderAudioState((prev) => ({ ...prev, status: 'paused' }));
        }
      })
      .catch(() => setReaderAudioState({ status: 'error', chapter: 0 }));
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [readerBookAbbrev, readerChapter, readerTranslation]);

  useEffect(() => () => {
    if (audioRef.current) {
      audioRef.current.pause();
      audioRef.current.src = '';
    }
  }, []);

  return {
    audioBook, setAudioBook,
    audioNarrator, setAudioNarrator,
    audioState,
    audioProgress,
    handlePlayBookAudio,
    handlePlayBookAudioFrom,
    handleStopBookAudio,
    handleToggleBookAudioPause,
    handleSkipBookChapter,
    handleSeekAudio,
    handleSeekAudioTo,
    readerAudioState,
    handlePlayReaderAudio,
    handleToggleReaderAudioPause,
  };
}