"use client";

import { useRef, useState } from "react";
import type { WordItem } from "../types";

type UsePkAudioOptions = {
  onGeneratedAudio: (word: WordItem) => void;
};

export function usePkAudio({ onGeneratedAudio }: UsePkAudioOptions) {
  const [speechTip, setSpeechTip] = useState("点击开始后可朗读单词。");
  const audioContextRef = useRef<AudioContext | null>(null);

  function ensureAudioContext() {
    if (!audioContextRef.current) {
      audioContextRef.current = new window.AudioContext();
    }
    return audioContextRef.current;
  }

  async function playTone(correct: boolean) {
    const audioContext = ensureAudioContext();
    if (audioContext.state === "suspended") {
      await audioContext.resume();
    }

    const osc = audioContext.createOscillator();
    const gain = audioContext.createGain();
    osc.connect(gain);
    gain.connect(audioContext.destination);

    const duration = correct ? 0.4 : 0.3;

    if (correct) {
      osc.frequency.setValueAtTime(523.25, audioContext.currentTime);
      osc.frequency.setValueAtTime(659.25, audioContext.currentTime + 0.1);
      osc.frequency.setValueAtTime(783.99, audioContext.currentTime + 0.2);
      gain.gain.setValueAtTime(0.25, audioContext.currentTime);
      gain.gain.exponentialRampToValueAtTime(0.01, audioContext.currentTime + 0.4);
    } else {
      osc.frequency.setValueAtTime(200, audioContext.currentTime);
      osc.frequency.setValueAtTime(150, audioContext.currentTime + 0.15);
      gain.gain.setValueAtTime(0.25, audioContext.currentTime);
      gain.gain.exponentialRampToValueAtTime(0.01, audioContext.currentTime + 0.3);
    }

    osc.start(audioContext.currentTime);
    osc.stop(audioContext.currentTime + duration);
  }

  async function speakWord(word: WordItem) {
    if (word.audio) {
      const audio = new Audio(word.audio);
      audio.play().catch(() => speakSystemWord(word.english));
      setSpeechTip(`正在播放：${word.english}`);
      return;
    }

    try {
      setSpeechTip(`正在生成语音：${word.english}`);
      const response = await fetch(`/api/words/${word.id}/generate-audio`, { method: "POST" });
      if (!response.ok) throw new Error("generate failed");
      const data = (await response.json()) as { word: WordItem };
      const audio = new Audio(data.word.audio);
      audio.play().catch(() => speakSystemWord(word.english));
      setSpeechTip(`正在播放：${word.english}`);
      onGeneratedAudio(data.word);
    } catch {
      speakSystemWord(word.english);
    }
  }

  function speakSystemWord(word: string) {
    if (!("speechSynthesis" in window)) {
      setSpeechTip("当前浏览器不支持英文朗读，请老师带读。");
      return;
    }

    window.speechSynthesis.cancel();
    const utterance = new SpeechSynthesisUtterance(word);
    const voices = window.speechSynthesis.getVoices();
    utterance.voice =
      voices.find((voice) => /^en[-_]?US/i.test(voice.lang)) ??
      voices.find((voice) => /^en/i.test(voice.lang)) ??
      null;
    utterance.lang = utterance.voice?.lang ?? "en-US";
    utterance.rate = 0.85;
    utterance.pitch = 1;
    window.speechSynthesis.speak(utterance);
    setSpeechTip(`正在朗读：${word}`);
  }

  return {
    speechTip,
    setSpeechTip,
    playTone,
    speakWord,
  };
}