import { STOP_WORDS } from '../data/stopwords.js';
import { state } from '../core/state.js';
import { saveSchedule, saveWords } from '../core/storage.js';
import { showToast } from '../ui/toast.js';
import { speak } from '../services/tts.js';
import { callAI, translateWord } from '../services/ai.js';
import { initWordSchedule } from '../services/ebbinghaus.js';
import { getMastery } from '../services/stats.js';
import { escapeHtml, formatFormsHtml } from '../ui/dom.js';
import { findWordContext } from '../services/extractor.js';
import { getNextId } from './words.js';
import { beginMailLearnRequest, isCurrentMailLearnRequest } from './mail-learn.js';

export let readerTranslations = {};
export let readerSentences = [];
let readerSessionGeneration = 0;
// ==================== Full-Text Reading Mode ====================
export function splitSentences(text) {
  const raw = text.split(/(?<=[.!?])\s+|(?:\r?\n){2,}/);
  return raw.map(s => s.trim()).filter(s => s.length > 0);
}

export function isStopWord(w) { return STOP_WORDS.has(w.toLowerCase()); }

export function buildReadingSentenceHtml(sentence) {
  const knownMap = {};
  state.words.forEach(w => { knownMap[w.english.toLowerCase()] = w; });

  const tokens = sentence.split(/(\s+|[,.;:!?'"()\[\]{}<>\/\\—–\-])/);
  let html = '';
  tokens.forEach(tok => {
    const clean = tok.toLowerCase().replace(/[^a-z'-]/g, '');
    const word = knownMap[clean];
    if (word && clean.length >= 2) {
      html += `<span class="reader-word known" data-word-id="${word.id}" data-action="reader.showReaderWordTip" data-element-arg="0" data-arg1="${word.id}" title="${escapeHtml(word.chinese || '')}">${escapeHtml(tok)}</span>`;
    } else if (/^[a-zA-Z]{2,}$/.test(clean) && !isStopWord(clean)) {
      html += `<span class="reader-word unknown" data-action="reader.showReaderUnknownTip" data-element-arg="0" data-arg1="${escapeHtml(clean)}" title="点击查看释义">${escapeHtml(tok)}</span>`;
    } else {
      html += escapeHtml(tok);
    }
  });
  return html;
}

export async function startFullReading() {
  const sessionGeneration = ++readerSessionGeneration;
  const text = document.getElementById('mail-learn-input').value.trim();
  if (!text) { showToast('请粘贴邮件内容', 'error'); return; }

  const sentences = splitSentences(text);
  if (!sentences.length) { showToast('无法解析邮件内容', 'error'); return; }

  const resultEl = document.getElementById('mail-learn-result');
  const request = beginMailLearnRequest(resultEl);
  resultEl.innerHTML = '<div class="loading"><div class="spinner"></div> 正在准备全文阅读...</div>';

  let translations = {};
  const hasAI = state.settings.apiKey && state.settings.apiUrl && state.settings.model;

  if (hasAI) {
    try {
      const numbered = sentences.map((s, i) => `${i + 1}. ${s}`).join('\n');
      const content = await callAI([
        { role: 'system', content: '你是翻译助手。用户给出编号的英文句子，请逐句翻译为中文，严格保持编号格式返回。只返回翻译结果，每行格式：编号. 中文翻译' },
        { role: 'user', content: numbered }
      ]);
      if (sessionGeneration !== readerSessionGeneration || !isCurrentMailLearnRequest(request)) return;
      content.split('\n').forEach(line => {
        const m = line.match(/^(\d+)\.\s*(.+)/);
        if (m) translations[Number(m[1]) - 1] = m[2].trim();
      });
    } catch (err) {
      if (sessionGeneration !== readerSessionGeneration || !isCurrentMailLearnRequest(request)) return;
      showToast('AI 翻译失败，阅读模式仍可使用：' + err.message, 'warning');
    }
  }

  if (sessionGeneration !== readerSessionGeneration || !isCurrentMailLearnRequest(request) || !resultEl.isConnected) return;
  const knownCount = countKnownWordsInText(text);
  const totalUniqueWords = countUniqueWords(text);
  const coveragePct = totalUniqueWords > 0 ? Math.round(knownCount / totalUniqueWords * 100) : 0;

  resultEl.innerHTML = `
    <div class="card reader-card">
      <div class="reader-header">
        <h3><i class="fas fa-book-reader"></i> 全文阅读</h3>
        <div class="reader-stats">
          <span class="badge badge-primary">${sentences.length} 句</span>
          <span class="badge badge-success">词库覆盖 ${coveragePct}%</span>
          <button class="btn btn-sm btn-ghost" data-action="reader.toggleAllTranslations" title="显示/隐藏全部翻译"><i class="fas fa-eye"></i> 全部翻译</button>
        </div>
      </div>
      <div class="reader-legend">
        <span><span class="reader-dot known-dot"></span> 词库中的单词（点击查看详情）</span>
        <span><span class="reader-dot unknown-dot"></span> 生词（点击查询）</span>
        <span><i class="fas fa-hand-pointer" style="font-size:12px"></i> 点击句子查看翻译</span>
      </div>
      <div class="reader-body" id="reader-body">
        ${sentences.map((s, i) => `
          <div class="reader-sentence-block" data-idx="${i}">
            <div class="reader-sentence-num">${i + 1}</div>
            <div class="reader-sentence-content">
              <div class="reader-sentence-en" data-action="reader.toggleSentenceTranslation" data-arg0="${i}">${buildReadingSentenceHtml(s)}</div>
              <div class="reader-sentence-cn" id="reader-cn-${i}" style="display:none">
                ${translations[i] ? escapeHtml(translations[i]) : '<span class="text-muted">点击上方英文句子查看翻译</span>'}
              </div>
              <div class="reader-sentence-tools">
                <button class="btn btn-sm btn-ghost" data-action="reader.speakSentence" data-arg0="${i}" title="朗读"><i class="fas fa-volume-up"></i></button>
                <button class="btn btn-sm btn-ghost" data-action="reader.toggleSentenceTranslation" data-arg0="${i}" title="翻译"><i class="fas fa-language"></i></button>
                ${!translations[i] && hasAI ? `<button class="btn btn-sm btn-ghost" id="ai-translate-btn-${i}" data-action="reader.aiTranslateSentence" data-arg0="${i}" data-element-arg="1" title="AI翻译"><i class="fas fa-magic"></i></button>` : ''}
              </div>
            </div>
          </div>`).join('')}
      </div>
    </div>
    <div id="reader-word-tooltip" class="reader-tooltip" style="display:none"></div>
  `;

  readerTranslations = translations;
  readerSentences = sentences;
}

export function countKnownWordsInText(text) {
  const knownSet = new Set(state.words.map(w => w.english.toLowerCase()));
  const tokens = text.match(/\b[a-zA-Z]{2,}\b/g) || [];
  const unique = new Set(tokens.map(t => t.toLowerCase()));
  let count = 0;
  unique.forEach(w => { if (!STOP_WORDS.has(w) && knownSet.has(w)) count++; });
  return count;
}

export function countUniqueWords(text) {
  const tokens = text.match(/\b[a-zA-Z]{2,}\b/g) || [];
  const unique = new Set(tokens.map(t => t.toLowerCase()));
  let count = 0;
  unique.forEach(w => { if (!STOP_WORDS.has(w)) count++; });
  return count;
}

export function speakSentence(idx) {
  const sentences = readerSentences;
  if (sentences && sentences[idx]) speak(sentences[idx]);
}

export function toggleSentenceTranslation(idx) {
  const el = document.getElementById(`reader-cn-${idx}`);
  if (!el) return;
  el.style.display = el.style.display === 'none' ? 'block' : 'none';
}

export function toggleAllTranslations() {
  const els = document.querySelectorAll('[id^="reader-cn-"]');
  const anyHidden = [...els].some(e => e.style.display === 'none');
  els.forEach(e => { e.style.display = anyHidden ? 'block' : 'none'; });
}

export async function aiTranslateSentence(idx, btnEl) {
  const sessionGeneration = readerSessionGeneration;
  const sentence = readerSentences?.[idx];
  if (!sentence) return;

  const cnEl = document.getElementById(`reader-cn-${idx}`);
  if (!cnEl) return;
  if (btnEl) btnEl.disabled = true;

  const isCurrentSentence = () => sessionGeneration === readerSessionGeneration
    && readerSentences?.[idx] === sentence
    && cnEl.isConnected
    && (!btnEl || btnEl.isConnected);

  try {
    const content = await callAI([
      { role: 'system', content: '你是翻译助手，只返回中文翻译结果，不要任何解释。' },
      { role: 'user', content: `翻译为中文：${sentence}` }
    ]);
    if (!isCurrentSentence()) return;
    const translation = content.trim();
    cnEl.textContent = translation;
    cnEl.style.display = 'block';
    readerTranslations[idx] = translation;
    if (btnEl) btnEl.remove();
  } catch (err) {
    if (!isCurrentSentence()) return;
    showToast('翻译失败: ' + err.message, 'error');
    if (btnEl) btnEl.disabled = false;
  }
}

export function positionReaderTooltip(tip, el) {
  const margin = 8;
  const gap = 6;
  const rect = el.getBoundingClientRect();
  const scrollTop = window.scrollY || document.documentElement.scrollTop;
  const tipWidth = tip.offsetWidth;
  const tipHeight = tip.offsetHeight;
  const left = Math.min(
    Math.max(rect.left, margin),
    Math.max(margin, window.innerWidth - tipWidth - margin)
  );
  const top = rect.bottom + gap + tipHeight <= window.innerHeight
    ? rect.bottom + scrollTop + gap
    : Math.max(scrollTop + margin, rect.top + scrollTop - tipHeight - gap);

  tip.style.left = `${left}px`;
  tip.style.top = `${top}px`;
}

let readerTipCloseHandler = null;
let readerTipCloseTimer = null;
let readerTipSeq = 0;

function bindReaderTipClose(tip, anchorEl) {
  if (readerTipCloseTimer !== null) {
    clearTimeout(readerTipCloseTimer);
    readerTipCloseTimer = null;
  }
  if (readerTipCloseHandler) {
    document.removeEventListener('click', readerTipCloseHandler);
    readerTipCloseHandler = null;
  }
  const handler = (e) => {
    if (!tip.contains(e.target) && e.target !== anchorEl) {
      ++readerTipSeq;
      tip.style.display = 'none';
      document.removeEventListener('click', handler);
      if (readerTipCloseHandler === handler) readerTipCloseHandler = null;
    }
  };
  readerTipCloseHandler = handler;
  readerTipCloseTimer = setTimeout(() => {
    readerTipCloseTimer = null;
    if (readerTipCloseHandler === handler) {
      document.addEventListener('click', handler);
    }
  }, 10);
}

export function showReaderWordTip(el, wordId) {
  ++readerTipSeq;
  const word = state.words.find(w => w.id === wordId);
  if (!word) return;

  const tip = document.getElementById('reader-word-tooltip');
  if (!tip) return;

  const mastery = getMastery(word.id);
  const masteryText = mastery === 'mastered' ? '已掌握' : mastery === 'learning' ? '学习中' : '新词';
  const badgeClass = mastery === 'mastered' ? 'badge-success' : mastery === 'learning' ? 'badge-warning' : 'badge-primary';

  tip.innerHTML = `
    <div class="reader-tip-header">
      <strong>${escapeHtml(word.english)}</strong>
      <span style="color:var(--text-muted);font-size:12px">${escapeHtml(word.phonetic || '')}</span>
      <span class="badge ${badgeClass}" style="font-size:11px;padding:2px 6px">${masteryText}</span>
      <button class="btn btn-sm btn-ghost" data-action="reader.speak" data-arg0="${escapeHtml(word.english)}"><i class="fas fa-volume-up"></i></button>
    </div>
    <div class="reader-tip-cn">${escapeHtml(word.chinese || '')}</div>
    ${word.forms ? `<div class="reader-tip-forms">${formatFormsHtml(word.forms)}</div>` : ''}
    ${word.example ? `<div class="reader-tip-example"><em>${escapeHtml(word.example.en)}</em><br><span>${escapeHtml(word.example.cn)}</span></div>` : ''}
  `;

  tip.style.display = 'block';
  positionReaderTooltip(tip, el);

  bindReaderTipClose(tip, el);
}

export async function showReaderUnknownTip(el, word) {
  const tip = document.getElementById('reader-word-tooltip');
  if (!tip) return;

  const seq = ++readerTipSeq;

  tip.innerHTML = `
    <div class="reader-tip-header">
      <strong>${escapeHtml(word)}</strong>
      <button class="btn btn-sm btn-ghost" data-action="reader.speak" data-arg0="${escapeHtml(word)}"><i class="fas fa-volume-up"></i></button>
    </div>
    <div class="reader-tip-cn" style="color:var(--text-muted)">查询中...</div>
  `;

  tip.style.display = 'block';
  positionReaderTooltip(tip, el);

  bindReaderTipClose(tip, el);

  const hasAI = state.settings.apiKey && state.settings.apiUrl && state.settings.model;
  if (hasAI) {
    try {
      const result = await translateWord(word);
      if (seq !== readerTipSeq) return;
      tip.innerHTML = `
        <div class="reader-tip-header">
          <strong>${escapeHtml(result.english || word)}</strong>
          <span style="color:var(--text-muted);font-size:12px">${escapeHtml(result.phonetic || '')}</span>
          <button class="btn btn-sm btn-ghost" data-action="reader.speak" data-arg0="${escapeHtml(word)}"><i class="fas fa-volume-up"></i></button>
        </div>
        <div class="reader-tip-cn">${escapeHtml(result.chinese || '')}</div>
        ${result.forms ? `<div class="reader-tip-forms">${formatFormsHtml(result.forms)}</div>` : ''}
        ${result.example ? `<div class="reader-tip-example"><em>${escapeHtml(result.example.en)}</em><br><span>${escapeHtml(result.example.cn)}</span></div>` : ''}
        <button class="btn btn-sm btn-primary" style="margin-top:8px;width:100%" data-action="reader.addWordFromReader" data-arg0="${escapeHtml(word)}" data-element-arg="1">
          <i class="fas fa-plus"></i> 加入词库
        </button>
      `;
      positionReaderTooltip(tip, el);
    } catch (err) {
      if (seq !== readerTipSeq) return;
      const cnEl = tip.querySelector('.reader-tip-cn');
      if (cnEl) cnEl.textContent = '查询失败: ' + err.message;
    }
  } else {
    const cnEl = tip.querySelector('.reader-tip-cn');
    if (cnEl) cnEl.textContent = '请先配置 AI 设置以启用翻译';
  }
}

export async function addWordFromReader(word, btnEl) {
  const key = String(word || '').trim().toLowerCase();
  const libraryId = state.activeWordLibrary;
  const sessionGeneration = readerSessionGeneration;
  const wordExists = () => state.words.some(item => String(item.english || '').trim().toLowerCase() === key);
  const isCurrentOperation = () => state.activeWordLibrary === libraryId
    && readerSessionGeneration === sessionGeneration
    && (!btnEl || btnEl.isConnected);
  if (!key) return false;
  if (wordExists()) {
    showToast(`「${word}」已在词库中`, 'info');
    if (btnEl) { btnEl.disabled = true; btnEl.textContent = '已添加 ✓'; }
    return true;
  }

  if (btnEl) { btnEl.disabled = true; btnEl.textContent = '添加中...'; }
  try {
    const result = await translateWord(word);
    if (!isCurrentOperation()) return false;
    if (wordExists()) {
      showToast(`「${word}」已在词库中`, 'info');
      if (btnEl) { btnEl.textContent = '已添加 ✓'; btnEl.classList.remove('btn-primary'); btnEl.classList.add('btn-success'); }
      return true;
    }
    const emailText = document.getElementById('mail-learn-input')?.value || '';
    const contextSentence = findWordContext(word, emailText);
    const emailTitle = emailText.slice(0, 40).replace(/\n/g, ' ') + '...';

    const previousWords = state.words.slice();
    const previousSchedule = { ...state.schedule };
    const id = getNextId();
    state.words.push({
      id,
      ...result,
      sourceContext: contextSentence ? { emailTitle, sentence: contextSentence } : null
    });
    initWordSchedule(id, false);
    if (!(saveWords() && saveSchedule())) {
      state.words = previousWords;
      state.schedule = previousSchedule;
      saveWords();
      saveSchedule();
      throw new Error('本地存储写入失败');
    }
    showToast(`已添加「${word}」到词库`, 'success');
    if (btnEl) { btnEl.textContent = '已添加 \u2713'; btnEl.classList.remove('btn-primary'); btnEl.classList.add('btn-success'); }
    return true;
  } catch (err) {
    if (!isCurrentOperation()) return false;
    showToast('添加失败: ' + err.message, 'error');
    if (btnEl) { btnEl.disabled = false; btnEl.textContent = '重试'; }
    return false;
  }
}