import { useState, useEffect } from 'react';
import { getStroke } from 'perfect-freehand';
import { pathFromStroke } from './inkRender.js';

// ---------------------------------------------------------------------------
// Study constants
// ---------------------------------------------------------------------------

export const COMMENTARY_OPTIONS = [
  { id: 'matthew-henry', name: 'Matthew Henry' },
  { id: 'john-gill', name: 'John Gill' },
  { id: 'jamieson-fausset-brown', name: 'Jamieson-Fausset-Brown' },
  { id: 'adam-clarke', name: 'Adam Clarke' },
  { id: 'keil-delitzsch', name: 'Keil & Delitzsch (OT)' },
  { id: 'tyndale', name: 'Tyndale Open Study Notes' },
];

export const STUDY_TABS = [
  { id: 'notes', label: 'Notes' },
  { id: 'crossRefs', label: 'Cross-Refs' },
  { id: 'wordStudy', label: 'Word Study' },
  { id: 'commentary', label: 'Commentary' },
  { id: 'script', label: 'Script' },
];

export const CHAPTER_COUNTS = {
  GEN:50,EXO:40,LEV:27,NUM:36,DEU:34,JOS:24,JDG:21,RUT:4,
  '1SA':31,'2SA':24,'1KI':22,'2KI':25,'1CH':29,'2CH':36,
  EZR:10,NEH:13,EST:10,JOB:42,PSA:150,PRO:31,ECC:12,SNG:8,
  ISA:66,JER:52,LAM:5,EZK:48,DAN:12,HOS:14,JOL:3,AMO:9,
  OBA:1,JON:4,MIC:7,NAM:3,HAB:3,ZEP:3,HAG:2,ZEC:14,MAL:4,
  MAT:28,MRK:16,LUK:24,JHN:21,ACT:28,ROM:16,'1CO':16,'2CO':13,
  GAL:6,EPH:6,PHP:4,COL:4,'1TH':5,'2TH':3,'1TI':6,'2TI':4,
  TIT:3,PHM:1,HEB:13,JAS:5,'1PE':5,'2PE':3,'1JN':5,'2JN':1,
  '3JN':1,JUD:1,REV:22,
};

export const bookOptions = [
  { name: 'Genesis', abbrev: 'GEN' },
  { name: 'Exodus', abbrev: 'EXO' },
  { name: 'Leviticus', abbrev: 'LEV' },
  { name: 'Numbers', abbrev: 'NUM' },
  { name: 'Deuteronomy', abbrev: 'DEU' },
  { name: 'Joshua', abbrev: 'JOS' },
  { name: 'Judges', abbrev: 'JDG' },
  { name: 'Ruth', abbrev: 'RUT' },
  { name: '1 Samuel', abbrev: '1SA' },
  { name: '2 Samuel', abbrev: '2SA' },
  { name: '1 Kings', abbrev: '1KI' },
  { name: '2 Kings', abbrev: '2KI' },
  { name: '1 Chronicles', abbrev: '1CH' },
  { name: '2 Chronicles', abbrev: '2CH' },
  { name: 'Ezra', abbrev: 'EZR' },
  { name: 'Nehemiah', abbrev: 'NEH' },
  { name: 'Esther', abbrev: 'EST' },
  { name: 'Job', abbrev: 'JOB' },
  { name: 'Psalms', abbrev: 'PSA' },
  { name: 'Proverbs', abbrev: 'PRO' },
  { name: 'Ecclesiastes', abbrev: 'ECC' },
  { name: 'Song', abbrev: 'SNG' },
  { name: 'Isaiah', abbrev: 'ISA' },
  { name: 'Jeremiah', abbrev: 'JER' },
  { name: 'Lamentations', abbrev: 'LAM' },
  { name: 'Ezekiel', abbrev: 'EZK' },
  { name: 'Daniel', abbrev: 'DAN' },
  { name: 'Hosea', abbrev: 'HOS' },
  { name: 'Joel', abbrev: 'JOL' },
  { name: 'Amos', abbrev: 'AMO' },
  { name: 'Obadiah', abbrev: 'OBA' },
  { name: 'Jonah', abbrev: 'JON' },
  { name: 'Micah', abbrev: 'MIC' },
  { name: 'Nahum', abbrev: 'NAM' },
  { name: 'Habakkuk', abbrev: 'HAB' },
  { name: 'Zephaniah', abbrev: 'ZEP' },
  { name: 'Haggai', abbrev: 'HAG' },
  { name: 'Zechariah', abbrev: 'ZEC' },
  { name: 'Malachi', abbrev: 'MAL' },
  { name: 'Matthew', abbrev: 'MAT' },
  { name: 'Mark', abbrev: 'MRK' },
  { name: 'Luke', abbrev: 'LUK' },
  { name: 'John', abbrev: 'JHN' },
  { name: 'Acts', abbrev: 'ACT' },
  { name: 'Romans', abbrev: 'ROM' },
  { name: '1 Corinthians', abbrev: '1CO' },
  { name: '2 Corinthians', abbrev: '2CO' },
  { name: 'Galatians', abbrev: 'GAL' },
  { name: 'Ephesians', abbrev: 'EPH' },
  { name: 'Philippians', abbrev: 'PHP' },
  { name: 'Colossians', abbrev: 'COL' },
  { name: '1 Thessalonians', abbrev: '1TH' },
  { name: '2 Thessalonians', abbrev: '2TH' },
  { name: '1 Timothy', abbrev: '1TI' },
  { name: '2 Timothy', abbrev: '2TI' },
  { name: 'Titus', abbrev: 'TIT' },
  { name: 'Philemon', abbrev: 'PHM' },
  { name: 'Hebrews', abbrev: 'HEB' },
  { name: 'James', abbrev: 'JAS' },
  { name: '1 Peter', abbrev: '1PE' },
  { name: '2 Peter', abbrev: '2PE' },
  { name: '1 John', abbrev: '1JN' },
  { name: '2 John', abbrev: '2JN' },
  { name: '3 John', abbrev: '3JN' },
  { name: 'Jude', abbrev: 'JUD' },
  { name: 'Revelation', abbrev: 'REV' },
];

export const NT_BOOK_NUMBER = {
  MAT: 40, MRK: 41, LUK: 42, JHN: 43, ACT: 44,
  ROM: 45, '1CO': 46, '2CO': 47, GAL: 48, EPH: 49,
  PHP: 50, COL: 51, '1TH': 52, '2TH': 53, '1TI': 54,
  '2TI': 55, TIT: 56, PHM: 57, HEB: 58, JAS: 59,
  '1PE': 60, '2PE': 61, '1JN': 62, '2JN': 63, '3JN': 64,
  JUD: 65, REV: 66,
};

export const storageKey = (translation, book, chapter) => `bible-study-${translation}-${book}-${chapter}`;
export const makeId = () => crypto.randomUUID?.() ?? `${Date.now()}-${Math.random()}`;

// ---------------------------------------------------------------------------
// Format helpers
// ---------------------------------------------------------------------------

export function formatRelativeDate(ts) {
  if (!ts) return '';
  const diff = Date.now() - ts;
  const mins = Math.floor(diff / 60000);
  if (mins < 1) return 'just now';
  if (mins < 60) return `${mins}m ago`;
  const hours = Math.floor(mins / 60);
  if (hours < 24) return `${hours}h ago`;
  const days = Math.floor(hours / 24);
  return `${days}d ago`;
}

export function chunkSpansNextChapter(project, startChapterIndex, chunk) {
  if (!project || !Array.isArray(project.chapters)) return false;
  if (!Number.isInteger(chunk?.spilloverEndVerse)) return false;
  if (startChapterIndex < 0 || startChapterIndex >= project.chapters.length - 1) return false;
  const startChapter = project.chapters[startChapterIndex];
  const nextChapter = project.chapters[startChapterIndex + 1];
  return startChapter?.bookAbbrev && startChapter.bookAbbrev === nextChapter?.bookAbbrev;
}

export function formatChunkReference(project, startChapterIndex, chunk, separator = '-') {
  if (!project || !chunk) return '';
  const startChapter = project.chapters?.[startChapterIndex];
  if (!startChapter) return '';

  if (chunkSpansNextChapter(project, startChapterIndex, chunk)) {
    const nextChapter = project.chapters[startChapterIndex + 1];
    return `${startChapter.book} ${startChapter.chapter}:${chunk.startVerse}${separator}${nextChapter.chapter}:${chunk.spilloverEndVerse}`;
  }

  if (chunk.startVerse === chunk.endVerse) {
    return `${startChapter.book} ${startChapter.chapter}:${chunk.startVerse}`;
  }
  return `${startChapter.book} ${startChapter.chapter}:${chunk.startVerse}${separator}${chunk.endVerse}`;
}

export function getChunkVerseEntries(project, startChapterIndex, chunk) {
  if (!project || !chunk) return [];
  const startChapter = project.chapters?.[startChapterIndex];
  if (!startChapter) return [];

  const startVerses = (startChapter.verses ?? [])
    .filter((verse) => verse.number >= chunk.startVerse && verse.number <= chunk.endVerse)
    .map((verse) => ({
      book: startChapter.book,
      chapter: startChapter.chapter,
      ...verse,
    }));

  if (!chunkSpansNextChapter(project, startChapterIndex, chunk)) {
    return startVerses;
  }

  const nextChapter = project.chapters[startChapterIndex + 1];
  const spilloverVerses = (nextChapter.verses ?? [])
    .filter((verse) => verse.number >= 1 && verse.number <= chunk.spilloverEndVerse)
    .map((verse) => ({
      book: nextChapter.book,
      chapter: nextChapter.chapter,
      ...verse,
    }));

  return [...startVerses, ...spilloverVerses];
}

// ---------------------------------------------------------------------------
// HTML export utilities
// ---------------------------------------------------------------------------

const escHtml = (s) => String(s ?? '').replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');

function inkStrokesToSvgHtml(strokes) {
  if (!strokes?.length) return '';
  const W = 700, H = 500;
  const lines = [];
  for (let y = 32; y < H; y += 32)
    lines.push(`<line x1="0" y1="${y}" x2="${W}" y2="${y}" stroke="#dde3ec" stroke-width="1"/>`);
  lines.push(`<line x1="40" y1="0" x2="40" y2="${H}" stroke="#fca5a5" stroke-width="1"/>`);
  const paths = strokes.map((s) => {
    const pts = s.points.map(([x, y, p]) => [x * W, y * H, p]);
    const outline = getStroke(pts, {
      size: s.size * H,
      thinning: s.tool === 'highlighter' ? 0 : 0.5,
      smoothing: 0.5,
      streamline: 0.4,
    });
    const d = pathFromStroke(outline);
    if (!d) return '';
    return `<path d="${d}" fill="${escHtml(s.color)}" opacity="${s.tool === 'highlighter' ? '0.35' : '1'}"/>`;
  }).filter(Boolean).join('');
  return `<div class="ink-notes"><strong>INK NOTES:</strong><div style="margin-top:8px;border:1px solid #e2e8f0;border-radius:8px;overflow:hidden;background:#fff;"><svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}" viewBox="0 0 ${W} ${H}" style="display:block;max-width:100%;height:auto;">${lines.join('')}${paths}</svg></div></div>`;
}

export function buildExportHtml(project) {
  const style = `
    body { font-family: Georgia, serif; color: #0f172a; margin: 0; padding: 32px; }
    .page { max-width: 900px; margin: auto; }
    h1, h2 { font-family: Georgia, serif; }
    h1 { margin-bottom: 0.5rem; }
    .chapter-heading { margin: 2rem 0 0.5rem; font-size: 1.2rem; font-weight: 700; border-bottom: 1px solid #cbd5e1; padding-bottom: 0.25rem; }
    .chunk { margin-bottom: 2rem; padding: 1.25rem 1.5rem; border: 1px solid #cbd5e1; border-radius: 0.75rem; background: #ffffff; }
    .verse { margin: 0 0 0.75rem; line-height: 1.7; }
    .scripture-ref { font-weight: 700; margin-bottom: 0.75rem; }
    .oia, .cross-refs, .greek, .ink-notes { margin-top: 1rem; }
    .oia-section { margin-bottom: 0.75rem; }
    .greek table { width: 100%; border-collapse: collapse; margin-top: 0.5rem; }
    .greek th, .greek td { border: 1px solid #d1d5db; padding: 0.65rem; text-align: left; }
    .greek th { background: #f8fafc; }
    .definition { margin-top: 0.75rem; font-size: 0.95rem; line-height: 1.6; }
    .definition-block { margin-top: 1rem; padding: 1rem; border: 1px solid #e2e8f0; border-radius: 0.75rem; background: #f8fafc; }
    @media print {
      body { padding: 0; }
      .chunk { break-inside: avoid; border-color: #cbd5e1; }
      .chapter-heading { break-after: avoid; }
    }
  `;

  const chapters = Array.isArray(project.chapters) ? project.chapters : [];

  const chunksHtml = chapters.map((ch, chapterIndex) => {
    const chapterHeader = `<h2 class="chapter-heading">${escHtml(ch.book)} ${escHtml(ch.chapter)}</h2>`;
    const chunkSections = ch.chunks.map((chunk) => {
      const scripture = formatChunkReference(project, chapterIndex, chunk, '-');
      const versesText = getChunkVerseEntries(project, chapterIndex, chunk)
        .map((verse) => `<p class="verse"><strong>${escHtml(verse.chapter)}:${escHtml(verse.number)}</strong> ${escHtml(verse.text)}</p>`)
        .join('');

      const observation = escHtml((chunk.observation ?? '').trim()).replace(/\n/g, '<br />') || '<em>No observation.</em>';
      const interpretation = escHtml((chunk.interpretation ?? '').trim()).replace(/\n/g, '<br />') || '<em>No interpretation.</em>';
      const application = escHtml((chunk.application ?? '').trim()).replace(/\n/g, '<br />') || '<em>No application.</em>';

      const crossRefsHtml = (chunk.crossReferences ?? []).length > 0
        ? `<div class="cross-refs"><strong>CROSS-REFERENCES:</strong> ${chunk.crossReferences.map(escHtml).join(', ')}</div>`
        : '';

      const greekRows = chunk.greekWords.map((word) => `
        <tr>
          <td><strong>${escHtml(word.strongNumber)}</strong></td>
          <td>${escHtml(word.lexeme)}</td>
          <td>${escHtml(word.transliteration)}</td>
          <td>${escHtml(word.partOfSpeech)}</td>
          <td>${escHtml(word.shortDefinition)}</td>
        </tr>
      `).join('');
      const greekTable = wordTableHtml(greekRows);
      const extendedDefinitions = chunk.greekWords
        .map((word) => {
          if (word.definitionHtml) {
            return `
              <div class="definition-block">
                <p><strong>${escHtml(word.strongNumber)} — ${escHtml(word.lexeme)}</strong></p>
                <div class="definition">${word.definitionHtml}</div>
              </div>
            `;
          }
          if ((word.shortDefinition === 'No definition found.' || word.shortDefinition === 'Lookup failed.') && !word.lexeme && !word.definitionHtml && word.query) {
            const raw = word.query.trim();
            const normalized = /^\d+$/.test(raw) ? `G${raw}` : raw.toUpperCase();
            const isStrongs = /^G\d+$/.test(normalized);
            const num = isStrongs ? normalized.slice(1) : null;
            const links = isStrongs && num
              ? `<a href="https://biblehub.com/greek/${num}.htm">BibleHub</a> · <a href="https://www.blueletterbible.org/lexicon/g${num}/esv/0-1/">Blue Letter Bible</a> · <a href="https://www.studylight.org/lexicons/eng/greek/${num}.html">StudyLight</a>`
              : `<a href="https://biblehub.com/search.php?q=${encodeURIComponent(raw)}">BibleHub</a> · <a href="https://www.blueletterbible.org/search/search.cfm?Criteria=${encodeURIComponent(raw)}&t=KJV#s=s_lexiconc">Blue Letter Bible</a>`;
            return `
              <div class="definition-block" style="border-color:#fcd34d;background:#fffbeb;">
                <p><strong>${escHtml(raw)}</strong> — definition not found in auto-lookup</p>
                <p style="margin-top:0.5rem;font-size:0.9rem;">Look it up manually: ${links}</p>
              </div>
            `;
          }
          return '';
        })
        .join('');

      const inkHtml = inkStrokesToSvgHtml(chunk.inkStrokes);

      return `
        <section class="chunk">
          <div class="scripture-ref">${escHtml(scripture)}</div>
          ${versesText}
          <div class="oia">
            <div class="oia-section"><strong>OBSERVATION:</strong><p>${observation}</p></div>
            <div class="oia-section"><strong>INTERPRETATION:</strong><p>${interpretation}</p></div>
            <div class="oia-section"><strong>APPLICATION:</strong><p>${application}</p></div>
          </div>
          ${crossRefsHtml}
          <div class="greek"><strong>GREEK WORDS:</strong>
            ${greekRows ? greekTable : '<p><em>No Greek word notes.</em></p>'}
            ${extendedDefinitions}
          </div>
          ${inkHtml}
        </section>
      `;
    }).join('');
    return chapterHeader + chunkSections;
  }).join('');

  return `<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>${escHtml(project.title)}</title>
  <style>${style}</style>
</head>
<body>
  <div class="page">
    <h1>${escHtml(project.title)}</h1>
    <p>${escHtml(project.translation)}</p>
    ${chunksHtml}
  </div>
</body>
</html>`;
}

export function wordTableHtml(rows) {
  return `
    <table>
      <thead>
        <tr>
          <th>Strong's</th>
          <th>Greek</th>
          <th>Transliteration</th>
          <th>Part of Speech</th>
          <th>Short Definition</th>
        </tr>
      </thead>
      <tbody>
        ${rows}
      </tbody>
    </table>
  `;
}

export function extractPartOfSpeech(definitionHtml) {
  const match = /Part\(s\) of speech:\s*([^<]+)/i.exec(definitionHtml || '');
  if (match && match[1]) {
    return match[1].trim();
  }
  return '';
}

export function htmlToPlainText(html = '') {
  const parser = new DOMParser();
  const doc = parser.parseFromString(html, 'text/html');
  const lines = [];
  doc.body.childNodes.forEach((node) => {
    if (node.nodeType === Node.TEXT_NODE) {
      lines.push(node.textContent || '');
      return;
    }
    if (node.nodeName === 'BR' || node.nodeName === 'P') {
      lines.push(node.textContent || '');
      lines.push('\n');
      return;
    }
    lines.push(node.textContent || '');
  });
  return lines.join('').replace(/\n{2,}/g, '\n').trim();
}

export function renderVerseContent(content) {
  if (typeof content === 'string') {
    return content;
  }
  if (Array.isArray(content)) {
    return content.map(renderVerseContent).join('');
  }
  if (content && typeof content === 'object') {
    if (content.lineBreak) {
      return '\n';
    }
    if (content.type === 'line_break') {
      return '\n';
    }
    if (Array.isArray(content.content)) {
      return renderVerseContent(content.content);
    }
    if (typeof content.text === 'string') {
      return content.text;
    }
    return '';
  }
  return '';
}

export function parseBibleChapter(data) {
  if (data?.verses && Array.isArray(data.verses)) {
    return data.verses.map((verse) => ({
      number: verse.number,
      text: verse.text,
    }));
  }

  const chapterContents = data?.chapter?.content;
  if (!Array.isArray(chapterContents)) {
    return [];
  }

  return chapterContents
    .filter((item) => item?.type === 'verse')
    .map((item) => ({
      number: item.number,
      text: renderVerseContent(item.content).replace(/\s+/g, ' ').trim(),
    }));
}

// ---------------------------------------------------------------------------
// Storage helpers
// ---------------------------------------------------------------------------

const INDEX_KEY_LEGACY = 'bible-study-index';
const projectKeyLegacy = (id) => `bible-study-project-${id}`;

let activeStorageUserId = null;

export function indexKey() {
  return activeStorageUserId ? `bible-study-index:${activeStorageUserId}` : INDEX_KEY_LEGACY;
}

export function projectKey(id) {
  return activeStorageUserId ? `bible-study-project:${activeStorageUserId}:${id}` : projectKeyLegacy(id);
}

export function loadProjectIndex() {
  try {
    const raw = window.localStorage.getItem(indexKey());
    return raw ? JSON.parse(raw) : [];
  } catch {
    return [];
  }
}

function migrateLegacyLocalDataToUser(userId) {
  if (!userId || window.localStorage.getItem(`bible-study-index:${userId}`)) return;
  const legacyRaw = window.localStorage.getItem(INDEX_KEY_LEGACY);
  if (!legacyRaw) return;
  try {
    const legacyIndex = JSON.parse(legacyRaw) ?? [];
    legacyIndex.forEach((entry) => {
      const raw = window.localStorage.getItem(projectKeyLegacy(entry.id));
      if (raw != null) {
        window.localStorage.setItem(`bible-study-project:${userId}:${entry.id}`, raw);
        window.localStorage.removeItem(projectKeyLegacy(entry.id));
      }
    });
    window.localStorage.setItem(`bible-study-index:${userId}`, legacyRaw);
    window.localStorage.removeItem(INDEX_KEY_LEGACY);
  } catch {
    // Leave legacy data in place if anything goes wrong
  }
}

export function switchStorageUser(userId) {
  activeStorageUserId = userId ?? null;
  if (userId) migrateLegacyLocalDataToUser(userId);
  return loadProjectIndex();
}

// ---------------------------------------------------------------------------
// Components
// ---------------------------------------------------------------------------

export function BookmarkIcon({ filled }) {
  return (
    <svg viewBox="0 0 20 20" width="16" height="16" fill={filled ? 'currentColor' : 'none'} stroke="currentColor" strokeWidth="1.6">
      <path d="M5 3.5C5 2.67 5.67 2 6.5 2h7c.83 0 1.5.67 1.5 1.5v14l-5-3.5-5 3.5v-14z" strokeLinejoin="round" />
    </svg>
  );
}

export function CopyIcon() {
  return (
    <svg viewBox="0 0 20 20" width="16" height="16" fill="none" stroke="currentColor" strokeWidth="1.6">
      <rect x="7" y="7" width="10" height="11" rx="1.5" />
      <path d="M4.5 13.5h-1A1.5 1.5 0 0 1 2 12V3.5A1.5 1.5 0 0 1 3.5 2H12a1.5 1.5 0 0 1 1.5 1.5v1" strokeLinecap="round" strokeLinejoin="round" />
    </svg>
  );
}

export function CrossRefChip({ label, onRemove, loadVerseText }) {
  const [hovered, setHovered] = useState(false);
  const [verseText, setVerseText] = useState(null);
  const [error, setError] = useState('');

  useEffect(() => {
    if (!hovered || verseText || error) return;
    let cancelled = false;
    loadVerseText(label)
      .then((text) => { if (!cancelled) setVerseText(text || 'Verse text unavailable.'); })
      .catch(() => { if (!cancelled) setError('Verse text unavailable.'); });
    return () => { cancelled = true; };
  }, [hovered]);

  return (
    <span
      className="relative inline-flex items-center gap-1 rounded-full bg-slate-200 px-3 py-1 text-sm text-slate-800"
      onMouseEnter={() => setHovered(true)}
      onMouseLeave={() => setHovered(false)}
    >
      {label}
      {onRemove && (
        <button
          type="button"
          onClick={onRemove}
          className="ml-1 text-slate-500 hover:text-rose-600"
          aria-label={`Remove ${label}`}
        >
          ×
        </button>
      )}
      {hovered && (
        <span className="absolute bottom-full left-0 z-10 mb-2 w-64 rounded-xl border border-slate-300 bg-white p-3 text-xs font-normal normal-case text-slate-700 shadow-lg">
          {error || verseText || 'Loading...'}
        </span>
      )}
    </span>
  );
}
