import { Hono } from 'hono';
import { serve } from '@hono/node-server';
import type { ImmersionTrackerService } from './immersion-tracker-service.js';
import { extname, resolve, sep } from 'node:path';
import { readFileSync, existsSync, statSync } from 'node:fs';

function parseIntQuery(raw: string | undefined, fallback: number, maxLimit?: number): number {
  if (raw === undefined) return fallback;
  const n = Number(raw);
  if (!Number.isFinite(n) || n < 0) {
    return fallback;
  }
  const parsed = Math.floor(n);
  return maxLimit === undefined ? parsed : Math.min(parsed, maxLimit);
}

export interface StatsServerConfig {
  port: number;
  staticDir: string; // Path to stats/dist/
  tracker: ImmersionTrackerService;
}

const STATS_STATIC_CONTENT_TYPES: Record<string, string> = {
  '.css': 'text/css; charset=utf-8',
  '.gif': 'image/gif',
  '.html': 'text/html; charset=utf-8',
  '.ico': 'image/x-icon',
  '.jpeg': 'image/jpeg',
  '.jpg': 'image/jpeg',
  '.js': 'text/javascript; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.mjs': 'text/javascript; charset=utf-8',
  '.png': 'image/png',
  '.svg': 'image/svg+xml',
  '.txt': 'text/plain; charset=utf-8',
  '.webp': 'image/webp',
  '.woff': 'font/woff',
  '.woff2': 'font/woff2',
};

function resolveStatsStaticPath(staticDir: string, requestPath: string): string | null {
  const normalizedPath = requestPath.replace(/^\/+/, '') || 'index.html';
  const decodedPath = decodeURIComponent(normalizedPath);
  const absoluteStaticDir = resolve(staticDir);
  const absolutePath = resolve(absoluteStaticDir, decodedPath);
  if (absolutePath !== absoluteStaticDir && !absolutePath.startsWith(`${absoluteStaticDir}${sep}`)) {
    return null;
  }
  if (!existsSync(absolutePath)) {
    return null;
  }
  const stats = statSync(absolutePath);
  if (!stats.isFile()) {
    return null;
  }
  return absolutePath;
}

function createStatsStaticResponse(staticDir: string, requestPath: string): Response | null {
  const absolutePath = resolveStatsStaticPath(staticDir, requestPath);
  if (!absolutePath) {
    return null;
  }

  const extension = extname(absolutePath).toLowerCase();
  const contentType =
    STATS_STATIC_CONTENT_TYPES[extension] ?? 'application/octet-stream';
  const body = readFileSync(absolutePath);
  return new Response(body, {
    headers: {
      'Content-Type': contentType,
      'Cache-Control': absolutePath.endsWith('index.html')
        ? 'no-cache'
        : 'public, max-age=31536000, immutable',
    },
  });
}

export function createStatsApp(
  tracker: ImmersionTrackerService,
  options?: { staticDir?: string },
) {
  const app = new Hono();

  app.get('/api/stats/overview', async (c) => {
    const [sessions, rollups, hints] = await Promise.all([
      tracker.getSessionSummaries(5),
      tracker.getDailyRollups(14),
      tracker.getQueryHints(),
    ]);
    return c.json({ sessions, rollups, hints });
  });

  app.get('/api/stats/daily-rollups', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 60, 500);
    const rollups = await tracker.getDailyRollups(limit);
    return c.json(rollups);
  });

  app.get('/api/stats/monthly-rollups', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 24, 120);
    const rollups = await tracker.getMonthlyRollups(limit);
    return c.json(rollups);
  });

  app.get('/api/stats/streak-calendar', async (c) => {
    const days = parseIntQuery(c.req.query('days'), 90, 365);
    return c.json(await tracker.getStreakCalendar(days));
  });

  app.get('/api/stats/trends/episodes-per-day', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 90, 365);
    return c.json(await tracker.getEpisodesPerDay(limit));
  });

  app.get('/api/stats/trends/new-anime-per-day', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 90, 365);
    return c.json(await tracker.getNewAnimePerDay(limit));
  });

  app.get('/api/stats/trends/watch-time-per-anime', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 90, 365);
    return c.json(await tracker.getWatchTimePerAnime(limit));
  });

  app.get('/api/stats/sessions', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 50, 500);
    const sessions = await tracker.getSessionSummaries(limit);
    return c.json(sessions);
  });

  app.get('/api/stats/sessions/:id/timeline', async (c) => {
    const id = parseIntQuery(c.req.query('id') ?? c.req.param('id'), 0);
    if (id <= 0) return c.json([], 400);
    const limit = parseIntQuery(c.req.query('limit'), 200, 1000);
    const timeline = await tracker.getSessionTimeline(id, limit);
    return c.json(timeline);
  });

  app.get('/api/stats/sessions/:id/events', async (c) => {
    const id = parseIntQuery(c.req.query('id') ?? c.req.param('id'), 0);
    if (id <= 0) return c.json([], 400);
    const limit = parseIntQuery(c.req.query('limit'), 500, 1000);
    const events = await tracker.getSessionEvents(id, limit);
    return c.json(events);
  });

  app.get('/api/stats/vocabulary', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 100, 500);
    const excludePos = c.req.query('excludePos')?.split(',').filter(Boolean);
    const vocab = await tracker.getVocabularyStats(limit, excludePos);
    return c.json(vocab);
  });

  app.get('/api/stats/vocabulary/occurrences', async (c) => {
    const headword = (c.req.query('headword') ?? '').trim();
    const word = (c.req.query('word') ?? '').trim();
    const reading = (c.req.query('reading') ?? '').trim();
    if (!headword || !word) {
      return c.json([], 400);
    }
    const limit = parseIntQuery(c.req.query('limit'), 50, 500);
    const offset = parseIntQuery(c.req.query('offset'), 0, 10_000);
    const occurrences = await tracker.getWordOccurrences(headword, word, reading, limit, offset);
    return c.json(occurrences);
  });

  app.get('/api/stats/kanji', async (c) => {
    const limit = parseIntQuery(c.req.query('limit'), 100, 500);
    const kanji = await tracker.getKanjiStats(limit);
    return c.json(kanji);
  });

  app.get('/api/stats/kanji/occurrences', async (c) => {
    const kanji = (c.req.query('kanji') ?? '').trim();
    if (!kanji) {
      return c.json([], 400);
    }
    const limit = parseIntQuery(c.req.query('limit'), 50, 500);
    const offset = parseIntQuery(c.req.query('offset'), 0, 10_000);
    const occurrences = await tracker.getKanjiOccurrences(kanji, limit, offset);
    return c.json(occurrences);
  });

  app.get('/api/stats/vocabulary/:wordId/detail', async (c) => {
    const wordId = parseIntQuery(c.req.param('wordId'), 0);
    if (wordId <= 0) return c.body(null, 400);
    const detail = await tracker.getWordDetail(wordId);
    if (!detail) return c.body(null, 404);
    const animeAppearances = await tracker.getWordAnimeAppearances(wordId);
    const similarWords = await tracker.getSimilarWords(wordId);
    return c.json({ detail, animeAppearances, similarWords });
  });

  app.get('/api/stats/kanji/:kanjiId/detail', async (c) => {
    const kanjiId = parseIntQuery(c.req.param('kanjiId'), 0);
    if (kanjiId <= 0) return c.body(null, 400);
    const detail = await tracker.getKanjiDetail(kanjiId);
    if (!detail) return c.body(null, 404);
    const animeAppearances = await tracker.getKanjiAnimeAppearances(kanjiId);
    const words = await tracker.getKanjiWords(kanjiId);
    return c.json({ detail, animeAppearances, words });
  });

  app.get('/api/stats/media', async (c) => {
    const library = await tracker.getMediaLibrary();
    return c.json(library);
  });

  app.get('/api/stats/media/:videoId', async (c) => {
    const videoId = parseIntQuery(c.req.param('videoId'), 0);
    if (videoId <= 0) return c.json(null, 400);
    const [detail, sessions, rollups] = await Promise.all([
      tracker.getMediaDetail(videoId),
      tracker.getMediaSessions(videoId, 100),
      tracker.getMediaDailyRollups(videoId, 90),
    ]);
    return c.json({ detail, sessions, rollups });
  });

  app.get('/api/stats/anime', async (c) => {
    const rows = await tracker.getAnimeLibrary();
    return c.json(rows);
  });

  app.get('/api/stats/anime/:animeId', async (c) => {
    const animeId = parseIntQuery(c.req.param('animeId'), 0);
    if (animeId <= 0) return c.body(null, 400);
    const detail = await tracker.getAnimeDetail(animeId);
    if (!detail) return c.body(null, 404);
    const [episodes, anilistEntries] = await Promise.all([
      tracker.getAnimeEpisodes(animeId),
      tracker.getAnimeAnilistEntries(animeId),
    ]);
    return c.json({ detail, episodes, anilistEntries });
  });

  app.get('/api/stats/anime/:animeId/words', async (c) => {
    const animeId = parseIntQuery(c.req.param('animeId'), 0);
    const limit = parseIntQuery(c.req.query('limit'), 50, 200);
    if (animeId <= 0) return c.body(null, 400);
    return c.json(await tracker.getAnimeWords(animeId, limit));
  });

  app.get('/api/stats/anime/:animeId/rollups', async (c) => {
    const animeId = parseIntQuery(c.req.param('animeId'), 0);
    const limit = parseIntQuery(c.req.query('limit'), 90, 365);
    if (animeId <= 0) return c.body(null, 400);
    return c.json(await tracker.getAnimeDailyRollups(animeId, limit));
  });

  app.patch('/api/stats/media/:videoId/watched', async (c) => {
    const videoId = parseIntQuery(c.req.param('videoId'), 0);
    if (videoId <= 0) return c.body(null, 400);
    const body = await c.req.json().catch(() => null);
    const watched = typeof body?.watched === 'boolean' ? body.watched : true;
    await tracker.setVideoWatched(videoId, watched);
    return c.json({ ok: true });
  });

  app.get('/api/stats/anime/:animeId/cover', async (c) => {
    const animeId = parseIntQuery(c.req.param('animeId'), 0);
    if (animeId <= 0) return c.body(null, 404);
    const art = await tracker.getAnimeCoverArt(animeId);
    if (!art?.coverBlob) return c.body(null, 404);
    return new Response(new Uint8Array(art.coverBlob), {
      headers: {
        'Content-Type': 'image/jpeg',
        'Cache-Control': 'public, max-age=86400',
      },
    });
  });

  app.get('/api/stats/media/:videoId/cover', async (c) => {
    const videoId = parseIntQuery(c.req.param('videoId'), 0);
    if (videoId <= 0) return c.body(null, 404);
    let art = await tracker.getCoverArt(videoId);
    if (!art?.coverBlob) {
      await tracker.ensureCoverArt(videoId);
      art = await tracker.getCoverArt(videoId);
    }
    if (!art?.coverBlob) return c.body(null, 404);
    return new Response(new Uint8Array(art.coverBlob), {
      headers: {
        'Content-Type': 'image/jpeg',
        'Cache-Control': 'public, max-age=604800',
      },
    });
  });

  app.get('/api/stats/episode/:videoId/detail', async (c) => {
    const videoId = parseIntQuery(c.req.param('videoId'), 0);
    if (videoId <= 0) return c.body(null, 400);
    const sessions = await tracker.getEpisodeSessions(videoId);
    const words = await tracker.getEpisodeWords(videoId);
    const cardEvents = await tracker.getEpisodeCardEvents(videoId);
    return c.json({ sessions, words, cardEvents });
  });

  app.post('/api/stats/anki/browse', async (c) => {
    const noteId = parseIntQuery(c.req.query('noteId'), 0);
    if (noteId <= 0) return c.body(null, 400);
    try {
      const response = await fetch('http://127.0.0.1:8765', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ action: 'guiBrowse', version: 6, params: { query: `nid:${noteId}` } }),
      });
      const result = await response.json();
      return c.json(result);
    } catch {
      return c.json({ error: 'Failed to reach AnkiConnect' }, 502);
    }
  });

  app.post('/api/stats/anki/notesInfo', async (c) => {
    const body = await c.req.json().catch(() => null);
    const noteIds = Array.isArray(body?.noteIds) ? body.noteIds.filter((id: unknown) => typeof id === 'number') : [];
    if (noteIds.length === 0) return c.json([]);
    try {
      const response = await fetch('http://127.0.0.1:8765', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ action: 'notesInfo', version: 6, params: { notes: noteIds } }),
      });
      const result = await response.json() as { result?: Array<{ noteId: number; fields: Record<string, { value: string }> }> };
      return c.json(result.result ?? []);
    } catch {
      return c.json([], 502);
    }
  });

  if (options?.staticDir) {
    app.get('/assets/*', (c) => {
      const response = createStatsStaticResponse(options.staticDir!, c.req.path);
      if (!response) return c.text('Not found', 404);
      return response;
    });

    app.get('/index.html', (c) => {
      const response = createStatsStaticResponse(options.staticDir!, '/index.html');
      if (!response) return c.text('Stats UI not built', 404);
      return response;
    });

    app.get('*', (c) => {
      const staticResponse = createStatsStaticResponse(options.staticDir!, c.req.path);
      if (staticResponse) return staticResponse;
      const fallback = createStatsStaticResponse(options.staticDir!, '/index.html');
      if (!fallback) return c.text('Stats UI not built', 404);
      return fallback;
    });
  }

  return app;
}

export function startStatsServer(config: StatsServerConfig): { close: () => void } {
  const app = createStatsApp(config.tracker, { staticDir: config.staticDir });

  const server = serve({
    fetch: app.fetch,
    port: config.port,
    hostname: '127.0.0.1',
  });

  return {
    close: () => {
      server.close();
    },
  };
}