SubMiner/src/core/services/stats-server.ts

import { Hono } from 'hono';
import http, { type IncomingMessage, type ServerResponse } from 'node:http';
import { Readable } from 'node:stream';
import type { AnkiConnectConfig } from '../../types.js';
import type { AnilistRateLimiter } from './anilist/rate-limiter.js';
import type { ImmersionTrackerService } from './immersion-tracker-service.js';
import type { RetimedSecondarySubtitleInput } from './secondary-subtitle-sidecar.js';
import type { StatsServerMediaGenerator } from './stats-server/mining-support.js';
import {
  registerStatsAnalyticsRoutes,
  registerStatsIntegrationRoutes,
  registerStatsLibraryRoutes,
  registerStatsMiningRoutes,
  registerStatsStaticRoutes,
} from './stats-server/routes.js';

export type { StatsMiningTimingEvent } from './stats-server/mining-support.js';
import type { StatsMiningTimingEvent } from './stats-server/mining-support.js';

function toFetchHeaders(headers: IncomingMessage['headers']): Headers {
  const fetchHeaders = new Headers();
  for (const [name, value] of Object.entries(headers)) {
    if (value === undefined) continue;
    if (Array.isArray(value)) {
      for (const entry of value) fetchHeaders.append(name, entry);
      continue;
    }
    fetchHeaders.set(name, value);
  }
  return fetchHeaders;
}

function toFetchRequest(req: IncomingMessage): Request {
  const method = req.method ?? 'GET';
  const url = new URL(req.url ?? '/', `http://${req.headers.host ?? '127.0.0.1'}`);
  const init: RequestInit & { duplex?: 'half' } = {
    method,
    headers: toFetchHeaders(req.headers),
  };
  if (method !== 'GET' && method !== 'HEAD') {
    init.body = Readable.toWeb(req) as BodyInit;
    init.duplex = 'half';
  }
  return new Request(url, init);
}

async function writeFetchResponse(res: ServerResponse, response: Response): Promise<void> {
  res.statusCode = response.status;
  response.headers.forEach((value, key) => res.setHeader(key, value));
  res.end(Buffer.from(await response.arrayBuffer()));
}

function startNodeHttpServer(app: Hono, config: StatsServerConfig): { close: () => void } {
  const server = http.createServer((req, res) => {
    void (async () => {
      try {
        await writeFetchResponse(res, await app.fetch(toFetchRequest(req)));
      } catch {
        res.statusCode = 500;
        res.end('Internal Server Error');
      }
    })();
  });
  server.listen(config.port, '127.0.0.1');
  return {
    close: () => {
      server.close();
    },
  };
}

export interface StatsServerConfig {
  port: number;
  staticDir: string; // Path to stats/dist/
  tracker: ImmersionTrackerService;
  knownWordCachePath?: string;
  mpvSocketPath?: string;
  ankiConnectConfig?: AnkiConnectConfig;
  getAnkiConnectConfig?: () => AnkiConnectConfig | undefined;
  getYomitanAnkiDeckName?: () => Promise<string | null | undefined> | string | null | undefined;
  secondarySubtitleLanguages?: string[];
  getSecondarySubtitleLanguages?: () => string[] | undefined;
  statsMiningAlassPath?: string;
  getStatsMiningAlassPath?: () => string | null | undefined;
  resolveRetimedSecondarySubtitleText?: (
    input: RetimedSecondarySubtitleInput,
  ) => Promise<string> | string;
  anilistRateLimiter?: AnilistRateLimiter;
  addYomitanNote?: (word: string) => Promise<number | null>;
  resolveAnkiNoteId?: (noteId: number) => number;
  resolveSentenceSearchHeadwords?: (term: string) => Promise<string[]> | string[];
}

export function createStatsApp(
  tracker: ImmersionTrackerService,
  options?: {
    staticDir?: string;
    knownWordCachePath?: string;
    mpvSocketPath?: string;
    ankiConnectConfig?: AnkiConnectConfig;
    getAnkiConnectConfig?: () => AnkiConnectConfig | undefined;
    getYomitanAnkiDeckName?: () => Promise<string | null | undefined> | string | null | undefined;
    secondarySubtitleLanguages?: string[];
    getSecondarySubtitleLanguages?: () => string[] | undefined;
    statsMiningAlassPath?: string;
    getStatsMiningAlassPath?: () => string | null | undefined;
    resolveRetimedSecondarySubtitleText?: (
      input: RetimedSecondarySubtitleInput,
    ) => Promise<string> | string;
    anilistRateLimiter?: AnilistRateLimiter;
    addYomitanNote?: (word: string) => Promise<number | null>;
    resolveAnkiNoteId?: (noteId: number) => number;
    resolveSentenceSearchHeadwords?: (term: string) => Promise<string[]> | string[];
    createMediaGenerator?: () => StatsServerMediaGenerator;
    onMiningTiming?: (event: StatsMiningTimingEvent) => void;
    nowMs?: () => number;
  },
) {
  const app = new Hono();
  registerStatsAnalyticsRoutes(app, tracker, options);
  registerStatsLibraryRoutes(app, tracker, options);
  registerStatsIntegrationRoutes(app, tracker, options);
  registerStatsMiningRoutes(app, options);
  registerStatsStaticRoutes(app, options?.staticDir);
  return app;
}

export function startStatsServer(config: StatsServerConfig): { close: () => void } {
  const app = createStatsApp(config.tracker, {
    staticDir: config.staticDir,
    knownWordCachePath: config.knownWordCachePath,
    mpvSocketPath: config.mpvSocketPath,
    ankiConnectConfig: config.ankiConnectConfig,
    getAnkiConnectConfig: config.getAnkiConnectConfig,
    getYomitanAnkiDeckName: config.getYomitanAnkiDeckName,
    secondarySubtitleLanguages: config.secondarySubtitleLanguages,
    getSecondarySubtitleLanguages: config.getSecondarySubtitleLanguages,
    statsMiningAlassPath: config.statsMiningAlassPath,
    getStatsMiningAlassPath: config.getStatsMiningAlassPath,
    resolveRetimedSecondarySubtitleText: config.resolveRetimedSecondarySubtitleText,
    anilistRateLimiter: config.anilistRateLimiter,
    addYomitanNote: config.addYomitanNote,
    resolveAnkiNoteId: config.resolveAnkiNoteId,
    resolveSentenceSearchHeadwords: config.resolveSentenceSearchHeadwords,
  });

  const bunRuntime = globalThis as typeof globalThis & {
    Bun?: {
      serve?: (options: { fetch: (typeof app)['fetch']; port: number; hostname: string }) => {
        stop: () => void;
      };
    };
  };
  if (bunRuntime.Bun?.serve) {
    const server = bunRuntime.Bun.serve({
      fetch: app.fetch,
      port: config.port,
      hostname: '127.0.0.1',
    });
    return { close: () => server.stop() };
  }
  return startNodeHttpServer(app, config);
}