/**
 * Kneron Toolchain Task Scheduler — entry point
 *
 * 職責：
 * 1. 啟動時 fail-fast 驗證 config（修 D3 — T1-deviations.md）
 * 2. 建立各層 dependency（redis / minio / sseService / jobService）
 * 3. 組裝 Express app，mount legacy 路由
 * 4. 在背景啟動 done queue listener
 * 5. listen port
 *
 * **本檔不應再寫業務邏輯**。所有路由 / service / storage 細節都在 src/ 下。
 *
 * 重構說明（T4）：
 *   src/redis.js                — Redis client 與 helper
 *   src/storage/minio.js        — MinIO facade
 *   src/storage/local.js        — local volume helper
 *   src/services/sseService.js  — SSE client 管理
 *   src/services/jobService.js  — Job CRUD / advance / fail
 *   src/services/doneListener.js— done queue 背景監聽
 *   src/middleware/upload.js    — multer 上傳設定
 *   src/routes/legacy.js        — 既有 7 個路由
 *   src/app.js                  — Express app 組裝
 *
 * 既有 /jobs* 端點行為**完全不變**（byte-for-byte，除時間戳）。
 * D3 修復：本檔在 require 階段即呼叫 loadConfig() — 必填 env 缺漏會 throw 並 exit(1)。
 */

'use strict';

/* eslint-disable no-console */

require('dotenv').config();

const { loadConfig } = require('./src/config');
const { createClients } = require('./src/redis');
const { createMinioFacade } = require('./src/storage/minio');
const { createSseService } = require('./src/services/sseService');
const { createJobService, STAGES } = require('./src/services/jobService');
const { ensureWorkerGroups, startListenDone } = require('./src/services/doneListener');
const { createUploader } = require('./src/middleware/upload');
const { createHealthService } = require('./src/services/healthService');
const { createApp } = require('./src/app');

// D3 fail-fast：缺必填 env 即 process.exit(1)
let config;
try {
  config = loadConfig();
} catch (err) {
  console.error('[Scheduler] Config validation failed:', err.message);
  process.exit(1);
}

// 既有 env — 待後續整合到 config.js
const PORT = process.env.PORT || 4000;
const REDIS_URL = process.env.REDIS_URL || 'redis://localhost:6379';
const JOB_DATA_DIR = process.env.JOB_DATA_DIR || '/data/jobs';
const STORAGE_BACKEND = process.env.STORAGE_BACKEND || 'local';

// 依賴組裝
const { redis, redisSub } = createClients(REDIS_URL);
const minio = createMinioFacade();
if (minio.client) {
  console.log(`[Scheduler] MinIO storage enabled: ${minio.endpoint}/${minio.bucket}`);
}
const sseService = createSseService();
// 2026-05-18 e2e bug fix：v1 API `POST /api/v1/jobs` → jobService.writeInputToMinIO 需要 minio facade。
// 原本 server.js 漏傳 minio dep、jobService.js:68 `deps.minio || null` fallback 成 null、
// writeInputToMinIO line 358 throw 「minio dep is required」、API 回 502 storage_unavailable。
// 修法：傳 minio facade 進來。legacy CRUD 介面（沒 minio dep）行為不變—minio 是 optional dep。
const jobService = createJobService({ redis, sseService, jobDataDir: JOB_DATA_DIR, minio });

// T10：multer uploader 從 config 取上限（修 D5）
//   - maxFileSize = MULTIPART_MODEL_MAX_BYTES（預設 500MB）
//   - maxRefImages = MULTIPART_REF_IMAGES_MAX_COUNT（預設 100）
//     ref_image per-file 10MB 上限由 validator 用 config.multipart.refImageMaxBytes 把關
const uploader = createUploader({
  maxFileSize: config.multipart.modelMaxBytes,
  maxRefImages: config.multipart.refImagesMaxCount,
});
// T8：建立 healthService（不在這裡 start，等 listenDoneQueue 起來後再 start）
const healthService = createHealthService({ redis, config });
const app = createApp(
  { redis, jobService, sseService, minio, uploader, healthService },
  { config, storageBackend: STORAGE_BACKEND }
);

async function start() {
  await ensureWorkerGroups(redis);

  // done queue listener（背景）
  startListenDone({ redis, redisSub, jobService })
    .start()
    .catch((err) => {
      console.error('[Scheduler] Done listener fatal error:', err);
      process.exit(1);
    });

  // T8：啟動 health background polling（30s 一次，第一次立即觸發）
  healthService.start();

  // T8：graceful shutdown — 收到 SIGTERM/SIGINT 時停 polling，避免 process 卡住
  const onShutdown = (signal) => {
    console.log(`[Scheduler] Received ${signal}, stopping health polling`);
    try {
      healthService.stop();
    } catch (err) {
      console.error('[Scheduler] healthService.stop error:', err);
    }
    // 不在此 process.exit；交由 Node 自然結束（unref 過的 timer 不會擋 exit）
  };
  process.once('SIGTERM', () => onShutdown('SIGTERM'));
  process.once('SIGINT', () => onShutdown('SIGINT'));

  app.listen(PORT, () => {
    console.log(`[Scheduler] Running on port ${PORT}`);
    console.log(`[Scheduler] Redis: ${REDIS_URL}`);
    console.log(`[Scheduler] Job data dir: ${JOB_DATA_DIR}`);
    console.log(
      `[Scheduler] Storage: ${STORAGE_BACKEND}${minio.client ? ` (${minio.endpoint}/${minio.bucket})` : ''}`
    );
    console.log(`[Scheduler] Stages: ${STAGES.join(' -> ')}`);
    console.log(
      `[Scheduler] Auth config OK: issuer=${config.memberCenter.issuer}, audience=${config.converter.audience}`
    );
    // T10：印出 multipart / concurrency 配置，方便 ops 確認生效值（不含 secret）
    console.log(
      `[Scheduler] Multipart limits: model=${config.multipart.modelMaxBytes}B, ` +
        `ref_image=${config.multipart.refImageMaxBytes}B, ` +
        `ref_images_count=${config.multipart.refImagesMaxCount}`
    );
    console.log(
      `[Scheduler] Upload concurrency: max=${config.uploadConcurrency.maxConcurrent} ` +
        `(503 retry-after=${config.uploadConcurrency.retryAfterSeconds}s when full)`
    );
  });
}

start().catch((err) => {
  console.error('[Scheduler] Failed to start:', err);
  process.exit(1);
});

module.exports = app;