/**
 * Kling 官方 API 适配器 · api-beijing.klingai.com
 * D136+ · 铸渊 ICE-GL-ZY001 · 2026-06-21
 * 
 * 文档: https://klingai.com/document-api/guides/get-started/quick-start
 * Base URL: https://api-beijing.klingai.com
 * 端点: POST /v1/videos/text2video (提交) + GET /v1/videos/{task_id} (查询)
 * 
 * 认证: Bearer <API_KEY> (JWT三段式token, 在 klingai.com/dev/api-key 生成)
 * 模型ID: kling-v2-6 (kling-v2.6) / kling-v3 / kling-video-o1 等
 * 
 * 价格: 试用包70元/月 · kling-v2-6 约0.049/s (5秒≈0.25元)
 */
const fs = require('fs');
const path = require('path');
const https = require('https');
const { loadVideoAiEnv } = require('./env-loader');

// ═══ 从环境变量读取 ═══
loadVideoAiEnv(path.resolve(__dirname, '../.env'));
const API_KEY = process.env.KLING_API_KEY || '';
const BASE_URL = 'api-beijing.klingai.com';
const POLL_INTERVAL = 2000;
const MAX_POLL = 180;

const JZAO_SHOTS = '/Volumes/JZAO/铸渊-ICE-GL-ZY001/OUT-输出/视频/zai-fu-fei-xiu-xian/ep01';
const LOCAL_SHOTS = path.resolve(__dirname, '../outputs/shots');
const OUT_DIR = fs.existsSync(JZAO_SHOTS) ? JZAO_SHOTS : LOCAL_SHOTS;

function apiRequest(method, path_, body = null) {
  return new Promise((resolve, reject) => {
    const options = {
      hostname: BASE_URL,
      path: path_,
      method,
      headers: {
        'Authorization': `Bearer ${API_KEY}`,
        'Content-Type': 'application/json',
      },
    };
    const req = https.request(options, (res) => {
      let data = '';
      res.on('data', chunk => data += chunk);
      res.on('end', () => {
        try { resolve({ status: res.statusCode, ...JSON.parse(data) }); }
        catch (e) { resolve({ status: res.statusCode, raw: data }); }
      });
    });
    req.on('error', reject);
    req.setTimeout(30000, () => { req.destroy(); reject(new Error('timeout')); });
    if (body) req.write(JSON.stringify(body));
    req.end();
  });
}

function downloadFile(url, dest) {
  return new Promise((resolve, reject) => {
    const file = fs.createWriteStream(dest);
    const proto = url.startsWith('https') ? https : require('http');
    proto.get(url, (res) => {
      if (res.statusCode >= 300 && res.statusCode < 400) {
        return downloadFile(res.headers.location, dest).then(resolve).catch(reject);
      }
      res.pipe(file);
      file.on('finish', () => { file.close(); resolve(dest); });
    }).on('error', reject);
  });
}

/**
 * 提交任务 + 轮询 + 下载
 */
async function generateVideo({ prompt, duration = 5, outputPath, model = 'kling-v2-6' }) {
  if (!API_KEY) throw new Error('KLING_API_KEY 未设置。在 klingai.com/dev/api-key 生成。');

  console.log('[Kling Official] 提交文生视频...');
  
  const submit = await apiRequest('POST', '/v1/videos/text2video', {
    model,
    prompt,
    duration: Math.min(duration, 10),
    aspect_ratio: '16:9',
    mode: 'std',
  });

  if (submit.code && submit.code !== 0) {
    throw new Error(`提交失败 [${submit.code}]: ${submit.message}`);
  }
  if (!submit.data?.task_id) {
    throw new Error(`提交失败: ${JSON.stringify(submit)}`);
  }

  const taskId = submit.data.task_id;
  console.log(`[Kling Official] 任务: ${taskId}`);

  // 轮询 → 查询端点 GET /v1/videos/text2video/{task_id}
  for (let i = 1; i <= MAX_POLL; i++) {
    await new Promise(r => setTimeout(r, POLL_INTERVAL));
    const status = await apiRequest('GET', `/v1/videos/text2video/${taskId}`);
    
    if (status.data?.task_status === 'succeed') {
      const videoUrl = status.data.task_result?.videos?.[0]?.url;
      if (!videoUrl) throw new Error('任务完成但无视频URL');
      
      const out = outputPath || path.join(OUT_DIR, `kling-official-${taskId}.mp4`);
      fs.mkdirSync(path.dirname(out), { recursive: true });
      console.log(`[Kling Official] 下载中...`);
      await downloadFile(videoUrl, out);
      console.log(`[Kling Official] ✅ ${path.basename(out)}`);
      return { videoPath: out, taskId };
    }
    
    if (status.data?.task_status === 'failed') {
      throw new Error(`生成失败: ${status.data.task_status_msg || JSON.stringify(status)}`);
    }
    
    if (i % 15 === 0) console.log(`[Kling Official] 生成中... ${status.data?.task_status} (${i}/${MAX_POLL})`);
  }
  throw new Error('轮询超时');
}

module.exports = { generateVideo };