'use strict';

const express = require('express');
const path    = require('path');
const fs      = require('fs');

const PORT   = 8195;
const HOST   = '0.0.0.0';

const app = express();
app.use(express.json());
app.use(express.static(__dirname));

// ── Config ──────────────────────────────────────────────────────

const CONFIG_FILE = path.join(__dirname, 'config.json');

function loadConfig() {
  try {
    return JSON.parse(fs.readFileSync(CONFIG_FILE, 'utf8'));
  } catch {
    return { baseUrl: 'https://api.minimaxi.com' };
  }
}

function saveConfig(cfg) {
  fs.writeFileSync(CONFIG_FILE, JSON.stringify(cfg, null, 2));
}

app.get('/api/config', (req, res) => {
  const cfg = loadConfig();
  res.json({ baseUrl: cfg.baseUrl || 'https://api.minimaxi.com' });
});

app.post('/api/config', (req, res) => {
  const { baseUrl } = req.body;
  if (typeof baseUrl !== 'string') {
    return res.status(400).json({ error: '参数格式错误' });
  }
  const cfg = { baseUrl: baseUrl.trim() || 'https://api.minimaxi.com' };
  saveConfig(cfg);
  res.json({ ok: true });
});

// ── Image Generation ─────────────────────────────────────────────

app.post('/api/generate', async (req, res) => {
  const {
    model, prompt, aspect_ratio,
    width, height, response_format, seed,
    n, prompt_optimizer, aigc_watermark, apiKey,
  } = req.body;

  // Validation
  if (!prompt || typeof prompt !== 'string' || !prompt.trim()) {
    return res.status(400).json({ error: '请输入图片描述' });
  }
  if (model !== 'image-01') {
    return res.status(400).json({ error: 'model 参数无效' });
  }
  if (!apiKey || typeof apiKey !== 'string') {
    return res.status(400).json({ error: '未配置 API Key，请先在设置中填写。' });
  }

  // Build payload — only include optional fields that are set
  const payload = {
    model,
    prompt: prompt.trim(),
    response_format: response_format || 'url',
  };

  if (aspect_ratio)    payload.aspect_ratio    = aspect_ratio;
  if (width && height) { payload.width = width; payload.height = height; }
  if (seed)            payload.seed           = seed;
  if (n)               payload.n               = Math.min(Math.max(Number(n), 1), 9);
  if (prompt_optimizer) payload.prompt_optimizer = true;
  if (aigc_watermark)  payload.aigc_watermark = true;

  const baseUrl  = loadConfig().baseUrl || 'https://api.minimaxi.com';
  const endpoint = `${baseUrl}/v1/image_generation`;

  let response;
  try {
    response = await fetch(endpoint, {
      method: 'POST',
      headers: {
        'Authorization':  `Bearer ${apiKey}`,
        'Content-Type':  'application/json',
      },
      body: JSON.stringify(payload),
    });
  } catch (err) {
    console.error('[generate] network error:', err.message);
    return res.status(502).json({ error: '无法连接 MiniMax API：' + err.message });
  }

  const data = await response.json();

  if (!response.ok) {
    const code    = data.base_resp?.status_code;
    const msg     = data.base_resp?.status_msg || data.error || `HTTP ${response.status}`;
    const friendly = friendlyError(code, msg);
    return res.status(response.status).json({ error: friendly });
  }

  // Return images + task id + metadata
  res.json({
    images:       data.data?.image_urls || data.data?.image_base64 || [],
    id:           data.id,
    success_count: data.metadata?.success_count ?? (Array.isArray(data.data?.image_urls || data.data?.image_base64) ? 1 : 0),
    failed_count:  data.metadata?.failed_count ?? 0,
  });
});

// ── Task Status (future-proofing) ───────────────────────────────

app.get('/api/task/:id', async (req, res) => {
  const apiKey = req.headers['x-api-key'];
  if (!apiKey) {
    return res.status(400).json({ error: '缺少 API Key。' });
  }
  const baseUrl = loadConfig().baseUrl || 'https://api.minimaxi.com';
  try {
    const response = await fetch(`${baseUrl}/v1/image_generation/${req.params.id}`, {
      headers: { 'Authorization': `Bearer ${apiKey}` },
    });
    const data = await response.json();
    if (!response.ok) {
      return res.status(response.status).json({ error: data.base_resp?.status_msg || '请求失败' });
    }
    res.json(data);
  } catch (err) {
    res.status(502).json({ error: err.message });
  }
});

// ── SPA fallback ───────────────────────────────────────────────

app.get('/', (req, res) => {
  res.sendFile(path.join(__dirname, 'index.html'));
});

app.listen(PORT, HOST, () => {
  console.log(`图片生成器运行于 http://0.0.0.0:${PORT}`);
});

// ── Helpers ─────────────────────────────────────────────────────

function friendlyError(code, msg) {
  const map = {
    1002: '触发限流，请稍后再试',
    1004: '账号鉴权失败，请检查 API Key 是否正确',
    1008: '账号余额不足',
    1026: '图片描述涉及敏感内容，请修改后重试',
    2013: '参数异常，请检查输入是否合规',
    2049: '无效的 API Key',
  };
  if (code && map[code]) return map[code];
  return msg;
}