const PURPOSES = new Set(['inline_image', 'hero', 'card_cover', 'feed_cover']);

async function handleGenerate(req, res, { service, userId, consumerPrefix }) {
    if (!service) {
      return res.status(503).json({
        ok: false,
        fallback: true,
        code: 'runtime_unavailable',
        message: '图片生成服务未配置',
      });
    }
    const purpose = String(req.body?.purpose ?? '').trim().toLowerCase();
    const prompt = String(req.body?.prompt ?? '').trim();
    if (!PURPOSES.has(purpose)) {
      return res.status(400).json({ message: '不支持的图片生成用途' });
    }
    if (!prompt || prompt.length > 1600) {
      return res.status(400).json({ message: '图片描述不能为空且不能超过 1600 字符' });
    }
    const headerIdempotencyKey = String(req.get('idempotency-key') ?? '').trim();
    const bodyIdempotencyKey = String(req.body?.idempotency_key ?? '').trim();
    const idempotencyKey = headerIdempotencyKey || bodyIdempotencyKey || undefined;
    if (idempotencyKey && idempotencyKey.length > 128) {
      return res.status(400).json({ message: '幂等键不能超过 128 字符' });
    }
    const result = await service.generate({
      userId,
      purpose,
      prompt,
      negativePrompt: req.body?.negative_prompt,
      consumerRef: `${consumerPrefix}:${idempotencyKey || req.requestId || 'request'}:${purpose}`,
      idempotencyKey,
    });
    if (!result.ok) {
      const unavailable = new Set([
        'runtime_unavailable',
        'image_make_unavailable',
        'IMAGE_MAKE_HTTP_ERROR',
        'IMAGE_MAKE_TIMEOUT',
      ]).has(result.code);
      return res.status(unavailable ? 503 : 409).json(result);
    }
    return res.status(201).json({ data: result });
}

export function attachMindSpaceImageGenerationRoutes(
  router,
  { getService, requireInternal = null } = {},
) {
  router.post('/mindspace/v1/images/generate', async (req, res) => {
    const service = getService?.();
    return handleGenerate(req, res, {
      service,
      userId: req.currentUser.id,
      consumerPrefix: 'mindspace',
    });
  });

  if (requireInternal) {
    router.post('/agent/mindspace_image_generate', async (req, res) => {
      if (!requireInternal(req, res)) return;
      const userId = String(req.body?.user_id ?? req.body?.userId ?? '').trim();
      if (!userId) return res.status(400).json({ message: '缺少 user_id' });
      return handleGenerate(req, res, {
        service: getService?.(),
        userId,
        consumerPrefix: 'mindspace-agent',
      });
    });
  }
}