import crypto from 'node:crypto';

const PURPOSES = {
  inline_image: { presetId: 'memind_square_illustration', filename: 'inline-image.webp' },
  hero: { presetId: 'memind_dark_hero', filename: 'hero.webp' },
  card_cover: { presetId: 'memind_card_cover', filename: 'card-cover.webp' },
  feed_cover: { presetId: 'memind_feed_cover_source', filename: 'feed-cover.webp' },
};

export function createMindSpaceImageGenerationService({
  configService,
  assetService,
  imageMakeClient,
  logger = console,
} = {}) {
  async function generate({
    userId,
    purpose,
    prompt,
    negativePrompt = '',
    consumerRef = '',
    idempotencyKey,
  } = {}) {
    const spec = PURPOSES[purpose];
    if (!spec) {
      return { ok: false, fallback: true, code: 'unsupported_purpose', message: '不支持的图片生成用途' };
    }
    if (!configService?.resolveImageGenerationPurpose) {
      return { ok: false, fallback: true, code: 'gateway_unavailable', message: '图片生成能力未启用' };
    }
    const gate = await configService.resolveImageGenerationPurpose(purpose);
    if (!gate.ok) return { ...gate, fallback: true };
    if (!imageMakeClient || !assetService?.createChatAsset) {
      return { ok: false, fallback: true, code: 'runtime_unavailable', message: '图片生成服务未配置' };
    }

    try {
      const generated = await imageMakeClient.generateImage({
        prompt,
        negativePrompt,
        presetId: gate.presetId ?? spec.presetId,
        consumerRef,
        idempotencyKey: idempotencyKey || `imgreq_${crypto.randomUUID()}`,
      });
      const asset = await assetService.createChatAsset(userId, {
        categoryCode: 'public',
        buffer: generated.buffer,
        filename: spec.filename,
        displayName: spec.filename,
        sourceType: 'image_make',
      });
      await imageMakeClient.acknowledge(generated.jobId, asset.id).catch((error) => {
        logger.warn?.('[image_make] acknowledge failed; TTL cleanup will apply:', error?.message ?? error);
      });
      return {
        ok: true,
        purpose,
        jobId: generated.jobId,
        asset,
        source: {
          mimeType: generated.mimeType,
          width: generated.width,
          height: generated.height,
          sha256: generated.sha256,
        },
      };
    } catch (error) {
      logger.warn?.('[image_make] generation failed; existing flow remains active:', error?.message ?? error);
      return {
        ok: false,
        fallback: true,
        code: error?.code ?? 'image_make_unavailable',
        message: '图片生成暂不可用，已保留原有流程',
      };
    }
  }

  return { purposes: Object.keys(PURPOSES), generate };
}