feat(round-12): 实体卡外贸生产工单/雷达多渠道归因漏斗/AI地道外联草拟/现代图片自适应协商 (87套件1007测试全绿)

backend/src/modules/card/service/media-negotiator.ts

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+import { Provide } from '@midwayjs/core';
+import { BaseService } from '@cool-midway/core';
+
+export type SupportedImageFormat = 'avif' | 'webp' | 'png' | 'jpg';
+
+export interface MediaNegotiationContext {
+  acceptHeader?: string;
+  networkType?: 'wifi' | '5g' | '4g' | '3g' | '2g' | 'unknown' | string;
+  targetWidth?: number;
+  dpr?: number;
+}
+
+export interface OptimizedMediaResult {
+  format: SupportedImageFormat;
+  width?: number;
+  quality: number;
+  optimizedUrl: string;
+}
+
+/**
+ * 协商最佳媒体交付 URL 与压缩参数
+ */
+export function negotiateOptimalMediaUrl(
+  url: string,
+  ctx: MediaNegotiationContext
+): OptimizedMediaResult {
+  if (!url || typeof url !== 'string' || !url.trim()) {
+    return {
+      format: 'jpg',
+      quality: 80,
+      optimizedUrl: '',
+    };
+  }
+
+  const accept = (ctx.acceptHeader || '').toLowerCase();
+  const net = (ctx.networkType || 'wifi').toLowerCase();
+  const isSlowNetwork = net === '2g' || net === '3g';
+
+  // 1. 协商格式: avif > webp > 原图扩展名(png/jpg)
+  let format: SupportedImageFormat = 'jpg';
+  if (accept.includes('image/avif')) {
+    format = 'avif';
+  } else if (accept.includes('image/webp')) {
+    format = 'webp';
+  } else if (url.toLowerCase().endsWith('.png') || accept.includes('image/png')) {
+    format = 'png';
+  }
+
+  // 2. 协商质量与宽度
+  let quality = 85;
+  if (isSlowNetwork) {
+    quality = 65;
+  }
+
+  let width = ctx.targetWidth;
+  if (width != null && width > 0) {
+    const dpr = ctx.dpr && ctx.dpr > 1 ? ctx.dpr : 1;
+    if (isSlowNetwork) {
+      // 弱网降规 75%
+      width = Math.round(width * 0.75);
+    } else {
+      width = Math.round(width * dpr);
+    }
+  }
+
+  // 3. 构造优化 URL 参数
+  const separator = url.includes('?') ? '&' : '?';
+  const queryParts: string[] = [`format=${format}`, `q=${quality}`];
+  if (width != null && width > 0) {
+    queryParts.push(`w=${width}`);
+  }
+
+  const optimizedUrl = `${url}${separator}${queryParts.join('&')}`;
+
+  return {
+    format,
+    width,
+    quality,
+    optimizedUrl,
+  };
+}
+
+/**
+ * 微官网现代图片自适应协商服务
+ */
+@Provide()
+export class PortalMediaNegotiatorService extends BaseService {
+  negotiate(url: string, ctx: MediaNegotiationContext): OptimizedMediaResult {
+    return negotiateOptimalMediaUrl(url, ctx);
+  }
+}