fix: recover WeChat page thumbnail delivery

wechat/verify/generated-thumbnail.mjs

@@ -1,5 +1,10 @@
+import crypto from 'node:crypto';
 import fs from 'node:fs';
 import path from 'node:path';
+import {
+  parseMindspaceCoverMeta,
+  upsertMindspaceCoverMeta,
+} from '../../mindspace-cover-meta.mjs';
 
 const RASTER_MIME_PATTERN = /^image\/(?:png|jpeg|webp)$/i;
 
@@ -29,6 +34,7 @@ function normalizeGeneratedImage(result) {
   if (!htmlSrc && !publicUrl && !workspaceRelativePath) return null;
   return {
     jobId: String(result.jobId),
+    purpose: String(result.purpose ?? '').trim() || null,
     mimeType,
     assetId: String(asset.id ?? '').trim() || null,
     htmlSrc: htmlSrc || null,
@@ -141,6 +147,7 @@ export function verifyFreshWechatPageThumbnails(artifacts = [], images = []) {
         ok: false,
         reason: cover ? 'cover_not_from_current_run' : 'missing_generated_cover',
         artifact,
+        cover: cover || null,
         matches,
         skippedArtifacts,
       };
@@ -150,3 +157,103 @@ export function verifyFreshWechatPageThumbnails(artifacts = [], images = []) {
   }
   return { ok: true, reason: null, matches, skippedArtifacts };
 }
+
+function uniqueArtifactsByLocalPath(artifacts = []) {
+  const unique = new Map();
+  for (const artifact of artifacts) {
+    const localPath = String(artifact?.localPath ?? '').trim();
+    if (localPath) unique.set(localPath, artifact);
+  }
+  return [...unique.values()];
+}
+
+function atomicWriteHtml(localPath, content) {
+  const tempPath = path.join(
+    path.dirname(localPath),
+    `.${path.basename(localPath)}.wechat-thumbnail-${process.pid}-${crypto.randomUUID()}.tmp`,
+  );
+  try {
+    fs.writeFileSync(tempPath, content, 'utf8');
+    fs.renameSync(tempPath, localPath);
+  } finally {
+    try {
+      if (fs.existsSync(tempPath)) fs.unlinkSync(tempPath);
+    } catch {
+      // Best-effort cleanup only; the destination write already decided the result.
+    }
+  }
+}
+
+export function repairUnambiguousFreshWechatPageThumbnail({
+  artifacts = [],
+  images = [],
+  currentRunHtmlArtifacts = [],
+  verificationReason = '',
+} = {}) {
+  if (!['missing_generated_cover', 'cover_not_from_current_run'].includes(verificationReason)) {
+    return { ok: false, reason: 'verification_not_repairable' };
+  }
+  const eligibleArtifacts = uniqueArtifactsByLocalPath(
+    artifacts.filter((artifact) => !isWechatAuxiliaryPageArtifact(artifact)),
+  );
+  const pageImages = images.filter((image) => image?.purpose === 'hero' || !image?.purpose);
+  if (eligibleArtifacts.length !== 1 || pageImages.length !== 1) {
+    return {
+      ok: false,
+      reason: 'ambiguous_page_image_mapping',
+      artifactCount: eligibleArtifacts.length,
+      imageCount: pageImages.length,
+    };
+  }
+
+  const artifact = eligibleArtifacts[0];
+  const image = pageImages[0];
+  const cover = String(image?.htmlSrc ?? '').trim();
+  const localPath = String(artifact?.localPath ?? '').trim();
+  if (!cover || !localPath || !fs.existsSync(localPath)) {
+    return { ok: false, reason: 'repair_source_unavailable', artifact, image };
+  }
+
+  const normalizedRelativePath = String(artifact.relativePath ?? '').trim().replace(/\\/g, '/');
+  const currentRunArtifact = currentRunHtmlArtifacts.find(
+    (candidate) => String(candidate?.relativePath ?? '').trim().replace(/\\/g, '/') === normalizedRelativePath,
+  );
+  const sourceHtml = typeof currentRunArtifact?.content === 'string'
+    ? currentRunArtifact.content
+    : fs.readFileSync(localPath, 'utf8');
+  const coverMeta = parseMindspaceCoverMeta(sourceHtml);
+  if (!coverMeta) {
+    return { ok: false, reason: 'valid_cover_meta_required', artifact, image };
+  }
+
+  const repairedHtml = upsertMindspaceCoverMeta(sourceHtml, { cover });
+  atomicWriteHtml(localPath, repairedHtml);
+  return {
+    ok: true,
+    reason: null,
+    artifact,
+    image,
+    cover,
+    restoredCurrentRunHtml: Boolean(currentRunArtifact),
+  };
+}
+
+export function summarizeFreshWechatThumbnailVerification(verification, images = []) {
+  return {
+    reason: String(verification?.reason ?? 'unknown'),
+    artifact: verification?.artifact
+      ? {
+          relativePath: String(verification.artifact.relativePath ?? ''),
+          localPath: path.basename(String(verification.artifact.localPath ?? '')),
+        }
+      : null,
+    cover: String(verification?.cover ?? ''),
+    matches: Array.isArray(verification?.matches) ? verification.matches.length : 0,
+    images: images.map((image) => ({
+      jobId: String(image?.jobId ?? ''),
+      purpose: String(image?.purpose ?? ''),
+      htmlSrc: String(image?.htmlSrc ?? ''),
+      workspaceRelativePath: String(image?.workspaceRelativePath ?? ''),
+    })),
+  };
+}