From fa4b4183cf9ee49b53c32970959d7dd0de937db4 Mon Sep 17 00:00:00 2001
From: Your Name <your.email@example.com>
Date: Tue, 2 Jun 2026 14:35:44 +0800
Subject: [PATCH] fix: stabilize detail replacement result images

---
 .../api/chat/_lib/detail-replacement.ts       | 70 ++++++++++---------
 app/(chat)/api/chat/route.ts                  | 13 ++++
 2 files changed, 51 insertions(+), 32 deletions(-)

diff --git a/app/(chat)/api/chat/_lib/detail-replacement.ts b/app/(chat)/api/chat/_lib/detail-replacement.ts
index c3ac8a05a..08c667820 100644
--- a/app/(chat)/api/chat/_lib/detail-replacement.ts
+++ b/app/(chat)/api/chat/_lib/detail-replacement.ts
@@ -118,42 +118,48 @@ export async function normalizeReplacementResultImage(params: {
   const generatedBuffer = await fetchImageBufferFromUrl(params.generatedImageUrl);
   let targetWidth = params.referenceGeometry?.width;
   let targetHeight = params.referenceGeometry?.height;
-
-  if (!targetWidth || !targetHeight) {
-    const referenceBuffer = await fetchImageBufferFromUrl(params.referenceImageUrl);
-    const referenceMetadata = await sharp(referenceBuffer, { failOn: "none" })
-      .rotate()
-      .metadata();
-    targetWidth = referenceMetadata.width;
-    targetHeight = referenceMetadata.height;
-  }
-
-  if (!targetWidth || !targetHeight) {
-    throw new Error("无法读取参考图尺寸");
-  }
-
   const generatedMetadata = await sharp(generatedBuffer, { failOn: "none" })
     .rotate()
     .metadata();
-  if (generatedMetadata.width === targetWidth && generatedMetadata.height === targetHeight) {
-    return {
-      originalUrl: params.generatedImageUrl,
-      thumbnailUrl: params.generatedThumbnailUrl || params.generatedImageUrl,
-      imageSize: `${targetWidth}x${targetHeight}`,
-    };
+
+  if (!targetWidth || !targetHeight) {
+    try {
+      const referenceBuffer = await fetchImageBufferFromUrl(params.referenceImageUrl);
+      const referenceMetadata = await sharp(referenceBuffer, { failOn: "none" })
+        .rotate()
+        .metadata();
+      targetWidth = referenceMetadata.width;
+      targetHeight = referenceMetadata.height;
+    } catch (error) {
+      chatApiLogger.warn("[Chat API] Failed to read replacement reference size, hosting generated output as-is:", {
+        referenceImageUrl: params.referenceImageUrl,
+        generatedImageUrl: params.generatedImageUrl,
+        error: error instanceof Error ? error.message : "unknown",
+      });
+    }
   }
 
-  const normalizedBuffer = await sharp(generatedBuffer, { failOn: "none" })
-    .rotate()
-    .resize(targetWidth, targetHeight, {
-      // Keep the model output proportional when adapting it back to the reference page.
-      // `fill` stretches the picture and can squash products; `cover` behaves like a screenshot crop.
-      fit: "cover",
-      position: "centre",
-      withoutEnlargement: false,
-    })
-    .png()
-    .toBuffer();
+  const outputWidth = targetWidth || generatedMetadata.width;
+  const outputHeight = targetHeight || generatedMetadata.height;
+
+  if (!outputWidth || !outputHeight) {
+    throw new Error("无法读取结果图尺寸");
+  }
+
+  const imagePipeline = sharp(generatedBuffer, { failOn: "none" }).rotate();
+  const normalizedBuffer =
+    targetWidth && targetHeight
+      ? await imagePipeline
+          .resize(targetWidth, targetHeight, {
+            // Keep the model output proportional when adapting it back to the reference page.
+            // `fill` stretches the picture and can squash products; `cover` behaves like a screenshot crop.
+            fit: "cover",
+            position: "centre",
+            withoutEnlargement: false,
+          })
+          .png()
+          .toBuffer()
+      : await imagePipeline.png().toBuffer();
   const thumbnailBuffer = await createAgentImageThumbnailBuffer(normalizedBuffer);
 
   const uniqueSuffix = `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
@@ -167,7 +173,7 @@ export async function normalizeReplacementResultImage(params: {
   return {
     originalUrl: originalUpload.url,
     thumbnailUrl: thumbnailUpload.url,
-    imageSize: `${targetWidth}x${targetHeight}`,
+    imageSize: `${outputWidth}x${outputHeight}`,
   };
 }
 
diff --git a/app/(chat)/api/chat/route.ts b/app/(chat)/api/chat/route.ts
index 3bb818aae..8fed6e34c 100644
--- a/app/(chat)/api/chat/route.ts
+++ b/app/(chat)/api/chat/route.ts
@@ -249,6 +249,7 @@ import {
   ensureStructuredAgentFriendlyMessage,
   extractMessageImageAssetIds,
   extractMessageImageUrls,
+  isRemoteImageAccessible,
   injectHistoryImagesToLastUserMessage,
   normalizeAssistantImageMarkdown,
   normalizeResolvedTargetImageUrls,
@@ -3544,6 +3545,12 @@ export async function POST(request: Request) {
                           ? normalizeError.message
                           : "unknown",
                     });
+                  const rawResultAccessible = await isRemoteImageAccessible(
+                    firstImage.originalUrl
+                  ).catch(() => false);
+                  if (!rawResultAccessible) {
+                    throw normalizeError;
+                  }
                 }
 
                 await emitReplacementResultMessage({
@@ -4341,6 +4348,12 @@ export async function POST(request: Request) {
                             ? normalizeError.message
                             : "unknown",
                       });
+                    const rawResultAccessible = await isRemoteImageAccessible(
+                      firstImage.originalUrl
+                    ).catch(() => false);
+                    if (!rawResultAccessible) {
+                      throw normalizeError;
+                    }
                   }
                   chatApiLogger.info("[Chat API] Replacement image generation completed:", {
                     mode: replacementSourceType,