fix: copy tool calls, generations, and timestamps when forking topics

Forked topics dropped toolCall/generation relations and rewrote part
lastUpdatedAt, which broke tool rendering, token stats, and reasoning durations.

server/api/topic/[topicId]/fork.post.ts

@@ -1,5 +1,5 @@
 import * as z from 'zod';
-import { messages, messageParts, attachments, topics } from '~~/drizzle/schema';
+import { messages, messageParts, attachments, topics, generations, toolCalls } from '~~/drizzle/schema';
 import { db } from '~~/server/lib/db';
 import { nanoid } from 'nanoid';
 import { eq, and, inArray } from 'drizzle-orm';
@@ -132,6 +132,38 @@ export default defineEventHandler(async (event) => {
     });
 
     const messageIdMap = new Map<string, string>();
+    const generationIdMap = new Map<string, string>();
+    const toolCallIdMap = new Map<string, string>();
+
+    const originalMessageIds = messagesToCopy.map(m => m.id);
+    const originalGenerationIds = [
+        ...new Set(
+            messagesToCopy
+                .map(m => m.generationId)
+                .filter((id): id is string => id !== null),
+        ),
+    ];
+
+    // Copy generations first so messages can reference them
+    if (originalGenerationIds.length > 0) {
+        const generationsToCopy = await db.select().from(generations)
+            .where(inArray(generations.id, originalGenerationIds));
+
+        for (const generation of generationsToCopy) {
+            const newGenerationId = nanoid();
+            generationIdMap.set(generation.id, newGenerationId);
+
+            await db.insert(generations).values({
+                id: newGenerationId,
+                userId,
+                topicId: newTopicId,
+                modelId: generation.modelId,
+                status: generation.status,
+                tokens: generation.tokens,
+                error: generation.error,
+            });
+        }
+    }
 
     for (const msg of messagesToCopy) {
         const newMessageId = nanoid();
@@ -142,13 +174,13 @@ export default defineEventHandler(async (event) => {
             userId,
             topicId: newTopicId,
             parentMessageId: msg.parentMessageId ? (messageIdMap.get(msg.parentMessageId) ?? null) : null,
-            generationId: null,
+            generationId: msg.generationId ? (generationIdMap.get(msg.generationId) ?? null) : null,
             role: msg.role,
             content: msg.content,
             activeChildId: null,
             deleted: msg.deleted,
             createdAt: msg.createdAt,
-            updatedAt: new Date(),
+            updatedAt: msg.updatedAt,
         });
     }
 
@@ -164,11 +196,40 @@ export default defineEventHandler(async (event) => {
         }
     }
 
-    const originalMessageIds = Array.from(messageIdMap.keys());
     if (originalMessageIds.length > 0) {
         const parts = await db.select().from(messageParts)
             .where(inArray(messageParts.messageId, originalMessageIds));
 
+        // Copy referenced tool calls before parts so FKs resolve
+        const originalToolCallIds = [
+            ...new Set(
+                parts
+                    .map(p => p.toolCallId)
+                    .filter((id): id is string => id !== null),
+            ),
+        ];
+
+        if (originalToolCallIds.length > 0) {
+            const toolCallsToCopy = await db.select().from(toolCalls)
+                .where(inArray(toolCalls.id, originalToolCallIds));
+
+            for (const toolCall of toolCallsToCopy) {
+                const newToolCallId = nanoid();
+                toolCallIdMap.set(toolCall.id, newToolCallId);
+
+                await db.insert(toolCalls).values({
+                    id: newToolCallId,
+                    userId,
+                    toolName: toolCall.toolName,
+                    status: toolCall.status,
+                    input: toolCall.input,
+                    output: toolCall.output,
+                    error: toolCall.error,
+                    createdAt: toolCall.createdAt,
+                });
+            }
+        }
+
         for (const part of parts) {
             const newMessageId = messageIdMap.get(part.messageId);
             if (!newMessageId) continue;
@@ -177,12 +238,14 @@ export default defineEventHandler(async (event) => {
                 userId,
                 topicId: newTopicId,
                 messageId: newMessageId,
+                toolCallId: part.toolCallId ? (toolCallIdMap.get(part.toolCallId) ?? null) : null,
                 type: part.type,
                 content: part.content,
                 providerOptions: part.providerOptions,
                 finished: part.finished,
+                // Preserve original timestamps so reasoning duration stays accurate
                 createdAt: part.createdAt,
-                lastUpdatedAt: new Date(),
+                lastUpdatedAt: part.lastUpdatedAt,
             });
         }
 
@@ -198,7 +261,7 @@ export default defineEventHandler(async (event) => {
                 topicId: newTopicId,
                 messageId: newMessageId,
                 fileId: attachment.fileId,
-                createdAt: new Date(),
+                createdAt: attachment.createdAt,
             });
         }
     }