Merge feat/delete-conversations-branches: DELETE conversations + branches endpoints

Author: scotty595

src/routes/drift/index.ts

@@ -218,6 +218,171 @@ const driftRoutes: FastifyPluginAsyncTypebox = async (fastify) => {
     }
   );
 
+  // Delete a conversation and everything belonging to it
+  fastify.delete(
+    '/conversations/:conversationId',
+    {
+      schema: {
+        description:
+          'Delete a conversation and all of its branches, messages, and facts. Use this to implement client "Clear history" flows. Returns 404 when the conversation does not exist (or belongs to another user).',
+        tags: ['Drift'],
+        params: Type.Object({
+          conversationId: Type.String(),
+        }),
+        response: {
+          200: Type.Object({
+            success: Type.Literal(true),
+            data: Type.Object({
+              deletedBranches: Type.Number(),
+              deletedMessages: Type.Number(),
+              deletedFacts: Type.Number(),
+            }),
+          }),
+          404: Type.Object({
+            success: Type.Literal(false),
+            error: Type.Object({ message: Type.String() }),
+          }),
+        },
+      },
+    },
+    async (request, reply) => {
+      const { conversationId } = request.params;
+      const userId = request.userId ?? '';
+
+      const conversation = await fastify.prisma.conversation.findUnique({
+        where: { userId_id: { userId, id: conversationId } },
+        select: { id: true },
+      });
+
+      if (!conversation) {
+        return reply.status(404).send({
+          success: false,
+          error: { message: 'Conversation not found' },
+        });
+      }
+
+      // Count what's about to go so we can report it back
+      const [deletedBranches, deletedMessages, deletedFacts] = await Promise.all([
+        fastify.prisma.branch.count({ where: { userId, conversationId } }),
+        fastify.prisma.message.count({ where: { userId, conversationId } }),
+        fastify.prisma.fact.count({
+          where: { branch: { userId, conversationId } },
+        }),
+      ]);
+
+      // Atomic cascade. Prisma cascades Conversation -> Branches/Clusters/Messages
+      // and Branch -> Facts/ClusterMemberships/TailRoutes/MergeEdges. TailRoutes
+      // anchored to these messages (anchorMessageId has no cascade) are cleared
+      // explicitly; DriftLog has no FK and is cleaned by conversationId.
+      await fastify.prisma.$transaction(async (tx) => {
+        const msgs = await tx.message.findMany({
+          where: { userId, conversationId },
+          select: { id: true },
+        });
+        const messageIds = msgs.map((m) => m.id);
+        if (messageIds.length > 0) {
+          await tx.tailRoute.deleteMany({
+            where: { anchorMessageId: { in: messageIds } },
+          });
+        }
+        await tx.driftLog.deleteMany({ where: { conversationId } });
+        await tx.conversation.delete({
+          where: { userId_id: { userId, id: conversationId } },
+        });
+      });
+
+      return reply.send({
+        success: true,
+        data: { deletedBranches, deletedMessages, deletedFacts },
+      });
+    }
+  );
+
+  // Delete a single branch. Children cascade: deleting a branch also deletes
+  // every descendant branch plus their messages and facts. Document this
+  // behaviour in the SDK / API reference.
+  fastify.delete(
+    '/branches/:branchId',
+    {
+      schema: {
+        description:
+          'Delete a branch and every descendant branch (cascading), including their messages and facts. Returns 404 when the branch does not exist or belongs to another user.',
+        tags: ['Drift'],
+        params: Type.Object({
+          branchId: Type.String(),
+        }),
+        response: {
+          200: Type.Object({
+            success: Type.Literal(true),
+            data: Type.Object({
+              deletedMessages: Type.Number(),
+              deletedFacts: Type.Number(),
+            }),
+          }),
+          404: Type.Object({
+            success: Type.Literal(false),
+            error: Type.Object({ message: Type.String() }),
+          }),
+        },
+      },
+    },
+    async (request, reply) => {
+      const { branchId } = request.params;
+      const userId = request.userId ?? '';
+
+      const branch = await fastify.prisma.branch.findUnique({
+        where: { id: branchId },
+        select: { userId: true },
+      });
+
+      // 404 covers both "does not exist" and "belongs to someone else" to avoid
+      // leaking branch ID existence across tenants.
+      if (!branch || branch.userId !== userId) {
+        return reply.status(404).send({
+          success: false,
+          error: { message: 'Branch not found' },
+        });
+      }
+
+      // Walk the subtree rooted at branchId via recursive CTE, scoped to user.
+      const rows = await fastify.prisma.$queryRaw<{ id: string }[]>`
+        WITH RECURSIVE branch_tree AS (
+          SELECT id FROM branches WHERE id = ${branchId} AND "userId" = ${userId}
+          UNION
+          SELECT b.id FROM branches b
+          INNER JOIN branch_tree bt ON b."parentId" = bt.id
+          WHERE b."userId" = ${userId}
+        )
+        SELECT id FROM branch_tree;
+      `;
+      const branchIds = rows.map((r) => r.id);
+
+      const [deletedMessages, deletedFacts] = await Promise.all([
+        fastify.prisma.message.count({ where: { branchId: { in: branchIds } } }),
+        fastify.prisma.fact.count({ where: { branchId: { in: branchIds } } }),
+      ]);
+
+      await fastify.prisma.$transaction(async (tx) => {
+        const msgs = await tx.message.findMany({
+          where: { branchId: { in: branchIds } },
+          select: { id: true },
+        });
+        const messageIds = msgs.map((m) => m.id);
+        if (messageIds.length > 0) {
+          await tx.tailRoute.deleteMany({
+            where: { anchorMessageId: { in: messageIds } },
+          });
+        }
+        await tx.branch.deleteMany({ where: { id: { in: branchIds } } });
+      });
+
+      return reply.send({
+        success: true,
+        data: { deletedMessages, deletedFacts },
+      });
+    }
+  );
+
   // Health check
   fastify.get(
     '/health',