fix(chat): handle question and todo state

tests/runtime/opencode.test.ts

@@ -0,0 +1,62 @@
+import { describe, expect, it } from "bun:test";
+
+import { OpencodeRuntimeAdapter } from "../../src/runtime/opencode.js";
+
+const createRuntimeAdapter = (
+  messages: unknown[],
+  calls: {
+    reverted: string[];
+    removed: string[];
+  } = { reverted: [], removed: [] },
+) =>
+  Object.assign(Object.create(OpencodeRuntimeAdapter.prototype), {
+    messages: async () => messages,
+    revertMessage: async (_sessionId: string, messageId: string) => {
+      calls.reverted.push(messageId);
+    },
+    removeMessage: async (_sessionId: string, messageId: string) => {
+      calls.removed.push(messageId);
+    },
+  }) as OpencodeRuntimeAdapter;
+
+describe("OpencodeRuntimeAdapter.revertToUserMessage", () => {
+  it("skips reverting the first user message when the runtime session is empty", async () => {
+    const calls = { reverted: [] as string[], removed: [] as string[] };
+    const runtime = createRuntimeAdapter([], calls);
+
+    await runtime.revertToUserMessage("session-1", { userOrdinal: 1 });
+
+    expect(calls).toEqual({ reverted: [], removed: [] });
+  });
+
+  it("keeps ordinal mismatches visible when runtime messages exist", async () => {
+    const runtime = createRuntimeAdapter([
+      { info: { id: "user-1", role: "user" } },
+      { info: { id: "assistant-1", role: "assistant" } },
+    ]);
+
+    await expect(
+      runtime.revertToUserMessage("session-1", { userOrdinal: 2 }),
+    ).rejects.toThrow("target user message not found to revert");
+  });
+
+  it("reverts and removes messages from the target user message onward", async () => {
+    const calls = { reverted: [] as string[], removed: [] as string[] };
+    const runtime = createRuntimeAdapter(
+      [
+        { info: { id: "user-1", role: "user" } },
+        { info: { id: "assistant-1", role: "assistant" } },
+        { info: { id: "user-2", role: "user" } },
+        { info: { id: "assistant-2", role: "assistant" } },
+      ],
+      calls,
+    );
+
+    await runtime.revertToUserMessage("session-1", { userOrdinal: 2 });
+
+    expect(calls).toEqual({
+      reverted: ["user-2"],
+      removed: ["assistant-2", "user-2"],
+    });
+  });
+});