import { rm } from "fs/promises";
import { describe, expect, it, onTestFinished, vi } from "vitest";
import { ParsedHttpExchange } from "../../../test/harness/replayingCapiProxy.js";
import { CopilotClient, approveAll, defineTool, RuntimeConnection } from "../../src/index.js";
import { createSdkTestContext, isCI } from "./harness/sdkTestContext.js";
import { getFinalAssistantMessage, getNextEventOfType, retry } from "./harness/sdkTestHelper.js";

describe("Sessions", async () => {
    const {
        copilotClient: client,
        openAiEndpoint,
        homeDir,
        workDir,
        env,
    } = await createSdkTestContext();

    async function waitForExchanges(minimumCount = 1) {
        await retry(
            `capture ${minimumCount} chat completion request(s)`,
            async () => {
                const exchanges = await openAiEndpoint.getExchanges();
                expect(exchanges.length).toBeGreaterThanOrEqual(minimumCount);
            },
            1_200
        );
        return openAiEndpoint.getExchanges();
    }

    it.each([
        ["stdio", () => RuntimeConnection.forStdio({ path: process.env.COPILOT_CLI_PATH })],
        ["tcp", () => RuntimeConnection.forTcp({ path: process.env.COPILOT_CLI_PATH })],
    ] as const)(
        "createSession works without onPermissionRequest (%s)",
        async (_name, makeConnection) => {
            const standaloneClient = new CopilotClient({
                workingDirectory: workDir,
                env,
                connection: makeConnection(),
            });
            onTestFinished(async () => {
                try {
                    await standaloneClient.forceStop();
                } catch {
                    // ignore
                }
            });

            const session = await standaloneClient.createSession({});
            expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);
            await session.disconnect();
        }
    );

    it("resumeSession works without onPermissionRequest", async () => {
        const connectionToken = "client-e2e-resume-token";

        const tcpClient = new CopilotClient({
            workingDirectory: workDir,
            env,
            connection: RuntimeConnection.forTcp({
                path: process.env.COPILOT_CLI_PATH,
                connectionToken,
            }),
        });
        onTestFinished(async () => {
            try {
                await tcpClient.forceStop();
            } catch {
                // ignore
            }
        });

        const originalSession = await tcpClient.createSession({});

        const port = (tcpClient as unknown as { runtimePort: number | null }).runtimePort;
        if (!port) {
            throw new Error("Client must be using TCP transport to support multi-client resume.");
        }

        const resumeClient = new CopilotClient({
            workingDirectory: workDir,
            env,
            connection: RuntimeConnection.forUri(`localhost:${port}`, { connectionToken }),
        });
        onTestFinished(async () => {
            try {
                await resumeClient.forceStop();
            } catch {
                // ignore
            }
        });

        const resumedSession = await resumeClient.resumeSession(originalSession.sessionId, {});
        expect(resumedSession.sessionId).toBe(originalSession.sessionId);
        await resumedSession.disconnect();
        await originalSession.disconnect();
    });
    it("should create and disconnect sessions", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            model: "claude-sonnet-4.5",
        });
        expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);

        const allEvents = await session.getEvents();
        const sessionStartEvents = allEvents.filter((e) => e.type === "session.start");
        expect(sessionStartEvents).toMatchObject([
            {
                type: "session.start",
                data: { sessionId: session.sessionId, selectedModel: "claude-sonnet-4.5" },
            },
        ]);

        await session.disconnect();
        await expect(() => session.getEvents()).rejects.toThrow(/Session not found/);
    });

    // TODO: Re-enable once test harness CAPI proxy supports this test's session lifecycle
    it.skip("should list sessions with context field", { timeout: 60000 }, async () => {
        // Create a session — just creating it is enough for it to appear in listSessions
        const session = await client.createSession({ onPermissionRequest: approveAll });
        expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);

        // Verify it has a start event (confirms session is active)
        const messages = await session.getEvents();
        expect(messages.length).toBeGreaterThan(0);

        // List sessions and find the one we just created
        const sessions = await client.listSessions();
        const ourSession = sessions.find((s) => s.sessionId === session.sessionId);

        expect(ourSession).toBeDefined();
        // Context may not be populated if workspace.yaml hasn't been written yet
        if (ourSession?.context) {
            expect(ourSession.context.workingDirectory).toMatch(/^(\/|[A-Za-z]:)/);
        }
    });

    it("should get session metadata by ID", { timeout: 60000 }, async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });
        expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);

        // Send a message to persist the session to disk
        await session.sendAndWait({ prompt: "Say hello" });

        // Poll until metadata is available rather than guessing a wait duration.
        let metadata: Awaited<ReturnType<typeof client.getSessionMetadata>> | undefined;
        const deadline = Date.now() + 10_000;
        while (Date.now() < deadline) {
            metadata = await client.getSessionMetadata(session.sessionId);
            if (metadata) break;
            await new Promise((r) => setTimeout(r, 50));
        }

        expect(metadata).toBeDefined();
        expect(metadata!.sessionId).toBe(session.sessionId);
        expect(metadata!.startTime).toBeInstanceOf(Date);
        expect(metadata!.modifiedTime).toBeInstanceOf(Date);
        expect(typeof metadata!.isRemote).toBe("boolean");

        // Verify non-existent session returns undefined
        const notFound = await client.getSessionMetadata("non-existent-session-id");
        expect(notFound).toBeUndefined();
    });

    it("should have stateful conversation", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });
        const assistantMessage = await session.sendAndWait({ prompt: "What is 1+1?" });
        expect(assistantMessage?.data.content).toContain("2");

        const secondAssistantMessage = await session.sendAndWait({
            prompt: "Now if you double that, what do you get?",
        });
        expect(secondAssistantMessage?.data.content).toContain("4");
    });

    it("should create a session with appended systemMessage config", async () => {
        const systemMessageSuffix = "End each response with the phrase 'Have a nice day!'";
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            systemMessage: {
                mode: "append",
                content: systemMessageSuffix,
            },
        });

        const assistantMessage = await session.sendAndWait({ prompt: "What is your full name?" });
        expect(assistantMessage?.data.content).toContain("GitHub");
        expect(assistantMessage?.data.content).toContain("Have a nice day!");

        // Also validate the underlying traffic
        const traffic = await openAiEndpoint.getExchanges();
        const systemMessage = getSystemMessage(traffic[0]);
        expect(systemMessage).toContain("GitHub");
        expect(systemMessage).toContain(systemMessageSuffix);
    });

    it("should create a session with replaced systemMessage config", async () => {
        const testSystemMessage = "You are an assistant called Testy McTestface. Reply succinctly.";
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            systemMessage: { mode: "replace", content: testSystemMessage },
        });

        const assistantMessage = await session.sendAndWait({ prompt: "What is your full name?" });
        expect(assistantMessage?.data.content).not.toContain("GitHub");
        expect(assistantMessage?.data.content).toContain("Testy");

        // Also validate the underlying traffic
        const traffic = await openAiEndpoint.getExchanges();
        const systemMessage = getSystemMessage(traffic[0]);
        expect(systemMessage).toEqual(testSystemMessage); // Exact match
    });

    it(
        "should create a session with customized systemMessage config",
        { timeout: 90_000 },
        async () => {
            const customTone = "Respond in a warm, professional tone. Be thorough in explanations.";
            const appendedContent = "Always mention quarterly earnings.";
            const session = await client.createSession({
                onPermissionRequest: approveAll,
                systemMessage: {
                    mode: "customize",
                    sections: {
                        tone: { action: "replace", content: customTone },
                        code_change_rules: { action: "remove" },
                    },
                    content: appendedContent,
                },
            });

            try {
                await session.send({ prompt: "Who are you?" });

                // Validate the system message sent to the model
                const traffic = await waitForExchanges();
                const systemMessage = getSystemMessage(traffic[0]);
                expect(systemMessage).toContain(customTone);
                expect(systemMessage).toContain(appendedContent);
                // The code_change_rules section should have been removed
                expect(systemMessage).not.toContain("<code_change_instructions>");
            } finally {
                await session.disconnect();
            }
        }
    );

    it("should create a session with availableTools", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            availableTools: ["view", "edit"],
        });

        try {
            await session.send({ prompt: "What is 1+1?" });

            // It only tells the model about the specified tools and no others
            const traffic = await waitForExchanges();
            expect(traffic[0].request.tools).toMatchObject([
                { function: { name: "view" } },
                { function: { name: "edit" } },
            ]);
        } finally {
            await session.disconnect();
        }
    });

    it("should create a session with excludedTools", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            excludedTools: ["view"],
        });

        try {
            await session.send({ prompt: "What is 1+1?" });

            // It has other tools, but not the one we excluded
            const traffic = await waitForExchanges();
            const functionNames = traffic[0].request.tools?.map(
                (t) => (t as { function: { name: string } }).function.name
            );
            expect(functionNames).toContain("edit");
            expect(functionNames).toContain("grep");
            expect(functionNames).not.toContain("view");
        } finally {
            await session.disconnect();
        }
    });

    it("should create a session with defaultAgent excludedTools", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            tools: [
                defineTool("secret_tool", {
                    description: "A secret tool hidden from the default agent",
                    parameters: {
                        type: "object",
                        properties: { input: { type: "string" } },
                        required: ["input"],
                    },
                    handler: async () => "SECRET",
                }),
            ],
            defaultAgent: {
                excludedTools: ["secret_tool"],
            },
        });

        try {
            await session.send({ prompt: "What is 1+1?" });

            // The secret_tool should be registered with the runtime but not advertised
            // to the default agent's underlying model call.
            const traffic = await waitForExchanges();
            const functionNames = traffic[0].request.tools?.map(
                (t) => (t as { function: { name: string } }).function.name
            );
            expect(functionNames).not.toContain("secret_tool");
        } finally {
            await session.disconnect();
        }
    });

    // TODO: This test shows there's a race condition inside client.ts. If createSession is called
    // concurrently and autoStart is on, it may start multiple child processes. This needs to be fixed.
    // Right now it manifests as being unable to delete the temp directories during afterAll even though
    // we stopped all the clients (one or more child processes were left orphaned).
    it.skip("should handle multiple concurrent sessions", async () => {
        const [s1, s2, s3] = await Promise.all([
            client.createSession({ onPermissionRequest: approveAll }),
            client.createSession({ onPermissionRequest: approveAll }),
            client.createSession({ onPermissionRequest: approveAll }),
        ]);

        // All sessions should have unique IDs
        const distinctSessionIds = new Set([s1.sessionId, s2.sessionId, s3.sessionId]);
        expect(distinctSessionIds.size).toBe(3);

        // All are connected
        for (const s of [s1, s2, s3]) {
            expect(await s.getEvents()).toMatchObject([
                {
                    type: "session.start",
                    data: { sessionId: s.sessionId },
                },
            ]);
        }

        // All can be disconnected
        await Promise.all([s1.disconnect(), s2.disconnect(), s3.disconnect()]);
        for (const s of [s1, s2, s3]) {
            await expect(() => s.getEvents()).rejects.toThrow(/Session not found/);
        }
    });

    it("should resume a session using the same client", async () => {
        // Create initial session
        const session1 = await client.createSession({ onPermissionRequest: approveAll });
        const sessionId = session1.sessionId;
        const answer = await session1.sendAndWait({ prompt: "What is 1+1?" });
        expect(answer?.data.content).toContain("2");

        // Resume using the same client
        const session2 = await client.resumeSession(sessionId, { onPermissionRequest: approveAll });
        expect(session2.sessionId).toBe(sessionId);
        const messages = await session2.getEvents();
        const assistantMessages = messages.filter((m) => m.type === "assistant.message");
        expect(assistantMessages[assistantMessages.length - 1].data.content).toContain("2");

        // Can continue the conversation statefully
        const secondAssistantMessage = await session2.sendAndWait({
            prompt: "Now if you double that, what do you get?",
        });
        expect(secondAssistantMessage?.data.content).toContain("4");
    });

    it("should resume a session using a new client", async () => {
        // Create initial session
        const session1 = await client.createSession({ onPermissionRequest: approveAll });
        const sessionId = session1.sessionId;
        const answer = await session1.sendAndWait({ prompt: "What is 1+1?" });
        expect(answer?.data.content).toContain("2");

        // Resume using a new client
        const newClient = new CopilotClient({
            env,
            gitHubToken: isCI ? "fake-token-for-e2e-tests" : undefined,
        });

        onTestFinished(() => newClient.forceStop());
        const session2 = await newClient.resumeSession(sessionId, {
            onPermissionRequest: approveAll,
        });
        expect(session2.sessionId).toBe(sessionId);

        // session.idle is ephemeral and not persisted, so use alreadyIdle
        // to find the assistant message from the completed session.
        const answer2 = await getFinalAssistantMessage(session2, { alreadyIdle: true });
        expect(answer2?.data.content).toContain("2");

        const messages = await session2.getEvents();
        expect(messages).toContainEqual(expect.objectContaining({ type: "user.message" }));
        expect(messages).toContainEqual(expect.objectContaining({ type: "session.resume" }));

        // Can continue the conversation statefully
        const secondAssistantMessage = await session2.sendAndWait({
            prompt: "Now if you double that, what do you get?",
        });
        expect(secondAssistantMessage?.data.content).toContain("4");
    });

    it("should throw error when resuming non-existent session", async () => {
        await expect(
            client.resumeSession("non-existent-session-id", { onPermissionRequest: approveAll })
        ).rejects.toThrow();
    });

    it("should create session with custom tool", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            tools: [
                {
                    name: "get_secret_number",
                    description: "Gets the secret number",
                    parameters: {
                        type: "object",
                        properties: {
                            key: { type: "string", description: "Key" },
                        },
                        required: ["key"],
                    },
                    // Shows that raw JSON schemas still work - Zod is optional
                    handler: async (args: { key: string }) => {
                        return {
                            textResultForLlm: args.key === "ALPHA" ? "54321" : "unknown",
                            resultType: "success" as const,
                        };
                    },
                },
            ],
        });

        const answer = await session.sendAndWait({
            prompt: "What is the secret number for key ALPHA?",
        });
        expect(answer?.data.content).toContain("54321");
    });

    it("should resume session with a custom provider", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });
        const sessionId = session.sessionId;

        // Resume the session with a provider
        const session2 = await client.resumeSession(sessionId, {
            onPermissionRequest: approveAll,
            provider: {
                type: "openai",
                baseUrl: "https://api.openai.com/v1",
                apiKey: "fake-key",
            },
        });

        expect(session2.sessionId).toBe(sessionId);
    });

    it("should abort a session", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        // Set up event listeners BEFORE sending to avoid race conditions
        const nextToolCallStart = getNextEventOfType(session, "tool.execution_start");
        const nextSessionIdle = getNextEventOfType(session, "session.idle");

        await session.send({
            prompt: "run the shell command 'sleep 100' (note this works on both bash and PowerShell)",
        });

        // Abort once we see a tool execution start
        await nextToolCallStart;
        await session.abort();
        await nextSessionIdle;

        // The session should still be alive and usable after abort
        const messages = await session.getEvents();
        expect(messages.length).toBeGreaterThan(0);
        expect(messages.some((m) => m.type === "abort")).toBe(true);

        // We should be able to send another message
        const answer = await session.sendAndWait({ prompt: "What is 2+2?" });
        expect(answer?.data.content).toContain("4");
    });

    it("should receive session events", async () => {
        // Use onEvent to capture events dispatched after session creation begins.
        // session.start is emitted during or shortly after the session.create RPC;
        // if the session weren't registered in the sessions map before the RPC,
        // the event would be dropped.
        const earlyEvents: Array<{ type: string }> = [];
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            onEvent: (event) => {
                earlyEvents.push(event);
            },
        });

        await vi.waitFor(
            () => expect(earlyEvents.some((e) => e.type === "session.start")).toBe(true),
            { timeout: 10_000 }
        );

        const receivedEvents: Array<{ type: string }> = [];

        session.on((event) => {
            receivedEvents.push(event);
        });

        // Send a message and wait for completion
        const assistantMessage = await session.sendAndWait({ prompt: "What is 100+200?" });

        // Should have received multiple events
        expect(receivedEvents.length).toBeGreaterThan(0);
        expect(receivedEvents.some((e) => e.type === "user.message")).toBe(true);
        expect(receivedEvents.some((e) => e.type === "assistant.message")).toBe(true);
        expect(receivedEvents.some((e) => e.type === "session.idle")).toBe(true);

        // Verify the assistant response contains the expected answer
        expect(assistantMessage?.data.content).toContain("300");
    });

    it("handler exception does not halt event delivery", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        let eventCount = 0;
        let gotIdle = false;
        const idlePromise = new Promise<void>((resolve) => {
            session.on((event) => {
                eventCount++;
                // Throw on the first event to verify the loop keeps going.
                if (eventCount === 1) {
                    throw new Error("boom");
                }
                if (event.type === "session.idle") {
                    gotIdle = true;
                    resolve();
                }
            });
        });

        await session.send({ prompt: "What is 1+1?" });

        await vi.waitFor(() => expect(gotIdle).toBe(true), { timeout: 30_000 });
        await idlePromise;

        // Handler saw more than just the first (throwing) event.
        expect(eventCount).toBeGreaterThan(1);

        await session.disconnect();
    });

    it("disposeAsync from handler does not deadlock", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        let disposed = false;
        const disposedPromise = new Promise<void>((resolve) => {
            session.on((event) => {
                if (event.type === "user.message") {
                    // Call disconnect from within a handler — must not deadlock.
                    session.disconnect().then(() => {
                        disposed = true;
                        resolve();
                    });
                }
            });
        });

        await session.send({ prompt: "What is 1+1?" });

        // If this times out, we deadlocked.
        await vi.waitFor(() => expect(disposed).toBe(true), { timeout: 10_000 });
        await disposedPromise;
    });

    it("should create session with custom config dir", async () => {
        const customConfigDir = `${homeDir}/custom-config`;
        onTestFinished(async () => {
            await rm(customConfigDir, { recursive: true, force: true }).catch(() => {});
        });
        const session = await client.createSession({
            onPermissionRequest: approveAll,
            configDir: customConfigDir,
        });

        expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);

        try {
            // Session should work normally with custom config dir
            await session.send({ prompt: "What is 1+1?" });
            const assistantMessage = await getFinalAssistantMessage(session);
            expect(assistantMessage.data.content).toContain("2");
        } finally {
            await session.disconnect();
        }
    });

    it("should log messages at all levels and emit matching session events", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        const events: Array<{ type: string; id?: string; data?: Record<string, unknown> }> = [];
        session.on((event) => {
            events.push(event as (typeof events)[number]);
        });

        await session.log("Info message");
        await session.log("Warning message", { level: "warning" });
        await session.log("Error message", { level: "error" });
        await session.log("Ephemeral message", { ephemeral: true });

        await vi.waitFor(
            () => {
                const notifications = events.filter(
                    (e) =>
                        e.data &&
                        ("infoType" in e.data || "warningType" in e.data || "errorType" in e.data)
                );
                expect(notifications).toHaveLength(4);
            },
            { timeout: 10_000 }
        );

        const byMessage = (msg: string) => events.find((e) => e.data?.message === msg)!;
        expect(byMessage("Info message").type).toBe("session.info");
        expect(byMessage("Info message").data).toEqual({
            infoType: "notification",
            message: "Info message",
        });

        expect(byMessage("Warning message").type).toBe("session.warning");
        expect(byMessage("Warning message").data).toEqual({
            warningType: "notification",
            message: "Warning message",
        });

        expect(byMessage("Error message").type).toBe("session.error");
        expect(byMessage("Error message").data).toEqual({
            errorType: "notification",
            message: "Error message",
        });

        expect(byMessage("Ephemeral message").type).toBe("session.info");
        expect(byMessage("Ephemeral message").data).toEqual({
            infoType: "notification",
            message: "Ephemeral message",
        });
    });

    it("should send with file attachment", async () => {
        const filePath = `${workDir}/attached-file.txt`;
        const { writeFile } = await import("fs/promises");
        await writeFile(filePath, "FILE_ATTACHMENT_SENTINEL");

        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "Read the attached file and reply with its contents.",
            attachments: [
                {
                    type: "file",
                    path: filePath,
                    displayName: "attached-file.txt",
                    // lineRange is not part of the public TS attachment shape, but
                    // is forwarded to the runtime to match the C# parity test.
                    lineRange: { start: 1, end: 1 },
                } as unknown as NonNullable<
                    Parameters<typeof session.send>[0]["attachments"]
                >[number],
            ],
        });

        const messages = await session.getEvents();
        const userMessage = messages.filter((m) => m.type === "user.message").at(-1);
        expect(userMessage).toBeDefined();
        const attachments = (userMessage as unknown as { data: { attachments?: unknown[] } }).data
            .attachments;
        expect(attachments).toHaveLength(1);
        const attachment = attachments![0] as {
            type: string;
            displayName: string;
            path: string;
            lineRange?: { start: number; end: number };
        };
        expect(attachment.type).toBe("file");
        expect(attachment.displayName).toBe("attached-file.txt");
        expect(attachment.path).toBe(filePath);
        expect(attachment.lineRange).toEqual({ start: 1, end: 1 });

        await session.disconnect();
    });

    it("should send with directory attachment", async () => {
        const directoryPath = `${workDir}/attached-directory`;
        const { writeFile, mkdir } = await import("fs/promises");
        await mkdir(directoryPath, { recursive: true });
        await writeFile(`${directoryPath}/readme.txt`, "DIRECTORY_ATTACHMENT_SENTINEL");

        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "List the attached directory.",
            attachments: [
                {
                    type: "directory",
                    path: directoryPath,
                    displayName: "attached-directory",
                },
            ],
        });

        const messages = await session.getEvents();
        const userMessage = messages.filter((m) => m.type === "user.message").at(-1);
        expect(userMessage).toBeDefined();
        const attachments = (userMessage as unknown as { data: { attachments?: unknown[] } }).data
            .attachments;
        expect(attachments).toHaveLength(1);
        const attachment = attachments![0] as { type: string; displayName: string; path: string };
        expect(attachment.type).toBe("directory");
        expect(attachment.displayName).toBe("attached-directory");
        expect(attachment.path).toBe(directoryPath);

        await session.disconnect();
    });

    it("should send with selection attachment", async () => {
        const filePath = `${workDir}/selected-file.cs`;
        const { writeFile } = await import("fs/promises");
        await writeFile(filePath, 'class C { string Value = "SELECTION_SENTINEL"; }');

        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "Summarize the selected code.",
            attachments: [
                {
                    type: "selection",
                    filePath,
                    displayName: "selected-file.cs",
                    text: 'string Value = "SELECTION_SENTINEL";',
                    selection: {
                        start: { line: 1, character: 10 },
                        end: { line: 1, character: 45 },
                    },
                },
            ],
        });

        const messages = await session.getEvents();
        const userMessage = messages.filter((m) => m.type === "user.message").at(-1);
        expect(userMessage).toBeDefined();
        const attachments = (userMessage as unknown as { data: { attachments?: unknown[] } }).data
            .attachments;
        expect(attachments).toHaveLength(1);
        const attachment = attachments![0] as {
            type: string;
            displayName: string;
            filePath: string;
            text: string;
            selection: {
                start: { line: number; character: number };
                end: { line: number; character: number };
            };
        };
        expect(attachment.type).toBe("selection");
        expect(attachment.displayName).toBe("selected-file.cs");
        expect(attachment.filePath).toBe(filePath);
        expect(attachment.text).toBe('string Value = "SELECTION_SENTINEL";');
        expect(attachment.selection.start).toEqual({ line: 1, character: 10 });
        expect(attachment.selection.end).toEqual({ line: 1, character: 45 });

        await session.disconnect();
    });

    it("should accept blob attachments", async () => {
        const pngBase64 =
            "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==";
        const { writeFile } = await import("fs/promises");
        await writeFile(`${workDir}/test-pixel.png`, Buffer.from(pngBase64, "base64"));

        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "Describe this image",
            attachments: [
                {
                    type: "blob",
                    data: pngBase64,
                    mimeType: "image/png",
                    displayName: "test-pixel.png",
                },
            ],
        });

        await session.disconnect();
    });

    it("should send with github reference attachment", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "Using only the GitHub reference metadata in this message, summarize the reference. Do not call any tools.",
            // GitHub reference is a valid runtime attachment type but not part of
            // the public TS attachment shape; cast through unknown to forward it.
            attachments: [
                {
                    type: "github_reference",
                    number: 1234,
                    referenceType: "issue",
                    state: "open",
                    title: "Add E2E attachment coverage",
                    url: "https://github.com/github/copilot-sdk/issues/1234",
                } as unknown as NonNullable<
                    Parameters<typeof session.send>[0]["attachments"]
                >[number],
            ],
        });

        const messages = await session.getEvents();
        const userMessage = messages.filter((m) => m.type === "user.message").at(-1);
        expect(userMessage).toBeDefined();
        const attachments = (userMessage as unknown as { data: { attachments?: unknown[] } }).data
            .attachments;
        expect(attachments).toHaveLength(1);
        const attachment = attachments![0] as {
            type: string;
            number: number;
            referenceType: string;
            state: string;
            title: string;
            url: string;
        };
        expect(attachment.type).toBe("github_reference");
        expect(attachment.number).toBe(1234);
        expect(attachment.referenceType).toBe("issue");
        expect(attachment.state).toBe("open");
        expect(attachment.title).toBe("Add E2E attachment coverage");
        expect(attachment.url).toBe("https://github.com/github/copilot-sdk/issues/1234");

        await session.disconnect();
    });

    it("should send with mode property", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "Say mode ok.",
            agentMode: "plan",
        });

        const messages = await session.getEvents();
        const userMessage = messages.filter((m) => m.type === "user.message").at(-1) as
            | { data: { content: string; agentMode?: string | null } }
            | undefined;
        expect(userMessage).toBeDefined();
        expect(userMessage!.data.content).toBe("Say mode ok.");
        expect(userMessage!.data.agentMode).toBe("plan");

        await session.disconnect();
    });

    it("should send with custom requestHeaders", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        await session.sendAndWait({
            prompt: "What is 1+1?",
            requestHeaders: {
                "x-copilot-sdk-test-header": "ts-request-headers",
            },
        });

        const exchanges = await openAiEndpoint.getExchanges();
        expect(exchanges.length).toBeGreaterThan(0);
        const headers = exchanges[exchanges.length - 1].requestHeaders ?? {};
        const matchingKey = Object.keys(headers).find(
            (k) => k.toLowerCase() === "x-copilot-sdk-test-header"
        );
        expect(matchingKey).toBeDefined();
        const headerValue = headers[matchingKey!];
        const headerStr = Array.isArray(headerValue) ? headerValue.join(",") : (headerValue ?? "");
        expect(headerStr).toContain("ts-request-headers");

        await session.disconnect();
    });
});

function getSystemMessage(exchange: ParsedHttpExchange): string | undefined {
    const systemMessage = exchange.request.messages.find((m) => m.role === "system") as
        | { role: "system"; content: string }
        | undefined;
    return systemMessage?.content;
}

describe("Send Blocking Behavior", async () => {
    // Tests for Issue #17: send() should return immediately, not block until turn completes
    const { copilotClient: client } = await createSdkTestContext();

    it("send returns immediately while events stream in background", async () => {
        const session = await client.createSession({
            onPermissionRequest: approveAll,
        });

        const events: string[] = [];
        session.on((event) => {
            events.push(event.type);
        });

        // Use a slow command so we can verify send() returns before completion
        await session.send({ prompt: "Run 'sleep 2 && echo done'" });

        // send() should return before turn completes (no session.idle yet)
        expect(events).not.toContain("session.idle");

        // Wait for turn to complete
        const message = await getFinalAssistantMessage(session);

        expect(message.data.content).toContain("done");
        expect(events).toContain("session.idle");
        expect(events).toContain("assistant.message");
    });

    it("sendAndWait blocks until session.idle and returns final assistant message", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        const events: string[] = [];
        session.on((event) => {
            events.push(event.type);
        });

        const response = await session.sendAndWait({ prompt: "What is 2+2?" });

        expect(response).toBeDefined();
        expect(response?.type).toBe("assistant.message");
        expect(response?.data.content).toContain("4");
        expect(events).toContain("session.idle");
        expect(events).toContain("assistant.message");
    });

    // This test validates client-side timeout behavior.
    // The snapshot has no assistant response since we expect timeout before completion.
    it("sendAndWait throws on timeout", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        // Use a slow command to ensure timeout triggers before completion
        await expect(
            session.sendAndWait({ prompt: "Run 'sleep 2 && echo done'" }, 100)
        ).rejects.toThrow(/Timeout after 100ms/);
    });

    it("should set model on existing session", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        // Subscribe for the model change event before calling setModel.
        const modelChangePromise = getNextEventOfType(session, "session.model_change");

        await session.setModel("gpt-4.1");

        // Verify a model_change event was emitted with the new model.
        const event = await modelChangePromise;
        expect(event.data.newModel).toBe("gpt-4.1");

        await session.disconnect();
    });

    it("should set model with reasoningEffort", async () => {
        const session = await client.createSession({ onPermissionRequest: approveAll });

        const modelChangePromise = getNextEventOfType(session, "session.model_change");

        await session.setModel("gpt-4.1", { reasoningEffort: "high" });

        const event = await modelChangePromise;
        expect(event.data.newModel).toBe("gpt-4.1");
        expect(event.data.reasoningEffort).toBe("high");
    });
});