import { beforeEach, describe, expect, it, vi } from "vitest";
import {
  evaluateChromeMcpScript,
  listChromeMcpTabs,
  openChromeMcpTab,
  resetChromeMcpSessionsForTest,
  setChromeMcpSessionFactoryForTest,
} from "./chrome-mcp.js";

type ToolCall = {
  name: string;
  arguments?: Record<string, unknown>;
};

type ChromeMcpSessionFactory = Exclude<
  Parameters<typeof setChromeMcpSessionFactoryForTest>[0],
  null
>;
type ChromeMcpSession = Awaited<ReturnType<ChromeMcpSessionFactory>>;

function createFakeSession(): ChromeMcpSession {
  const callTool = vi.fn(async ({ name }: ToolCall) => {
    if (name === "list_pages") {
      return {
        content: [
          {
            type: "text",
            text: [
              "## Pages",
              "1: https://developer.chrome.com/blog/chrome-devtools-mcp-debug-your-browser-session [selected]",
              "2: https://github.com/openclaw/openclaw/pull/45318",
            ].join("\n"),
          },
        ],
      };
    }
    if (name === "new_page") {
      return {
        content: [
          {
            type: "text",
            text: [
              "## Pages",
              "1: https://developer.chrome.com/blog/chrome-devtools-mcp-debug-your-browser-session",
              "2: https://github.com/openclaw/openclaw/pull/45318",
              "3: https://example.com/ [selected]",
            ].join("\n"),
          },
        ],
      };
    }
    if (name === "evaluate_script") {
      return {
        content: [
          {
            type: "text",
            text: "```json\n123\n```",
          },
        ],
      };
    }
    throw new Error(`unexpected tool ${name}`);
  });

  return {
    client: {
      callTool,
      listTools: vi.fn().mockResolvedValue({ tools: [{ name: "list_pages" }] }),
      close: vi.fn().mockResolvedValue(undefined),
      connect: vi.fn().mockResolvedValue(undefined),
    },
    transport: {
      pid: 123,
    },
    ready: Promise.resolve(),
  } as unknown as ChromeMcpSession;
}

describe("chrome MCP page parsing", () => {
  beforeEach(async () => {
    await resetChromeMcpSessionsForTest();
  });

  it("parses list_pages text responses when structuredContent is missing", async () => {
    const factory: ChromeMcpSessionFactory = async () => createFakeSession();
    setChromeMcpSessionFactoryForTest(factory);

    const tabs = await listChromeMcpTabs("chrome-live");

    expect(tabs).toEqual([
      {
        targetId: "1",
        title: "",
        url: "https://developer.chrome.com/blog/chrome-devtools-mcp-debug-your-browser-session",
        type: "page",
      },
      {
        targetId: "2",
        title: "",
        url: "https://github.com/openclaw/openclaw/pull/45318",
        type: "page",
      },
    ]);
  });

  it("parses new_page text responses and returns the created tab", async () => {
    const factory: ChromeMcpSessionFactory = async () => createFakeSession();
    setChromeMcpSessionFactoryForTest(factory);

    const tab = await openChromeMcpTab("chrome-live", "https://example.com/");

    expect(tab).toEqual({
      targetId: "3",
      title: "",
      url: "https://example.com/",
      type: "page",
    });
  });

  it("parses evaluate_script text responses when structuredContent is missing", async () => {
    const factory: ChromeMcpSessionFactory = async () => createFakeSession();
    setChromeMcpSessionFactoryForTest(factory);

    const result = await evaluateChromeMcpScript({
      profileName: "chrome-live",
      targetId: "1",
      fn: "() => 123",
    });

    expect(result).toBe(123);
  });

  it("surfaces MCP tool errors instead of JSON parse noise", async () => {
    const factory: ChromeMcpSessionFactory = async () => {
      const session = createFakeSession();
      const callTool = vi.fn(async ({ name }: ToolCall) => {
        if (name === "evaluate_script") {
          return {
            content: [
              {
                type: "text",
                text: "Cannot read properties of null (reading 'value')",
              },
            ],
            isError: true,
          };
        }
        throw new Error(`unexpected tool ${name}`);
      });
      session.client.callTool = callTool as typeof session.client.callTool;
      return session;
    };
    setChromeMcpSessionFactoryForTest(factory);

    await expect(
      evaluateChromeMcpScript({
        profileName: "chrome-live",
        targetId: "1",
        fn: "() => document.getElementById('missing').value",
      }),
    ).rejects.toThrow(/Cannot read properties of null/);
  });

  it("reuses a single pending session for concurrent requests", async () => {
    let factoryCalls = 0;
    let releaseFactory!: () => void;
    const factoryGate = new Promise<void>((resolve) => {
      releaseFactory = resolve;
    });

    const factory: ChromeMcpSessionFactory = async () => {
      factoryCalls += 1;
      await factoryGate;
      return createFakeSession();
    };
    setChromeMcpSessionFactoryForTest(factory);

    const tabsPromise = listChromeMcpTabs("chrome-live");
    const evalPromise = evaluateChromeMcpScript({
      profileName: "chrome-live",
      targetId: "1",
      fn: "() => 123",
    });

    releaseFactory();
    const [tabs, result] = await Promise.all([tabsPromise, evalPromise]);

    expect(factoryCalls).toBe(1);
    expect(tabs).toHaveLength(2);
    expect(result).toBe(123);
  });

  it("preserves session after tool-level errors (isError)", async () => {
    let factoryCalls = 0;
    const factory: ChromeMcpSessionFactory = async () => {
      factoryCalls += 1;
      const session = createFakeSession();
      const callTool = vi.fn(async ({ name }: ToolCall) => {
        if (name === "evaluate_script") {
          return {
            content: [{ type: "text", text: "element not found" }],
            isError: true,
          };
        }
        if (name === "list_pages") {
          return {
            content: [{ type: "text", text: "## Pages\n1: https://example.com [selected]" }],
          };
        }
        throw new Error(`unexpected tool ${name}`);
      });
      session.client.callTool = callTool as typeof session.client.callTool;
      return session;
    };
    setChromeMcpSessionFactoryForTest(factory);

    // First call: tool error (isError: true) — should NOT destroy session
    await expect(
      evaluateChromeMcpScript({ profileName: "chrome-live", targetId: "1", fn: "() => null" }),
    ).rejects.toThrow(/element not found/);

    // Second call: should reuse the same session (factory called only once)
    const tabs = await listChromeMcpTabs("chrome-live");
    expect(factoryCalls).toBe(1);
    expect(tabs).toHaveLength(1);
  });

  it("destroys session on transport errors so next call reconnects", async () => {
    let factoryCalls = 0;
    const factory: ChromeMcpSessionFactory = async () => {
      factoryCalls += 1;
      const session = createFakeSession();
      if (factoryCalls === 1) {
        // First session: transport error (callTool throws)
        const callTool = vi.fn(async () => {
          throw new Error("connection reset");
        });
        session.client.callTool = callTool as typeof session.client.callTool;
      }
      return session;
    };
    setChromeMcpSessionFactoryForTest(factory);

    // First call: transport error — should destroy session
    await expect(listChromeMcpTabs("chrome-live")).rejects.toThrow(/connection reset/);

    // Second call: should create a new session (factory called twice)
    const tabs = await listChromeMcpTabs("chrome-live");
    expect(factoryCalls).toBe(2);
    expect(tabs).toHaveLength(2);
  });

  it("clears failed pending sessions so the next call can retry", async () => {
    let factoryCalls = 0;
    const factory: ChromeMcpSessionFactory = async () => {
      factoryCalls += 1;
      if (factoryCalls === 1) {
        throw new Error("attach failed");
      }
      return createFakeSession();
    };
    setChromeMcpSessionFactoryForTest(factory);

    await expect(listChromeMcpTabs("chrome-live")).rejects.toThrow(/attach failed/);

    const tabs = await listChromeMcpTabs("chrome-live");
    expect(factoryCalls).toBe(2);
    expect(tabs).toHaveLength(2);
  });
});
