import { createServer, type Socket } from "node:net";

import { describe, expect, it, vi } from "vitest";

import { CdpBrowserProvider } from "../../../src/browser/CdpBrowserProvider.js";
import { openCdpEndpoint } from "../../../src/browser/CdpTargetSession.js";
import { AnalysisError } from "../../../src/domain/analysisErrorBase.js";
import { projectAnalysisError } from "../../../src/domain/analysisErrorProjection.js";
import {
  browserObservationEndpointSchema,
  inspectWebPageInputSchema,
  listBrowserTargetsInputSchema,
} from "../../../src/domain/browserObservation.js";
import { startFakeCdpBrowser } from "../../fixtures/fakeCdpBrowser.js";
import { trackBrowser } from "./cdpBrowserProvider.support.js";

describe("CdpBrowserProvider: browser socket without HTTP discovery", () => {
  it("discovers and inspects a page through one browser socket", async () => {
    const browser = await startFakeCdpBrowser();
    trackBrowser(browser);
    const provider = new CdpBrowserProvider();
    const throughHttp = await provider.listTargets(
      listBrowserTargetsInputSchema.parse({ cdp_endpoint: browser.endpoint }),
    );
    if (!throughHttp.ok) throw throughHttp.error;
    const httpRequests = browser.httpRequests.length;
    const openedBefore = browser.openedConnectionCount();

    const listed = await provider.listTargets(
      listBrowserTargetsInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl,
      }),
    );
    if (!listed.ok) throw listed.error;
    expect(listed.value.targets).toEqual(throughHttp.value.targets);
    expect(listed.value.excluded).toEqual(throughHttp.value.excluded);
    expect(listed.value.browser).toEqual({
      ...throughHttp.value.browser,
      revision: "@fake-revision",
    });

    const commandsBefore = browser.commands.length;
    const inspected = await provider.inspectPage(
      inspectWebPageInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl,
        target_id: "allowed-page",
        observation_ms: 0,
      }),
    );
    if (!inspected.ok) throw inspected.error;
    expect(inspected.value.target.origin).toBe(browser.allowedOrigin);
    expect(
      browser.commands
        .slice(commandsBefore, commandsBefore + 3)
        .map(({ method, params }) => ({ method, params })),
    ).toEqual([
      { method: "Browser.getVersion", params: {} },
      { method: "Target.getTargets", params: {} },
      {
        method: "Target.attachToTarget",
        params: { targetId: "allowed-page", flatten: true },
      },
    ]);
    expect(browser.httpRequests).toHaveLength(httpRequests);
    expect(browser.openedConnectionCount()).toBe(openedBefore + 2);
    await vi.waitFor(() => expect(browser.activeConnectionCount()).toBe(0));
  });
});

describe("CdpBrowserProvider: browser socket failures and cleanup", () => {
  it("closes an unadopted browser socket when the target is missing", async () => {
    const browser = await startFakeCdpBrowser();
    trackBrowser(browser);
    const result = await new CdpBrowserProvider().inspectPage(
      inspectWebPageInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl,
        target_id: "missing",
        observation_ms: 0,
      }),
    );

    expect(result).toMatchObject({
      ok: false,
      error: { _tag: "BrowserObservationError", reason: "target_not_found" },
    });
    expect(browser.commands.map(({ method }) => method)).toEqual([
      "Browser.getVersion",
      "Target.getTargets",
    ]);
    await vi.waitFor(() => expect(browser.activeConnectionCount()).toBe(0));
  });

  it("rejects malformed browser-socket discovery and closes the socket", async () => {
    const browser = await startFakeCdpBrowser({
      commandResult: ({ method }) =>
        method === "Browser.getVersion"
          ? { product: "FakeChrome/1.0" }
          : undefined,
    });
    trackBrowser(browser);
    const result = await new CdpBrowserProvider().listTargets(
      listBrowserTargetsInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl,
      }),
    );

    expect(result).toMatchObject({
      ok: false,
      error: {
        _tag: "BrowserObservationError",
        operation: "list_browser_targets",
        reason: "invalid_endpoint_response",
      },
    });
    await vi.waitFor(() => expect(browser.activeConnectionCount()).toBe(0));
  });

  it("reports a refused browser socket as unreachable", async () => {
    const browser = await startFakeCdpBrowser();
    trackBrowser(browser);
    const result = await new CdpBrowserProvider().listTargets(
      listBrowserTargetsInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl.replace(
          /fake$/u,
          "not-this-browser",
        ),
      }),
    );

    expect(result).toMatchObject({
      ok: false,
      error: {
        _tag: "BrowserObservationError",
        reason: "endpoint_unreachable",
      },
    });
    expect(JSON.stringify(result)).not.toContain("not-this-browser");
  });

  it("cancels browser-socket discovery and releases the socket", async () => {
    const browser = await startFakeCdpBrowser({
      hangOnMethod: "Target.getTargets",
    });
    trackBrowser(browser);
    const controller = new AbortController();
    const pending = new CdpBrowserProvider().inspectPage(
      inspectWebPageInputSchema.parse({
        cdp_endpoint: browser.browserWebSocketUrl,
        target_id: "allowed-page",
        observation_ms: 0,
      }),
      { signal: controller.signal },
    );
    await vi.waitFor(() =>
      expect(browser.commands.map(({ method }) => method)).toContain(
        "Target.getTargets",
      ),
    );
    controller.abort();

    expect(await pending).toMatchObject({
      ok: false,
      error: { _tag: "AnalysisCancelledError", operation: "inspect_web_page" },
    });
    expect(browser.commands.map(({ method }) => method)).not.toContain(
      "Target.attachToTarget",
    );
    await vi.waitFor(() => expect(browser.activeConnectionCount()).toBe(0));
  });
});

/** Expect a discovery timeout that projects publicly as a provider timeout. */
const expectDiscoveryTimeout = async (url: string): Promise<void> => {
  let failure: unknown;
  try {
    await openCdpEndpoint(
      browserObservationEndpointSchema.parse(url),
      "list_browser_targets",
      undefined,
      50,
    );
  } catch (cause: unknown) {
    failure = cause;
  }
  expect(failure).toMatchObject({
    _tag: "BrowserObservationError",
    reason: "timeout",
  });
  if (!(failure instanceof AnalysisError))
    throw new Error("Expected a typed discovery failure");
  expect(projectAnalysisError(failure)).toMatchObject({
    code: "provider_timeout",
    category: "timeout",
  });
};

describe("CdpBrowserProvider: browser socket discovery deadline", () => {
  it("times out a discovery reply that never arrives and closes the socket", async () => {
    const browser = await startFakeCdpBrowser({
      hangOnMethod: "Target.getTargets",
    });
    trackBrowser(browser);
    await expectDiscoveryTimeout(browser.browserWebSocketUrl);
    await vi.waitFor(() => expect(browser.activeConnectionCount()).toBe(0));
  });

  it("times out a WebSocket handshake that never completes", async () => {
    const sockets = new Set<Socket>();
    // Read the upgrade request but never answer it; reading lets the
    // client's close be observed here.
    const server = createServer((socket) => {
      sockets.add(socket);
      socket.on("close", () => sockets.delete(socket));
      socket.resume();
    });
    await new Promise<void>((resolve) =>
      server.listen(0, "127.0.0.1", resolve),
    );
    const address = server.address();
    if (address === null || typeof address === "string")
      throw new Error("Expected a TCP listener address");
    try {
      await expectDiscoveryTimeout(
        `ws://127.0.0.1:${String(address.port)}/devtools/browser/stalled`,
      );
      await vi.waitFor(() => expect(sockets.size).toBe(0));
    } finally {
      for (const socket of sockets) socket.destroy();
      await new Promise<void>((resolve) => server.close(() => resolve()));
    }
  });
});