import { mkdir, open as fsOpen, readFile, writeFile } from "node:fs/promises";
import { dirname, join } from "node:path";

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

import type { DoctorHost } from "../../../src/application/Doctor.js";
import { ConfigurationError } from "../../../src/domain/configurationErrors.js";
import {
  filterClientsNeedingConfigure,
  systemSetupHost,
} from "../../../src/application/SetupHost.js";
import { RegularFileCleanupFailure } from "../../../src/application/RegularFileRead.js";
import { configureDetectedClients } from "../../../src/application/SetupClients.js";
import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";

vi.mock("node:fs/promises", async (importOriginal) => {
  const actual = await importOriginal<typeof import("node:fs/promises")>();
  return { ...actual, open: vi.fn(actual.open) };
});

const openMock = vi.mocked(fsOpen);
let actualFs: typeof import("node:fs/promises");

beforeEach(async () => {
  actualFs =
    await vi.importActual<typeof import("node:fs/promises")>(
      "node:fs/promises",
    );
  openMock.mockImplementation((...args) => actualFs.open(...args));
});

afterEach(() => openMock.mockReset());

describe("setup client configuration cleanup ownership", () => {
  it("stops client configuration and retries the same alignment handle from host close", async () => {
    const home = await createTestTempDirectory("rea-setup-config-close-");
    const environment = {
      HOME: home,
      XDG_CONFIG_HOME: join(home, "xdg"),
    };
    const host = systemSetupHost(
      { platform: "linux", homeDirectory: home } as DoctorHost,
      environment,
    );
    const client = (await host.supportedClients()).find(
      ({ name }) => name === "vscode",
    );
    if (client === undefined) throw new Error("VS Code setup client missing");
    await mkdir(dirname(client.configPath), { recursive: true });
    const original = Buffer.from('{"servers": {"other": {}}}\n');
    await writeFile(client.configPath, original);

    const closeAttempts: object[] = [];
    let allowClose = false;
    openMock.mockImplementation(async (...args) => {
      const handle = await actualFs.open(...args);
      if (String(args[0]) !== client.configPath) return handle;
      const nativeClose = handle.close.bind(handle);
      vi.spyOn(handle, "close").mockImplementation(async () => {
        closeAttempts.push(handle);
        if (!allowClose) throw new Error("test holds the config handle open");
        await nativeClose();
      });
      return handle;
    });
    const configure = vi.spyOn(host, "configureClient");

    try {
      const failure = await filterClientsNeedingConfigure(host, [client], {}, [
        "rea",
        "mcp",
      ])
        .then((detectedClients) =>
          configureDetectedClients({
            host,
            detectedClients,
            providerEnvironment: {},
            command: ["rea", "mcp"],
            clients: {},
            appliedActions: [],
          }),
        )
        .then(
          () => undefined,
          (cause: unknown) => cause,
        );
      expect(failure).toBeInstanceOf(ConfigurationError);
      expect(failure).toMatchObject({
        _tag: "ConfigurationError",
        cause: expect.any(RegularFileCleanupFailure),
        cleanup: {
          resources: [client.configPath],
          reason: expect.stringContaining("test holds the config handle open"),
        },
      });
      expect(configure).not.toHaveBeenCalled();
      expect(closeAttempts).toHaveLength(2);
      expect(closeAttempts[0]).toBe(closeAttempts[1]);
      expect(await readFile(client.configPath)).toEqual(original);

      allowClose = true;
      const close = host.close;
      if (close === undefined) throw new Error("Setup host close is missing");
      expect(await close()).toBeUndefined();
      expect(closeAttempts).toHaveLength(3);
      expect(closeAttempts[2]).toBe(closeAttempts[0]);
    } finally {
      allowClose = true;
      await host.close?.();
    }
  });

  it("waits for an admitted configuration read and rejects later admissions", async () => {
    const home = await createTestTempDirectory("rea-setup-config-inflight-");
    const environment = {
      HOME: home,
      XDG_CONFIG_HOME: join(home, "xdg"),
    };
    const host = systemSetupHost(
      { platform: "linux", homeDirectory: home } as DoctorHost,
      environment,
    );
    const client = (await host.supportedClients()).find(
      ({ name }) => name === "vscode",
    );
    if (client === undefined) throw new Error("VS Code setup client missing");
    await mkdir(dirname(client.configPath), { recursive: true });
    await writeFile(client.configPath, '{"servers": {}}\n');

    let beginRead!: () => void;
    const readStarted = new Promise<void>((resolve) => {
      beginRead = resolve;
    });
    let unblockRead!: () => void;
    const readGate = new Promise<void>((resolve) => {
      unblockRead = resolve;
    });
    let heldRead = false;
    openMock.mockImplementation(async (...args) => {
      const handle = await actualFs.open(...args);
      if (String(args[0]) !== client.configPath || heldRead) return handle;
      heldRead = true;
      const nativeRead = handle.read.bind(handle);
      vi.spyOn(handle, "read").mockImplementation(async (...readArgs) => {
        beginRead();
        await readGate;
        return nativeRead(...readArgs);
      });
      return handle;
    });

    let hostCloseFinished = false;
    let alignment: Promise<boolean> | undefined;
    try {
      alignment = host.clientNeedsConfigure(client, {}, ["rea", "mcp"]);
      await readStarted;

      const close = host.close;
      if (close === undefined) throw new Error("Setup host close is missing");
      const closeResult = close().then((result) => {
        hostCloseFinished = true;
        return result;
      });

      const lateAdmission = await host
        .clientNeedsConfigure(client, {}, ["rea", "mcp"])
        .then(
          () => undefined,
          (cause: unknown) => cause,
        );
      expect(lateAdmission).toBeInstanceOf(ConfigurationError);
      expect(lateAdmission).toMatchObject({
        message: expect.stringContaining("Artifact resource scope is closed"),
      });
      expect(hostCloseFinished).toBe(false);

      unblockRead();
      await expect(alignment).resolves.toBe(true);
      expect(await closeResult).toBeUndefined();
      expect(hostCloseFinished).toBe(true);
    } finally {
      unblockRead();
      await alignment?.catch(() => undefined);
      await host.close?.();
    }
  });
});