import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
import { TEST_UNDICI_RUNTIME_DEPS_KEY } from "./undici-runtime.js";

const { agentCtor, envHttpProxyAgentCtor, proxyAgentCtor } = vi.hoisted(() => ({
  agentCtor: vi.fn(function MockAgent(this: { options: unknown }, options: unknown) {
    this.options = options;
  }),
  envHttpProxyAgentCtor: vi.fn(function MockEnvHttpProxyAgent(
    this: { options: unknown },
    options: unknown,
  ) {
    this.options = options;
  }),
  proxyAgentCtor: vi.fn(function MockProxyAgent(this: { options: unknown }, options: unknown) {
    this.options = options;
  }),
}));

import type { PinnedHostname } from "./ssrf.js";

let createPinnedDispatcher: typeof import("./ssrf.js").createPinnedDispatcher;

beforeAll(async () => {
  ({ createPinnedDispatcher } = await import("./ssrf.js"));
});

beforeEach(() => {
  agentCtor.mockClear();
  envHttpProxyAgentCtor.mockClear();
  proxyAgentCtor.mockClear();
  (globalThis as Record<string, unknown>)[TEST_UNDICI_RUNTIME_DEPS_KEY] = {
    Agent: agentCtor,
    EnvHttpProxyAgent: envHttpProxyAgentCtor,
    ProxyAgent: proxyAgentCtor,
    fetch: vi.fn(),
  };
});

afterEach(() => {
  Reflect.deleteProperty(globalThis as object, TEST_UNDICI_RUNTIME_DEPS_KEY);
});

function createPinnedTelegramHost(lookup: PinnedHostname["lookup"]): PinnedHostname {
  return {
    hostname: "api.telegram.org",
    addresses: ["149.154.167.221"],
    lookup,
  };
}

function createDispatcherWithPinnedOverride(lookup: PinnedHostname["lookup"]) {
  createPinnedDispatcher(createPinnedTelegramHost(lookup), {
    mode: "direct",
    pinnedHostname: {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.220"],
    },
  });

  return (agentCtor.mock.calls.at(-1)?.[0] as { connect?: { lookup?: PinnedHostname["lookup"] } })
    ?.connect?.lookup;
}

describe("createPinnedDispatcher", () => {
  it("uses pinned lookup without overriding global family policy", () => {
    const lookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const pinned: PinnedHostname = {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.220"],
      lookup,
    };

    const dispatcher = createPinnedDispatcher(pinned);

    expect(dispatcher).toBeDefined();
    expect(agentCtor).toHaveBeenCalledWith({
      connect: {
        lookup,
      },
      allowH2: false,
    });
    const firstCallArg = agentCtor.mock.calls[0]?.[0] as
      | { connect?: Record<string, unknown> }
      | undefined;
    expect(firstCallArg?.connect?.autoSelectFamily).toBeUndefined();
  });

  it("preserves caller transport hints while overriding lookup", () => {
    const lookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const previousLookup = vi.fn();
    const pinned: PinnedHostname = {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.220"],
      lookup,
    };

    createPinnedDispatcher(pinned, {
      mode: "direct",
      connect: {
        autoSelectFamily: true,
        autoSelectFamilyAttemptTimeout: 300,
        lookup: previousLookup,
      },
    });

    expect(agentCtor).toHaveBeenCalledWith({
      connect: {
        autoSelectFamily: true,
        autoSelectFamilyAttemptTimeout: 300,
        lookup,
      },
      allowH2: false,
    });
  });

  it("replaces the pinned lookup when a dispatcher override hostname is provided", () => {
    const originalLookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const lookup = createDispatcherWithPinnedOverride(originalLookup);

    expect(lookup).toBeTypeOf("function");
    const callback = vi.fn();
    lookup?.("api.telegram.org", callback);

    expect(callback).toHaveBeenCalledWith(null, "149.154.167.220", 4);
    expect(originalLookup).not.toHaveBeenCalled();
  });

  it("keeps the override bound to the matching hostname only", () => {
    const originalLookup = vi.fn(
      (_hostname: string, callback: (err: null, address: string, family: number) => void) => {
        callback(null, "93.184.216.34", 4);
      },
    ) as unknown as PinnedHostname["lookup"];
    const lookup = createDispatcherWithPinnedOverride(originalLookup);
    const callback = vi.fn();
    lookup?.("example.com", callback);

    expect(originalLookup).toHaveBeenCalledWith("example.com", expect.any(Function));
    expect(callback).toHaveBeenCalledWith(null, "93.184.216.34", 4);
  });

  it("rejects pinned override addresses that violate SSRF policy", () => {
    const originalLookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const pinned: PinnedHostname = {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.221"],
      lookup: originalLookup,
    };

    expect(() =>
      createPinnedDispatcher(
        pinned,
        {
          mode: "direct",
          pinnedHostname: {
            hostname: "api.telegram.org",
            addresses: ["127.0.0.1"],
          },
        },
        undefined,
      ),
    ).toThrow(/private|internal|blocked/i);
  });

  it("keeps env proxy route while pinning the direct no-proxy path", () => {
    const lookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const pinned: PinnedHostname = {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.220"],
      lookup,
    };

    createPinnedDispatcher(pinned, {
      mode: "env-proxy",
      connect: {
        autoSelectFamily: true,
      },
      proxyTls: {
        autoSelectFamily: true,
      },
    });

    expect(envHttpProxyAgentCtor).toHaveBeenCalledWith({
      connect: {
        autoSelectFamily: true,
        lookup,
      },
      allowH2: false,
      proxyTls: {
        autoSelectFamily: true,
      },
    });
  });

  it("keeps explicit proxy routing intact", () => {
    const lookup = vi.fn() as unknown as PinnedHostname["lookup"];
    const pinned: PinnedHostname = {
      hostname: "api.telegram.org",
      addresses: ["149.154.167.220"],
      lookup,
    };

    createPinnedDispatcher(pinned, {
      mode: "explicit-proxy",
      proxyUrl: "http://127.0.0.1:7890",
      proxyTls: {
        autoSelectFamily: false,
      },
    });

    expect(proxyAgentCtor).toHaveBeenCalledWith({
      uri: "http://127.0.0.1:7890",
      allowH2: false,
      requestTls: {
        autoSelectFamily: false,
        lookup,
      },
    });
  });
});