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

const poolConstructor = vi.hoisted(() => vi.fn());

vi.mock("pg", () => ({ Pool: poolConstructor }));

import { createValidatedPostgresPool, PostgresPoolError } from "../src/database/pool.js";

describe("createValidatedPostgresPool", () => {
  it("does not construct a pool merely because the module is imported", () => {
    expect(poolConstructor).not.toHaveBeenCalled();
  });

  it.each([
    "",
    "   ",
    "not-a-database-url",
    "https://admin:do-not-log@db.example.test/database",
  ])("rejects an invalid connection string without exposing it (%s)", (connectionString) => {
    let captured: unknown;
    try {
      createValidatedPostgresPool(connectionString);
    } catch (error) {
      captured = error;
    }

    expect(captured).toBeInstanceOf(PostgresPoolError);
    expect(captured).toMatchObject({ code: "POSTGRES_POOL_CONFIGURATION_INVALID" });
    const publicText = `${String(captured)}\n${
      captured instanceof Error ? (captured.stack ?? "") : ""
    }`;
    if (connectionString) {
      expect(publicText).not.toContain(connectionString);
    }
    expect(poolConstructor).not.toHaveBeenCalled();
  });

  it("explicitly constructs the pool only when called", () => {
    poolConstructor.mockImplementation(function fakePool() {
      return { end: async () => undefined, on: vi.fn() };
    });

    const handle = createValidatedPostgresPool(
      "postgresql://operator:do-not-log@example.test/ekklesia",
    );

    expect(poolConstructor).toHaveBeenCalledTimes(1);
    expect(handle.pool).toBeDefined();
    expect(typeof handle.close).toBe("function");
    expect(Object.isFrozen(handle)).toBe(true);
  });

  it("passes the connection timeout through to the pool configuration", () => {
    poolConstructor.mockImplementation(function fakePool() {
      return { end: async () => undefined, on: vi.fn() };
    });
    poolConstructor.mockClear();

    createValidatedPostgresPool("postgresql://example.test/ekklesia", {
      connectionTimeoutMs: 5_000,
    });

    expect(poolConstructor).toHaveBeenCalledWith(
      expect.objectContaining({ connectionTimeoutMillis: 5_000 }),
    );
  });

  it("passes the operation timeout through as both query_timeout and statement_timeout", () => {
    poolConstructor.mockImplementation(function fakePool() {
      return { end: async () => undefined, on: vi.fn() };
    });
    poolConstructor.mockClear();

    createValidatedPostgresPool("postgresql://example.test/ekklesia", {
      operationTimeoutMs: 7_500,
    });

    expect(poolConstructor).toHaveBeenCalledWith(
      expect.objectContaining({ query_timeout: 7_500, statement_timeout: 7_500 }),
    );
  });

  it.each([
    ["operationTimeoutMs", 0],
    ["operationTimeoutMs", -1],
    ["operationTimeoutMs", Number.NaN],
    ["connectionTimeoutMs", 0],
    ["connectionTimeoutMs", -1],
  ] as const)("rejects an invalid %s (%s) without constructing a pool and without leaking the value", (optionName, value) => {
    poolConstructor.mockClear();

    let captured: unknown;
    try {
      createValidatedPostgresPool("postgresql://example.test/ekklesia", {
        [optionName]: value,
      });
    } catch (error) {
      captured = error;
    }

    expect(captured).toBeInstanceOf(PostgresPoolError);
    expect(captured).toMatchObject({ code: "POSTGRES_POOL_CONFIGURATION_INVALID" });
    expect(poolConstructor).not.toHaveBeenCalled();
  });

  it("registers a pool-level error listener so an idle client failure never becomes an uncaught exception", () => {
    const on = vi.fn();
    poolConstructor.mockImplementation(function fakePool() {
      return { end: async () => undefined, on };
    });

    createValidatedPostgresPool("postgresql://example.test/ekklesia");

    expect(on).toHaveBeenCalledWith("error", expect.any(Function));
    const handler = on.mock.calls.find((call) => call[0] === "error")?.[1] as
      | ((error: unknown) => void)
      | undefined;
    expect(() =>
      handler?.(new Error("terminating connection due to administrator command")),
    ).not.toThrow();
  });
});