import type { BackgroundJobHandlers } from "@rakazo/adapter-kit";
import type { Runner } from "graphile-worker";
import type { Pool } from "pg";
import { afterEach, describe, expect, it, vi } from "vitest";

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

vi.mock("graphile-worker", () => ({
  run: (...args: unknown[]) => run(...args),
  makeWorkerUtils: vi.fn(),
}));

import { databaseCapacityBackoffMs, GraphileJobWorkerHost } from "./wakeup.js";

function handlers(): BackgroundJobHandlers {
  return {
    "run.continue": vi.fn(async () => undefined),
    "routine.wakeup": vi.fn(async () => undefined),
    "computer.update": vi.fn(async () => undefined),
    "computer.sleep": vi.fn(async () => undefined),
    "computer.control-expire": vi.fn(async () => undefined),
    "skill.teaching-expire": vi.fn(async () => undefined),
    "history.compact": vi.fn(async () => undefined),
    "messaging.deliver": vi.fn(async () => undefined),
    "cloud_agent.poll": vi.fn(async () => undefined),
    "profile.consolidate": vi.fn(async () => undefined),
    "media.run": vi.fn(async () => undefined),
    "media.library.sync": vi.fn(async () => undefined),
  };
}

function deferred() {
  let resolve!: () => void;
  let reject!: (reason?: unknown) => void;
  const promise = new Promise<void>((yes, no) => {
    resolve = yes;
    reject = no;
  });
  return { promise, resolve, reject };
}

function mockRunner() {
  const life = deferred();
  // Keep a rejection handler so Node does not treat the mock lifecycle as an
  // unexpected unhandledRejection before the host attaches supervise().
  life.promise.catch(() => undefined);
  const runner = {
    promise: life.promise,
    stop: vi.fn(async () => {
      life.resolve();
    }),
    kill: vi.fn(async () => undefined),
    addJob: vi.fn(),
    events: { on: vi.fn(), off: vi.fn(), once: vi.fn(), emit: vi.fn() },
  } as unknown as Runner;
  return {
    runner,
    rejectLife: (error: unknown) => life.reject(error),
  };
}

const tooMany = Object.assign(new Error("sorry, too many clients already"), { code: "53300" });

describe("databaseCapacityBackoffMs", () => {
  it("matches the worker startup backoff curve", () => {
    expect(databaseCapacityBackoffMs(0)).toBe(200);
    expect(databaseCapacityBackoffMs(3)).toBe(1_600);
    expect(databaseCapacityBackoffMs(8)).toBe(30_000);
    expect(databaseCapacityBackoffMs(20)).toBe(30_000);
  });
});

describe("GraphileJobWorkerHost runner lifecycle", () => {
  afterEach(() => {
    run.mockReset();
  });

  it("backs off then restarts when runner.promise rejects with 53300", async () => {
    const first = mockRunner();
    const second = mockRunner();
    run.mockResolvedValueOnce(first.runner).mockResolvedValueOnce(second.runner);
    const sleeps: number[] = [];
    const host = new GraphileJobWorkerHost({} as Pool, {
      sleep: async (ms) => {
        sleeps.push(ms);
      },
    });

    await host.start(handlers());
    expect(run).toHaveBeenCalledTimes(1);

    first.rejectLife(tooMany);
    await vi.waitFor(() => expect(run).toHaveBeenCalledTimes(2));
    expect(sleeps).toEqual([200]);

    await host.stop();
    expect(second.runner.stop).toHaveBeenCalled();
  });

  it("retries launch with escalating backoff when restart start hits 53300", async () => {
    const first = mockRunner();
    const recovered = mockRunner();
    run
      .mockResolvedValueOnce(first.runner)
      .mockRejectedValueOnce(tooMany)
      .mockResolvedValueOnce(recovered.runner);
    const sleeps: number[] = [];
    const host = new GraphileJobWorkerHost({} as Pool, {
      sleep: async (ms) => {
        sleeps.push(ms);
      },
    });

    await host.start(handlers());
    first.rejectLife(tooMany);
    await vi.waitFor(() => expect(run).toHaveBeenCalledTimes(3));
    expect(sleeps).toEqual([200, 400]);

    await host.stop();
    expect(recovered.runner.stop).toHaveBeenCalled();
  });

  it("does not restart when runner.promise rejects for a non-53300 error", async () => {
    const first = mockRunner();
    run.mockResolvedValueOnce(first.runner);
    const host = new GraphileJobWorkerHost({} as Pool, {
      sleep: async () => undefined,
    });
    await host.start(handlers());
    const superviseTask = (host as unknown as { superviseTask: Promise<void> }).superviseTask;

    first.rejectLife(new Error("runner exploded"));
    await expect(superviseTask).rejects.toThrow("runner exploded");
    expect(run).toHaveBeenCalledTimes(1);

    await host.stop();
  });

  it("wakes a pending restart delay when stop is called", async () => {
    const first = mockRunner();
    run.mockResolvedValueOnce(first.runner);
    const sleepStarted = deferred();
    const host = new GraphileJobWorkerHost({} as Pool, {
      sleep: () => {
        sleepStarted.resolve();
        return new Promise(() => undefined);
      },
    });
    await host.start(handlers());
    first.rejectLife(tooMany);
    await sleepStarted.promise;

    await host.stop();
    expect(run).toHaveBeenCalledTimes(1);
  });
});