import type { Handle } from '@sveltejs/kit';
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';

vi.mock('../../src/lib/server/db/migrate.js', () => ({ migrate: vi.fn() }));
vi.mock('../../src/lib/server/pipeline/worker.js', () => ({ startWorker: vi.fn() }));
vi.mock('../../src/lib/server/provisioning/history.js', () => ({ interruptDeployments: vi.fn() }));
vi.mock('../../src/lib/server/auth/guard.js', () => ({ authenticationHandle: vi.fn(async () => new Response('OK')) }));
vi.mock('../../src/lib/server/pipeline/bus.js', () => ({ invalidateFleet: vi.fn() }));
vi.mock('../../src/lib/server/performance.js', () => ({ startPerformanceMonitor: vi.fn() }));

let originalListeners = process.listeners('unhandledRejection');
beforeEach(() => {
    vi.resetModules(); vi.clearAllMocks();
    originalListeners = process.listeners('unhandledRejection');
});
afterEach(() => {
    for (const listener of process.listeners('unhandledRejection')) {
        if (!originalListeners.includes(listener)) process.off('unhandledRejection', listener);
    }
    vi.restoreAllMocks();
});

describe('controller error handling', () => {
    it('registers one process rejection logger before starting workers, even across requests', async () => {
        const on = vi.spyOn(process, 'on');
        const log = vi.spyOn(console, 'error').mockImplementation(() => {});
        const { handle } = await import('../../src/hooks.server.js');
        const { startWorker } = await import('../../src/lib/server/pipeline/worker.js');
        const input = {
            event: { request: new Request('http://localhost/'), route: { id: '/' }, locals: {} },
            resolve: vi.fn()
        } as unknown as Parameters<Handle>[0];

        await handle(input);
        await handle(input);

        const listeners = process.listeners('unhandledRejection').filter(listener => !originalListeners.includes(listener));
        expect(listeners).toHaveLength(1);
        expect(startWorker).toHaveBeenCalledTimes(1);
        const registration = on.mock.calls.findIndex(([event]) => event === 'unhandledRejection');
        expect(on.mock.invocationCallOrder[registration]).toBeLessThan(vi.mocked(startWorker).mock.invocationCallOrder[0]);

        const failure = new Error('unexpected background failure');
        listeners[0](failure, Promise.resolve());
        listeners[0]('non-Error rejection', Promise.resolve());
        expect(log.mock.calls).toEqual([
            ['[process] unhandled rejection:', failure],
            ['[process] unhandled rejection:', 'non-Error rejection']
        ]);
    });
});