import { Stitcher } from '../src/stitcher.js';
import { describe, expect, it, vi, beforeEach } from 'vitest';
import { EventEmitter } from 'events';
import { spawn } from 'child_process';

const mockChildProcess = new (class MockChildProcess
    extends EventEmitter {
    kill = vi.fn(() => {
        return true;
    });
})();

vi.mock('child_process', () => {
    return {
        spawn: vi.fn(() => mockChildProcess)
    }
});

describe('stitcher', () => {

    beforeEach(() => {
        vi.clearAllMocks();
    });

    it('passes the correct arguments to ffmpeg', async () => {
        const p = Stitcher(['1.flac', 'dir/2.flac']);
        mockChildProcess.emit('exit', 0, null);
        await p;
        expect(spawn).toBeCalledWith('ffmpeg', [
            "-i",
            '1.flac',
            '-i',
            'dir/2.flac',
            '-filter_complex',
            '[0:a][1:a][2:a]concat=n=2:v=0:a=1[out]',
            '-map',
            '[out]',
            '-ar',
            '44100',
            '-ac',
            '2',
            '-c:a',
            'pcm_s16le',
            'output.wav'
        ]);
    });

    it('throws an error when ffmpeg fails', async () => {
        const p = Stitcher(['sound.mp3']);
        mockChildProcess.emit('exit', 1, null);
        await expect(p).rejects.toThrow('exited with 1');
        expect(spawn).toBeCalledWith('ffmpeg', [
            "-i",
            'sound.mp3',
            '-filter_complex',
            '[0:a][1:a][2:a]concat=n=1:v=0:a=1[out]',
            '-map',
            '[out]',
            '-ar',
            '44100',
            '-ac',
            '2',
            '-c:a',
            'pcm_s16le',
            'output.wav'
        ]);
    });

    it('throws an error when ffmpeg takes longer than expected', { timeout: 6000 }, async () => {
        await expect(Stitcher(['in.wav'])).rejects.toThrow('timed out');
        expect(spawn).toBeCalledWith('ffmpeg', [
            "-i",
            'in.wav',
            '-filter_complex',
            '[0:a][1:a][2:a]concat=n=1:v=0:a=1[out]',
            '-map',
            '[out]',
            '-ar',
            '44100',
            '-ac',
            '2',
            '-c:a',
            'pcm_s16le',
            'output.wav'
        ]);
    });
});