import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { rm } from 'fs/promises';
import type { TranscriptResponse } from 'youtube-transcript';

const { mockExecFile, mockFetchTranscript } = vi.hoisted(() => ({
	mockExecFile: vi.fn(),
	mockFetchTranscript: vi.fn()
}));

const TEST_DATA_DIR = `/tmp/tonemark-downloader-test-${Date.now()}`;
vi.stubEnv('DATA_DIR', TEST_DATA_DIR);

vi.mock('child_process', () => ({
	execFile: mockExecFile
}));

vi.mock('youtube-transcript', () => ({
	fetchTranscript: mockFetchTranscript
}));

import { downloadYouTube, transcriptEntriesToSegments } from '$lib/server/downloader.js';

beforeEach(() => {
	vi.clearAllMocks();
	mockExecFile.mockImplementation((...args: unknown[]) => {
		const cb = args.at(-1) as (...callbackArgs: unknown[]) => void;
		cb(null, JSON.stringify({ title: 'Fetched Title' }), '');
	});
});

afterEach(async () => {
	await rm(TEST_DATA_DIR, { recursive: true, force: true }).catch(() => {});
});

describe('transcriptEntriesToSegments', () => {
	it('converts millisecond transcript offsets into second-based segments', () => {
		const entries: TranscriptResponse[] = [
			{ text: 'Hello everyone.', offset: 15240, duration: 4240, lang: 'en' },
			{ text: 'Um, welcome to this talk.', offset: 16600, duration: 5080, lang: 'en' }
		];

		expect(transcriptEntriesToSegments(entries)).toEqual([
			{ index: 0, start: 15.24, end: 19.48, text: 'Hello everyone.', words: [] },
			{ index: 1, start: 16.6, end: 21.68, text: 'Um, welcome to this talk.', words: [] }
		]);
	});

	it('preserves second-based transcript offsets and drops empty text', () => {
		const entries: TranscriptResponse[] = [
			{ text: '  ', offset: 0, duration: 1.5, lang: 'en' },
			{ text: 'Clean caption cue', offset: 91.08, duration: 3.72, lang: 'en' }
		];

		expect(transcriptEntriesToSegments(entries)).toEqual([
			{ index: 0, start: 91.08, end: 94.8, text: 'Clean caption cue', words: [] }
		]);
	});
});

describe('downloadYouTube', () => {
	it('uses fetched transcript entries directly for caption jobs', async () => {
		mockFetchTranscript.mockResolvedValue([
			{ text: 'Hello everyone.', offset: 15240, duration: 4240, lang: 'en' },
			{ text: 'Um, welcome to this talk.', offset: 16600, duration: 5080, lang: 'en' }
		] satisfies TranscriptResponse[]);

		const result = await downloadYouTube('https://youtube.com/watch?v=qdh_x-uRs9g', 'job-1');

		expect(mockFetchTranscript).toHaveBeenCalledWith('https://youtube.com/watch?v=qdh_x-uRs9g', {
			lang: 'en'
		});
		expect(result).toMatchObject({
			type: 'captions',
			segments: [
				{ index: 0, start: 15.24, end: 19.48, text: 'Hello everyone.', words: [] },
				{ index: 1, start: 16.6, end: 21.68, text: 'Um, welcome to this talk.', words: [] }
			]
		});
	});
});