import {spawn} from 'node:child_process';
import fs from 'node:fs/promises';
import Path from 'node:path';
import {Ai} from './ai.ts';

export class Audio {
	private downloads: {[key: string]: Promise<string>} = {};
	private whisperModel!: string;

	constructor(private ai: Ai) {
		if(ai.options.whisper?.binary) {
			this.whisperModel = ai.options.whisper?.model.endsWith('.bin') ? ai.options.whisper?.model : ai.options.whisper?.model + '.bin';
			this.downloadAsrModel();
		}
	}

	/**
	 * Convert audio to text using Auditory Speech Recognition
	 * @param {string} path Path to audio
	 * @param model Whisper model
	 * @returns {Promise<any>} Extracted text
	 */
	asr(path: string, model: string = this.whisperModel): {abort: () => void, response: Promise<string | null>} {
		if(!this.ai.options.whisper?.binary) throw new Error('Whisper not configured');
		let abort: any = () => {};
		const response = new Promise<string | null>((resolve, reject) => {
			this.downloadAsrModel(model).then(m => {
				let output = '';
				const proc = spawn(<string>this.ai.options.whisper?.binary, ['-nt', '-np', '-m', m, '-f', path], {stdio: ['ignore', 'pipe', 'ignore']});
				abort = () => proc.kill('SIGTERM');
				proc.on('error', (err: Error) => reject(err));
				proc.stdout.on('data', (data: Buffer) => output += data.toString());
				proc.on('close', (code: number) => {
					if(code === 0) resolve(output.trim() || null);
					else reject(new Error(`Exit code ${code}`));
				});
			});
		});
		return {response, abort};
	}

	/**
	 * Downloads the specified Whisper model if it is not already present locally.
	 *
	 * @param {string} model Whisper model that will be downloaded
	 * @return {Promise<string>} Absolute path to model file, resolves once downloaded
	 */
	async downloadAsrModel(model: string = this.whisperModel): Promise<string> {
		if(!this.ai.options.whisper?.binary) throw new Error('Whisper not configured');
		if(!model.endsWith('.bin')) model += '.bin';
		const p = Path.join(this.ai.options.whisper.path, model);
		if(await fs.stat(p).then(() => true).catch(() => false)) return p;
		if(!!this.downloads[model]) return this.downloads[model];
		this.downloads[model] = fetch(`https://huggingface.co/ggerganov/whisper.cpp/resolve/main/${model}`)
			.then(resp => resp.arrayBuffer())
			.then(arr => Buffer.from(arr)).then(async buffer => {
				await fs.writeFile(p, buffer);
				delete this.downloads[model];
				return p;
			});
		return this.downloads[model];
	}
}