import * as path from 'path';
import * as fs from 'fs/promises';
import { exec } from 'child_process';
import { hashBuffer } from './hash';

export async function convertVideo(video: Uint8Array) {
    let random = Math.floor(Math.random() * 10000000);
    let hash = await hashBuffer(video.buffer);
    
    const tempInPath = `/tmp/${hash}-${random}.in.mp4`;
    const tempOutPath = `/tmp/${hash}-${random}.out.mp4`;
    try {
        await fs.writeFile(tempInPath, video);

        const status = await new Promise((resolve, reject) => {
            const child = exec(`ffmpeg -i "${tempInPath}" -preset ultrafast -vf "scale=320:480,eq=saturation=1.4,unsharp=5:5:1.5:5:5:0.0" -b:v 420k -b:a 64k "${tempOutPath}"`, (err) => {
                if (err) {
                    reject(err);
                    return;
                }

                resolve(child.exitCode);
            });
        });

        if (status) return null;

        const result = await fs.readFile(tempOutPath);
        const resultUint8 = new Uint8Array(result);

        return resultUint8;
    } finally {
        await fs.unlink(tempInPath).catch((_) => {});
        await fs.unlink(tempOutPath).catch((_) => {});
    }
}