ytdlp-gui/Main.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ytdlp_gui
{
    public partial class Main : Form
    {
        public Main()
        {
            ytdlp = new YTdlp();
            downloads = new List<Download>();
            InitializeComponent();
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void btnDownload_Click(object sender, EventArgs e)
        {
            // Get user download folder on Windows
            string user = Environment.GetEnvironmentVariable("USERNAME");
            string workdir = @"C:\Users\" + user + @"\Downloads\";

            if (checkDownloadPlaylist.Checked && checkPlaylistFolder.Checked)
            {
                workdir = Path.Combine(workdir, textPlaylistFolder.Text);
                if (!Directory.Exists(workdir))
                    System.IO.Directory.CreateDirectory(workdir);
            }

            YTdlpProcess process = ytdlp.Download(
                textUrl.Text,
                checkAudioOnly.Checked,
                checkDownloadPlaylist.Checked,
                workdir
            );
            Download download = new Download(
                process,
                workdir,
                checkConvert.Checked ? comboConvertFormat.Text : null
            );

            download.Show();
            downloads.Add(download);

            download.FormClosed += (_sender, _e) => {
                downloads.Remove(download);
            };
        }

        private void Main_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (downloads.Count == 0)
                return;
            var window = MessageBox.Show(
                "Close the window?\nClosing current window will cancel current downloads!",
                "Are you sure?",
                MessageBoxButtons.YesNo
            );
            e.Cancel = (window == DialogResult.No);
        }
        
        private void checkAudioOnly_CheckedChanged(object sender, EventArgs e)
        {
            if (checkAudioOnly.Checked)
                comboConvertFormat.Text = "mp3";
            else
                comboConvertFormat.Text = "mp4";
        }

        private void checkConvert_CheckedChanged(object sender, EventArgs e)
        {
            comboConvertFormat.Enabled = checkConvert.Checked;
        }

        private void checkDownloadPlaylist_CheckedChanged(object sender, EventArgs e)
        {
            groupPlaylist.Enabled = checkDownloadPlaylist.Checked;
        }

        private void checkPlaylistFolder_CheckedChanged(object sender, EventArgs e)
        {
            textPlaylistFolder.Enabled = checkPlaylistFolder.Checked;
            lblPlaylistFolder.Enabled = checkPlaylistFolder.Checked;
        }

        protected List<Download> downloads;
        protected YTdlp ytdlp;
    }
}