using System.Text;
using ErsatzTV.Core.Domain;

namespace ErsatzTV.Core.Iptv;

public class ChannelPlaylist
{
    private readonly List<Channel> _channels;
    private readonly string _host;
    private readonly string _baseUrl;
    private readonly string _scheme;

    public ChannelPlaylist(string scheme, string host, string baseUrl, List<Channel> channels)
    {
        _scheme = scheme;
        _host = host;
        _baseUrl = baseUrl;
        _channels = channels;
    }

    public string ToM3U()
    {
        var sb = new StringBuilder();

        string xmltv = $"{_scheme}://{_host}{_baseUrl}/iptv/xmltv.xml";
        sb.AppendLine($"#EXTM3U url-tvg=\"{xmltv}\" x-tvg-url=\"{xmltv}\"");
        foreach (Channel channel in _channels.OrderBy(c => decimal.Parse(c.Number)))
        {
            string logo = Optional(channel.Artwork).Flatten()
                .Filter(a => a.ArtworkKind == ArtworkKind.Logo)
                .HeadOrNone()
                .Match(
                    artwork => $"{_scheme}://{_host}{_baseUrl}/iptv/logos/{artwork.Path}.jpg",
                    () => $"{_scheme}://{_host}{_baseUrl}/iptv/images/ersatztv-500.png");

            string shortUniqueId = Convert.ToBase64String(channel.UniqueId.ToByteArray())
                .TrimEnd('=')
                .Replace("/", "_")
                .Replace("+", "-");

            string format = channel.StreamingMode switch
            {
                StreamingMode.HttpLiveStreamingDirect => "m3u8?mode=hls-direct",
                StreamingMode.HttpLiveStreamingSegmenter => "m3u8?mode=segmenter",
                StreamingMode.TransportStreamHybrid => "ts",
                _ => "ts?mode=ts-legacy"
            };

            string vcodec = channel.FFmpegProfile.VideoFormat.ToString().ToLowerInvariant();
            string acodec = channel.FFmpegProfile.AudioFormat.ToString().ToLowerInvariant();

            sb.AppendLine(
                $"#EXTINF:0 tvg-id=\"{channel.Number}.etv\" channel-id=\"{shortUniqueId}\" channel-number=\"{channel.Number}\" CUID=\"{shortUniqueId}\" tvg-chno=\"{channel.Number}\" tvg-name=\"{channel.Name}\" tvg-logo=\"{logo}\" group-title=\"{channel.Group}\" tvc-stream-vcodec=\"{vcodec}\" tvc-stream-acodec=\"{acodec}\", {channel.Name}");
            sb.AppendLine($"{_scheme}://{_host}{_baseUrl}/iptv/channel/{channel.Number}.{format}");
        }

        return sb.ToString();
    }
}