using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using log4net;

namespace MovieBarcodeGenerator {
    public class SharpFF {
        public static string ffmpegPath { get; set; }
        private static log4net.ILog log = log4net.LogManager.GetLogger("SharpFF");

        public static void ExecuteCommand(string parameters) {
            if (String.IsNullOrEmpty(ffmpegPath) || !File.Exists(Path.Combine(ffmpegPath, "ffmpeg.exe"))) {
                log.FatalFormat("FFmpeg was not found at '{0}'.", ffmpegPath);
                throw new Exception("Path to ffmpeg not specified. Set ffmpeg path (excluding exe) before attempting to use SharpFF.");
            }
            log.DebugFormat("Calling ffmpeg at {0} with parameters {1}", ffmpegPath, parameters);
            Process p = new Process();
            p.StartInfo.FileName = Path.Combine(ffmpegPath, "ffmpeg");
            p.StartInfo.Arguments = parameters;
            p.StartInfo.UseShellExecute = false;
            p.Start();
            // this could potentially be speeded up by not waiting, but then we end up trying to delete files before ffmpeg
            // is actually finished
            p.WaitForExit();
        }

        public static decimal GetDuration(string videoPath) {
            string parameters = String.Format("-hide_banner -i \"{0}\"", videoPath);

            if (String.IsNullOrEmpty(ffmpegPath) || !File.Exists(Path.Combine(ffmpegPath, "ffmpeg.exe"))) {
                log.FatalFormat("FFmpeg was not found at '{0}'.", ffmpegPath);
                throw new Exception("Path to ffmpeg not specified. Set ffmpeg path (excluding exe) before attempting to use SharpFF.");
            }
            log.DebugFormat("Calling ffmpeg at {0} with parameters {1}", ffmpegPath, parameters);
            Process p = new Process();
            p.StartInfo.FileName = Path.Combine(ffmpegPath, "ffmpeg");
            p.StartInfo.Arguments = parameters;
            p.StartInfo.RedirectStandardError = true;
            p.StartInfo.UseShellExecute = false;
            p.Start();
            string stderr = p.StandardError.ReadToEnd();
            List<string> outLines = stderr.Split(System.Environment.NewLine[0])
                .Where(line => string.IsNullOrWhiteSpace(line) == false && string.IsNullOrEmpty(line.Trim()) == false)
                .Select(s => s.Trim()).ToList();

            foreach (var line in outLines) {
                if (line.StartsWith("Duration")) {
                    string timecode = line.Split(' ')[1].Trim();
                    return TimecodeToSeconds(timecode);
                }
            }
            p.WaitForExit();
            return 0.0M;
        }

        public static decimal TimecodeToSeconds(string timecode) {
            timecode = timecode.Replace(",", String.Empty);

            decimal totalSeconds = 0;
            string[] timeElements = timecode.Split(':');
            totalSeconds += Int32.Parse(timeElements[0]) * 3600;
            totalSeconds += Int32.Parse(timeElements[1]) * 60;
            totalSeconds += Math.Floor(decimal.Parse(timeElements[2]) * 100) / 100;
            return totalSeconds;
        }

        public static string SecondsToTimecode(object seconds) {
            decimal betterSeconds = System.Convert.ToDecimal(seconds);
            decimal hours = Math.Floor(betterSeconds / 3600);
            if (hours >= 1) {
                betterSeconds -= hours * 3600;
            }
            decimal minutes = Math.Floor(betterSeconds / 60);
            if (minutes >= 1) {
                betterSeconds -= minutes * 60;
            }
            return String.Format("{0:00}:{1:00}:{2:00.00}", hours, minutes, Math.Floor(betterSeconds * 100) / 100);
        }
    }
}