using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using FFMpegCore;

namespace videoRetailor
{
    public class analyzedMedia
    {
        public List<string> path { get; set; } = new List<string>();
        public List<IMediaAnalysis> ffprobed { get; set; } = new List<IMediaAnalysis>();
        public double TotalSeconds { get { return ffprobed.Sum(ima => ima.Duration.TotalSeconds); } }
        public double durationVariance { get; set; }
    }
    class Program
    {
        static async Task Main(string[] args)
        {
            Console.WriteLine(Directory.GetCurrentDirectory());
            var mkvFiles = Directory.GetFiles(Directory.GetCurrentDirectory(), "*.mkv");

            var mediaInfos = new List<analyzedMedia>();
            var totalTime = new TimeSpan();
            foreach (var file in mkvFiles.OrderBy(f => f))
            {
                var thisMeta = new analyzedMedia();
                thisMeta.path.Add(file);
                thisMeta.ffprobed.Add(await FFProbe.AnalyseAsync(file));
                mediaInfos.Add(thisMeta);
            }
            if (mediaInfos.Count < 8)
            {
                Console.WriteLine($"there's only {mkvFiles.Length}, can't recombine. just going to send them all as-is.");
            }
            else
            {
                foreach (var thisMeta in mediaInfos)
                {
                    totalTime += thisMeta.ffprobed[0].Duration;
                }
                var averageTime = totalTime.TotalSeconds / mediaInfos.Count();
                Console.WriteLine($"average time: {averageTime}");
                foreach (var thisMeta in mediaInfos)
                {
                    thisMeta.durationVariance = thisMeta.TotalSeconds / averageTime;
                    Console.WriteLine($"{string.Join(", ", thisMeta.path)}: {thisMeta.TotalSeconds} seconds");
                    Console.WriteLine($"  duration ratio: {thisMeta.durationVariance}");
                }
                Console.WriteLine($"...am I crashing? {mediaInfos.Min(af => af.durationVariance)}");
                while (mediaInfos.Count() > 7 &&
                    (mediaInfos.Min(af => af.durationVariance) < 0.9))
                {
                    Console.WriteLine("gluestick at the ready.");
                    var idx = 0;
                    var targetMinDuration = mediaInfos.Min(af => af.durationVariance);
                    Console.WriteLine($"targetMinDuration = {targetMinDuration}");
                    foreach (var af in mediaInfos)
                    {
                        if (af.durationVariance == targetMinDuration)
                        {
                            break;
                        }
                        idx++;
                    }
                    var previousDuration = (idx == 0) ? Double.MaxValue : mediaInfos[idx - 1].TotalSeconds;
                    var nextDuration = (idx > mediaInfos.Count() - 2) ? Double.MaxValue : mediaInfos[idx - 1].TotalSeconds;
                    analyzedMedia partner;
                    if (nextDuration > previousDuration)
                    {
                        partner = mediaInfos[idx - 1];
                        Console.WriteLine($"combining with previous, previously at {partner.TotalSeconds}");
                        partner.ffprobed.AddRange(mediaInfos[idx].ffprobed);
                        partner.path.AddRange(mediaInfos[idx].path);
                    }
                    else
                    {
                        partner = mediaInfos[idx + 1];
                        Console.WriteLine($"combining with next, previously at {partner.TotalSeconds}");
                        mediaInfos[idx].ffprobed.AddRange(partner.ffprobed);
                        partner.ffprobed = mediaInfos[idx].ffprobed;
                        mediaInfos[idx].path.AddRange(partner.path);
                        partner.path = mediaInfos[idx].path;
                    }
                    mediaInfos.RemoveAt(idx);
                    averageTime = totalTime.TotalSeconds / mediaInfos.Count();
                    foreach (var thisMeta in mediaInfos)
                    {
                        thisMeta.durationVariance = thisMeta.TotalSeconds / averageTime;
                    }
                }
            }
            Console.WriteLine($"{mediaInfos.Count()} infos.");
            var i = 1;
            foreach (var mi in mediaInfos)
            {
                Console.WriteLine($"going to export {string.Join(", ", mi.path)} as part {i}");
                FFMpeg.Join($"./{DateTime.Today.ToShortDateString()} (part {i}/{mediaInfos.Count()}).mp4",
                    mi.path.ToArray()
                );

                i++;
            }
        }
    }
}