using PowerArgs;
using Newtonsoft.Json.Linq;
using System.Net;

namespace SBT_Downloader
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Welcome to the Sound Booth Theater Personal Archiving Tool!");
            try
            {
                MyArgs parsed = Args.Parse<MyArgs>(args);
                Console.WriteLine("Downloading book now...");
                (List<string> mp3Urls, List<string> chapters) = ParseHar(parsed.Har);
                DownloadMp3s(mp3Urls, chapters, parsed);
            }
            catch (ArgException ex)
            {
                Console.WriteLine(ex.Message);
                Console.WriteLine(ArgUsage.GenerateUsageFromTemplate<MyArgs>());
            }
        }

        static (List<string> mp3Urls, List<string> chapters) ParseHar(string har)
        {
            try
            {
                string harContents = LoadHar(har);
                JObject harObject = JObject.Parse(harContents);
                List<JToken> requestObjects = ParseRequests(harObject);
                List<string> mp3Urls = ParseUrls(requestObjects);
                List<string> chapters = ParseChapters(mp3Urls);
                return (mp3Urls, chapters);

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Environment.Exit(0);
                return (new List<string>(), new List<string>());
            }
        }

        private static List<JToken?> ParseRequests(JObject harObject)
        {
            List<JToken?> requests = harObject["log"]["entries"]
                .Where(x => x.SelectToken("_resourceType").ToString() == "media")
                .Select(y => y.SelectToken("request"))
                .DistinctBy(z => z.SelectToken("url")).ToList();

            return requests;
        }

        private static List<string> ParseChapters(List<string> mp3Urls)
        {
            List<string> chapters = new();
            foreach (string url in mp3Urls)
            {
                Uri uri = new(url);
                string fixedUri = uri.AbsoluteUri.Replace(uri.Query, string.Empty);
                List<string> urlTokens = fixedUri.Split("/").ToList();
                //string series = urlTokens[5];
                //string title = urlTokens[6];
                //string episode = urlTokens[7];
                var chapterTokens = urlTokens.Last().Split("_").ToList();
                chapterTokens.RemoveRange(0,5);
                string chapterLastToken = chapterTokens.Last().Split(".").First();
                chapterTokens[^1] = chapterLastToken;
                chapters.Add(string.Join(" ", chapterTokens));
            }

            return chapters;
        }

        static List<string> ParseUrls(List<JToken> requestList)
        {
            List<string> urls = requestList.Select(x => x.SelectToken("url").ToString()).ToList();

            Console.WriteLine(urls.Count + " total requests");

            return urls;
        }

        private static void DownloadMp3s(List<string> mp3Urls, List<string> chapters, MyArgs arguments)
        {
            Parallel.ForEach(
                mp3Urls,
                new ParallelOptions { MaxDegreeOfParallelism = 10 },
                (url, state, index) =>
                {
                    int chapterNumber = (int)index + 1;
                    string chapterName = chapters[(int)index];
                    string fileName = $"{chapterNumber} {chapterName}.mp3";
                    using var client = new WebClient();
                    Console.WriteLine("Downloading file #" + index);
                    client.DownloadFile(url, fileName);
                    TagFile(chapterName, chapterNumber, chapters.Count, arguments);
                });
        }

            private static void TagFile(string chapterName, int chapterNumber, int chapterCount, MyArgs arguments)
        {
            Console.WriteLine($"Tagging chapter {chapterNumber} ({chapterCount})");
            var file = TagLib.File.Create($"{chapterNumber} {chapterName}.mp3");

            file.Tag.Album = arguments.Title.IsNullOrEmpty() ? string.Empty : arguments.Title;
            List<string> artistsList = new();
            if (!arguments.Author.IsNullOrEmpty())  artistsList.Add(arguments.Author);
            if (!arguments.Narrator.IsNullOrEmpty()) artistsList.Add(arguments.Narrator);
            file.Tag.AlbumArtists = artistsList.ToArray();
            file.Tag.Title = chapterName;
            file.Tag.Track = (uint)chapterNumber;
            file.Tag.TrackCount = (uint)chapterCount;

            file.Save();
        }

        static string LoadHar(string harFileName)
        {
            string harContents;
            try
            {
                using StreamReader streamReader = new(harFileName);
                harContents = streamReader.ReadToEnd();
                return harContents;
            }
            catch (Exception e)
            {
                Console.WriteLine("The file could not be read:");
                Console.WriteLine(e.Message);
                Environment.Exit(0);
                return string.Empty;
            }
        }


    }
}