using Serilog;

namespace TvSyncApp
{
    public class Loader
    {
        private readonly Downloader _downloader;

        public Loader()
        {
            _downloader = new Downloader();
        }

        public async Task<(int Success, int Failed)> LoadJsonAsync(
            Dictionary<string, string> directories,
            List<string> updateList,
            Dictionary<string, long> updateDict,
            Settings settings,
            int maxParallelDownloads = 5)
        {
            int success = 0;
            int failed = 0;
            int completed = 0;


            var semaphore = new System.Threading.SemaphoreSlim(maxParallelDownloads);

            var filesNeeded = new List<(string Directory, string FileName)>();
            
            foreach (var seriesId in updateList)
            {
                foreach (var dir in directories.Values)
                {
                    string filePath = Path.Combine(dir, $"{seriesId}.json");
                    if (!File.Exists(filePath))
                        filesNeeded.Add((dir, $"{seriesId}.json"));
                }
            }

            Log.Information("Downloading {Count} files...", filesNeeded.Count);
            var totalFiles = filesNeeded.Count;
            var progress = new Progress<int>(value =>
            {
                completed += value;
                Console.Write($"\rDownloading files: {completed}/{totalFiles}");
            });

            var tasks = new List<Task>();
            foreach (var file in filesNeeded)
            {
                tasks.Add(DownloadWithThrottleAsync(file.Directory, file.FileName, settings, semaphore, progress));
            }

            await Task.WhenAll(tasks);
            Console.WriteLine("\nDownload complete.");

            foreach (var file in filesNeeded)
            {
                string path = Path.Combine(file.Directory, file.FileName);
                if (File.Exists(path)) success++;
                else failed++;
            }

            return (success, failed);
        }

        private async Task DownloadWithThrottleAsync(
            string directory,
            string fileName,
            Settings settings,
            System.Threading.SemaphoreSlim semaphore,
            IProgress<int> progress)
        {
            await semaphore.WaitAsync();
            try
            {
                string seriesId = Path.GetFileNameWithoutExtension(fileName);
                string url;

                if (directory.Contains("series", StringComparison.OrdinalIgnoreCase))
                    url = settings.Json.ShowApi.Replace("<tvmazeid>", seriesId);
                else if (directory.Contains("episodes", StringComparison.OrdinalIgnoreCase))
                    url = settings.Json.EpisodeApi.Replace("<tvmazeid>", seriesId);
                else if (directory.Contains("cast", StringComparison.OrdinalIgnoreCase))
                    url = settings.Json.CastApi.Replace("<tvmazeid>", seriesId);
                else if (directory.Contains("crew", StringComparison.OrdinalIgnoreCase))
                    url = settings.Json.CrewApi.Replace("<tvmazeid>", seriesId);
                else
                    url = $"https://api.tvmaze.com/shows/{seriesId}";

                // Download the file
                await Task.Run(() => _downloader.Download(url, directory, fileName, Log.Logger));

                // Report progress
                progress?.Report(1);
            }
            catch (Exception ex)
            {
                Log.Error(ex, "Failed to download {FileName}", fileName);
                progress?.Report(1); // still report so progress moves forward
            }
            finally
            {
                semaphore.Release();
            }
        }
    }
}