added playlist loader

registered appconfig as singleton
added config interfaces

Tv7Playlist.Core/PlaylistLoader.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Tv7Playlist.Core.Parsers;
+
+namespace Tv7Playlist.Core
+{
+    public class PlaylistLoader : IPlaylistLoader
+    {
+        private readonly ILogger<PlaylistLoader> _logger;
+        private readonly IPlaylistParser _playlistParser;
+        private readonly string _tv7Url;
+
+        public PlaylistLoader(ILogger<PlaylistLoader> logger, IAppConfig appConfig, IPlaylistParser playlistParser)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _playlistParser = playlistParser ?? throw new ArgumentNullException(nameof(playlistParser));
+
+            _tv7Url = appConfig.TV7Url;
+
+        }
+
+        public async Task<IReadOnlyCollection<ParsedTrack>> LoadPlaylistFromUrl()
+        {
+            using (var httpClient = new HttpClient())
+            {
+                _logger.LogInformation(LoggingEvents.Playlist, "Downloading playlist from {tv7url}", _tv7Url);
+                
+                var tv7Response = await httpClient.GetAsync(_tv7Url);
+                if (!tv7Response.IsSuccessStatusCode)
+                {
+                    _logger.LogWarning(LoggingEvents.PlaylistNotFound, "Could not download playlist from {tv7url}. The StatusCode was: {StatusCode}", _tv7Url, tv7Response.StatusCode);
+                }
+
+                return await ParseTracksFromResponseAsync(tv7Response);
+            }
+        }
+        
+        private async Task<IReadOnlyCollection<ParsedTrack>> ParseTracksFromResponseAsync(HttpResponseMessage tv7Response)
+        {
+            _logger.LogInformation(LoggingEvents.Playlist, "Parse");
+
+            using (var tv7ReadStream = await tv7Response.Content.ReadAsStreamAsync())
+            {
+                return await _playlistParser.ParseFromStreamAsync(tv7ReadStream);
+            }
+        }
+    }
+}