using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace EpicMorg.Atlassian.Downloader
{
    class DonloaderService : IHostedService
    {
        private readonly ILogger<DonloaderService> logger;
        private readonly DownloaderOptions options;
        private readonly HttpClient client;
        private readonly IHostApplicationLifetime hostApplicationLifetime;

        public DonloaderService(IHostApplicationLifetime hostApplicationLifetime, ILogger<DonloaderService> logger, HttpClient client, DownloaderOptions options)
        {
            this.logger = logger;
            this.client = client;
            this.options = options;
            this.hostApplicationLifetime = hostApplicationLifetime;
        }

        public async Task StartAsync(CancellationToken cancellationToken)
        {
            this.SetConsoleTitle();
            var feedUrls = this.GetFeedUrls();

            logger.LogInformation($"Task started");
            foreach (var feedUrl in feedUrls)
            {
                if (cancellationToken.IsCancellationRequested)
                {
                    return;
                }
                var (json, versions) = await this.GetJson(feedUrl, cancellationToken).ConfigureAwait(false);

                switch (options.Action)
                {
                    case DownloadAction.ShowRawJson:
                        Console.Out.WriteLine(json);
                        break;
                    case DownloadAction.Download:
                        await this.DownloadFilesFromFreed(feedUrl, versions, cancellationToken).ConfigureAwait(false);
                        break;
                    case DownloadAction.ListURLs:
                        foreach (var versionProg in versions)
                        {
                            foreach (var file in versionProg.Value)
                            {
                                Console.Out.WriteLine(file.ZipUrl);
                            }
                        }
                        break;
                    case DownloadAction.ListVersions:
                        foreach (var versionProg in versions)
                        {
                            foreach (var file in versionProg.Value)
                            {
                                Console.Out.WriteLine(file.Version);
                            }
                        }
                        break;
                }
            }
            logger.LogInformation($"Complete");
            this.hostApplicationLifetime.StopApplication();
        }

        private async Task<(string json, IDictionary<string, ResponseItem[]> versions)> GetJson(string feedUrl, CancellationToken cancellationToken)
        {
            var atlassianJson = await client.GetStringAsync(feedUrl, cancellationToken).ConfigureAwait(false);
            var json = atlassianJson.Trim()["downloads(".Length..^1];
            var parsed = JsonSerializer.Deserialize<ResponseItem[]>(json, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true
            });
            var versions = parsed.GroupBy(a => a.Version).ToDictionary(a => a.Key, a => a.ToArray());

            return (json, versions);
        }

        private string[] GetFeedUrls() => options.CustomFeed != null
            ? options.CustomFeed.Select(a => a.ToString()).ToArray()
            : new[] {
                "https://my.atlassian.com/download/feeds/archived/bamboo.json",
                "https://my.atlassian.com/download/feeds/archived/clover.json",
                "https://my.atlassian.com/download/feeds/archived/confluence.json",
                "https://my.atlassian.com/download/feeds/archived/crowd.json",
                "https://my.atlassian.com/download/feeds/archived/crucible.json",
                "https://my.atlassian.com/download/feeds/archived/fisheye.json",
                "https://my.atlassian.com/download/feeds/archived/jira-core.json",
                "https://my.atlassian.com/download/feeds/archived/jira-servicedesk.json",
                "https://my.atlassian.com/download/feeds/archived/jira-software.json",
                "https://my.atlassian.com/download/feeds/archived/jira.json",
                "https://my.atlassian.com/download/feeds/archived/stash.json",

                "https://my.atlassian.com/download/feeds/current/bamboo.json",
                "https://my.atlassian.com/download/feeds/current/clover.json",
                "https://my.atlassian.com/download/feeds/current/confluence.json",
                "https://my.atlassian.com/download/feeds/current/crowd.json",
                "https://my.atlassian.com/download/feeds/current/crucible.json",
                "https://my.atlassian.com/download/feeds/current/fisheye.json",
                "https://my.atlassian.com/download/feeds/current/jira-core.json",
                "https://my.atlassian.com/download/feeds/current/jira-servicedesk.json",
                "https://my.atlassian.com/download/feeds/current/jira-software.json",
                "https://my.atlassian.com/download/feeds/current/stash.json",

                "https://my.atlassian.com/download/feeds/eap/bamboo.json",
                "https://my.atlassian.com/download/feeds/eap/confluence.json",
                "https://my.atlassian.com/download/feeds/eap/jira.json",
                "https://my.atlassian.com/download/feeds/eap/jira-servicedesk.json",
                "https://my.atlassian.com/download/feeds/eap/stash.json",
				
				//https://raw.githubusercontent.com/EpicMorg/atlassian-json/master/json-backups/archived/sourcetree.json
				"https://raw.githack.com/EpicMorg/atlassian-json/master/json-backups/archived/sourcetree.json",
				
				//https://raw.githubusercontent.com/EpicMorg/atlassian-json/master/json-backups/current/sourcetree.json
				"https://raw.githack.com/EpicMorg/atlassian-json/master/json-backups/current/sourcetree.json"
				
            };

        private void SetConsoleTitle()
        {
            const string appBuildType =
#if DEBUG
                "[Debug]"
#else
            
                "[Release]"
#endif
            ;
            var assemblyName = System.Reflection.Assembly.GetExecutingAssembly().GetName();
            Console.Title = $@"{assemblyName.Name} {assemblyName.Version} {appBuildType}";
        }

        private async Task DownloadFilesFromFreed(string feedUrl, IDictionary<string, ResponseItem[]> versions, CancellationToken cancellationToken)
        {
            var feedDir = Path.Combine(options.OutputDir, feedUrl[(feedUrl.LastIndexOf('/') + 1)..(feedUrl.LastIndexOf('.'))]);
            logger.LogInformation($"Download from JSON \"{feedUrl}\" started");
            foreach (var version in versions)
            {
                if (cancellationToken.IsCancellationRequested)
                {
                    return;
                }

                var directory = Path.Combine(feedDir, version.Key);
                if (!Directory.Exists(directory))
                {
                    Directory.CreateDirectory(directory);
                }
                foreach (var file in version.Value)
                {
                    if (cancellationToken.IsCancellationRequested)
                    {
                        return;
                    }
                    if (file.ZipUrl == null) { continue; }
                    var serverPath = file.ZipUrl.PathAndQuery;
                    var outputFile = Path.Combine(directory, serverPath[(serverPath.LastIndexOf("/") + 1)..]);
                    if (!File.Exists(outputFile))
                    {
                        await DownloadFile(file, outputFile, cancellationToken).ConfigureAwait(false);
                    }
                    else
                    {
                        logger.LogWarning($"File \"{outputFile}\" already exists. Download from \"{file.ZipUrl}\" skipped.");
                    }
                }
            }
            logger.LogInformation($"All files from \"{feedUrl}\" successfully downloaded.");
        }

        private async Task DownloadFile(ResponseItem file, string outputFile, CancellationToken cancellationToken)
        {
            if (!string.IsNullOrEmpty(file.Md5))
            {
                File.WriteAllText(outputFile + ".md5", file.Md5);
            }
            try
            {
                using var outputStream = File.OpenWrite(outputFile);
                using var request = await client.GetStreamAsync(file.ZipUrl, cancellationToken).ConfigureAwait(false);
                await request.CopyToAsync(outputStream, cancellationToken).ConfigureAwait(false);
            }
            catch (Exception downloadEx)
            {
                logger.LogError(downloadEx, $"Failed to download file {file.ZipUrl} to {outputFile}.");
                try
                {
                    File.Delete(outputFile);
                }
                catch (Exception removeEx)
                {
                    logger.LogError(removeEx, $"Failed to remove incomplete file {outputFile}.");
                }
            }
            logger.LogInformation($"File \"{file.ZipUrl}\" successfully downloaded to \"{outputFile}\".");
        }

        public async Task StopAsync(CancellationToken cancellationToken) { }
    }
}