using System.Net.Http;
using System.Net.Http.Headers;
using Млаумчерб.Клиент.зримое;
using Млаумчерб.Клиент.классы;

namespace Млаумчерб.Клиент.сеть;

public static class Сеть
{
    private static HttpClient _http = new();

    static Сеть()
    {
        // thanks for Sashok :3
        // https://github.com/new-sashok724/Launcher/blob/23485c3f7de6620d2c6b7b2dd9339c3beb6a0366/Launcher/source/helper/IOHelper.java#L259
        _http.DefaultRequestHeaders.Add("User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)");
    }

    public static Task<string> GetString(string url, CancellationToken ct = default) => _http.GetStringAsync(url, ct);
    public static Task<Stream> GetStream(string url, CancellationToken ct = default) => _http.GetStreamAsync(url, ct);
    
    public static async Task DownloadFile(string url, Stream outStream, CancellationToken ct = default, 
        params TransformStream.TransformFuncDelegate[] transforms)
    {
        await using var pipe = new TransformStream(await GetStream(url, ct));
        if (transforms.Length > 0) 
            pipe.AddTransforms(transforms);
        await pipe.CopyToAsync(outStream, ct);
    }
    
    public static async Task DownloadFile(string url, IOPath outPath, CancellationToken ct = default, 
        params TransformStream.TransformFuncDelegate[] transforms)
    {
        await using var file = File.OpenWrite(outPath);
        await DownloadFile(url, file, ct, transforms);
    }
    
    public static async Task<T> DownloadStringAndDeserialize<T>(string url)
    {
        var text = await _http.GetStringAsync(url);
        var result = JsonConvert.DeserializeObject<T>(text)
            ?? throw new Exception($"can't deserialize {typeof(T).Name}");
        return result;
    }
    
    private static readonly string[] VERSION_MANIFEST_URLS =
    {
        "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json"
    };

    private static async Task<List<RemoteVersionDescriptorProps>> GetRemoteVersionDescriptorsAsync()
    {
        List<RemoteVersionDescriptorProps> descriptors = new();
        foreach (var url in VERSION_MANIFEST_URLS)
        {
            try
            {
                var catalog = await DownloadStringAndDeserialize<GameVersionCatalog>(url);
                descriptors.AddRange(catalog.versions);
            }
            catch (Exception ex)
            {
                Приложение.Логгер.LogWarn(nameof(Сеть), ex);
            }
        }

        return descriptors;
    }

    private static List<GameVersionProps>? _versionPropsList;

    /// <returns>empty list if couldn't find any remote versions</returns>
    public static async Task<IReadOnlyList<GameVersionProps>> GetDownloadableVersions()
    {
        if (_versionPropsList == null)
        {
            _versionPropsList = new();
            var rvdlist = await GetRemoteVersionDescriptorsAsync();
            foreach (var r in rvdlist)
            {
                if (r.type == "release")
                    _versionPropsList.Add(new GameVersionProps(r.id, r.url));
            }
        }

        return _versionPropsList;
    }
}