using System;
using System.IO;
using System.IO.Compression;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;
using Pf2e.Scrapper.Helpers;

namespace Pf2e.Scrapper.Importers.Repositories;

public abstract class AbstractGitHubRepository(AbstractImporter importer)
    : AbstractImporterRepository(importer)
{
    public abstract string Repository { get; }
    public abstract string AssetName { get; }

    public override void Update(ProcessProgress progress)
    {
        ReleaseInformation releaseInformation = GetReleaseInformation();
        string? currentVersion = GetCurrentVersion();

        if (currentVersion == releaseInformation.TagName)
        {
            progress.Local.Complete();
            progress.Information(
                $"Данные {Repository} актуальны, текущая версия {currentVersion}."
            );
            return;
        }

        progress.Information(
            $"Данные {Repository} устарели, обновляем {RepositoryDirPath} до версии {releaseInformation.TagName}..."
        );

        string assetFile = DownloadAsset(progress, releaseInformation);

        ExtractAsset(assetFile, RepositoryDirPath, progress);

        File.WriteAllText(
            Path.Combine(RepositoryDirPath, "version.txt"),
            releaseInformation.TagName
        );
    }

    private ReleaseInformation GetReleaseInformation()
    {
        string releasesUrl = $"https://api.github.com/repos/{Repository}/releases/latest";
        using HttpClient client = new();
        client.DefaultRequestHeaders.UserAgent.Add(
            new ProductInfoHeaderValue("Pf2eDataScrapper", "1.0")
        );
        string json = client.GetStringAsync(releasesUrl).Result;
        JObject jObject = JObject.Parse(json);

        return new()
        {
            TagName = jObject.SelectToken("tag_name")!.ToObject<string>()!,
            DownloadUrl = jObject
                .SelectToken("assets[?(@.name == '" + AssetName + "')].browser_download_url")!
                .ToObject<string>()!,
            Size = jObject
                .SelectToken("assets[?(@.name == '" + AssetName + "')].size")!
                .ToObject<int>()!,
        };
    }

    private string? GetCurrentVersion()
    {
        string versionFilePath = Path.Combine(RepositoryDirPath, "version.txt");
        if (File.Exists(versionFilePath))
        {
            return File.ReadAllText(versionFilePath).Trim();
        }
        return null;
    }

    private string DownloadAsset(ProcessProgress progress, ReleaseInformation releaseInformation)
    {
        string fileName = System.IO.Path.GetTempPath() + Guid.NewGuid().ToString() + ".zip";
        using var fileStream = new FileStream(fileName, FileMode.Create, FileAccess.Write);

        progress.Local.Reset(releaseInformation.Size);
        progress.Local.Start(
            $"[1/2] Загрузка {releaseInformation.TagName} ({releaseInformation.Size / 1024 / 1024} МБ)..."
        );

        Task.Run(async () =>
            {
                using HttpClient client = new();
                using var response = await client.GetAsync(
                    releaseInformation.DownloadUrl,
                    HttpCompletionOption.ResponseHeadersRead
                );

                using var download = await response.Content.ReadAsStreamAsync();

                var buffer = new byte[81920];
                int bytesRead;
                var t = CancellationToken.None;

                while ((bytesRead = await download.ReadAsync(buffer, t).ConfigureAwait(false)) != 0)
                {
                    await fileStream
                        .WriteAsync(buffer.AsMemory(0, bytesRead), t)
                        .ConfigureAwait(false);
                    progress.Local.Current += bytesRead;
                }
            })
            .Wait();

        progress.Local.Complete();
        return fileName;
    }

    private void ExtractAsset(string assetFile, string targetDir, ProcessProgress progress)
    {
        using var zip = ZipFile.OpenRead(assetFile);

        progress.Local.Reset(zip.Entries.Count);
        progress.Local.Start("[2/2] Распаковка архива...");

        foreach (var entry in zip.Entries)
        {
            if (string.IsNullOrEmpty(entry.Name))
                continue; // Skip directories

            string destinationPath = Path.Combine(targetDir, entry.FullName);

            string directoryPath = Path.GetDirectoryName(destinationPath)!;
            if (!Directory.Exists(directoryPath))
            {
                Directory.CreateDirectory(directoryPath);
            }

            entry.ExtractToFile(destinationPath, true);
            progress.Local.Current++;
        }

        progress.Local.Complete();
    }

    private class ReleaseInformation
    {
        public string TagName { get; init; } = null!;
        public string DownloadUrl { get; init; } = null!;
        public int Size { get; init; } = 0;
    }
}