using System.IO.Compression;

namespace Pilz.Updating.Client;

public class UpdateClient(string updateUrl, AppVersion currentVersion, Channels minimumChannel)
{
    // E v e n t s

    public event UpdateClientStatusChangedEventHandler? OnStatusChanged;

    // F i e l d s

    private readonly Dictionary<UpdatePackageInfo, string> dicPackagePaths = [];

    // P r o p e r t i e s

    public HttpClient WebClient { get; private set; } = new();
    public string UpdateUrl { get; private set; } = updateUrl;
    public AppVersion CurrentVersion { get; private set; } = currentVersion;
    public Channels MinimumChannel { get; private set; } = (Channels)Math.Max((int)minimumChannel, (int)currentVersion.Channel);
    public UpdateInfo? UpdateInfo { get; private set; }
    public UpdatePackageInfo? UpdatePackageInfo { get; private set; }
    public string HostApplicationPath { get; set; } = string.Empty;
    public string ApplicationName { get; set; } = string.Empty;
    public bool InstallAsAdmin { get; set; } = false;
    public bool UIDarkMode { get; set; } = false;
    public bool HasUpdates => UpdatePackageInfo != null;

    // E v e n t   M e t h o d s

    private void RaiseStatusChanged(UpdateStatus status)
    {
        RaiseStatusChanged(status, UpdateStatusEvent.Default);
    }

    private void RaiseStatusChanged(UpdateStatus status, UpdateStatusEvent statusEvent)
    {
        RaiseStatusChanged(status, statusEvent, false);
    }

    private bool RaiseStatusChanged(UpdateStatus status, UpdateStatusEvent statusEvent, bool canCancel)
    {
        var args = new UpdateStatusEventArgs(this, status, statusEvent, canCancel);
        OnStatusChanged?.Invoke(this, args);
        return args.CanCancel && args.Cancel;
    }

    // U p d a t e   r o u t i n e s

    public async Task UpdateInteractive()
    {
        var latestVersion = await CheckForUpdate();

        if (HasUpdates && latestVersion is not null)
            await UpdateInteractive(latestVersion);
    }

    public async Task UpdateInteractive(UpdatePackageInfo package)
    {
        if (await DownloadPackageAsync(package))
            await InstallPackageAsync(package);
    }

    // F e a t u r e s

    public async Task<UpdateInfo?> GetUpdateInfo()
    {
        string str = await WebClient.GetStringAsync(UpdateUrl);
        var info = UpdateInfo.Parse(str);
        return info;
    }

    private async Task<UpdatePackageInfo?> CheckForUpdate()
    {
        RaiseStatusChanged(UpdateStatus.Searching, UpdateStatusEvent.PreEvent);

        UpdateInfo = await GetUpdateInfo();

        if (UpdateInfo is null)
            return null;

        return CheckForUpdate(UpdateInfo);
    }

    private UpdatePackageInfo? CheckForUpdate(UpdateInfo updateInfo)
    {
        var latestVersion = CurrentVersion;

        foreach (UpdatePackageInfo pkgInfo in updateInfo.Packages)
        {
            if (pkgInfo.Version.Channel <= MinimumChannel && pkgInfo.Version > latestVersion)
            {
                UpdatePackageInfo = pkgInfo;
                latestVersion = pkgInfo.Version;
            }
        }

        if (!RaiseStatusChanged(UpdateStatus.Searching, UpdateStatusEvent.PostEvent, true))
        {
            UpdatePackageInfo = null;
            return null;
        }

        return UpdatePackageInfo;
    }

    public async Task<bool> DownloadPackageAsync(UpdatePackageInfo package)
    {
        RaiseStatusChanged(UpdateStatus.Downloading, UpdateStatusEvent.PreEvent);

        if (package.AddressType == PackageAddressType.Http)
        {
            var dirPath = Path.Combine(MyPaths.GetMyAppDataPath(), package.GetHashCode().ToString());
            var zipPath = Path.Combine(dirPath, "package.zip");
            var dir = new DirectoryInfo(dirPath);

            try
            {
                // Ensure existing and empty directory for the Zip File
                if (dir.Exists)
                    dir.Delete(true);
                dir.Create();

                // Download zip package
                using var zipFile = new FileStream(zipPath, FileMode.Create, FileAccess.ReadWrite);
                using var zipStream = await WebClient.GetStreamAsync(package.Address);
                await zipStream.CopyToAsync(zipFile);

                // Remember path to package directory
                dicPackagePaths.Add(package, dirPath);
            }
            catch (Exception)
            {
                return false;
            }
        }
        else if (package.AddressType == PackageAddressType.Local)
            dicPackagePaths.Add(package, package.Address);
        else
            return false;

        if (!RaiseStatusChanged(UpdateStatus.Downloading, UpdateStatusEvent.PostEvent, true))
        {
            RaiseStatusChanged(UpdateStatus.Canceled);
            return false;
        }

        return true;
    }

    private void InstallPackage(UpdatePackageInfo package)
    {
        // Extract Package
        if (!RaiseStatusChanged(UpdateStatus.Extracting, UpdateStatusEvent.PreEvent, true))
        {
            RaiseStatusChanged(UpdateStatus.Canceled);
            return;
        }
        if (!dicPackagePaths.TryGetValue(package, out var packagePath))
        {
            RaiseStatusChanged(UpdateStatus.Failed);
            return;
        }
        string dataPath;
        if (package.Type == PackageType.Zip)
        {
            dataPath = packagePath + ".extracted";
            var packagePathDir = new DirectoryInfo(packagePath);
            if (packagePathDir.Exists)
            {
                packagePathDir.Delete(true);
                Task.Delay(1000);
            }
            ZipFile.ExtractToDirectory(packagePath, dataPath);
        }
        else if (package.Type == PackageType.Folder)
            dataPath = packagePath;
        else
            throw new NotImplementedException("This PackageType is not defined and not support!");
        RaiseStatusChanged(UpdateStatus.Extracting, UpdateStatusEvent.PostEvent);

        // Install Package
        RaiseStatusChanged(UpdateStatus.Copying, UpdateStatusEvent.PreEvent);
        var dataPathDir = new DirectoryInfo(dataPath);
        var destDir = new DirectoryInfo(HostApplicationPath);
        Utils.CopyFiles(dataPathDir, destDir);
        RaiseStatusChanged(UpdateStatus.Copying, UpdateStatusEvent.PostEvent);

        // Delete Package
        RaiseStatusChanged(UpdateStatus.Cleanup, UpdateStatusEvent.PreEvent);
        File.Delete(packagePath);
        Directory.Delete(dataPath, true);
        RaiseStatusChanged(UpdateStatus.Cleanup, UpdateStatusEvent.PostEvent);

        // Finish
        RaiseStatusChanged(UpdateStatus.Done, UpdateStatusEvent.Default);
    }

    public Task InstallPackageAsync(UpdatePackageInfo package)
    {
        return Task.Run(() => InstallPackage(package));
    }
}