using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;
using Explorer.Application;
using Explorer.Domain;

namespace Explorer.Windows;

public sealed class SevenZipArchiveExecutor : IArchiveExecutor
{
    private static readonly Regex Percent = new(@"(\d{1,3})\s*%", RegexOptions.CultureInvariant);
    private readonly Func<string?> _configuredPath;

    public SevenZipArchiveExecutor(UiPreferencesStore preferences)
        => _configuredPath = () => preferences.Load().SevenZipPath;

    public bool IsAvailable => SevenZipLocator.Find(_configuredPath()) is not null;

    public string MissingHint => SevenZipLocator.MissingHint;

    public Task ExtractAsync(
        string archivePath,
        string destinationDirectory,
        IProgress<ArchiveProgress>? progress,
        CancellationToken cancellationToken)
    {
        Directory.CreateDirectory(PathRules.ToExtended(destinationDirectory));
        return RunAsync(
            ["x", archivePath, "-o" + destinationDirectory, "-y", "-aoa", "-bb1", "-bsp1"],
            PathRules.Parent(archivePath),
            progress,
            cancellationToken);
    }

    public Task CompressAsync(
        IReadOnlyList<string> sources,
        string archivePath,
        ArchiveFormat format,
        IProgress<ArchiveProgress>? progress,
        CancellationToken cancellationToken)
    {
        var type = format == ArchiveFormat.SevenZip ? "-t7z" : "-tzip";
        var args = new List<string> { "a", type, "-y", "-bb1", "-bsp1", archivePath };
        args.AddRange(RelativeSources(sources, out var workDir));
        return RunAsync(args, workDir, progress, cancellationToken);
    }

    public Task AddAsync(
        string archivePath,
        IReadOnlyList<string> sources,
        IProgress<ArchiveProgress>? progress,
        CancellationToken cancellationToken)
    {
        var args = new List<string> { "a", "-y", "-bb1", "-bsp1", archivePath };
        args.AddRange(RelativeSources(sources, out var workDir));
        return RunAsync(args, workDir, progress, cancellationToken);
    }

    public Task VerifyAsync(
        string archivePath,
        IProgress<ArchiveProgress>? progress,
        CancellationToken cancellationToken)
        => RunAsync(
            ["t", archivePath, "-bb1", "-bsp1"],
            PathRules.Parent(archivePath),
            progress,
            cancellationToken);

    private async Task RunAsync(
        IReadOnlyList<string> arguments,
        string? workingDirectory,
        IProgress<ArchiveProgress>? progress,
        CancellationToken cancellationToken)
    {
        var exe = SevenZipLocator.Find(_configuredPath())
                  ?? throw new InvalidOperationException(MissingHint);

        var psi = new ProcessStartInfo
        {
            FileName = exe,
            WorkingDirectory = string.IsNullOrWhiteSpace(workingDirectory) ? Environment.CurrentDirectory : workingDirectory,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true,
            StandardOutputEncoding = Encoding.UTF8,
            StandardErrorEncoding = Encoding.UTF8
        };
        foreach (var argument in arguments)
        {
            psi.ArgumentList.Add(argument);
        }

        using var process = new Process { StartInfo = psi, EnableRaisingEvents = true };
        var errors = new StringBuilder();
        var files = 0L;
        process.OutputDataReceived += (_, e) =>
        {
            if (string.IsNullOrEmpty(e.Data))
            {
                return;
            }

            var match = Percent.Match(e.Data);
            if (match.Success && int.TryParse(match.Groups[1].Value, out var pct))
            {
                progress?.Report(new ArchiveProgress(Math.Clamp(pct, 0, 100), files, null));
            }

            if (e.Data.StartsWith('+') || e.Data.StartsWith('-') || e.Data.StartsWith('T'))
            {
                files++;
                progress?.Report(new ArchiveProgress(0, files, e.Data.Trim()));
            }
        };
        process.ErrorDataReceived += (_, e) =>
        {
            if (!string.IsNullOrEmpty(e.Data))
            {
                errors.AppendLine(e.Data);
            }
        };

        if (!process.Start())
        {
            throw new IOException("7-Zip could not be started.");
        }

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();
        await using var kill = cancellationToken.Register(() =>
        {
            try { process.Kill(entireProcessTree: true); } catch { /* already exited */ }
        });
        await process.WaitForExitAsync(CancellationToken.None).ConfigureAwait(false);
        cancellationToken.ThrowIfCancellationRequested();
        if (process.ExitCode > 1)
        {
            var detail = errors.ToString().Trim();
            throw new IOException(string.IsNullOrEmpty(detail) ? $"7-Zip failed ({process.ExitCode})." : detail);
        }
    }

    private static IEnumerable<string> RelativeSources(IReadOnlyList<string> sources, out string workDir)
    {
        if (sources.All(s => PathRules.Parent(s).Equals(PathRules.Parent(sources[0]), StringComparison.OrdinalIgnoreCase)))
        {
            workDir = PathRules.Parent(sources[0]);
            return sources.Select(PathRules.GetFileName).ToList();
        }

        workDir = PathRules.Parent(sources[0]);
        return sources;
    }
}