using System.IO;
using SpdUp.Core;

namespace SpdUp.Services;

/// <summary>
/// Cleans DirectX shader cache, NVIDIA shader cache, and temp files
/// to reduce micro-stuttering in games.
/// </summary>
public static class ShaderCacheCleanerService
{
    public static ShaderCleanResult CleanAll()
    {
        long totalBytes = 0;
        int totalFiles = 0;

        totalBytes += CleanDirectory(GetDirectXShaderCachePath(), ref totalFiles);
        totalBytes += CleanDirectory(GetNvidiaShaderCachePath(), ref totalFiles);
        totalBytes += CleanDirectory(GetWindowsTempPath(), ref totalFiles);
        totalBytes += CleanDirectory(GetLocalTempPath(), ref totalFiles);

        Logger.Info($"Shader cache clean: {totalFiles} files, {totalBytes / 1048576.0:F1} MB freed.");
        return new ShaderCleanResult(totalFiles, totalBytes);
    }

    public static ShaderCleanResult CleanDirectXCache()
    {
        long totalBytes = 0;
        int totalFiles = 0;
        totalBytes += CleanDirectory(GetDirectXShaderCachePath(), ref totalFiles);
        return new ShaderCleanResult(totalFiles, totalBytes);
    }

    public static ShaderCleanResult CleanNvidiaCache()
    {
        long totalBytes = 0;
        int totalFiles = 0;
        totalBytes += CleanDirectory(GetNvidiaShaderCachePath(), ref totalFiles);
        return new ShaderCleanResult(totalFiles, totalBytes);
    }

    public static ShaderCleanResult CleanTempFiles()
    {
        long totalBytes = 0;
        int totalFiles = 0;
        totalBytes += CleanDirectory(GetWindowsTempPath(), ref totalFiles);
        totalBytes += CleanDirectory(GetLocalTempPath(), ref totalFiles);
        return new ShaderCleanResult(totalFiles, totalBytes);
    }

    // ── Paths ──────────────────────────────────────────────────────────
    private static string GetDirectXShaderCachePath()
        => Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "D3DSCache");

    private static string GetNvidiaShaderCachePath()
        => Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "NVIDIA", "DXCache");

    private static string GetWindowsTempPath()
        => Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), "Temp");

    private static string GetLocalTempPath()
        => Path.GetTempPath();

    // ── Helpers ────────────────────────────────────────────────────────
    private static long CleanDirectory(string path, ref int fileCount)
    {
        if (!Directory.Exists(path)) return 0;
        long bytes = 0;

        try
        {
            foreach (var file in Directory.EnumerateFiles(path, "*", SearchOption.AllDirectories))
            {
                try
                {
                    var fi = new FileInfo(file);
                    bytes += fi.Length;
                    fi.Delete();
                    fileCount++;
                }
                catch { /* locked / in use – skip */ }
            }

            // Remove empty dirs
            foreach (var dir in Directory.EnumerateDirectories(path, "*", SearchOption.AllDirectories)
                         .OrderByDescending(d => d.Length))
            {
                try
                {
                    if (!Directory.EnumerateFileSystemEntries(dir).Any())
                        Directory.Delete(dir);
                }
                catch { }
            }
        }
        catch (Exception ex)
        {
            Logger.Warn($"Error cleaning {path}: {ex.Message}");
        }

        return bytes;
    }
}

public record struct ShaderCleanResult(int FilesDeleted, long BytesFreed)
{
    public double MBFreed => BytesFreed / 1048576.0;
}