using System.Diagnostics;
using System.Reflection;
using Microsoft.Extensions.Logging;
using Microsoft.Win32;
using Octokit;
using StabilityMatrix.Core.Models.Progress;
using StabilityMatrix.Core.Processes;
using StabilityMatrix.Core.Python;
using StabilityMatrix.Core.Services;

namespace StabilityMatrix.Core.Helper;

public class PrerequisiteHelper : IPrerequisiteHelper
{
    private readonly ILogger<PrerequisiteHelper> logger;
    private readonly IGitHubClient gitHubClient;
    private readonly IDownloadService downloadService;
    private readonly ISettingsManager settingsManager;
    
    private const string VcRedistDownloadUrl = "https://aka.ms/vs/16/release/vc_redist.x64.exe";
    private const string PythonDownloadUrl = "https://www.python.org/ftp/python/3.10.11/python-3.10.11-embed-amd64.zip";
    private const string PythonDownloadHashBlake3 = "24923775f2e07392063aaa0c78fbd4ae0a320e1fc9c6cfbab63803402279fe5a";
    
    private string HomeDir => settingsManager.LibraryDir;
    
    private string VcRedistDownloadPath => Path.Combine(HomeDir, "vcredist.x64.exe");

    private string AssetsDir => Path.Combine(HomeDir, "Assets");
    private string SevenZipPath => Path.Combine(AssetsDir, "7za.exe");
    
    private string PythonDownloadPath => Path.Combine(AssetsDir, "python-3.10.11-embed-amd64.zip");
    private string PythonDir => Path.Combine(AssetsDir, "Python310");
    private string PythonDllPath => Path.Combine(PythonDir, "python310.dll");
    private string PythonLibraryZipPath => Path.Combine(PythonDir, "python310.zip");
    private string GetPipPath => Path.Combine(PythonDir, "get-pip.pyc");
    // Temporary directory to extract venv to during python install
    private string VenvTempDir => Path.Combine(PythonDir, "venv");
    
    private string PortableGitInstallDir => Path.Combine(HomeDir, "PortableGit");
    private string PortableGitDownloadPath => Path.Combine(HomeDir, "PortableGit.7z.exe");
    private string GitExePath => Path.Combine(PortableGitInstallDir, "bin", "git.exe");
    public string GitBinPath => Path.Combine(PortableGitInstallDir, "bin");
    
    public bool IsPythonInstalled => File.Exists(PythonDllPath);

    public PrerequisiteHelper(ILogger<PrerequisiteHelper> logger, IGitHubClient gitHubClient,
        IDownloadService downloadService, ISettingsManager settingsManager)
    {
        this.logger = logger;
        this.gitHubClient = gitHubClient;
        this.downloadService = downloadService;
        this.settingsManager = settingsManager;
    }

    public async Task RunGit(string? workingDirectory = null, params string[] args)
    {
        var process = ProcessRunner.StartProcess(GitExePath, args, workingDirectory: workingDirectory);
        await ProcessRunner.WaitForExitConditionAsync(process);
    }
    
    public async Task InstallAllIfNecessary(IProgress<ProgressReport>? progress = null)
    {
        await InstallVcRedistIfNecessary(progress);
        await UnpackResourcesIfNecessary(progress);
        await InstallPythonIfNecessary(progress);
        await InstallGitIfNecessary(progress);
    }

    private static IEnumerable<string> GetEmbeddedResources()
    {
        return Assembly.GetExecutingAssembly().GetManifestResourceNames();
    }

    private async Task ExtractEmbeddedResource(string resourceName, string outputDirectory)
    {
        // Convert resource name to file name
        // from "StabilityMatrix.Assets.Python310.libssl-1_1.dll"
        // to "Python310\libssl-1_1.dll"
        var fileExt = Path.GetExtension(resourceName);
        var fileName = resourceName
            .Replace(fileExt, "")
            .Replace("StabilityMatrix.Assets.", "")
            .Replace(".", Path.DirectorySeparatorChar.ToString()) + fileExt;
        await using var resourceStream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName)!;
        if (resourceStream == null)
        {
            throw new Exception($"Resource {resourceName} not found");
        }
        await using var fileStream = File.Create(Path.Combine(outputDirectory, fileName));
        await resourceStream.CopyToAsync(fileStream);
    }

    /// <summary>
    /// Extracts all embedded resources starting with resourceDir to outputDirectory
    /// </summary>
    private async Task ExtractAllEmbeddedResources(string resourceDir, string outputDirectory, string resourceRoot = "StabilityMatrix.Assets.")
    {
        Directory.CreateDirectory(outputDirectory);
        // Unpack from embedded resources
        var resources = GetEmbeddedResources().Where(r => r.StartsWith(resourceDir)).ToArray();
        var total = resources.Length;
        logger.LogInformation("Unpacking {Num} embedded resources...", total);

        // Unpack all resources
        var copied = new List<string>();
        foreach (var resourceName in resources)
        {
            // Convert resource name to file name
            // from "StabilityMatrix.Assets.Python310.libssl-1_1.dll"
            // to "Python310\libssl-1_1.dll"
            var fileExt = Path.GetExtension(resourceName);
            var fileName = resourceName
                .Replace(fileExt, "")
                .Replace(resourceRoot, "")
                .Replace(".", Path.DirectorySeparatorChar.ToString()) + fileExt;
            // Unpack resource
            await using var resourceStream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName)!;
            var outputFilePath = Path.Combine(outputDirectory, fileName);
            // Create missing directories
            var outputDir = Path.GetDirectoryName(outputFilePath);
            if (outputDir != null)
            {
                Directory.CreateDirectory(outputDir);
            }
            await using var fileStream = File.Create(outputFilePath);
            await resourceStream.CopyToAsync(fileStream);
            copied.Add(outputFilePath);
        }
        logger.LogInformation("Successfully unpacked {Num} embedded resources: [{Resources}]", total, string.Join(",", copied));
    }

    public async Task UnpackResourcesIfNecessary(IProgress<ProgressReport>? progress = null)
    {
        // Skip if all files exist
        if (File.Exists(SevenZipPath) && File.Exists(PythonDllPath) && File.Exists(PythonLibraryZipPath))
        {
            return;
        }
        // Start Progress
        progress?.Report(new ProgressReport(-1, "Unpacking resources...", isIndeterminate: true));
        // Create directories
        Directory.CreateDirectory(AssetsDir);
        Directory.CreateDirectory(PythonDir);
        
        // Run if 7za missing
        if (!File.Exists(SevenZipPath))
        {
            await ExtractEmbeddedResource("StabilityMatrix.Assets.7za.exe", AssetsDir);
            await ExtractEmbeddedResource("StabilityMatrix.Assets.7za - LICENSE.txt", AssetsDir);
        }
        
        progress?.Report(new ProgressReport(1f, "Unpacking complete"));
    }

    public async Task InstallPythonIfNecessary(IProgress<ProgressReport>? progress = null)
    {
        if (File.Exists(PythonDllPath))
        {
            logger.LogDebug("Python already installed at {PythonDllPath}", PythonDllPath);
            return;
        }

        logger.LogInformation("Python not found at {PythonDllPath}, downloading...", PythonDllPath);

        Directory.CreateDirectory(AssetsDir);
        
        // Delete existing python zip if it exists
        if (File.Exists(PythonLibraryZipPath))
        {
            File.Delete(PythonLibraryZipPath);
        }
        
        logger.LogInformation(
            "Downloading Python from {PythonLibraryZipUrl} to {PythonLibraryZipPath}", 
            PythonDownloadUrl, PythonLibraryZipPath);
        
        // Cleanup to remove zip if download fails
        try
        {
            // Download python zip
            await downloadService.DownloadToFileAsync(PythonDownloadUrl, PythonDownloadPath, progress: progress);
        
            // Verify python hash
            var downloadHash = await FileHash.GetBlake3Async(PythonDownloadPath, progress);
            if (downloadHash != PythonDownloadHashBlake3)
            {
                var fileExists = File.Exists(PythonDownloadPath);
                var fileSize = new FileInfo(PythonDownloadPath).Length;
                var msg = $"Python download hash mismatch: {downloadHash} != {PythonDownloadHashBlake3} " +
                          $"(file exists: {fileExists}, size: {fileSize})";
                throw new Exception(msg);
            }
            
            progress?.Report(new ProgressReport(progress: 1f, message: "Python download complete"));
        
            progress?.Report(new ProgressReport(-1, "Installing Python...", isIndeterminate: true));
            
            // We also need 7z if it's not already unpacked
            if (!File.Exists(SevenZipPath))
            {
                await ExtractEmbeddedResource("StabilityMatrix.Assets.7za.exe", AssetsDir);
                await ExtractEmbeddedResource("StabilityMatrix.Assets.7za - LICENSE.txt", AssetsDir);
            }
        
            // Delete existing python dir
            if (Directory.Exists(PythonDir))
            {
                Directory.Delete(PythonDir, true);
            }
            // Unzip python
            
            // TODO: Update when ArchiveHelper is implemented
            // await ArchiveHelper.Extract7Z(PythonDownloadPath, PythonDir);
        
            try
            {
                // Extract embedded venv
                await ExtractAllEmbeddedResources("StabilityMatrix.Assets.venv", PythonDir);
                // Add venv to python's library zip
                
                // TODO: Update when ArchiveHelper is implemented
                //await ArchiveHelper.AddToArchive7Z(PythonLibraryZipPath, VenvTempDir);
            }
            finally
            {
                // Remove venv
                if (Directory.Exists(VenvTempDir))
                {
                    Directory.Delete(VenvTempDir, true);
                }
            }
        
            // Extract get-pip.pyc
            await ExtractEmbeddedResource("StabilityMatrix.Assets.get-pip.pyc", PythonDir);
        
            // We need to uncomment the #import site line in python310._pth for pip to work
            var pythonPthPath = Path.Combine(PythonDir, "python310._pth");
            var pythonPthContent = await File.ReadAllTextAsync(pythonPthPath);
            pythonPthContent = pythonPthContent.Replace("#import site", "import site");
            await File.WriteAllTextAsync(pythonPthPath, pythonPthContent);
        
            progress?.Report(new ProgressReport(1f, "Python install complete"));
        }
        finally
        {
            // Always delete zip after download
            if (File.Exists(PythonDownloadPath))
            {
                File.Delete(PythonDownloadPath);
            }
        }
    }

    public async Task InstallGitIfNecessary(IProgress<ProgressReport>? progress = null)
    {
        if (File.Exists(GitExePath))
        {
            logger.LogDebug("Git already installed at {GitExePath}", GitExePath);
            return;
        }
        
        logger.LogInformation("Git not found at {GitExePath}, downloading...", GitExePath);

        var portableGitUrl =
            "https://github.com/git-for-windows/git/releases/download/v2.41.0.windows.1/PortableGit-2.41.0-64-bit.7z.exe";

        if (!File.Exists(PortableGitDownloadPath))
        {
            await downloadService.DownloadToFileAsync(portableGitUrl, PortableGitDownloadPath, progress: progress);
            progress?.Report(new ProgressReport(progress: 1f, message: "Git download complete"));
        }

        await UnzipGit(progress);
    }

    public async Task InstallVcRedistIfNecessary(IProgress<ProgressReport>? progress = null)
    {
        var registry = Registry.LocalMachine;
        var key = registry.OpenSubKey(
            @"SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64", false);
        if (key != null)
        {
            var buildId = Convert.ToUInt32(key.GetValue("Bld"));
            if (buildId >= 30139)
            {
                return;
            }
        }
        
        logger.LogInformation("Downloading VC Redist");

        await downloadService.DownloadToFileAsync(VcRedistDownloadUrl, VcRedistDownloadPath, progress: progress);
        progress?.Report(new ProgressReport(progress: 1f, message: "Visual C++ download complete",
            type: ProgressType.Download));
        
        logger.LogInformation("Installing VC Redist");
        progress?.Report(new ProgressReport(progress: 0.5f, isIndeterminate: true, type: ProgressType.Generic, message: "Installing prerequisites..."));
        var process = ProcessRunner.StartProcess(VcRedistDownloadPath, "/install /quiet /norestart");
        await process.WaitForExitAsync();
        progress?.Report(new ProgressReport(progress: 1f, message: "Visual C++ install complete",
            type: ProgressType.Generic));
        
        File.Delete(VcRedistDownloadPath);
    }

    public async Task SetupPythonDependencies(string installLocation, string requirementsFileName,
        IProgress<ProgressReport>? progress = null, Action<ProcessOutput>? onConsoleOutput = null)
    {
        // Setup dependencies
        progress?.Report(new ProgressReport(-1, isIndeterminate: true));
        var venvRunner = new PyVenvRunner(Path.Combine(installLocation, "venv"));

        if (!venvRunner.Exists())
        {
            await venvRunner.Setup();
        }

        void HandleConsoleOutput(ProcessOutput s)
        {
            Debug.WriteLine($"venv stdout: {s}");
            onConsoleOutput?.Invoke(s);
        }

        // Install torch
        logger.LogDebug("Starting torch install...");
        await venvRunner.PipInstall(venvRunner.GetTorchInstallCommand(), installLocation, HandleConsoleOutput);

        // Install xformers if nvidia
        if (HardwareHelper.HasNvidiaGpu())
        {
            await venvRunner.PipInstall("xformers", installLocation, HandleConsoleOutput);
        }

        // Install requirements
        logger.LogDebug("Starting requirements install...");
        await venvRunner.PipInstall($"-r {requirementsFileName}", installLocation, HandleConsoleOutput);

        logger.LogDebug("Finished installing requirements!");
        progress?.Report(new ProgressReport(1, isIndeterminate: false));
    }

    public void UpdatePathExtensions()
    {
        settingsManager.Settings.PathExtensions?.Clear();
        settingsManager.AddPathExtension(GitBinPath);
        settingsManager.InsertPathExtensions();
    }

    private async Task UnzipGit(IProgress<ProgressReport>? progress = null)
    {
        
        // TODO: Update when ArchiveHelper is implemented
        // if (progress == null)
        // {
        //     await ArchiveHelper.Extract7Z(PortableGitDownloadPath, PortableGitInstallDir);
        // }
        // else
        // {
        //     await ArchiveHelper.Extract7Z(PortableGitDownloadPath, PortableGitInstallDir, progress);
        // }

        logger.LogInformation("Extracted Git");

        File.Delete(PortableGitDownloadPath);
        // Also add git to the path
        settingsManager.AddPathExtension(GitBinPath);
        settingsManager.InsertPathExtensions();
    }

}