using System.Diagnostics.CodeAnalysis;
using System.IO.Compression;
using NLog;
using Octokit;
using StabilityMatrix.Core.Helper;
using StabilityMatrix.Core.Helper.Cache;
using StabilityMatrix.Core.Models.Database;
using StabilityMatrix.Core.Models.FileInterfaces;
using StabilityMatrix.Core.Models.Progress;
using StabilityMatrix.Core.Python;
using StabilityMatrix.Core.Services;

namespace StabilityMatrix.Core.Models.Packages;

/// <summary>
/// Base class for packages that are hosted on Github.
/// Author and Name should be the Github username and repository name respectively.
/// </summary>
[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
[SuppressMessage("ReSharper", "VirtualMemberNeverOverridden.Global")]
public abstract class BaseGitPackage : BasePackage
{
    private static readonly Logger Logger = LogManager.GetCurrentClassLogger();

    protected readonly IGithubApiCache GithubApi;
    protected readonly ISettingsManager SettingsManager;
    protected readonly IDownloadService DownloadService;
    protected readonly IPrerequisiteHelper PrerequisiteHelper;
    public PyVenvRunner? VenvRunner;

    /// <summary>
    /// URL of the hosted web page on launch
    /// </summary>
    protected string WebUrl = string.Empty;

    public override string GithubUrl => $"https://github.com/{Author}/{Name}";

    public string DownloadLocation =>
        Path.Combine(SettingsManager.LibraryDir, "Packages", $"{Name}.zip");

    protected string GetDownloadUrl(DownloadPackageVersionOptions versionOptions)
    {
        if (!string.IsNullOrWhiteSpace(versionOptions.CommitHash))
        {
            return $"https://github.com/{Author}/{Name}/archive/{versionOptions.CommitHash}.zip";
        }

        if (!string.IsNullOrWhiteSpace(versionOptions.VersionTag))
        {
            return $"https://api.github.com/repos/{Author}/{Name}/zipball/{versionOptions.VersionTag}";
        }

        if (!string.IsNullOrWhiteSpace(versionOptions.BranchName))
        {
            return $"https://api.github.com/repos/{Author}/{Name}/zipball/{versionOptions.BranchName}";
        }

        throw new Exception("No download URL available");
    }

    protected BaseGitPackage(
        IGithubApiCache githubApi,
        ISettingsManager settingsManager,
        IDownloadService downloadService,
        IPrerequisiteHelper prerequisiteHelper
    )
    {
        GithubApi = githubApi;
        SettingsManager = settingsManager;
        DownloadService = downloadService;
        PrerequisiteHelper = prerequisiteHelper;
    }

    protected async Task<Release> GetLatestRelease(bool includePrerelease = false)
    {
        var releases = await GithubApi.GetAllReleases(Author, Name).ConfigureAwait(false);
        return includePrerelease ? releases.First() : releases.First(x => !x.Prerelease);
    }

    public override Task<IEnumerable<Branch>> GetAllBranches()
    {
        return GithubApi.GetAllBranches(Author, Name);
    }

    public override Task<IEnumerable<Release>> GetAllReleases()
    {
        return GithubApi.GetAllReleases(Author, Name);
    }

    public override Task<IEnumerable<GitCommit>?> GetAllCommits(
        string branch,
        int page = 1,
        int perPage = 10
    )
    {
        return GithubApi.GetAllCommits(Author, Name, branch, page, perPage);
    }

    public override async Task<PackageVersionOptions> GetAllVersionOptions()
    {
        var packageVersionOptions = new PackageVersionOptions();

        var allReleases = await GetAllReleases().ConfigureAwait(false);
        var releasesList = allReleases.ToList();
        if (releasesList.Any())
        {
            packageVersionOptions.AvailableVersions = releasesList.Select(
                r =>
                    new PackageVersion
                    {
                        TagName = r.TagName!,
                        ReleaseNotesMarkdown = r.Body,
                        IsPrerelease = r.Prerelease
                    }
            );
        }

        // Branch mode
        var allBranches = await GetAllBranches().ConfigureAwait(false);
        packageVersionOptions.AvailableBranches = allBranches.Select(
            b => new PackageVersion { TagName = $"{b.Name}", ReleaseNotesMarkdown = string.Empty }
        );

        return packageVersionOptions;
    }

    /// <summary>
    /// Setup the virtual environment for the package.
    /// </summary>
    [MemberNotNull(nameof(VenvRunner))]
    public async Task<PyVenvRunner> SetupVenv(
        string installedPackagePath,
        string venvName = "venv",
        bool forceRecreate = false
    )
    {
        var venvPath = Path.Combine(installedPackagePath, venvName);
        if (VenvRunner != null)
        {
            await VenvRunner.DisposeAsync().ConfigureAwait(false);
        }

        VenvRunner = new PyVenvRunner(venvPath)
        {
            WorkingDirectory = installedPackagePath,
            EnvironmentVariables = SettingsManager.Settings.EnvironmentVariables,
        };

        if (!VenvRunner.Exists() || forceRecreate)
        {
            await VenvRunner.Setup(forceRecreate).ConfigureAwait(false);
        }
        return VenvRunner;
    }

    public override async Task<IEnumerable<Release>> GetReleaseTags()
    {
        var allReleases = await GithubApi.GetAllReleases(Author, Name).ConfigureAwait(false);
        return allReleases;
    }

    public override async Task DownloadPackage(
        string installLocation,
        DownloadPackageVersionOptions versionOptions,
        IProgress<ProgressReport>? progress = null
    )
    {
        var downloadUrl = GetDownloadUrl(versionOptions);

        if (!Directory.Exists(DownloadLocation.Replace($"{Name}.zip", "")))
        {
            Directory.CreateDirectory(DownloadLocation.Replace($"{Name}.zip", ""));
        }

        await DownloadService
            .DownloadToFileAsync(downloadUrl, DownloadLocation, progress: progress)
            .ConfigureAwait(false);

        progress?.Report(new ProgressReport(100, message: "Download Complete"));
    }

    public override async Task InstallPackage(
        string installLocation,
        TorchVersion torchVersion,
        IProgress<ProgressReport>? progress = null
    )
    {
        await UnzipPackage(installLocation, progress).ConfigureAwait(false);
        File.Delete(DownloadLocation);
    }

    protected Task UnzipPackage(string installLocation, IProgress<ProgressReport>? progress = null)
    {
        using var zip = ZipFile.OpenRead(DownloadLocation);
        var zipDirName = string.Empty;
        var totalEntries = zip.Entries.Count;
        var currentEntry = 0;

        foreach (var entry in zip.Entries)
        {
            currentEntry++;
            if (string.IsNullOrWhiteSpace(entry.Name) && entry.FullName.EndsWith("/"))
            {
                if (string.IsNullOrWhiteSpace(zipDirName))
                {
                    zipDirName = entry.FullName;
                }

                var folderPath = Path.Combine(
                    installLocation,
                    entry.FullName.Replace(zipDirName, string.Empty)
                );
                Directory.CreateDirectory(folderPath);
                continue;
            }

            var destinationPath = Path.GetFullPath(
                Path.Combine(installLocation, entry.FullName.Replace(zipDirName, string.Empty))
            );
            entry.ExtractToFile(destinationPath, true);

            progress?.Report(
                new ProgressReport(
                    current: Convert.ToUInt64(currentEntry),
                    total: Convert.ToUInt64(totalEntries)
                )
            );
        }

        return Task.CompletedTask;
    }

    public override async Task<bool> CheckForUpdates(InstalledPackage package)
    {
        var currentVersion = package.Version;
        if (currentVersion == null)
        {
            return false;
        }

        try
        {
            if (currentVersion.IsReleaseMode)
            {
                var latestVersion = await GetLatestVersion().ConfigureAwait(false);
                UpdateAvailable = latestVersion != currentVersion.InstalledReleaseVersion;
                return UpdateAvailable;
            }

            var allCommits = (
                await GetAllCommits(currentVersion.InstalledBranch).ConfigureAwait(false)
            )?.ToList();
            if (allCommits == null || !allCommits.Any())
            {
                Logger.Warn("No commits found for {Package}", package.PackageName);
                return false;
            }
            var latestCommitHash = allCommits.First().Sha;
            return latestCommitHash != currentVersion.InstalledCommitSha;
        }
        catch (ApiException e)
        {
            Logger.Warn(e, "Failed to check for package updates");
            return false;
        }
    }

    public override async Task<InstalledPackageVersion> Update(
        InstalledPackage installedPackage,
        TorchVersion torchVersion,
        IProgress<ProgressReport>? progress = null,
        bool includePrerelease = false
    )
    {
        if (installedPackage.Version == null)
            throw new NullReferenceException("Version is null");

        if (installedPackage.Version.IsReleaseMode)
        {
            var releases = await GetAllReleases().ConfigureAwait(false);
            var latestRelease = releases.First(x => includePrerelease || !x.Prerelease);

            await DownloadPackage(
                    installedPackage.FullPath,
                    new DownloadPackageVersionOptions { VersionTag = latestRelease.TagName },
                    progress
                )
                .ConfigureAwait(false);

            await InstallPackage(installedPackage.FullPath, torchVersion, progress)
                .ConfigureAwait(false);

            return new InstalledPackageVersion { InstalledReleaseVersion = latestRelease.TagName };
        }

        // Commit mode
        var allCommits = await GetAllCommits(installedPackage.Version.InstalledBranch)
            .ConfigureAwait(false);
        var latestCommit = allCommits?.First();

        if (latestCommit is null || string.IsNullOrEmpty(latestCommit.Sha))
        {
            throw new Exception("No commits found for branch");
        }

        await DownloadPackage(
                installedPackage.FullPath,
                new DownloadPackageVersionOptions { CommitHash = latestCommit.Sha },
                progress
            )
            .ConfigureAwait(false);
        await InstallPackage(installedPackage.FullPath, torchVersion, progress)
            .ConfigureAwait(false);

        return new InstalledPackageVersion
        {
            InstalledBranch = installedPackage.Version.InstalledBranch,
            InstalledCommitSha = latestCommit.Sha
        };
    }

    public override Task SetupModelFolders(
        DirectoryPath installDirectory,
        SharedFolderMethod sharedFolderMethod
    )
    {
        if (sharedFolderMethod == SharedFolderMethod.Symlink && SharedFolders is { } folders)
        {
            StabilityMatrix.Core.Helper.SharedFolders.SetupLinks(
                folders,
                SettingsManager.ModelsDirectory,
                installDirectory
            );
        }

        return Task.CompletedTask;
    }

    public override async Task UpdateModelFolders(
        DirectoryPath installDirectory,
        SharedFolderMethod sharedFolderMethod
    )
    {
        if (SharedFolders is not null && sharedFolderMethod == SharedFolderMethod.Symlink)
        {
            await StabilityMatrix.Core.Helper.SharedFolders
                .UpdateLinksForPackage(this, SettingsManager.ModelsDirectory, installDirectory)
                .ConfigureAwait(false);
        }
    }

    public override Task RemoveModelFolderLinks(
        DirectoryPath installDirectory,
        SharedFolderMethod sharedFolderMethod
    )
    {
        if (SharedFolders is not null && sharedFolderMethod == SharedFolderMethod.Symlink)
        {
            StabilityMatrix.Core.Helper.SharedFolders.RemoveLinksForPackage(this, installDirectory);
        }
        return Task.CompletedTask;
    }

    // Send input to the running process.
    public virtual void SendInput(string input)
    {
        var process = VenvRunner?.Process;
        if (process == null)
        {
            Logger.Warn("No process running for {Name}", Name);
            return;
        }
        process.StandardInput.WriteLine(input);
    }

    public virtual async Task SendInputAsync(string input)
    {
        var process = VenvRunner?.Process;
        if (process == null)
        {
            Logger.Warn("No process running for {Name}", Name);
            return;
        }
        await process.StandardInput.WriteLineAsync(input).ConfigureAwait(false);
    }

    /// <inheritdoc />
    public override void Shutdown()
    {
        if (VenvRunner is not null)
        {
            VenvRunner.Dispose();
            VenvRunner = null;
        }
    }

    /// <inheritdoc />
    public override async Task WaitForShutdown()
    {
        if (VenvRunner is not null)
        {
            await VenvRunner.DisposeAsync().ConfigureAwait(false);
            VenvRunner = null;
        }
    }
}