using Godot;
using System.IO;
using BSEnroll;
using System.Collections.Generic;

public partial class ModelDownloadManager : Node
{
    // This class is responsible for downloading models from the server and removing old versions
    // As a model is training on the server, partially trained models can be downloaded and used locally
    // This class is also responsible for removing old versions of a model when a new version is selected(downloaded)

    // The model filename will consist of its name and percentage of completion
    // Example: model_name(10% trained).model or model_name.model, signifying it's fully trained
    [Signal]
    public delegate void ModelReadyEventHandler(string modelPath);

    public async void OnModelSelected(string modelPath)
    {
        GD.Print($"Model selected: {modelPath}");
        UserDataManager.Instance.ModelLoadingError = "";

        // Provided model is a local path
        // Send ready signal if it is valid
        if (File.Exists(modelPath))
        {
            EmitSignal(SignalName.ModelReady, modelPath);
            return;
        }

        string fileName = Path.GetFileName(modelPath);
        string parentFolderName = Path.GetFileName(Path.GetDirectoryName(modelPath)); // date and time of the enrollment
        string downloadName = parentFolderName + "_" + fileName;
        string localPath = Path.Combine("user://models", downloadName);
        string systemPath = ProjectSettings.GlobalizePath(localPath);

        if (!File.Exists(systemPath))
        {
            RemoveOldVersions(downloadName);
            GD.Print($"Model not found locally, downloading...");
            await UserDataManager.Instance.DownloadModelAsync(modelPath, systemPath);
        }

        EmitSignal(SignalName.ModelReady, systemPath);
    }

    private string GetBaseModelName(string fileName)
    {
        int openParenIndex = fileName.IndexOf('(');
        return openParenIndex > 0 ? fileName[..openParenIndex] : fileName;
    }

    private List<string> FindModelVariants(string fileName)
    {
        List<string> variants = new List<string>();
        string baseModelName = GetBaseModelName(fileName);
        string modelsDir = ProjectSettings.GlobalizePath("user://models");

        if (!Directory.Exists(modelsDir))
            return variants;

        foreach (string file in Directory.GetFiles(modelsDir))
        {
            string currentFileName = Path.GetFileName(file);
            if (GetBaseModelName(currentFileName) == baseModelName)
            {
                variants.Add(currentFileName);
            }
        }

        return variants;
    }

    private void RemoveOldVersions(string newModelFileName)
    {
        foreach (string variant in FindModelVariants(newModelFileName))
        {
            if (variant == newModelFileName)
                continue;

            string variantPath = ProjectSettings.GlobalizePath(Path.Combine("user://models", variant));
            GD.Print($"Removing old model: {variantPath}");

            try
            {
                File.Delete(variantPath);
                GD.Print($"Successfully removed old model: {variantPath}");
            }
            catch
            {
                GD.PrintErr($"Failed to remove old model: {variantPath}");
            }
        }
    }
}