using VRage.ObjectBuilders;
using VRage.ObjectBuilders.Private;

namespace SpaceEngineersBlueprintEditor.SpaceEngineersCore;

public class SpaceEngineerDefinitions
{
    public static T Load<T>(string path) where T : MyObjectBuilder_Base
    {
        MyObjectBuilderSerializerKeen.DeserializeXML(path, out T objectBuilder);
        return objectBuilder;
    }

    public static string Serialize<T>(MyObjectBuilder_Base item) where T : MyObjectBuilder_Base
    {
        using var outStream = new MemoryStream();
        if (MyObjectBuilderSerializerKeen.SerializeXML(outStream, item))
        {
            outStream.Position = 0;
            var streamReader = new StreamReader(outStream);
            return streamReader.ReadToEnd();
        }
        return string.Empty;
    }

    /// <summary>
    /// Atomically saves an object builder as an uncompressed SBC file. When the
    /// destination already exists, its previous contents are retained as sbcB5.
    /// </summary>
    public static void Save(string path, MyObjectBuilder_Base item)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            throw new ArgumentException("A blueprint path is required.", nameof(path));
        }
        if (item is null)
        {
            throw new ArgumentNullException(nameof(item));
        }

        var fullPath = Path.GetFullPath(path);
        var directory = Path.GetDirectoryName(fullPath)
            ?? throw new DirectoryNotFoundException("The blueprint directory could not be determined.");
        Directory.CreateDirectory(directory);

        var temporaryPath = Path.Combine(directory, $".{Path.GetFileName(fullPath)}.{Guid.NewGuid():N}.tmp");
        try
        {
            byte[] serializedBlueprint;
            using (var stream = new MemoryStream())
            {
                if (!MyObjectBuilderSerializerKeen.SerializeXML(stream, item))
                {
                    throw new InvalidOperationException("Space Engineers could not serialize the blueprint.");
                }
                serializedBlueprint = stream.ToArray();
            }
            File.WriteAllBytes(temporaryPath, serializedBlueprint);

            if (File.Exists(fullPath))
            {
                var backupPath = fullPath + "B5";
                if (File.Exists(backupPath))
                {
                    File.Delete(backupPath);
                }
                File.Replace(temporaryPath, fullPath, backupPath, true);
            }
            else
            {
                File.Move(temporaryPath, fullPath);
            }
        }
        finally
        {
            if (File.Exists(temporaryPath))
            {
                File.Delete(temporaryPath);
            }
        }
    }
}