using System.Globalization;

namespace Lity3DEditor;

public static class SceneIO
{
    public static List<SceneNode> Load(string path)
    {
        var nodes = new List<SceneNode>();
        using var reader = new StreamReader(path);
        string? header = reader.ReadLine();
        if (header == null || !header.StartsWith("LITY3D_SCENE"))
            throw new InvalidDataException("不是有效的 Lity3D 场景文件");

        int lineIdx = 1;
        string? line;
        while ((line = reader.ReadLine()) != null)
        {
            if (string.IsNullOrWhiteSpace(line)) continue;
            var parts = line.Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
            if (parts.Length < 13) continue;

            var node = new SceneNode
            {
                Name = parts[0],
                ParentIndex = int.Parse(parts[1]),
                Mesh = Enum.Parse<MeshType>(parts[2], true),
                MeshPath = parts[3],
                PosX = float.Parse(parts[4], CultureInfo.InvariantCulture),
                PosY = float.Parse(parts[5], CultureInfo.InvariantCulture),
                PosZ = float.Parse(parts[6], CultureInfo.InvariantCulture),
                RotX = float.Parse(parts[7], CultureInfo.InvariantCulture),
                RotY = float.Parse(parts[8], CultureInfo.InvariantCulture),
                RotZ = float.Parse(parts[9], CultureInfo.InvariantCulture),
                ScaleX = float.Parse(parts[10], CultureInfo.InvariantCulture),
                ScaleY = float.Parse(parts[11], CultureInfo.InvariantCulture),
                ScaleZ = float.Parse(parts[12], CultureInfo.InvariantCulture),
                LineIndex = lineIdx
            };
            nodes.Add(node);
            lineIdx++;
        }
        return nodes;
    }

    public static void Save(string path, List<SceneNode> nodes)
    {
        using var writer = new StreamWriter(path);
        writer.WriteLine("LITY3D_SCENE 1");
        foreach (var node in nodes)
        {
            int parent = node.ParentIndex;
            writer.WriteLine(node.ToSceneLine(parent));
        }
    }
}