ModernUO/Projects/Server/JsonConfiguration/Converters/Rectangle3DConverter.cs

/*************************************************************************
 * ModernUO                                                              *
 * Copyright (C) 2019-2020 - ModernUO Development Team                   *
 * Email: hi@modernuo.com                                                *
 * File: Rectangle3DConverter.cs                                         *
 * Created: 2020/05/23 - Updated: 2020/05/23                             *
 *                                                                       *
 * This program is free software: you can redistribute it and/or modify  *
 * it under the terms of the GNU General Public License as published by  *
 * the Free Software Foundation, either version 3 of the License, or     *
 * (at your option) any later version.                                   *
 *                                                                       *
 * This program is distributed in the hope that it will be useful,       *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 * GNU General Public License for more details.                          *
 *                                                                       *
 * You should have received a copy of the GNU General Public License     *
 * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 *************************************************************************/

using System;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Server.Json
{
  public class Rectangle3DConverter : JsonConverter<Rectangle3D>
  {
    private Rectangle3D DeserializeArray(ref Utf8JsonReader reader)
    {
      Span<int> data = stackalloc int[6];
      var count = 0;

      while (true)
      {
        reader.Read();
        if (reader.TokenType == JsonTokenType.EndArray)
          break;

        if (reader.TokenType == JsonTokenType.Number)
        {
          if (count < 6)
            data[count] = reader.GetInt32();

          count++;
        }
      }

      if (count > 6)
        throw new JsonException("Rectangle3D must be an array of x, y, z, h, w, d");

      return new Rectangle3D(data[0], data[1], data[2], data[3], data[4], data[5]);
    }

    private Rectangle3D DeserializeObj(ref Utf8JsonReader reader, JsonSerializerOptions options)
    {
      Span<int> data = stackalloc int[6];

      // 0 - xyzwhd, 1 - x1y1z1x2y2z2, 2 - start/end
      int objType = -1;

      while (true)
      {
        reader.Read();
        if (reader.TokenType == JsonTokenType.EndObject)
          break;

        if (reader.TokenType != JsonTokenType.PropertyName)
          throw new JsonException("Invalid Json structure for Rectangle3D object");

        var key = reader.GetString();

        reader.Read();

        if (key == "start" || key == "end")
        {
          if (objType > -1 && objType != 2)
            throw new JsonException("Rectangle3D must have a start/end, or x/y/z/w/h/d, but not both.");

          objType = 2;

          var point3D = reader.ToObject<Point3D>(options);
          var offset = key == "end" ? 3 : 0;
          data[0 + offset] = point3D.X;
          data[1 + offset] = point3D.Y;
          data[1 + offset] = point3D.Z;
          continue;
        }

        var i = key switch
        {
          "x" => 0,
          "y" => 1,
          "z" => 2,
          "w" => 3,
          "width" => 3,
          "h" => 4,
          "height" => 4,
          "d" => 5,
          "depth" => 5,
          "x1" => 10,
          "y1" => 11,
          "z1" => 12,
          "x2" => 13,
          "y2" => 14,
          "z2" => 15,
          _ => throw new JsonException($"Invalid property {key} for Rectangle3D")
        };

        if (i < 10)
        {
          if (objType > -1 && objType != 0)
            throw new JsonException("Rectangle3D must have a start/end, or x/y/z/w/h/d, but not both.");

          objType = 0;
          data[i] = reader.GetInt32();
          continue;
        }

        if (objType > -1 && objType != 1)
          throw new JsonException("Rectangle3D must have a start/end, or x/y/z/w/h/d, but not both.");

        objType = 1;
        data[i - 10] = reader.GetInt32();
      }

      return objType == 0
        ? new Rectangle3D(data[0], data[1], data[2], data[3], data[4], data[5])
        : new Rectangle3D(
          new Point3D(data[0], data[1], data[2]),
          new Point3D(data[3], data[4], data[5])
        );
    }

    public override Rectangle3D Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>
      reader.TokenType switch
      {
        JsonTokenType.StartArray => DeserializeArray(ref reader),
        JsonTokenType.StartObject => DeserializeObj(ref reader, options),
        _ => throw new JsonException("Invalid Json for Point3D")
      };

    public override void Write(Utf8JsonWriter writer, Rectangle3D value, JsonSerializerOptions options)
    {
      writer.WriteStartArray();
      writer.WriteNumberValue(value.Start.X);
      writer.WriteNumberValue(value.Start.Y);
      writer.WriteNumberValue(value.Start.Z);
      writer.WriteNumberValue(value.Width);
      writer.WriteNumberValue(value.Height);
      writer.WriteNumberValue(value.Depth);
      writer.WriteEndArray();
    }
  }
}