#region License
// The MIT License (MIT)
//
// Copyright (c) 2020 Wanzyee Studio
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#endregion

using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json.UnityConverters.Helpers;
using UnityEngine;

namespace Newtonsoft.Json.UnityConverters.Math
{
    /// <summary>
    /// Custom Newtonsoft.Json converter <see cref="JsonConverter"/> for the Unity Matrix4x4 type <see cref="Matrix4x4"/>.
    /// </summary>
    public class Matrix4x4Converter : PartialConverter<Matrix4x4>
    {
        // https://github.com/Unity-Technologies/UnityCsReference/blob/2019.2/Runtime/Export/Math/Matrix4x4.cs#L21-L29
        private static readonly string[] _names = GetMemberNames();
        private static readonly Dictionary<string, int> _namesToIndex = GetNamesToIndex(_names);

        /// <summary>
        /// Get the property names include from <c>m00</c> to <c>m33</c>.
        /// </summary>
        /// <returns>The property names.</returns>
        private static string[] GetMemberNames()
        {
            string[] indexes = new[] { "0", "1", "2", "3" };
            return indexes.SelectMany((row) => indexes.Select((column) => "m" + column + row)).ToArray();
        }

        // Reusing the same strings here instead of creating new ones. Tiny bit lower memory footprint
        private static Dictionary<string, int> GetNamesToIndex(string[] names)
        {
            var dict = new Dictionary<string, int>();
            for (int i = 0; i < names.Length; i++)
            {
                dict[names[i]] = i;
            }
            return dict;
        }

        protected override void ReadValue(ref Matrix4x4 value, string name, JsonReader reader, JsonSerializer serializer)
        {
            if (_namesToIndex.TryGetValue(name, out var index))
            {
                value[index] = reader.ReadAsFloat() ?? 0;
            }
        }

        protected override void WriteJsonProperties(JsonWriter writer, Matrix4x4 value, JsonSerializer serializer)
        {
            for (int i = 0; i < _names.Length; i++)
            {
                writer.WritePropertyName(_names[i]);
                writer.WriteValue(value[i]);
            }
        }
    }
}