using System;
using System.Collections.Immutable;
using System.Collections.Generic;
using System.Text.Json;
using System.Text.Json.Serialization;
using Observatory.Framework.Files.ParameterTypes;

namespace Observatory.Framework.Files.Converters
{
    /// <summary>
    /// The format used for materials changed from an object with a key for each material to an array of objects containing "name" and "percent".
    /// Need to handle both if we're going to read historical data. This reads the old format into a class reflecting the new structure.
    /// </summary>
    public class MaterialCompositionConverter : JsonConverter<ImmutableList<MaterialComposition>>
    {
        public override ImmutableList<MaterialComposition> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType == JsonTokenType.StartObject)
            {
                var materialComposition = new List<MaterialComposition>();
                while (reader.Read())
                {
                    if (reader.TokenType != JsonTokenType.EndObject)
                    {
                        if (reader.TokenType == JsonTokenType.PropertyName)
                        {
                            string name = reader.GetString();
                            reader.Read();
                            float percent = reader.GetSingle();
                            var material = new MaterialComposition
                            {
                                Name = name,
                                Percent = percent
                            };
                            materialComposition.Add(material);
                        }
                    }
                    else
                    {
                        break;
                    }
                }
                return materialComposition.ToImmutableList();
            }
            else
            {
                return (ImmutableList<MaterialComposition>)JsonSerializer.Deserialize(ref reader, typeof(ImmutableList<MaterialComposition>));
            }
        }

        public override void Write(Utf8JsonWriter writer, ImmutableList<MaterialComposition> value, JsonSerializerOptions options)
        {
            throw new NotImplementedException();
        }
    }
}