using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System;
using System.Text.Json;
using System.Text.Json.Serialization;
using MCCFMD.Serialization.Modpack;

namespace MCCFMD.Serialization
{
    public class ManifestConverter : JsonConverter<Manifest>
    {
        PropertyInfo[] manifestProperties;
        Type manifestType;

        public ManifestConverter()
        {
            manifestType = typeof(Manifest);
            manifestProperties = manifestType.GetProperties();
        }
        public override Manifest Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            string[] propertyNames = new string[manifestProperties.Length];
            for (int i = 0; i < propertyNames.Length; i++) propertyNames[i] = manifestProperties[i].Name;
            Manifest result = new Manifest();
            HashSet<string> pendingProperties = new HashSet<string>(propertyNames);
            while (reader.Read())
            {
                if (reader.TokenType == JsonTokenType.EndObject)
                {
                    if (pendingProperties.Count != 0)
                    {
                        throw new JsonException("Manifest is missing data. Will not proceed.");
                    }
                    return result;
                }

                if (reader.TokenType == JsonTokenType.PropertyName)
                {
                    string propertyName = reader.GetString() ?? throw new JsonException();
                    if (propertyNames.Contains(propertyName))
                    {
                        PropertyInfo property = manifestProperties[Array.IndexOf(propertyNames, propertyName)];
                        pendingProperties.Remove(propertyName);
                        property.SetValue(result, JsonSerializer.Deserialize(ref reader, property.PropertyType, options));
                    }
                    else if (Enum.GetNames(typeof(ManifestGames)).Contains(propertyName, StringComparer.CurrentCultureIgnoreCase))
                    {
                        Game game = JsonSerializer.Deserialize<Game>(ref reader);
                        game.gameType = Enum.Parse<ManifestGames>(propertyName, true);
                        result.game = game;
                    }
                }
                else
                {
                    throw new JsonException();
                }
            }
            throw new JsonException(); // Reached end of stream and did not find ending token.
        }

        public override void Write(Utf8JsonWriter writer, Manifest value, JsonSerializerOptions options)
        {
            writer.WriteStartObject();
            writer.WritePropertyName(value.game.gameType.ToString().ToLower());
            JsonSerializer.Serialize(writer, value.game, typeof(Game), options);
            for (int i = 0; i < manifestProperties.Length; i++)
            {
                PropertyInfo property = manifestProperties[i];
                writer.WritePropertyName(property.Name);
                JsonSerializer.Serialize(writer, property.GetValue(value), property.PropertyType, options);
            }

            writer.WriteEndObject();
        }
    }
}