using System;
using System.Reflection;
using NBitcoin;
using Newtonsoft.Json;

namespace Stratis.Bitcoin.Utilities.JsonConverters
{
    /// <summary>
    /// Converter used to convert an object implementing <see cref="IBitcoinString"/> to and from JSON.
    /// </summary>
    /// <seealso cref="Newtonsoft.Json.JsonConverter" />
    public class BitcoinStringJsonConverter : JsonConverter
    {
        public Network Network { get; set; }

        public BitcoinStringJsonConverter(Network network)
        {
            this.Network = network;
        }

        /// <inheritdoc />
        public override bool CanConvert(Type objectType)
        {
            return
                typeof(IBitcoinString).GetTypeInfo().IsAssignableFrom(objectType.GetTypeInfo()) ||
                (typeof(IDestination).GetTypeInfo().IsAssignableFrom(objectType.GetTypeInfo()) && objectType.GetTypeInfo().AssemblyQualifiedName.Contains("NBitcoin"));
        }

        /// <inheritdoc />
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if(reader.TokenType == JsonToken.Null)
                return null;

            try
            {
                IBitcoinString result = Network.Parse(reader.Value.ToString(), null);
                if(result == null)
                {
                    throw new JsonObjectException("Invalid BitcoinString data", reader);
                }

                if(this.Network != null)
                {
                    if(result.Network != this.Network)
                    {
                        result = this.Network.Parse(reader.Value.ToString());
                        if(result.Network != this.Network)
                        {
                            throw new JsonObjectException("Invalid BitcoinString network", reader);
                        }
                    }
                }

                if(!objectType.GetTypeInfo().IsAssignableFrom(result.GetType().GetTypeInfo()))
                {
                    throw new JsonObjectException("Invalid BitcoinString type expected " + objectType.Name + ", actual " + result.GetType().Name, reader);
                }

                return result;
            }
            catch(FormatException)
            {
                throw new JsonObjectException("Invalid Base58Check data", reader);
            }
        }

        /// <inheritdoc />
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            var base58 = value as IBitcoinString;
            if(base58 != null)
            {
                writer.WriteValue(value.ToString());
            }
        }
    }
}