APJSON

using System;
using System.Diagnostics;
using System.Linq;
using Apolyton.FastJson.Registry;
using Apolyton.FastJson.Serialization;

namespace Apolyton.FastJson.Data
{
    /// <summary>
    /// Represents a json primitive value.
    /// </summary>
    public struct JsonPrimitive : IJsonValue, IConvertible
    {
        private readonly JsonRegistry _registry;
        private readonly String _localValue;
        private object _typedValue;
        private DeserializationHandler _deserializationHandler;

        #region Constructors

        /// <summary>
        /// Creates an instance of the type.
        /// </summary>
        /// <param name="localValue">The string representation of the Json Primitive.</param>
        public JsonPrimitive(String localValue)
        {
            this._deserializationHandler = null;
            this._registry = null;
            this._localValue = localValue;
            this._typedValue = null;
        }

        /// <summary>
        /// Creates an instance of the type.
        /// </summary>
        /// <param name="boolean"></param>
        internal JsonPrimitive(bool boolean)
        {
            this._deserializationHandler = null;
            this._registry = null;
            this._localValue = null;
            this._typedValue = boolean;
        }

        /// <summary>
        /// Creates an instance of the primitive.
        /// </summary>
        /// <param name="localValue">The string representation of the Json Primitive.</param>
        /// <param name="parameters">The registry of the given parameters will be used to resolve the custom deserializer, if required.</param>
        public JsonPrimitive(JsonParameters parameters, String localValue)
            : this (parameters.Registry, localValue)
        {
        }

        /// <summary>
        /// Creates an instance of the primitive.
        /// </summary>
        /// <param name="localValue">The string representation of the Json Primitive.</param>
        /// <param name="registry">The registry which is used to resolve the custom deserializer, if required.</param>
        internal JsonPrimitive(JsonRegistry registry, String localValue)
        {
            this._deserializationHandler = null;
            this._registry = registry;
            this._localValue = localValue;
            this._typedValue = null;
        }

        #endregion

        /// <summary>
        /// Gets the json primitive type.
        /// </summary>
        public JsonType Type
        {
            get { return JsonType.JsonPrimitive; }
        }

        /// <summary>
        /// Returns json primitive.
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            return "JsonPrimitive";
        }

        /// <summary>
        /// Gets the value as string.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public string AsString
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = Deserialization.ChangeType(_localValue, typeof(String));
                }

                return (string)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as integer.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public int AsInteger
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = Int32.Parse(_localValue);
                }

                return (int)_typedValue;
            }
        }


        /// <summary>
        /// Gets the value as bool.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public bool AsBool
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = bool.Parse(_localValue);
                }

                return (bool)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as double.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public Double AsDouble
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = double.Parse(_localValue);
                }

                return (Double)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as float.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public float AsFloat
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = float.Parse(_localValue);
                }

                return (float)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as date time.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public DateTime AsDateTime
        {
            get
            {
                if (_typedValue == null)
                {
                    // Since JsonPrimitive is a generic value, we cannot specify the date time kind we want. Instead, we take it as it is
                    // Later, when the real object is built (and if), the adjustment is done over there.
                    _typedValue = Deserialization.CreateDateTime(_localValue, DateTimeKind.Unspecified);
                }

                return (DateTime)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as time span.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public TimeSpan AsTimeSpan
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = TimeSpan.Parse(_localValue);
                }

                return (TimeSpan)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as guid.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public Guid AsGuid
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = Deserialization.CreateGuid(_localValue);
                }

                return (Guid)_typedValue;
            }
        }

        /// <summary>
        /// Gets the value as long.
        /// </summary>
        [DebuggerDisplay("Click to expand. This operation has side effects.")]
        public long AsLong
        {
            get
            {
                if (_typedValue == null)
                {
                    _typedValue = Deserialization.CreateLong(_localValue);
                }

                return (long)_typedValue;
            }
        }

        public int Count
        {
            get { throw new NotSupportedException(); }
        }

        public IJsonValue this[int i]
        {
            get { throw new NotSupportedException(); }
        }

        public IJsonValue this[string key]
        {
            get { throw new NotSupportedException(); }
        }

        #region IConvertible Members

        TypeCode IConvertible.GetTypeCode()
        {
            return TypeCode.Boolean | TypeCode.Char | TypeCode.DateTime | TypeCode.Decimal | TypeCode.Double | TypeCode.Int16 | TypeCode.Int32 | TypeCode.Int64
                | TypeCode.String | TypeCode.UInt16 | TypeCode.UInt32 | TypeCode.UInt64;
        }

        bool IConvertible.ToBoolean(IFormatProvider provider)
        {
            return AsBool;
        }

        byte IConvertible.ToByte(IFormatProvider provider)
        {
            throw new NotSupportedException();
        }

        char IConvertible.ToChar(IFormatProvider provider)
        {
            if (_typedValue == null)
            {
                _typedValue = _localValue.ToCharArray().First();
            }

            return (char)_typedValue;
        }

        DateTime IConvertible.ToDateTime(IFormatProvider provider)
        {
            return AsDateTime;
        }

        decimal IConvertible.ToDecimal(IFormatProvider provider)
        {
            return AsInteger;
        }

        double IConvertible.ToDouble(IFormatProvider provider)
        {
            return AsDouble;
        }

        short IConvertible.ToInt16(IFormatProvider provider)
        {
            return (short)AsInteger;
        }

        int IConvertible.ToInt32(IFormatProvider provider)
        {
            return AsInteger;
        }

        long IConvertible.ToInt64(IFormatProvider provider)
        {
            return AsLong;
        }

        sbyte IConvertible.ToSByte(IFormatProvider provider)
        {
            throw new NotImplementedException();
        }

        float IConvertible.ToSingle(IFormatProvider provider)
        {
            return AsFloat;
        }

        string IConvertible.ToString(IFormatProvider provider)
        {
            return _localValue;
        }

        object IConvertible.ToType(Type conversionType, IFormatProvider provider)
        {
            if (conversionType == typeof(Guid))
            {
                return AsGuid;
            }
            else if (conversionType == typeof(TimeSpan))
            {
                return AsTimeSpan;
            }
            else if (conversionType.IsEnum)
            {
                if (_typedValue != null) { return _typedValue; }
                else { _typedValue = Deserialization.CreateEnum(conversionType, _localValue); ; return _typedValue; }
            }
            else if (conversionType == typeof(byte[]))
            {
                if (_typedValue != null) { return _typedValue; }
                else { _typedValue = Deserialization.CreateByteArray(_localValue, typeof(byte[])); return _typedValue; }
            }
            else if (_registry != null && _registry._customDeserializer.TryGetValue(conversionType, out _deserializationHandler))
            {
                if (_typedValue != null) { return _typedValue; }
                else { _typedValue = _deserializationHandler(_localValue); return _typedValue; }
            }
            else if (conversionType == typeof(int?))
            {
                if (_localValue != null) { return AsInteger; }
                else { return null; }
            }
            else if (conversionType == typeof(double?))
            {
                if (_localValue != null) { return AsDouble; }
                else { return null; }
            }
            else if (conversionType == typeof(Guid?))
            {
                if (_localValue != null) { return AsGuid; }
                else { return null; }
            }
            else if (conversionType == typeof(short?))
            {
                if (_localValue != null) { return (short)AsInteger; }
                else { return null; }
            }
            else if (conversionType == typeof(long?))
            {
                if (_localValue != null) { return AsLong; }
                else { return null; }
            }
            else if (conversionType == typeof(DateTime?))
            {
                if (_localValue != null) { return AsDateTime; }
                else { return null; }
            }
            else if (conversionType == typeof(TimeSpan?))
            {
                if (_localValue != null) { return AsTimeSpan; }
                else { return null; }
            }
            else if (conversionType == typeof(float?))
            {
                if (_localValue != null) { return AsFloat; }
                else if (_localValue == null) { return null; }
                else { return null; }
            }
            else if (conversionType == typeof(uint?))
            {
                if (_typedValue != null) { return _typedValue; }
                else if (_localValue == null) { return null; }
                else { _typedValue = uint.Parse(_localValue); return _typedValue; }
            }
            else if (conversionType == typeof(ushort?))
            {
                if (_typedValue != null) { return _typedValue; }
                else if (_localValue == null) { return null; }
                else { _typedValue = ushort.Parse(_localValue); return _typedValue; }
            }
            else if (conversionType == typeof(ulong?))
            {
                if (_typedValue != null) { return _typedValue; }
                else if (_localValue == null) { return null; }
                else { _typedValue = ulong.Parse(_localValue); return _typedValue; }
            }
            else if (conversionType == typeof(decimal))
            {
                if (_typedValue != null) { return _typedValue; }
                else { _typedValue = decimal.Parse(_localValue); return _typedValue; }
            }
            else if (conversionType == typeof(decimal?))
            {
                if (_typedValue != null) { return _typedValue; }
                else if (_localValue == null) { return null; }
                else { _typedValue = decimal.Parse(_localValue); return _typedValue; }
            }
            else
            {
                throw new NotSupportedException("Cannot convert json primitive to: " + conversionType.ToString());
            }
        }

        ushort IConvertible.ToUInt16(IFormatProvider provider)
        {
            if (_typedValue == null)
            {
                _typedValue = ushort.Parse(_localValue);
            }

            return (ushort)_typedValue;
        }

        uint IConvertible.ToUInt32(IFormatProvider provider)
        {
            if (_typedValue == null)
            {
                _typedValue = UInt32.Parse(_localValue);
            }

            return (UInt32)_typedValue;
        }

        ulong IConvertible.ToUInt64(IFormatProvider provider)
        {
            if (_typedValue == null)
            {
                _typedValue = UInt64.Parse(_localValue);
            }

            return (UInt64)_typedValue;
        }

        #endregion
    }
}