using System;
using System.Collections.Generic;
using System.Globalization;
using sharp.json.attributes;
using System.Reflection;
using sharp.extensions;
namespace sharp.json
{
	public static class JSONConverter
	{
		delegate object ConvertToDelegate(Type t,JSON json);

		static Dictionary<Type, ConvertToDelegate> toDelegates = new Dictionary<Type, ConvertToDelegate>{
			{ typeof(string), (t, json) => json.String },
			{ typeof(int), (t, json) => (int)json.Integer },
			{ typeof(short), (t, json) => (short)json.Integer },
			{ typeof(long), (t, json) => json.Integer },
			{ typeof(uint), (t, json) => (uint)json.Integer },
			{ typeof(ushort), (t, json) => (ushort)json.Integer },
			{ typeof(ulong), (t, json) => (ulong)json.Integer },
			{ typeof(double), (t, json) => json.Double },
			{ typeof(float), (t, json) => json.Double },
			{ typeof(bool), (t, json) => json.Boolean },
			{ typeof(DateTime), (t, json) => DateTime.Parse(json.String, CultureInfo.InvariantCulture) },
			{ typeof(Guid), (t, json) => Guid.Parse(json.String)},
			{ typeof(object), ToObject }
		};

		public static T To<T>(JSON json)
		{
			Type t = typeof(T);
			return (T)(object)To(t, json);
		}

		public static JSON From(object value)
		{
			if (value == null)
			{
				return JSONSpecial.Null;
			}
			return From(value.GetType(), value);
		}

		public static object To(Type t,JSON json){
			
			if (json.JSONType == JSONTypes.Null){
				return null;
			}

			if (t.IsEnum){
				return Enum.Parse(t, json.String);
			}

			if (toDelegates.ContainsKey(t))
			{
				return toDelegates[t](t, json);
			}

			if (t.IsArray){
				return ToArray(t, json);
			}

			if (!t.IsPrimitive){
				return ToObject(t, json);
			}


			throw new InvalidCastException(String.Format("JSON {0} can't be casted to {1}", json.JSONType.ToString(), t.Name));

		}

		public static void ApplyObject(JSON json, object o)
		{
			FieldPropertyInfo[] fpilist = fpi(o.GetType());
			foreach (FieldPropertyInfo fpi in fpilist)
			{
				if (json.Contains(fpi.Key))
				{
					fpi.setValue(o, To(fpi.ValueType, json[fpi.Key]));
				}
			}

		}

		public static object ToObject(Type t,JSON json){
			ConstructorInfo ci = t.GetConstructor(new Type[] { typeof(JSON) });
			if (ci != null)
			{
				if (ci.GetParameters()[0].ParameterType.Equals(typeof(JSON)))
				{
					return Activator.CreateInstance(t, (object)json);
				}
			}

			JSONClassPolicy cp = t.GetCustomAttribute<JSONClassPolicy>();
			if (cp == null)
			{
				cp = new JSONClassPolicy();
			}
			return ToObject(t, json, cp.Policy);
		}


		private static object ToObject(Type t, JSON json,JSONPolicy policy)
		{
			object oi = Activator.CreateInstance(t);

			ApplyObject(json,oi);

			return oi;
		}

		private static object ToArray(Type t,JSON json)
		{
			Array a = Array.CreateInstance(t.GetElementType(), json.Count);
			Type et = t.GetElementType();

			JSONField jfield = t.GetCustomAttribute<JSONField>();
			if (!jfield.IsNull())
			{
				et = jfield.ConstructWithType;
			}

			for (int n = 0; n < json.Count; n++)
			{
				a.SetValue(To(et ,json[n]), n);
			}

			return a;
		}

		public static JSON From(Type t, object value)
		{
			if (value == null)
			{
				return JSONSpecial.Null;
			}

			if (t == null)
			{
				t = value.GetType();
			}

			if ((t.IsPrimitive) || (t == typeof(string)))
			{
				return FromPrimitive(value);
			}

			if (t == typeof(DateTime))
			{
				return new JSONString(((DateTime)value).ToString(CultureInfo.InvariantCulture));
			}

			if (t == typeof(Guid))
			{
				return ((Guid)value).ToString();
			}

			if (t.IsEnum)
			{
				return new JSONString(value.ToString());
			}

			if (t.IsArray)
			{
				JSONArray ja = new JSONArray();

				Array a = (Array)value;

				Type et = t.GetElementType();
				if (et == typeof(object))
				{
					et = null;
				}
				foreach (object e in a)
				{
					ja.Add(From(et, e));
				}

				return ja;
			}

			return FromObject(value);
		}

		public static JSON FromPrimitive(object value)
		{
			Type t = value.GetType();

			if (typeof(int).Equals(t))
			{
				return new JSONNumber((int)value);
			}
			if (typeof(long).Equals(t))
			{
				return new JSONNumber((long)value);
			}
			if (typeof(double).Equals(t))
			{
				return new JSONNumber((double)value);
			}
			if (typeof(float).Equals(t))
			{
				return new JSONNumber((float)value);
			}
			if (typeof(string).Equals(t))
			{
				return new JSONString(value.ToString());
			}
			if (typeof(bool).Equals(t))
			{
				return ((bool)value) ? JSONSpecial.True : JSONSpecial.False;
			}

			throw new NotImplementedException(String.Format("Cast of {0} to JSON is not (yet) supported", t.Name));
		}

		public static JSON FromObject(object value)
		{
			return FromObject(value.GetType(), value);
		}
		public static JSON FromObject(Type type, object value)
		{
			Type t = value.GetType();
			JSONObject jo = new JSONObject();

			foreach (FieldPropertyInfo fpi in fpi(t)){
				jo[fpi.Key] = JSON.From(fpi.getValue(value));
			}

			return jo;
		}

		private static FieldPropertyInfo[] fpi(Type t)
		{
			JSONClassPolicy cp = t.GetCustomAttribute<JSONClassPolicy>();
			if (cp == null)
			{
				cp = new JSONClassPolicy();
			}
			return fpi(t, cp);
		}

		private static FieldPropertyInfo[] fpi(Type t,JSONClassPolicy cp)
		{
			BindingFlags bf;
			switch (cp.Policy){
				case JSONPolicy.ALL:
					bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.DeclaredOnly;
					break;
				case JSONPolicy.ATTRIBUTED:
					bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.DeclaredOnly;
					break;
				case JSONPolicy.NONPUBLIC:
					bf = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.DeclaredOnly;
					break;
				default:
					bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly;
					break;
			}


			List<FieldPropertyInfo> fpilist = new List<FieldPropertyInfo>();

			foreach (FieldInfo fi in t.GetFields(bf))
			{
				fpilist.Add(new FieldPropertyInfo(fi));
			}
			foreach (PropertyInfo pi in t.GetProperties(bf))
			{
				if (pi.GetIndexParameters().Length == 0){
					fpilist.Add(new FieldPropertyInfo(pi));					
				}
			}

			FieldPropertyInfo[] temp = fpilist.ToArray();
			fpilist.Clear();

			foreach (FieldPropertyInfo fpi in temp){
				if ((cp.Policy != JSONPolicy.ATTRIBUTED) || (fpi.JSONField != null))
				{
					fpilist.Add(fpi);
				}
			}

			if (!t.BaseType.IsNull()){
				fpilist.AddRange(fpi(t.BaseType,cp));
			}

			return fpilist.ToArray();
		}

		struct FieldPropertyInfo
		{
			public String Key { get; set; }

			FieldInfo FieldInfo { get; set; }
			PropertyInfo PropertyInfo { get; set; }

			public JSONField JSONField { get; set; }

			public FieldPropertyInfo(PropertyInfo propertyInfo)
			{
				this.PropertyInfo = propertyInfo;
				this.FieldInfo = null;
				this.JSONField = propertyInfo.GetCustomAttribute<JSONField>();
				this.Key = (this.JSONField == null) ? propertyInfo.Name : ((this.JSONField.Alias == null) ? propertyInfo.Name : this.JSONField.Alias);
			}
			public FieldPropertyInfo(FieldInfo fieldInfo)
			{
				this.PropertyInfo = null;
				this.FieldInfo = fieldInfo;
				this.JSONField = fieldInfo.GetCustomAttribute<JSONField>();
				this.Key = (this.JSONField == null) ? fieldInfo.Name : ((this.JSONField.Alias == null) ? fieldInfo.Name : this.JSONField.Alias);
			}

			public void setValue(object inst, object value)
			{
				if (PropertyInfo != null)
				{
					if (PropertyInfo.SetMethod != null)
					{
						PropertyInfo.SetValue(inst, value);						
					}
				}
				else if (FieldInfo != null)
				{
					FieldInfo.SetValue(inst, value);
				}
			}
			public object getValue(object inst)
			{
				if ((PropertyInfo != null)&&(!PropertyInfo.GetMethod.IsNull()))
				{
					return PropertyInfo.GetValue(inst);
				}
				else if (FieldInfo != null)
				{
					return FieldInfo.GetValue(inst);
				}
				return null;
			}

			public Type ValueType
			{
				get
				{
					if ((JSONField != null)&&(JSONField.ConstructWithType != null))
					{
						return JSONField.ConstructWithType;
					}
					if (PropertyInfo != null)
					{
						return PropertyInfo.PropertyType;
					}
					else if (FieldInfo != null)
					{
						return FieldInfo.FieldType;
					}
					return null;
				}
			}
		}

	}
}