using System;
using System.Collections;
using System.Linq;
using System.Collections.Generic;

namespace LeanCloud.Storage.Internal.Operation {
    internal class LCNumberOperation : ILCOperation {
        static readonly IDictionary<Tuple<Type, Type>, Func<object, object, object>> adders;

        static LCNumberOperation() {
            adders = new Dictionary<Tuple<Type, Type>, Func<object, object, object>> {
                {new Tuple<Type, Type>(typeof(sbyte), typeof(sbyte)), (left, right) => (sbyte)left + (sbyte)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(short)), (left, right) => (sbyte)left + (short)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(int)), (left, right) => (sbyte)left + (int)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(long)), (left, right) => (sbyte)left + (long)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(float)), (left, right) => (sbyte)left + (float)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(double)), (left, right) => (sbyte)left + (double)right},
                {new Tuple<Type, Type>(typeof(sbyte), typeof(decimal)), (left, right) => (sbyte)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(byte)), (left, right) => (byte)left + (byte)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(short)), (left, right) => (byte)left + (short)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(ushort)), (left, right) => (byte)left + (ushort)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(int)), (left, right) => (byte)left + (int)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(uint)), (left, right) => (byte)left + (uint)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(long)), (left, right) => (byte)left + (long)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(ulong)), (left, right) => (byte)left + (ulong)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(float)), (left, right) => (byte)left + (float)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(double)), (left, right) => (byte)left + (double)right},
                {new Tuple<Type, Type>(typeof(byte), typeof(decimal)), (left, right) => (byte)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(short), typeof(short)), (left, right) => (short)left + (short)right},
                {new Tuple<Type, Type>(typeof(short), typeof(int)), (left, right) => (short)left + (int)right},
                {new Tuple<Type, Type>(typeof(short), typeof(long)), (left, right) => (short)left + (long)right},
                {new Tuple<Type, Type>(typeof(short), typeof(float)), (left, right) => (short)left + (float)right},
                {new Tuple<Type, Type>(typeof(short), typeof(double)), (left, right) => (short)left + (double)right},
                {new Tuple<Type, Type>(typeof(short), typeof(decimal)), (left, right) => (short)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(ushort)), (left, right) => (ushort)left + (ushort)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(int)), (left, right) => (ushort)left + (int)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(uint)), (left, right) => (ushort)left + (uint)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(long)), (left, right) => (ushort)left + (long)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(ulong)), (left, right) => (ushort)left + (ulong)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(float)), (left, right) => (ushort)left + (float)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(double)), (left, right) => (ushort)left + (double)right},
                {new Tuple<Type, Type>(typeof(ushort), typeof(decimal)), (left, right) => (ushort)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(int), typeof(int)), (left, right) => (int)left + (int)right},
                {new Tuple<Type, Type>(typeof(int), typeof(long)), (left, right) => (int)left + (long)right},
                {new Tuple<Type, Type>(typeof(int), typeof(float)), (left, right) => (int)left + (float)right},
                {new Tuple<Type, Type>(typeof(int), typeof(double)), (left, right) => (int)left + (double)right},
                {new Tuple<Type, Type>(typeof(int), typeof(decimal)), (left, right) => (int)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(uint)), (left, right) => (uint)left + (uint)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(long)), (left, right) => (uint)left + (long)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(ulong)), (left, right) => (uint)left + (ulong)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(float)), (left, right) => (uint)left + (float)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(double)), (left, right) => (uint)left + (double)right},
                {new Tuple<Type, Type>(typeof(uint), typeof(decimal)), (left, right) => (uint)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(long), typeof(long)), (left, right) => (long)left + (long)right},
                {new Tuple<Type, Type>(typeof(long), typeof(float)), (left, right) => (long)left + (float)right},
                {new Tuple<Type, Type>(typeof(long), typeof(double)), (left, right) => (long)left + (double)right},
                {new Tuple<Type, Type>(typeof(long), typeof(decimal)), (left, right) => (long)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(char), typeof(char)), (left, right) => (char)left + (char)right},
                {new Tuple<Type, Type>(typeof(char), typeof(ushort)), (left, right) => (char)left + (ushort)right},
                {new Tuple<Type, Type>(typeof(char), typeof(int)), (left, right) => (char)left + (int)right},
                {new Tuple<Type, Type>(typeof(char), typeof(uint)), (left, right) => (char)left + (uint)right},
                {new Tuple<Type, Type>(typeof(char), typeof(long)), (left, right) => (char)left + (long)right},
                {new Tuple<Type, Type>(typeof(char), typeof(ulong)), (left, right) => (char)left + (ulong)right},
                {new Tuple<Type, Type>(typeof(char), typeof(float)), (left, right) => (char)left + (float)right},
                {new Tuple<Type, Type>(typeof(char), typeof(double)), (left, right) => (char)left + (double)right},
                {new Tuple<Type, Type>(typeof(char), typeof(decimal)), (left, right) => (char)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(float), typeof(float)), (left, right) => (float)left + (float)right},
                {new Tuple<Type, Type>(typeof(float), typeof(double)), (left, right) => (float)left + (double)right},
                {new Tuple<Type, Type>(typeof(ulong), typeof(ulong)), (left, right) => (ulong)left + (ulong)right},
                {new Tuple<Type, Type>(typeof(ulong), typeof(float)), (left, right) => (ulong)left + (float)right},
                {new Tuple<Type, Type>(typeof(ulong), typeof(double)), (left, right) => (ulong)left + (double)right},
                {new Tuple<Type, Type>(typeof(ulong), typeof(decimal)), (left, right) => (ulong)left + (decimal)right},
                {new Tuple<Type, Type>(typeof(double), typeof(double)), (left, right) => (double)left + (double)right},
                {new Tuple<Type, Type>(typeof(decimal), typeof(decimal)), (left, right) => (decimal)left + (decimal)right}
            };
            foreach (var pair in adders.Keys.ToList()) {
                if (pair.Item1.Equals(pair.Item2)) {
                    continue;
                }
                var reversePair = new Tuple<Type, Type>(pair.Item2, pair.Item1);
                var func = adders[pair];
                adders[reversePair] = (left, right) => func(right, left);
            }
        }

        protected object value;

        internal LCNumberOperation(object value) {
            this.value = value;
        }

        public ILCOperation MergeWithPrevious(ILCOperation previousOp) {
            if (previousOp is LCSetOperation || previousOp is LCDeleteOperation) {
                return previousOp;
            }
            if (previousOp is LCNumberOperation incrementOp) {
                object otherAmount = incrementOp.value;
                return new LCNumberOperation(Add(otherAmount, value));
            }
            return this;
        }

        public object Encode() {
            return new Dictionary<string, object> {
                { "__op", "Increment" },
                { "amount", value }
            };
        }

        public object Apply(object oldValue, string key) {
            oldValue = oldValue ?? 0;
            return Add(oldValue, value);
        }

        public IEnumerable GetNewObjectList() {
            return null;
        }

        static object Add(object obj1, object obj2) {
            Func<object, object, object> adder;
            if (adders.TryGetValue(new Tuple<Type, Type>(obj1.GetType(), obj2.GetType()), out adder)) {
                return adder(obj1, obj2);
            }
            throw new InvalidCastException("Cannot add " + obj1.GetType() + " to " + obj2.GetType());
        }
    }
}