using System;
using System.Collections.Generic;
using System.Reflection.Emit;
using System.Text;
using Sunweaver.Commands.Attributes;
using Sunweaver.VM;

namespace Sunweaver.Commands
{
    [BasePair("Given a point (x,y), returns the angle from (1,0) in the range [-180 degrees, 180 degrees]. " +
              "That range is mapped to [-4500, 4500].]")]
    public class atan : Abstracts.BinaryOperation
    {
        public override void Operation(long a, long b)
        {
            VM.Stack.Push( (long)Math.Round(Math.Atan2(a,b) / (2 * Math.PI) * DNASystem.UnitsInAFullCircle));
        }

        public override void CompileOperation(ILGenerator il, Locals locals)
        {
            il.Emit(OpCodes.Ldloc, locals[typeof(VirtualMachine)]);
            il.Emit(OpCodes.Ldfld, typeof(VirtualMachine).GetField("Stack"));
            il.Emit(OpCodes.Ldloc, locals[typeof(long), 0]);
            il.Emit(OpCodes.Conv_I8);
            il.Emit(OpCodes.Ldloc, locals[typeof(long), 1]);
            il.Emit(OpCodes.Conv_I8);
            il.Emit(OpCodes.Call, typeof(Math).GetMethod("Atan2"));
            il.Emit(OpCodes.Ldc_R8, Math.PI);
            il.Emit(OpCodes.Div);
            il.Emit(OpCodes.Ldc_R8, DNASystem.UnitsInAFullCircle);
            il.Emit(OpCodes.Div);
            il.Emit(OpCodes.Call, typeof(Math).GetMethod("Round"));
            il.Emit(OpCodes.Conv_I8);
            il.Emit(OpCodes.Call, typeof(IntStack).GetMethod("Push"));
        }
    }
}