using Qrakhen.Qamp.Core.Collections;
using Qrakhen.Qamp.Core.Logging;
using Qrakhen.Qamp.Core.Values;

namespace Qrakhen.Qamp.Core.Execution;

public readonly record struct Operation(OpCode OpCode, Value Left, Value Right);

public delegate Value OperationHandler(Operation operation);

public static class ValueOperation
{
   private static readonly ILogger _logger = LoggerService.Get(nameof(ValueOperation));

   private static readonly Register<OpCode, OperationHandler> _operations;

   public static Value Resolve(Operation operation)
   {
#if LOG
        _logger.Method($"{operation.Left} {operation.OpCode} {operation.Right}");
#endif
      // p sure switch is faster here (as opposed to dict lookup)
      return operation.OpCode switch {
         OpCode.Equal => Equal(operation),
         OpCode.Greater => Greater(operation),
         OpCode.Less => Less(operation),
         OpCode.Not => Not(operation),
         OpCode.Add => Add(operation),
         OpCode.Subtract => Subtract(operation),
         OpCode.Divide => Divide(operation),
         OpCode.Modulo => Modulo(operation),
         OpCode.Multiply => Multiply(operation),
         OpCode.Negate => Negate(operation),
         OpCode.BitwiseOr => BitwiseOr(operation),
         OpCode.BitwiseAnd => BitwiseAnd(operation),
         OpCode.BitwiseLeft => BitwiseLeft(operation),
         OpCode.BitwiseRight => BitwiseRight(operation),
         OpCode.BitwiseNot => BitwiseInvert(operation),
         OpCode.BitwiseXor => BitwiseXor(operation),
         _ => throw new NotImplementedException($"Unknown operator {operation.OpCode}.")
      };
   }

   static ValueOperation()
   {
      _operations = new Register<OpCode, OperationHandler> {
         { OpCode.Equal,         Equal },
         { OpCode.Greater,       Greater },
         { OpCode.Less,          Less },
         { OpCode.Not,           Not },
         { OpCode.Add,           Add },
         { OpCode.Subtract,      Subtract },
         { OpCode.Divide,        Divide },
         { OpCode.Modulo,        Modulo },
         { OpCode.Multiply,      Multiply },
         { OpCode.Negate,        Negate },
         { OpCode.BitwiseOr,     BitwiseOr },
         { OpCode.BitwiseAnd,    BitwiseAnd },
         { OpCode.BitwiseLeft,   BitwiseLeft },
         { OpCode.BitwiseRight,  BitwiseRight },
         { OpCode.BitwiseNot,    BitwiseInvert },
         { OpCode.BitwiseXor,    BitwiseXor }
      };
   }

   public static Value Equal(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      return new Value(a.Dynamic == b.Dynamic);
   }

   public static Value Greater(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      return new Value(a.Dynamic > b.Dynamic);
   }

   public static Value Less(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      return new Value(a.Dynamic < b.Dynamic);
   }

   public static Value Not(Operation operation)
   {
      Value value = operation.Left;
      Assert.NotVoid(value);
      ulong inner = value.Unsigned;
      return new Value(inner == 0);
   }

   public static Value Add(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      if (a.IsString)
         return Values.Objects.String.Make($"{a}{b}");
      Assert.IsPrimitive(a, b);
      bool convert = a.Type != b.Type;
      return new Value(a.Dynamic + b.Dynamic);
   }

   public static Value Subtract(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      return new Value(a.Dynamic - b.Dynamic);
   }

   public static Value Divide(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.NotZero(b);
      return new Value(a.Dynamic / b.Dynamic);
   }

   public static Value Modulo(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.NotZero(b);
      return new Value(a.Dynamic % b.Dynamic);
   }

   public static Value Multiply(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      return new Value(a.Dynamic * b.Dynamic);
   }

   public static Value Negate(Operation operation)
   {
      Value value = operation.Left;
      Assert.NotVoid(value);
      Assert.IsPrimitive(value);
      return new Value(-value.Dynamic);
   }

   public static Value BitwiseOr(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.IsInteger(a, b);
      return new Value(a.Dynamic | b.Dynamic);
   }

   public static Value BitwiseAnd(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.IsInteger(a, b);
      return new Value(a.Dynamic & b.Dynamic);
   }

   public static Value BitwiseXor(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.IsInteger(a, b);
      return new Value(a.Dynamic ^ b.Dynamic);
   }

   public static Value BitwiseLeft(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.IsInteger(a, b);
      return new Value(a.Dynamic << (int)(b.Dynamic ?? 0));
   }

   public static Value BitwiseRight(Operation operation)
   {
      Value a = operation.Left;
      Value b = operation.Right;
      Assert.NotVoid(a, b);
      Assert.IsPrimitive(a, b);
      Assert.IsInteger(a, b);
      return new Value(a.Dynamic >> (int)(b.Dynamic ?? 0));
   }

   public static Value BitwiseInvert(Operation operation)
   {
      Value a = operation.Left;
      Assert.NotVoid(a);
      Assert.IsPrimitive(a);
      Assert.IsInteger(a);
      return new Value(~a.Dynamic);
   }
}