package vm

import (
	"jinx/pkg/lang/vm/code"
	"jinx/pkg/lang/vm/value"
)

func (vm *VM) createCoreNullType() value.Type {
	return value.Type{
		Kind: value.NullType,
	}
}

func (vm *VM) createCoreIntType() value.Type {
	return value.Type{
		Kind: value.IntType,
	}
}

func (vm *VM) createCoreFloatType() value.Type {
	return value.Type{
		Kind: value.FloatType,
	}
}

func (vm *VM) createCoreStringType() value.Type {
	return value.Type{
		Kind: value.StringType,
	}
}

func (vm *VM) createCoreBoolType() value.Type {
	return value.Type{
		Kind: value.BoolType,
	}
}

func (vm *VM) createCoreArrayType() value.Type {
	return value.Type{
		Kind: value.ArrayType,
		Methods: map[string]value.FunctionData{
			"length": makeCoreFn(vm.coreArrayLength, 0),
		},
	}
}

func (vm *VM) createCoreFunctionType() value.Type {
	return value.Type{
		Kind: value.FunctionType,
	}
}

func (vm *VM) coreArrayLength(args []value.Value) (value.Value, error) {
	a, err := vm.getThis()
	if err != nil {
		return value.Value{}, err
	}

	switch a.Type() {
	case value.ArrayType:
		arr := a.Data().(value.ArrayData)
		len, err := arr.Len(vm.memory)
		if err != nil {
			return value.Value{}, err
		}
		res := value.NewInt(int64(len))
		return res, nil
	default:
		return value.Value{}, ErrInvalidOperandType{
			Op: code.OpTempArrLen,
			X:  a.Type(),
		}
	}
}

func makeCoreFn(f value.NativeFunc, argCount uint) value.FunctionData {
	return value.NewNativeFunction(f, argCount).Data().(value.FunctionData)
}

func (vm *VM) getThis() (value.Value, error) {
	err := vm.execGetEnv(0)
	if err != nil {
		return value.Value{}, err
	}

	// Take it back!
	this, err := vm.popAndDrop()
	if err != nil {
		return value.Value{}, err
	}

	return this, nil
}