package vfunc

import (
	"reflect"
	"unsafe"
)

// UCastFunc create function caller by unsafe pointer
func UCastFunc(fn interface{}) func(...interface{}) interface{} {
	f := fn
	fRefl := reflect.ValueOf(f)
	return *(*func(...interface{}) interface{})(unsafe.Pointer(fRefl.Pointer()))
}

// NCastFunc creates a function caller by Reflection
func NCastFunc(fn interface{}) func(...interface{}) interface{} {
	fnRefl := reflect.ValueOf(fn)
	ret := func(args ...interface{}) interface{} {
		nargs := []reflect.Value{}
		for _, a := range args {
			nargs = append(nargs, reflect.ValueOf(a))
		}
		return fnRefl.Call(nargs)[0].Interface()
	}

	return ret
}

//CastFunc creates a function caller by MakeFunc
func RCastFunc(fn interface{}) func(...interface{}) interface{} {
	var dummy func(...interface{}) interface{}
	fnRefl := reflect.ValueOf(fn)
	myFunci := reflect.MakeFunc(reflect.TypeOf(dummy), func(args []reflect.Value) (results []reflect.Value) {
		// Expect variadic so
		var nargs []reflect.Value
		for _, v := range args[0].Interface().([]interface{}) {
			nargs = append(nargs, reflect.ValueOf(v))
		}
		ret := fnRefl.Call(nargs)[0].Interface()

		return []reflect.Value{reflect.ValueOf(&ret).Elem()}
		// Convert the fucker"
	}).Interface().(func(...interface{}) interface{})
	return myFunci
}