package dbx

import (
	"reflect"
	"strings"
	"time"
)

// NowPtr returns a pointer to the current time.
func NowPtr() *time.Time {
	now := time.Now()
	return &now
}

// Ptr returns a pointer to the given value of any scalar type. Returns nil if the value is a zero value.
func Ptr[T any](val T) *T {
	if reflect.ValueOf(val).IsZero() {
		return nil
	}
	return &val
}

// Val returns the value of the pointer to a scalar type, or the zero value if the pointer is nil.
func Val[T any](ptr *T) T {
	if ptr == nil {
		var zero T
		return zero
	}
	return *ptr
}

// TrimPtr trims the whitespace from a pointer to a string and returns nil only if the pointer is nil.
func TrimPtr(s *string) *string {
	if s == nil {
		return nil
	}
	trimmed := strings.TrimSpace(*s)
	return &trimmed
}

// TrimPtrToNil trims the whitespace from a pointer to a string and returns nil
// if the resulting string is empty or if the pointer is nil.
func TrimPtrToNil(s *string) *string {
	if s == nil {
		return nil
	}
	trimmed := strings.TrimSpace(*s)
	if trimmed == "" {
		return nil
	}
	return &trimmed
}

// IsZero checks if a pointer references the zero value of a given type and
// returns an error if this condition is met, otherwise returns nil if the
// pointer is nil or the value is not zero.
func IsZero[T any](ptr *T) error {
	if ptr == nil {
		return nil
	}
	if reflect.ValueOf(*ptr).IsZero() {
		return ErrValueIsZero
	}
	return nil
}