refactor: password requirements variables;

refactor: password validation function moved to custom validators;
refactor: adjusted model's validation fields

backend/internal/validation/custom.go

@@ -18,6 +18,7 @@
 package validation
 
 import (
+	"easywish/config"
 	"regexp"
 
 	"github.com/go-playground/validator/v10"
@@ -46,6 +47,36 @@ func GetCustomHandlers() []CustomValidatorHandler {
         return regexp.MustCompile(`^[.]{1,75}$`).MatchString(username)
 		}},
 
+		{
+			FieldName: "password",
+			Function: func(fl validator.FieldLevel) bool {
+				password := fl.Field().String()
+				cfg := config.GetConfig()
+
+				if cfg.PasswordMaxLength < len(password) || len(password) < cfg.PasswordMinLength {
+					return false
+				}
+
+				if cfg.PasswordCheckNumbers && !regexp.MustCompile(`\d+`).MatchString(password) {
+					return false
+				}
+
+				if cfg.PasswordCheckCases && !regexp.MustCompile(`^(?=.*[a-z])(?=.*[A-Z]).*$`).MatchString(password) ||
+					cfg.PasswordCheckCharacters && !regexp.MustCompile(`[a-zA-Z]`).MatchString(password) {
+						return false
+				}
+
+				if cfg.PasswordCheckSymbols && !regexp.MustCompile(`[.,/;'[\]\-=_+{}:"<>?\/|!@#$%^&*()~]`).MatchString(password) {
+						return false
+				}
+
+				if cfg.PasswordCheckLeaked {
+					// TODO: implement rockme check
+				}
+
+				return true
+		}},
+		
 	} 
 
 	return handlers