Main

Main.go

package main

import (
	"encoding/json"
	"errors"
	"log"
	"regexp"
)

var (
	ErrSmallLettersRequired = errors.New("password must contain small letters")
	ErrCapitalRequired      = errors.New("password must contain capital letters")
	ErrSpecialCharRequired  = errors.New("password must contain a special character")
	ErrPasswordDontMatch    = errors.New("invalid password")
)

type EmptyPasswordErr struct {
	Msg string
}

func (p *EmptyPasswordErr) Error() string {
	return p.Msg
}

func main() {
	password := "password"
	response := make(map[string]any)
	var passwordErrs []string

	err := passwordValidator(password)
	if err != nil {
		var emptyPassword *EmptyPasswordErr
		if errors.As(err, &emptyPassword) {
			passwordErrs = append(passwordErrs, emptyPassword.Msg)
		} else {
			//passwordErrs = append(passwordErrs, strings.Split(err.Error(), "\n")...)
			if errors.Is(err, ErrCapitalRequired) {
				passwordErrs = append(passwordErrs, ErrCapitalRequired.Error())
			}

			if errors.Is(err, ErrSmallLettersRequired) {
				passwordErrs = append(passwordErrs, ErrSmallLettersRequired.Error())
			}

			if errors.Is(err, ErrPasswordDontMatch) {
				passwordErrs = append(passwordErrs, ErrPasswordDontMatch.Error())
			}

			if errors.Is(err, ErrSpecialCharRequired) {
				passwordErrs = append(passwordErrs, ErrSpecialCharRequired.Error())
			}
		}

		response["password"] = passwordErrs
	}

	jsonResponse, err := json.Marshal(&response)
	if err != nil {
		log.Fatal(err)
	}
	log.Println(string(jsonResponse))
}

func passwordValidator(password string) error {
	var errs []error
	// validates if password is empty
	if password == "" {
		emptyPasswordErr := &EmptyPasswordErr{
			Msg: "Password is required and must have uppercase, lowercase, and special character.",
		}
		errs = append(errs, emptyPasswordErr)
	}

	// validates if password contains small(lowercase) letters
	pattern1 := `[a-z]`
	ok, err := regexp.MatchString(pattern1, password)
	if err != nil {
		errs = append(errs, err)
	} else if !ok {
		errs = append(errs, ErrSmallLettersRequired)
	}

	// validates if password contains capital(uppercase) letters
	pattern2 := `[A-Z]`
	ok, err = regexp.MatchString(pattern2, password)
	if err != nil {
		errs = append(errs, err)
	} else if !ok {
		errs = append(errs, ErrCapitalRequired)
	}

	// validate if password contains special characters
	pattern3 := `[~!@#$%^&*()-_+=[\]{}|\\;:\"<>,./?]`
	ok, err = regexp.MatchString(pattern3, password)
	if err != nil {
		errs = append(errs, err)
	} else if !ok {
		errs = append(errs, ErrSpecialCharRequired)
	}

	// Basic password validation
	if password != "pas$0Word" && errs == nil {
		errs = append(errs, ErrPasswordDontMatch)
	}

	return errors.Join(errs...)
}