add generate and hash password

internal/modules/password_generator/generator.go

@@ -0,0 +1,32 @@
+package password_generator
+
+import (
+	"crypto/rand"
+	"math/big"
+)
+
+const (
+	charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+)
+
+type generator struct {
+	length int
+}
+
+func NewGenerator(length int) IPasswordGenerator {
+	return &generator{
+		length: length,
+	}
+}
+
+func (g *generator) Generate() (string, error) {
+	password := make([]byte, g.length)
+	for i := range password {
+		num, err := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
+		if err != nil {
+			return "", err
+		}
+		password[i] = charset[num.Int64()]
+	}
+	return string(password), nil
+}

internal/modules/password_generator/interface.go

@@ -0,0 +1,5 @@
+package password_generator
+
+type IPasswordGenerator interface {
+	Generate() (string, error)
+}

internal/services/users_service/service.go

@@ -2,16 +2,24 @@ package users_service
 
 import (
 	"context"
+	"evening_detective_server/internal/modules/password_generator"
 	"evening_detective_server/internal/repos/users_repo"
+
+	"golang.org/x/crypto/bcrypt"
 )
 
 type UsersService struct {
-	usersRepo *users_repo.UsersRepo
+	usersRepo         *users_repo.UsersRepo
+	passwordGenerator password_generator.IPasswordGenerator
 }
 
-func NewUsersService(usersRepo *users_repo.UsersRepo) *UsersService {
+func NewUsersService(
+	usersRepo *users_repo.UsersRepo,
+	passwordGenerator password_generator.IPasswordGenerator,
+) *UsersService {
 	return &UsersService{
-		usersRepo: usersRepo,
+		usersRepo:         usersRepo,
+		passwordGenerator: passwordGenerator,
 	}
 }
 
@@ -20,11 +28,19 @@ func (s *UsersService) AddUser(
 	username string,
 	email string,
 ) error {
-	err := s.usersRepo.AddUser(
+	password, err := s.passwordGenerator.Generate()
+	if err != nil {
+		return err
+	}
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+	err = s.usersRepo.AddUser(
 		ctx,
 		username,
 		email,
-		"hello", // TODO: generate password and send email
+		string(hashedPassword),
 		"user",
 	)
 	return err