move structs in right packages + impl sender service to build and send e-mail

config/smtp.go

@@ -0,0 +1,43 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+)
+
+// mandatory parameters for the STMP server connection
+type SMTPConfig struct {
+	User     string
+	Password string
+	Url      string
+	Port     string
+}
+
+func NewSMTPConfig(user, password, url, port string) (SMTPConfig, error) {
+	var config SMTPConfig
+	if user == "" {
+		return config, errors.New("SMTP user can't be empty")
+	}
+	config.User = user
+
+	if password == "" {
+		return config, errors.New("SMTP password can't be empty")
+	}
+	config.Password = password
+
+	if url == "" {
+		return config, errors.New("SMTP server url can't be empty")
+	}
+	config.Url = url
+
+	if port == "" {
+		return config, errors.New("SMTP server port can't be empty")
+	}
+	config.Port = port
+
+	return config, nil
+}
+
+func (c SMTPConfig) GetFullUrl() string {
+	return fmt.Sprintf("%s:%s", c.Url, c.Port)
+}