feat(pkg): init send email

Author: AfandyW

pkg/email/email.go

@@ -0,0 +1,175 @@
+package email
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"html/template"
+	"net/smtp"
+	"strings"
+
+	"github.com/hammer-code/lms-be/pkg/ngelog"
+)
+
+// SMTPSender interface for dependency injection
+type SMTPSender interface {
+	SendMail(addr string, a smtp.Auth, from string, to []string, msg []byte) error
+}
+
+// DefaultSMTPSender implements SMTPSender using the real smtp.SendMail
+type DefaultSMTPSender struct{}
+
+func (s *DefaultSMTPSender) SendMail(addr string, a smtp.Auth, from string, to []string, msg []byte) error {
+	return smtp.SendMail(addr, a, from, to, msg)
+}
+
+type SMTP struct {
+	Email    string
+	Password string
+	Host     string
+	Port     string
+}
+
+type Receiver struct {
+	Email string
+	Data  any
+}
+
+type PayloadEmail struct {
+	HtmlTemplate *template.Template
+	Subject      string
+	Mime         string
+	Sender       SMTP
+	Receiver     []Receiver
+	CC           []string
+	smtpSender   SMTPSender // injected SMTP sender
+}
+
+type failedToSend struct {
+	Subject  string
+	Receiver Receiver
+}
+
+// Updated constructor with optional SMTPSender
+func NewSendEmail(ctx context.Context, smtp SMTP, mime string, subject string, HtmlTemplate *template.Template) PayloadEmail {
+	return PayloadEmail{
+		HtmlTemplate: HtmlTemplate,
+		Subject:      subject,
+		Mime:         mime,
+		Sender:       smtp,
+		CC:           []string{},
+		smtpSender:   &DefaultSMTPSender{}, // Use default implementation
+	}
+}
+
+// New constructor for testing that allows injecting the SMTPSender
+func NewSendEmailWithSender(ctx context.Context, smtp SMTP, mime string, subject string, HtmlTemplate *template.Template, sender SMTPSender) PayloadEmail {
+	if sender == nil {
+		sender = &DefaultSMTPSender{}
+	}
+	return PayloadEmail{
+		HtmlTemplate: HtmlTemplate,
+		Subject:      subject,
+		Mime:         mime,
+		Sender:       smtp,
+		CC:           []string{},
+		smtpSender:   sender,
+	}
+}
+
+func (p *PayloadEmail) AddReceiver(ctx context.Context, receiver Receiver) error {
+	if receiver.Email == "" {
+		ngelog.Error(ctx, "email cannot be null", nil)
+		return errors.New("email cannot be null")
+	}
+
+	p.Receiver = append(p.Receiver, receiver)
+	return nil
+}
+
+func (p *PayloadEmail) AddCC(ctx context.Context, ccEmail string) error {
+	if ccEmail == "" {
+		ngelog.Error(ctx, "cc email cannot be null", nil)
+		return errors.New("cc email cannot be null")
+	}
+
+	p.CC = append(p.CC, ccEmail)
+	return nil
+}
+
+func (p *PayloadEmail) AddMultipleCC(ctx context.Context, ccEmails []string) error {
+	for _, email := range ccEmails {
+		if email == "" {
+			ngelog.Error(ctx, "cc email cannot be null", nil)
+			return errors.New("cc email cannot be null")
+		}
+	}
+
+	p.CC = append(p.CC, ccEmails...)
+	return nil
+}
+
+// Updated SendEmail method using the injected sender
+func (p PayloadEmail) SendEmail(ctx context.Context) {
+	var failedSendedEmails []failedToSend
+	for _, receiver := range p.Receiver {
+
+		// Create a temporary buffer to hold the parsed HTML
+		var bodyContent string
+		bodyBuffer := new(bytes.Buffer)
+		// Execute the template with data
+		if err := p.HtmlTemplate.Execute(bodyBuffer, receiver.Data); err != nil {
+			ngelog.Error(ctx, fmt.Sprintf("Error executing template for %s", receiver.Email), err)
+			failedSendedEmails = append(failedSendedEmails, failedToSend{
+				Subject:  p.Subject,
+				Receiver: receiver,
+			})
+			continue
+		}
+
+		bodyContent = bodyBuffer.String()
+		
+		// Build message headers
+		headers := fmt.Sprintf("To: %s\r\n", receiver.Email)
+		
+		// Add CC header if there are CC recipients
+		if len(p.CC) > 0 {
+			headers += fmt.Sprintf("Cc: %s\r\n", strings.Join(p.CC, ", "))
+		}
+		
+		headers += fmt.Sprintf("Subject: %s\r\n%s\r\n", p.Subject, p.Mime)
+		
+		message := []byte(headers + bodyContent + "\r\n")
+
+		auth := smtp.PlainAuth("", p.Sender.Email, p.Sender.Password, p.Sender.Host)
+
+		// Combine recipient and CC addresses for SMTP
+		allRecipients := []string{receiver.Email}
+		allRecipients = append(allRecipients, p.CC...)
+
+		host := fmt.Sprintf("%s:%s", p.Sender.Host, p.Sender.Port)
+		
+		// Use the injected SMTP sender
+		if err := p.smtpSender.SendMail(host, auth, p.Sender.Email, allRecipients, message); err != nil {
+			ngelog.Error(ctx, fmt.Sprintf("failed to send to %s", receiver.Email), err)
+			failedSendedEmails = append(failedSendedEmails, failedToSend{
+				Subject:  p.Subject,
+				Receiver: receiver,
+			})
+			continue
+		}
+
+		ngelog.Info(ctx, "success send email", ngelog.AddFields{
+			"email":   receiver.Email,
+			"subject": p.Subject,
+			"cc":      p.CC,
+		})
+	}
+
+	if len(failedSendedEmails) > 0 {
+		ngelog.Error(ctx, "failed to send email", nil, ngelog.AddFields{
+			"data": failedSendedEmails,
+		})
+	}
+}