package email

import (
	"bytes"
	"context"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/ses"
	"github.com/pkg/errors"
	gomail "gopkg.in/gomail.v2"
)

// Send sends email without attachments.
func (c *EmailClient) Send(ctx context.Context, sender string, mailList []*string, title string, body string) error {
	if err := check(sender, mailList); err != nil {
		return err
	}
	sesEmailInput := &ses.SendEmailInput{
		Destination: &ses.Destination{
			ToAddresses: mailList,
		},
		Message: &ses.Message{
			Body: &ses.Body{
				Html: &ses.Content{
					Data: aws.String(body)},
			},
			Subject: &ses.Content{
				Data: aws.String(title),
			},
		},
		Source: aws.String(sender),
	}
	if _, err := c.ses.SendEmail(sesEmailInput); err != nil {
		return errors.Wrap(err, "send email failed")
	}
	return nil
}

// SendRaw send email that supports attachments.
func (c *EmailClient) SendRaw(ctx context.Context, sender string, mailList []*string, title string, body string, attachments []string) error {
	if err := check(sender, mailList); err != nil {
		return err
	}
	msg := gomail.NewMessage(gomail.SetCharset("UTF-8"))
	msg.SetHeader("From", sender)
	toList := make([]string, len(mailList))
	for i, l := range mailList {
		toList[i] = *l
	}
	msg.SetHeader("To", toList...)
	msg.SetHeader("Subject", title)
	msg.SetBody("text/html", body)
	for _, a := range attachments {
		msg.Attach(a)
	}
	var emailRaw bytes.Buffer
	_, _ = msg.WriteTo(&emailRaw)
	if _, err := c.ses.SendRawEmail(&ses.SendRawEmailInput{
		RawMessage: &ses.RawMessage{Data: emailRaw.Bytes()},
	}); err != nil {
		return errors.Wrap(err, "send raw email failed")
	}
	return nil
}

func check(sender string, mailList []*string) error {
	if sender == "" {
		return errors.New("no sender")
	}
	if len(mailList) == 0 {
		return errors.New("no recipient")
	}
	return nil
}