package email

import (
	"crypto/tls"
	"fmt"
	"net/smtp"
	"strconv"
	"strings"

	"gopkg.in/gomail.v2"
)

type EmailConfig struct {
	Enabled       bool   `yaml:"enabled" json:"enabled"`             // 是否启用邮件发送
	Host          string `yaml:"host" json:"host"`                   // SMTP服务器地址
	Port          int    `yaml:"port" json:"port"`                   // SMTP服务器端口
	Username      string `yaml:"username" json:"username"`           // SMTP用户名
	Password      string `yaml:"password" json:"password"`           // SMTP密码
	TLSSkipVerify bool   `yaml:"tlsSkipVerify" json:"tlsSkipVerify"` // 是否跳过TLS证书验证
	From          string `yaml:"from" json:"from"`                   // 发件人邮箱地址
	To            string `yaml:"to" json:"to"`                       // 收件人邮箱地址列表
	Subject       string `yaml:"subject" json:"subject"`             // 邮件主题
	Body          string `yaml:"body" json:"body"`                   // 邮件正文内容
}

// 简单邮件发送函数
// 该函数使用标准库的 smtp 包发送邮件
// 注意：此函数不支持 TLS 加密，建议使用 gomail 包发送邮件以支持 TLS 和其他高级功能
// gomail 包的使用示例见 SendEmailWithGomail 函数
func SendEmail(email EmailConfig) error {
	username := email.Username
	from := email.From
	password := email.Password
	to := email.To
	subject := email.Subject
	body := email.Body
	smtpHost := email.Host
	smtpPort := email.Port

	msg := "From: " + from + "\n" +
		"To: " + to + "\n" +
		"Subject: " + subject + "\n\n" +
		body
	auth := smtp.PlainAuth(from, username, password, smtpHost)
	return smtp.SendMail(smtpHost+":"+strconv.Itoa(smtpPort), auth, from, []string{to}, []byte(msg))
}

func SendEmailWithGomail(email EmailConfig) error {
	m := gomail.NewMessage()
	m.SetHeader("From", email.From)
	m.SetHeader("To", strings.Split(email.To, ",")...) // 支持多个收件人
	m.SetHeader("Subject", email.Subject)
	m.SetBody("text/plain", email.Body)

	d := gomail.NewDialer(email.Host, email.Port, email.Username, email.Password)

	// 配置 TLS
	d.TLSConfig = &tls.Config{
		InsecureSkipVerify: email.TLSSkipVerify,
	}

	// gomail 会自动处理 STARTTLS
	if err := d.DialAndSend(m); err != nil {
		fmt.Printf("Failed to DialAndSend:%v", err)
		return err
	}
	return nil
}

// RemoveDuplicateEmails 去除重复的邮箱地址
func RemoveDuplicateEmails(emails []string) []string {
	emailMap := make(map[string]struct{})
	var uniqueEmails []string

	for _, email := range emails {
		if _, exists := emailMap[email]; !exists {
			emailMap[email] = struct{}{}
			uniqueEmails = append(uniqueEmails, email)
		}
	}

	return uniqueEmails
}