package services

import (
	"crypto/tls"
	"fmt"
	"strings"

	"mengpost-backend/models"
)

// 微软个人邮箱常见后缀（Outlook / Hotmail / Live 等）.
var microsoftConsumerSuffixes = []string{
	"@outlook.com",
	"@hotmail.com",
	"@live.com",
	"@msn.com",
}

// IsMicrosoftConsumerEmail 判断是否为消费者微软邮箱（非 Exchange 自建域）.
func IsMicrosoftConsumerEmail(email string) bool {
	e := strings.ToLower(strings.TrimSpace(email))
	for _, suf := range microsoftConsumerSuffixes {
		if strings.HasSuffix(e, suf) {
			return true
		}
	}
	return false
}

// IMAPTLSConfig 为 IMAP TLS 握手提供 ServerName（微软等场景与证书一致）.
func IMAPTLSConfig(acc *models.Account) *tls.Config {
	if acc == nil || !acc.UseTLS {
		return nil
	}
	sn := acc.IMAPHost
	if IsMicrosoftConsumerEmail(acc.Email) && strings.EqualFold(acc.IMAPHost, "outlook.office365.com") {
		sn = "outlook.office365.com"
	}
	return &tls.Config{
		MinVersion: tls.VersionTLS12,
		ServerName: sn,
	}
}

// SMTPTLSConfig 发信使用 587 STARTTLS 时校验证书（微软 smtp.office365.com）.
func SMTPTLSConfig(acc *models.Account) *tls.Config {
	if acc == nil || !IsMicrosoftConsumerEmail(acc.Email) {
		return nil
	}
	if strings.EqualFold(acc.SMTPHost, "smtp.office365.com") {
		return &tls.Config{
			MinVersion: tls.VersionTLS12,
			ServerName: "smtp.office365.com",
		}
	}
	return nil
}

// WrapMicrosoftMailErr 为微软邮箱附加常见配置说明（IMAP 开关、基础认证与 OAuth）.
func WrapMicrosoftMailErr(email string, err error) error {
	if err == nil || !IsMicrosoftConsumerEmail(email) {
		return err
	}
	hint := "（微软邮箱：网页端需开启 IMAP；OAuth 账户无需应用密码。若仍失败请检查令牌是否过期、Azure 权限是否含 IMAP。）"
	return fmt.Errorf("%w %s", err, hint)
}