package mailgun

import (
	"context"
	"errors"
	"fmt"
	"time"

	"code.yun.ink/pkg/mailx/interfaces"
	"github.com/mailgun/mailgun-go/v4"
)

const (
	MaxRetries    = 3
	MaxRecipients = 1000 // Mailgun limit
)

type MailGun struct {
	interfaces.DefaultEmail
	// params *interfaces.EmialConfigDataMailgun
	mg *mailgun.MailgunImpl
	// logger loggerx.LoggerInterface
}

func NewMailGun() *MailGun {
	mailgun := &MailGun{}
	mailgun.Options = interfaces.DefaultOptions()
	mailgun.EmailType = interfaces.EmailTypeMailgun
	return mailgun
}

func (l *MailGun) SetOption(ctx context.Context, opt ...interfaces.Option) (interfaces.EmailInterface, error) {
	for _, o := range opt {
		o(&l.Options)
	}

	if l.Options.Mailgun == nil {
		return nil, fmt.Errorf("Mailgun configuration is required")
	}

	// 验证配置
	if err := l.validateConfig(); err != nil {
		return nil, fmt.Errorf("invalid Mailgun config: %w", err)
	}

	// 安全日志输出
	l.Options.Logger.Infof(ctx, "Mailgun configured - Domain:%s Sender:%s", 
		l.Options.Mailgun.Domain, l.Options.Mailgun.Sender)

	l.mg = mailgun.NewMailgun(l.Options.Mailgun.Domain, l.Options.Mailgun.ApiKey)

	return l, nil
}

func (l *MailGun) Send(ctx context.Context, params interfaces.Message) error {
	if l.mg == nil {
		return fmt.Errorf("Mailgun client not initialized")
	}

	// 验证消息
	if err := l.validateMessage(params); err != nil {
		return fmt.Errorf("invalid message: %w", err)
	}

	// 重试机制
	var lastErr error
	for i := 0; i < MaxRetries; i++ {
		if i > 0 {
			l.Options.Logger.Infof(ctx, "Retrying Mailgun email send, attempt %d/%d", i+1, MaxRetries)
			time.Sleep(time.Duration(i) * time.Second)
		}

		lastErr = l.sendEmail(ctx, params)
		if lastErr == nil {
			l.Options.Logger.Infof(ctx, "Mailgun email sent successfully to %v", params.To)
			return nil
		}

		l.Options.Logger.Errorf(ctx, "Mailgun send attempt %d failed: %v", i+1, lastErr)
	}

	return fmt.Errorf("failed to send Mailgun email after %d attempts: %w", MaxRetries, lastErr)
}

// 验证配置
func (l *MailGun) validateConfig() error {
	if l.Options.Mailgun.Domain == "" {
		return errors.New("Domain is required")
	}
	if l.Options.Mailgun.ApiKey == "" {
		return errors.New("ApiKey is required")
	}
	if l.Options.Mailgun.Sender == "" {
		return errors.New("Sender is required")
	}
	return nil
}

// 验证消息
func (l *MailGun) validateMessage(params interfaces.Message) error {
	if len(params.To) == 0 {
		return errors.New("at least one recipient is required")
	}
	if len(params.To) > MaxRecipients {
		return fmt.Errorf("too many recipients: %d (max: %d)", len(params.To), MaxRecipients)
	}
	if params.Subject == "" {
		return errors.New("subject is required")
	}
	if params.Body == "" {
		return errors.New("body is required")
	}
	return nil
}

// 发送邮件核心逻辑
func (l *MailGun) sendEmail(ctx context.Context, params interfaces.Message) error {
	// 创建邮件消息
	message := l.mg.NewMessage(l.Options.Mailgun.Sender, params.Subject, "", params.To...)

	// 设置HTML内容
	message.SetHtml(params.Body)

	// 设置Cc收件人
	for _, cc := range params.Cc {
		message.AddCC(cc)
	}

	// 设置Bcc收件人
	for _, bcc := range params.Bcc {
		message.AddBCC(bcc)
	}

	// 设置回复地址
	if params.ReplyTo != "" {
		message.SetReplyTo(params.ReplyTo)
	}

	// 设置发件人名称
	if params.Form != "" {
		//
	}

	// 添加附件
	for _, attachment := range params.Attachment {
		message.AddAttachment(attachment.Content)
	}

	// 发送邮件
	resp, id, err := l.mg.Send(ctx, message)
	if err != nil {
		return fmt.Errorf("Mailgun API call failed: %w", err)
	}

	// 记录响应信息
	l.Options.Logger.Infof(ctx, "Mailgun email sent - ID:%s Response:%s", id, resp)

	return nil
}