package biz

import (
	"context"
	"errors"
	"strings"
)

type EmailRepo interface {
	Send(context.Context, []string, string, string) error
	DefaultRecipients() []string
	Enabled() bool
}

type EmailUsecase struct{ repo EmailRepo }

func NewEmailUsecase(repo EmailRepo) *EmailUsecase { return &EmailUsecase{repo: repo} }

func splitRecipients(value string) []string {
	parts := strings.Split(value, ",")
	result := make([]string, 0, len(parts))
	for _, part := range parts {
		if recipient := strings.TrimSpace(part); recipient != "" {
			result = append(result, recipient)
		}
	}
	return result
}

func (uc *EmailUsecase) Send(ctx context.Context, to, subject, body string) error {
	recipients := splitRecipients(to)
	if len(recipients) == 0 || subject == "" {
		return errors.New("收件人和邮件标题不能为空")
	}
	return uc.repo.Send(ctx, recipients, subject, body)
}

func (uc *EmailUsecase) Test(ctx context.Context) error {
	recipients := uc.repo.DefaultRecipients()
	if len(recipients) == 0 {
		return errors.New("未配置测试邮件收件人")
	}
	return uc.repo.Send(ctx, recipients, "test", "test")
}

func (uc *EmailUsecase) Alert(ctx context.Context, subject, body string) error {
	if !uc.repo.Enabled() {
		return nil
	}
	recipients := uc.repo.DefaultRecipients()
	if len(recipients) == 0 {
		return nil
	}
	return uc.repo.Send(ctx, recipients, subject, body)
}