"""
邮件发送引擎 (底层)

职能：提供基础的 SMTP 邮件发送功能
- SMTP 服务器连接
- 邮件发送
- 配置管理
- 不包含业务逻辑
"""

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import logging
from typing import List, Optional

from backend.services.email_settings_service import EmailSettingsService

logger = logging.getLogger(__name__)


class EmailNotifier:
    """邮件发送引擎（底层服务）"""

    @staticmethod
    def get_email_config() -> Optional[dict]:
        """
        读取有效邮件配置

        Returns:
            dict: 邮件配置，如果配置不完整则返回 None
        """
        email_config = EmailSettingsService.get_smtp_config()
        if not email_config:
            logger.debug(
                "邮件配置未完成（SMTP_SERVER 或 SMTP_SENDER_EMAIL 为空），邮件发送功能已禁用"
            )
            return None

        return email_config

    @staticmethod
    def send_email(
        to_emails: List[str], subject: str, html_content: str, from_email: Optional[str] = None
    ) -> bool:
        """
        发送邮件（底层方法）

        Args:
            to_emails: 收件人邮箱列表
            subject: 邮件主题
            html_content: HTML 邮件内容
            from_email: 发件人邮箱（可选，默认使用配置中的发件人）

        Returns:
            是否发送成功
        """
        email_config = EmailNotifier.get_email_config()
        if not email_config:
            logger.warning("邮件配置不完整，跳过发送邮件")
            return False

        try:
            # 创建邮件
            msg = MIMEMultipart("alternative")
            msg["From"] = from_email or email_config["sender_email"]
            msg["To"] = ", ".join(to_emails)
            msg["Subject"] = subject

            # 添加 HTML 正文
            html_part = MIMEText(html_content, "html", "utf-8")
            msg.attach(html_part)

            # 连接 SMTP 服务器并发送
            if email_config.get("use_ssl", True):
                server = smtplib.SMTP_SSL(
                    email_config["smtp_server"], int(email_config["smtp_port"])
                )
            else:
                server = smtplib.SMTP(email_config["smtp_server"], int(email_config["smtp_port"]))
                server.starttls()

            server.login(email_config["sender_email"], email_config["sender_password"])
            server.sendmail(msg["From"], to_emails, msg.as_string())
            server.quit()

            logger.info(f"邮件发送成功: {subject} -> {', '.join(to_emails)}")
            return True

        except Exception as e:
            logger.error(f"邮件发送失败: {e}")
            return False

    @staticmethod
    def is_email_enabled() -> bool:
        """
        检查邮件功能是否启用

        Returns:
            邮件功能是否可用
        """
        return EmailNotifier.get_email_config() is not None