"""
邮件发送服务模块
=============================================================

封装 Flask-Mail 提供邮件发送能力，供业务模块和定时任务调用。

使用方式：
    from application.services import mail_svc

    # 简单发送
    mail_svc.send_mail(to='user@example.com', subject='标题', body='内容')

    # HTML 邮件
    mail_svc.send_mail(to='user@example.com', subject='标题', html='<h1>Hello</h1>')

    # 多收件人 / 抄送
    mail_svc.send_mail(
        to=['a@example.com', 'b@example.com'],
        subject='标题',
        body='内容',
        cc=['cc@example.com'],
    )
"""

import logging
from typing import List, Optional, Union

from extensions.mail import mail
from flask import current_app
from flask_mail import Message

logger = logging.getLogger(__name__)


def send_mail(
    to: Union[str, List[str]],
    subject: str,
    body: Optional[str] = None,
    html: Optional[str] = None,
    cc: Optional[Union[str, List[str]]] = None,
    bcc: Optional[Union[str, List[str]]] = None,
    reply_to: Optional[str] = None,
) -> bool:
    """
    发送邮件

    Args:
        to:      收件人地址，字符串或列表
        subject: 邮件主题
        body:    纯文本正文（与 html 二选一，都提供时邮件客户端自行选择显示）
        html:    HTML 正文
        cc:      抄送地址
        bcc:     密送地址
        reply_to: 回复地址

    Returns:
        bool: 发送成功返回 True，失败返回 False
    """
    if not to:
        logger.warning("发送邮件失败：收件人不能为空")
        return False

    if not subject:
        logger.warning("发送邮件失败：主题不能为空")
        return False

    if not body and not html:
        logger.warning("发送邮件失败：正文不能为空")
        return False

    # 统一转为列表
    if isinstance(to, str):
        to = [to]
    if cc and isinstance(cc, str):
        cc = [cc]
    if bcc and isinstance(bcc, str):
        bcc = [bcc]

    try:
        msg = Message(
            subject=subject,
            recipients=to,
            cc=cc,
            bcc=bcc,
            reply_to=reply_to,
            body=body,
            html=html,
        )
        mail.send(msg)

        logger.info(f"邮件发送成功: to={to}, subject={subject}")
        return True

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