#!/usr/bin/env python3
"""
周报邮件发送脚本

SMTP 服务器地址和端口优先级：
  1. report-config.json 中的 smtp_host / smtp_port（最高优先级）
  2. 根据 SMTP_USER 邮箱后缀自动匹配内置服务商
  3. 环境变量 SMTP_HOST / SMTP_PORT（兜底）

账号和密码从环境变量读取（敏感，不入库）：
  SMTP_USER     - 发件人邮箱
  SMTP_PASSWORD - SMTP 密码或授权码
"""

import argparse
import json
import os
import smtplib
import sys
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

# 内置服务商：邮箱后缀 -> (host, port)
SMTP_PROVIDERS = {
    "gmail.com":     ("smtp.gmail.com",          587),
    "qq.com":        ("smtp.qq.com",              465),
    "163.com":       ("smtp.163.com",             465),
    "126.com":       ("smtp.126.com",             465),
    "outlook.com":   ("smtp.office365.com",       587),
    "hotmail.com":   ("smtp.office365.com",       587),
    "live.com":      ("smtp.office365.com",       587),
}


def load_config(config_path: str) -> dict:
    try:
        with open(config_path, "r", encoding="utf-8") as f:
            return json.load(f)
    except FileNotFoundError:
        print(f"错误：找不到配置文件 {config_path}", file=sys.stderr)
        print("请在项目根目录创建 report-config.json，格式：", file=sys.stderr)
        print('{"recipients": ["email@example.com"], "project_name": "项目名"}', file=sys.stderr)
        sys.exit(1)
    except json.JSONDecodeError as e:
        print(f"错误：report-config.json 格式错误 - {e}", file=sys.stderr)
        sys.exit(1)


def get_smtp_config(config: dict) -> tuple:
    user = os.environ.get("SMTP_USER")
    password = os.environ.get("SMTP_PASSWORD")

    # 根据邮箱后缀自动匹配服务商默认值
    auto_host, auto_port = None, None
    if user and "@" in user:
        suffix = user.split("@", 1)[1].lower()
        if suffix in SMTP_PROVIDERS:
            auto_host, auto_port = SMTP_PROVIDERS[suffix]
            print(f"自动识别服务商：{suffix} -> {auto_host}:{auto_port}", file=sys.stderr)

    # 优先级：config > 自动识别 > 环境变量
    host = config.get("smtp_host") or auto_host or os.environ.get("SMTP_HOST")
    port = config.get("smtp_port") or auto_port or os.environ.get("SMTP_PORT", "465")

    if not host:
        print("错误：无法确定 SMTP 服务器地址", file=sys.stderr)
        print("请在 report-config.json 中添加 smtp_host，或使用内置服务商（gmail/qq/163/outlook）", file=sys.stderr)
        sys.exit(1)

    missing = [k for k, v in {"SMTP_USER": user, "SMTP_PASSWORD": password}.items() if not v]
    if missing:
        print(f"错误：缺少以下环境变量：{', '.join(missing)}", file=sys.stderr)
        print("请在 shell 中设置（不要写入任何文件）：", file=sys.stderr)
        for k in missing:
            print(f"  export {k}=your_value", file=sys.stderr)
        sys.exit(1)

    try:
        port = int(port)
    except ValueError:
        print(f"错误：smtp_port 必须是数字，当前值为 '{port}'", file=sys.stderr)
        sys.exit(1)

    return host, port, user, password


def send_email(recipients: list, subject: str, body_html: str, sender: str, config: dict):
    host, port, user, password = get_smtp_config(config)

    msg = MIMEMultipart("alternative")
    msg["Subject"] = subject
    msg["From"] = sender or user
    msg["To"] = ", ".join(recipients)
    msg.attach(MIMEText(body_html, "html", "utf-8"))

    # 465 和 994 均为 SSL 直连端口，587 使用 STARTTLS
    ssl_ports = {465, 994}
    try:
        if port in ssl_ports:
            with smtplib.SMTP_SSL(host, port, timeout=30) as smtp:
                smtp.login(user, password)
                smtp.sendmail(user, recipients, msg.as_string())
        else:
            with smtplib.SMTP(host, port, timeout=30) as smtp:
                smtp.ehlo()
                smtp.starttls()
                smtp.login(user, password)
                smtp.sendmail(user, recipients, msg.as_string())
    except smtplib.SMTPAuthenticationError:
        print("错误：SMTP 认证失败，请检查 SMTP_USER 和 SMTP_PASSWORD", file=sys.stderr)
        sys.exit(1)
    except smtplib.SMTPConnectError:
        print(f"错误：无法连接到 {host}:{port}，请检查 SMTP_HOST 和 SMTP_PORT", file=sys.stderr)
        sys.exit(1)
    except Exception as e:
        print(f"错误：发送失败 - {e}", file=sys.stderr)
        sys.exit(1)

    print(f"邮件已发送至：{', '.join(recipients)}")


def main():
    parser = argparse.ArgumentParser(description="发送周报邮件")
    parser.add_argument("--config", required=True, help="report-config.json 路径")
    parser.add_argument("--subject", required=True, help="邮件主题")
    parser.add_argument("--body-file", required=True, help="HTML 正文文件路径")
    args = parser.parse_args()

    config = load_config(args.config)
    recipients = config.get("recipients", [])
    if not recipients:
        print("错误：report-config.json 中 recipients 为空", file=sys.stderr)
        sys.exit(1)

    try:
        with open(args.body_file, "r", encoding="utf-8") as f:
            body_html = f.read()
    except FileNotFoundError:
        print(f"错误：找不到邮件正文文件 {args.body_file}", file=sys.stderr)
        sys.exit(1)

    send_email(recipients, args.subject, body_html, sender=config.get("sender", ""), config=config)


if __name__ == "__main__":
    main()