import os
import re
import json
import time
import uuid
import smtplib
import threading
import traceback

from email.mime.text import MIMEText
from email.header import Header
from flask import render_template, request, jsonify
from common.logger import system_logger

# =====================================
# Path
# =====================================
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
UPLOAD_FOLDER = os.path.join(BASE_DIR, "uploads")
PROGRESS_FOLDER = os.path.join(BASE_DIR, "logs", "progress")
os.makedirs(UPLOAD_FOLDER, exist_ok=True)
os.makedirs(PROGRESS_FOLDER, exist_ok=True)

# =====================================
# 进度文件存储（跨进程共享）
# =====================================

def progress_path(task_id):
    return os.path.join(PROGRESS_FOLDER, f"{task_id}.json")


def write_progress(task_id, **kwargs):
    path = progress_path(task_id)
    data = {}
    if os.path.exists(path):
        try:
            with open(path, "r", encoding="utf-8") as f:
                data = json.load(f)
            # results 列表累积
            old_results = data.get("results", [])
        except Exception:
            old_results = []
    else:
        old_results = []

    data.update(kwargs)

    # 处理 results 追加
    results_append = data.pop("results_append", None)
    if results_append:
        old_results.append(results_append)
        data["results"] = old_results
    elif "results" not in data:
        data["results"] = old_results

    with open(path, "w", encoding="utf-8") as f:
        json.dump(data, f, ensure_ascii=False)


def read_progress(task_id):
    path = progress_path(task_id)
    if not os.path.exists(path):
        return None
    with open(path, "r", encoding="utf-8") as f:
        return json.load(f)


def clean_progress(task_id):
    path = progress_path(task_id)
    if os.path.exists(path):
        os.remove(path)


# =====================================
# TXT 解析
# =====================================
def parse_users(file_path):
    users = []
    with open(file_path, "r", encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            parts = re.split(r"[\s\t\|:;]+", line)
            if len(parts) < 2:
                continue
            email = parts[0].strip()
            password = parts[1].strip()
            if not email or "@" not in email:
                continue
            users.append({"email": email, "password": password})
    return users


# =====================================
# 清理 textarea 缩进
# =====================================
def normalize_template(text):
    if not text:
        return ""
    lines = text.splitlines()
    while lines and not lines[0].strip():
        lines.pop(0)
    while lines and not lines[-1].strip():
        lines.pop()
    return "\n".join(lines)


# =====================================
# 模板变量替换
# =====================================
def render_template_text(template, email, password):
    template = normalize_template(template)
    return (
        str(template)
        .replace("{{email}}", str(email or ""))
        .replace("{{password}}", str(password or ""))
    )


# =====================================
# SMTP 连接
# =====================================
def build_smtp(smtp_server, smtp_port, sender_email, sender_pass):
    smtp_port = int(smtp_port)
    try:
        if smtp_port == 465:
            server = smtplib.SMTP_SSL(smtp_server, smtp_port, timeout=30)
        else:
            server = smtplib.SMTP(smtp_server, smtp_port, timeout=30)
            server.ehlo()
            if smtp_port == 587:
                server.starttls()
                server.ehlo()
        server.login(sender_email, sender_pass)
        return server
    except Exception as e:
        raise Exception(f"SMTP连接失败：{smtp_server}:{smtp_port} {str(e)}")


# =====================================
# 发单封邮件
# =====================================
def send_single_mail(server, sender_email, receiver_email, subject, content, reply_to=None):
    msg = MIMEText(content, "plain", "utf-8")
    msg["From"] = sender_email
    msg["To"] = receiver_email
    msg["Subject"] = Header(subject or "邮件通知", "utf-8")
    if reply_to:
        msg["Reply-To"] = reply_to
    server.sendmail(sender_email, [receiver_email], msg.as_string())


def send_with_retry(server, sender_email, receiver_email, subject, content, reply_to=None, max_retries=3):
    last_error = None
    for attempt in range(1, max_retries + 1):
        try:
            send_single_mail(server, sender_email, receiver_email, subject, content, reply_to)
            return True, None
        except smtplib.SMTPServerDisconnected:
            last_error = "SMTPServerDisconnected"
            if attempt < max_retries:
                time.sleep(2 ** attempt)
        except smtplib.SMTPResponseException as e:
            code = e.smtp_code
            if 400 <= code < 500 and attempt < max_retries:
                last_error = f"SMTP {code}"
                time.sleep(2 ** attempt)
            else:
                return False, str(e)
        except Exception as e:
            return False, str(e)
    return False, last_error


# =====================================
# 异步后台任务：批量发送
# =====================================
def batch_send_worker(
    task_id,
    smtp_server,
    smtp_port,
    sender_email,
    sender_pass,
    subject,
    template_content,
    users,
    reply_to,
):
    server = None
    total = len(users)
    success_count = 0
    failed_count = 0

    write_progress(task_id, status="running", total=total, success=0, failed=0, current=0, results=[])

    try:
        server = build_smtp(smtp_server, smtp_port, sender_email, sender_pass)

        for idx, user in enumerate(users):
            email = user.get("email", "")
            password = user.get("password", "")

            ok, err = send_with_retry(
                server, sender_email, email,
                subject, render_template_text(template_content, email, password),
                reply_to=reply_to
            )

            if ok:
                success_count += 1
                result = {"email": email, "status": "success"}
                write_progress(task_id,
                    success=success_count,
                    current=idx + 1,
                    results_append=result
                )
            else:
                failed_count += 1
                result = {"email": email, "status": f"failed: {err}"}
                write_progress(task_id,
                    failed=failed_count,
                    current=idx + 1,
                    results_append=result
                )

            # 每封间隔 1s 防垃圾标记
            time.sleep(1)

    except Exception as e:
        write_progress(task_id, error=str(e))

    finally:
        if server:
            try:
                server.quit()
            except Exception:
                pass
        write_progress(task_id, status="done")


# =====================================
# 进度查询接口
# =====================================
def mail_notify_progress(task_id):
    data = read_progress(task_id)
    if data is None:
        return jsonify({"error": "task_id not found"}), 404
    # 只返回最近 50 条结果
    if "results" in data:
        data["results"] = data["results"][-50:]
    return jsonify(data)


# =====================================
# 页面入口
# =====================================
def mail_notify_page():
    message = None
    preview_content = ""
    task_id = None

    smtp_server = "smtp.ctvit.com.cn"
    smtp_port = "25"
    reply_to = ""
    sender_email = ""
    sender_pass = ""
    subject = "账号及口令通知"

    template_content = """尊敬的老师/同事：

    您好！

    根据系统账号开通安排，您的账号已创建完成。现将相关登录信息通知如下，请妥善保存并注意账号安全。

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

账号（邮箱）：{{email}}
初始口令：{{password}}

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    请在首次登录后及时修改初始口令，并妥善保管个人账号信息。

此致
敬礼！

信息技术支持中心"""

    try:
        if request.method == "POST":
            action = request.form.get("action", "send")

            smtp_server = (request.form.get("smtp_server") or smtp_server).strip()
            smtp_port = (request.form.get("smtp_port") or smtp_port).strip()
            sender_email = (request.form.get("sender_email") or "").strip()
            sender_pass = (request.form.get("sender_pass") or "").strip()
            subject = (request.form.get("subject") or subject).strip()
            reply_to = (request.form.get("reply_to") or "").strip()
            template_content = request.form.get("template_content") or template_content
            upload_file = request.files.get("user_file") or request.files.get("file")

            if not sender_email:
                raise Exception("请输入发件邮箱")
            if not sender_pass:
                raise Exception("请输入SMTP密码")

            if action == "test":
                preview_content = render_template_text(template_content, sender_email, "123456")
                server = None
                try:
                    server = build_smtp(smtp_server, smtp_port, sender_email, sender_pass)
                    send_single_mail(server, sender_email, sender_email, f"[测试] {subject}", preview_content, reply_to=reply_to)
                finally:
                    if server:
                        server.quit()
                message = "✅ 测试邮件发送成功（已发送至自己邮箱）"
                system_logger.info(f"[MailNotify-Test] sender={sender_email}")

            elif action == "send":
                if not upload_file or not upload_file.filename:
                    raise Exception("请上传 TXT 文件")
                ext = os.path.splitext(upload_file.filename)[1].lower()
                if ext != ".txt":
                    raise Exception("仅支持 txt 文件")

                temp_name = f"{uuid.uuid4().hex}.txt"
                save_path = os.path.join(UPLOAD_FOLDER, temp_name)
                upload_file.save(save_path)

                users = parse_users(save_path)
                if not users:
                    raise Exception("未识别到有效用户数据")

                task_id = uuid.uuid4().hex
                write_progress(task_id,
                    status="queued", total=len(users),
                    success=0, failed=0, current=0,
                    results=[], error=None
                )

                thread = threading.Thread(
                    target=batch_send_worker,
                    args=(
                        task_id,
                        smtp_server, smtp_port,
                        sender_email, sender_pass,
                        subject, template_content,
                        users, reply_to,
                    ),
                    daemon=True,
                )
                thread.start()

                message = f"⏳ 批量发送已启动，任务ID：{task_id}（共 {len(users)} 封，每封间隔1s）"
                system_logger.info(f"[MailNotify] task={task_id} total={len(users)} sender={sender_email}")

            preview_content = render_template_text(template_content, "demo@test.com", "123456")

    except Exception as e:
        message = f"❌ 错误：{str(e)}"
        system_logger.exception("[MailNotify ERROR]")

    # 不回传密码
    return render_template(
        "mail_notify.html",
        message=message,
        smtp_server=smtp_server,
        smtp_port=smtp_port,
        sender_email=sender_email,
        sender_pass="",
        reply_to=reply_to,
        subject=subject,
        template_content=template_content,
        preview_content=preview_content,
        task_id=task_id,
    )