import os
import re
import subprocess

from django.conf import settings
from django.shortcuts import render
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import AllowAny, IsAdminUser
from rest_framework.response import Response
from rest_framework import status
from rest_framework.exceptions import NotFound

LOCAL_RE = re.compile(r"^[a-z0-9](?:[a-z0-9._-]{0,62}[a-z0-9])?$")


def _require_enabled():
    # settings.py에 MAIL_SIGNUP_ENABLED 토글이 있으면 사용
    if not getattr(settings, "MAIL_SIGNUP_ENABLED", False):
        raise NotFound("Not Found")  # 숨김(404)


def _run_setup(cmd_args):
    """
    ./setup.sh -c dms-mailserver email add|list ...
    """
    setup_sh = getattr(settings, "MAIL_SETUP_SH", None) or os.getenv("MAIL_SETUP_SH", "./setup.sh")
    workdir = getattr(settings, "MAIL_SETUP_WORKDIR", None) or os.getenv("MAIL_SETUP_WORKDIR", os.getcwd())
    container = getattr(settings, "MAIL_DMS_CONTAINER", None) or os.getenv("MAIL_DMS_CONTAINER", "dms-mailserver")

    if not os.path.exists(setup_sh):
        raise RuntimeError(f"setup.sh not found: {setup_sh}")

    full = [setup_sh, "-c", container] + cmd_args
    p = subprocess.run(full, cwd=workdir, capture_output=True, text=True)
    out = (p.stdout or "").strip()
    err = (p.stderr or "").strip()

    if p.returncode != 0:
        raise ValueError(err or out or "setup.sh failed")

    return out


def _email_list():
    out = _run_setup(["email", "list"])
    return [ln.strip() for ln in out.splitlines() if ln.strip()]


def signup_page(request):
    _require_enabled()
    return render(request, "mail/signup.html")


@api_view(["POST"])
@permission_classes([AllowAny])
def request_account(request):
    _require_enabled()

    invite_expected = getattr(settings, "MAIL_INVITE_CODE", None) or os.getenv("MAIL_INVITE_CODE", "")
    dms_domain = getattr(settings, "MAIL_DMS_DOMAIN", None) or os.getenv("MAIL_DMS_DOMAIN", "")

    local = (request.data.get("local") or "").strip().lower()
    password = request.data.get("password") or ""
    invite = (request.data.get("invite") or "").strip()

    if not invite_expected or invite != invite_expected:
        return Response({"detail": "초대코드가 올바르지 않습니다."}, status=status.HTTP_403_FORBIDDEN)

    if not dms_domain:
        return Response({"detail": "서버 설정(MAIL_DMS_DOMAIN)이 비어있습니다."},
                        status=status.HTTP_500_INTERNAL_SERVER_ERROR)

    if not LOCAL_RE.match(local):
        return Response({"detail": "아이디 형식이 올바르지 않습니다. (영문소문자/숫자/._- 허용)"},
                        status=status.HTTP_400_BAD_REQUEST)

    if len(password) < 10:
        return Response({"detail": "비밀번호는 10자 이상으로 설정하세요."},
                        status=status.HTTP_400_BAD_REQUEST)

    address = f"{local}@{dms_domain}"

    try:
        emails = _email_list()
        if address in emails:
            return Response({"message": f"ℹ️ {address} 는 이미 존재합니다. (email list에서 확인됨)"})

        _run_setup(["email", "add", address, password])

        emails2 = _email_list()
        if address in emails2:
            return Response({"message": f"✅ {address} 계정이 잘 만들어졌습니다! (email list에서 확인됨)"})

        return Response({"detail": "계정 생성 후 list에서 확인이 안 됩니다."},
                        status=status.HTTP_500_INTERNAL_SERVER_ERROR)

    except ValueError as e:
        return Response({"detail": str(e)}, status=status.HTTP_400_BAD_REQUEST)
    except Exception as e:
        return Response({"detail": f"서버 오류: {e}"}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)


@api_view(["GET"])
@permission_classes([IsAdminUser])
def admin_list(request):
    _require_enabled()

    try:
        emails = _email_list()
        return Response({"count": len(emails), "emails": emails})
    except Exception as e:
        return Response({"detail": f"서버 오류: {e}"}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)