"use client";

import React, { useState, useEffect } from "react";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import {
  Inbox,
  Mail,
  RefreshCw,
  Loader2,
  CheckCircle,
  Paperclip,
  AlertCircle,
  Search,
  Filter,
  SortAsc,
  SortDesc,
  LayoutDashboard,
} from "lucide-react";
import { useRouter } from "next/navigation";
import {
  MailAccount,
  ReceivedMail,
  getMailAccounts,
  getReceivedMails,
  testImapConnection,
} from "@/lib/api/mail";
import MailDetailModal from "@/components/mail/MailDetailModal";

export default function MailReceivePage() {
  const router = useRouter();
  const [accounts, setAccounts] = useState<MailAccount[]>([]);
  const [selectedAccountId, setSelectedAccountId] = useState<string>("");
  const [mails, setMails] = useState<ReceivedMail[]>([]);
  const [loading, setLoading] = useState(false);
  const [testing, setTesting] = useState(false);
  const [testResult, setTestResult] = useState<{
    success: boolean;
    message: string;
  } | null>(null);

  // 메일 상세 모달 상태
  const [isDetailModalOpen, setIsDetailModalOpen] = useState(false);
  const [selectedMailId, setSelectedMailId] = useState<string>("");

  // 검색 및 필터 상태
  const [searchTerm, setSearchTerm] = useState<string>("");
  const [filterStatus, setFilterStatus] = useState<string>("all"); // all, unread, read, attachment
  const [sortBy, setSortBy] = useState<string>("date-desc"); // date-desc, date-asc, from-asc, from-desc

  // 계정 목록 로드
  useEffect(() => {
    loadAccounts();
  }, []);

  // 계정 선택 시 메일 로드
  useEffect(() => {
    if (selectedAccountId) {
      loadMails();
    }
  }, [selectedAccountId]);

  // 자동 새로고침 (30초마다)
  useEffect(() => {
    if (!selectedAccountId) return;

    const interval = setInterval(() => {
      loadMails();
    }, 30000); // 30초

    return () => clearInterval(interval);
  }, [selectedAccountId]);

  const loadAccounts = async () => {
    try {
      const data = await getMailAccounts();
      if (Array.isArray(data)) {
        const activeAccounts = data.filter((acc) => acc.status === "active");
        setAccounts(activeAccounts);
        if (activeAccounts.length > 0 && !selectedAccountId) {
          setSelectedAccountId(activeAccounts[0].id);
        }
      }
    } catch (error) {
      console.error("계정 로드 실패:", error);
    }
  };

  const loadMails = async () => {
    if (!selectedAccountId) return;

    setLoading(true);
    setTestResult(null);
    try {
      const data = await getReceivedMails(selectedAccountId, 50);
      setMails(data);
    } catch (error) {
      console.error("메일 로드 실패:", error);
      alert(
        error instanceof Error
          ? error.message
          : "메일을 불러오는데 실패했습니다."
      );
      setMails([]);
    } finally {
      setLoading(false);
    }
  };

  const handleTestConnection = async () => {
    if (!selectedAccountId) return;

    setTesting(true);
    setTestResult(null);
    try {
      const result = await testImapConnection(selectedAccountId);
      setTestResult(result);
      if (result.success) {
        // 연결 성공 후 자동으로 메일 로드
        setTimeout(() => loadMails(), 1000);
      }
    } catch (error) {
      setTestResult({
        success: false,
        message:
          error instanceof Error
            ? error.message
            : "IMAP 연결 테스트 실패",
      });
    } finally {
      setTesting(false);
    }
  };

  const formatDate = (dateString: string) => {
    const date = new Date(dateString);
    const now = new Date();
    const diffMs = now.getTime() - date.getTime();
    const diffMins = Math.floor(diffMs / 60000);
    const diffHours = Math.floor(diffMs / 3600000);
    const diffDays = Math.floor(diffMs / 86400000);

    if (diffMins < 60) {
      return `${diffMins}분 전`;
    } else if (diffHours < 24) {
      return `${diffHours}시간 전`;
    } else if (diffDays < 7) {
      return `${diffDays}일 전`;
    } else {
      return date.toLocaleDateString("ko-KR");
    }
  };

  const handleMailClick = (mail: ReceivedMail) => {
    setSelectedMailId(mail.id);
    setIsDetailModalOpen(true);
  };

  const handleMailRead = () => {
    // 메일을 읽었으므로 목록 새로고침
    loadMails();
  };

  // 필터링 및 정렬된 메일 목록
  const filteredAndSortedMails = React.useMemo(() => {
    let result = [...mails];

    // 검색
    if (searchTerm) {
      const searchLower = searchTerm.toLowerCase();
      result = result.filter(
        (mail) =>
          mail.subject.toLowerCase().includes(searchLower) ||
          mail.from.toLowerCase().includes(searchLower) ||
          mail.preview.toLowerCase().includes(searchLower)
      );
    }

    // 필터
    if (filterStatus === "unread") {
      result = result.filter((mail) => !mail.isRead);
    } else if (filterStatus === "read") {
      result = result.filter((mail) => mail.isRead);
    } else if (filterStatus === "attachment") {
      result = result.filter((mail) => mail.hasAttachments);
    }

    // 정렬
    if (sortBy === "date-desc") {
      result.sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime());
    } else if (sortBy === "date-asc") {
      result.sort((a, b) => new Date(a.date).getTime() - new Date(b.date).getTime());
    } else if (sortBy === "from-asc") {
      result.sort((a, b) => a.from.localeCompare(b.from));
    } else if (sortBy === "from-desc") {
      result.sort((a, b) => b.from.localeCompare(a.from));
    }

    return result;
  }, [mails, searchTerm, filterStatus, sortBy]);

  return (
    <div className="min-h-screen bg-gray-50">
      <div className="w-full max-w-none px-4 py-8 space-y-8">
        {/* 페이지 제목 */}
        <div className="flex items-center justify-between bg-white rounded-lg shadow-sm border p-6">
          <div>
            <h1 className="text-3xl font-bold text-gray-900">메일 수신함</h1>
            <p className="mt-2 text-gray-600">
              IMAP으로 받은 메일을 확인합니다
            </p>
          </div>
          <div className="flex gap-2">
            <Button 
              variant="outline" 
              size="sm"
              onClick={() => router.push('/admin/mail/dashboard')}
            >
              <LayoutDashboard className="w-4 h-4 mr-2" />
              대시보드
            </Button>
            <Button
              variant="outline"
              size="sm"
              onClick={loadMails}
              disabled={loading || !selectedAccountId}
            >
              <RefreshCw
                className={`w-4 h-4 mr-2 ${loading ? "animate-spin" : ""}`}
              />
              새로고침
            </Button>
            <Button
              variant="outline"
              size="sm"
              onClick={handleTestConnection}
              disabled={testing || !selectedAccountId}
            >
              {testing ? (
                <Loader2 className="w-4 h-4 mr-2 animate-spin" />
              ) : (
                <CheckCircle className="w-4 h-4 mr-2" />
              )}
              연결 테스트
            </Button>
          </div>
        </div>

        {/* 계정 선택 */}
        <Card className="shadow-sm">
          <CardContent className="p-4">
            <div className="flex items-center gap-4">
              <label className="text-sm font-medium text-gray-700 whitespace-nowrap">
                메일 계정:
              </label>
              <select
                value={selectedAccountId}
                onChange={(e) => setSelectedAccountId(e.target.value)}
                className="flex-1 px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-orange-500 focus:border-orange-500"
              >
                <option value="">계정 선택</option>
                {accounts.map((account) => (
                  <option key={account.id} value={account.id}>
                    {account.name} ({account.email})
                  </option>
                ))}
              </select>
            </div>

            {/* 연결 테스트 결과 */}
            {testResult && (
              <div
                className={`mt-4 p-3 rounded-lg flex items-center gap-2 ${
                  testResult.success
                    ? "bg-green-50 text-green-800 border border-green-200"
                    : "bg-red-50 text-red-800 border border-red-200"
                }`}
              >
                {testResult.success ? (
                  <CheckCircle className="w-5 h-5" />
                ) : (
                  <AlertCircle className="w-5 h-5" />
                )}
                <span>{testResult.message}</span>
              </div>
            )}
          </CardContent>
        </Card>

        {/* 검색 및 필터 */}
        {selectedAccountId && (
          <Card className="shadow-sm">
            <CardContent className="p-4">
              <div className="flex flex-col md:flex-row gap-3">
                {/* 검색 */}
                <div className="flex-1 relative">
                  <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-gray-400" />
                  <input
                    type="text"
                    value={searchTerm}
                    onChange={(e) => setSearchTerm(e.target.value)}
                    placeholder="제목, 발신자, 내용으로 검색..."
                    className="w-full pl-10 pr-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-orange-500 focus:border-orange-500"
                  />
                </div>

                {/* 필터 */}
                <div className="flex items-center gap-2">
                  <Filter className="w-4 h-4 text-gray-500" />
                  <select
                    value={filterStatus}
                    onChange={(e) => setFilterStatus(e.target.value)}
                    className="px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-orange-500 focus:border-orange-500"
                  >
                    <option value="all">전체</option>
                    <option value="unread">읽지 않음</option>
                    <option value="read">읽음</option>
                    <option value="attachment">첨부파일 있음</option>
                  </select>
                </div>

                {/* 정렬 */}
                <div className="flex items-center gap-2">
                  {sortBy.includes("desc") ? (
                    <SortDesc className="w-4 h-4 text-gray-500" />
                  ) : (
                    <SortAsc className="w-4 h-4 text-gray-500" />
                  )}
                  <select
                    value={sortBy}
                    onChange={(e) => setSortBy(e.target.value)}
                    className="px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-orange-500 focus:border-orange-500"
                  >
                    <option value="date-desc">날짜 ↓ (최신순)</option>
                    <option value="date-asc">날짜 ↑ (오래된순)</option>
                    <option value="from-asc">발신자 ↑ (A-Z)</option>
                    <option value="from-desc">발신자 ↓ (Z-A)</option>
                  </select>
                </div>
              </div>

              {/* 검색 결과 카운트 */}
              {(searchTerm || filterStatus !== "all") && (
                <div className="mt-3 text-sm text-gray-600">
                  {filteredAndSortedMails.length}개의 메일이 검색되었습니다
                  {searchTerm && (
                    <span className="ml-2">
                      (검색어: <span className="font-medium text-orange-600">{searchTerm}</span>)
                    </span>
                  )}
                </div>
              )}
            </CardContent>
          </Card>
        )}

        {/* 메일 목록 */}
        {loading ? (
          <Card className="shadow-sm">
            <CardContent className="flex justify-center items-center py-16">
              <Loader2 className="w-8 h-8 animate-spin text-orange-500" />
              <span className="ml-3 text-gray-600">메일을 불러오는 중...</span>
            </CardContent>
          </Card>
        ) : filteredAndSortedMails.length === 0 ? (
          <Card className="text-center py-16 bg-white shadow-sm">
            <CardContent className="pt-6">
              <Mail className="w-16 h-16 mx-auto mb-4 text-gray-300" />
              <p className="text-gray-500 mb-4">
                {!selectedAccountId
                  ? "메일 계정을 선택하세요"
                  : searchTerm || filterStatus !== "all"
                  ? "검색 결과가 없습니다"
                  : "받은 메일이 없습니다"}
              </p>
              {selectedAccountId && (
                <Button
                  onClick={handleTestConnection}
                  variant="outline"
                  disabled={testing}
                >
                  {testing ? (
                    <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                  ) : (
                    <CheckCircle className="w-4 h-4 mr-2" />
                  )}
                  IMAP 연결 테스트
                </Button>
              )}
            </CardContent>
          </Card>
        ) : (
          <Card className="shadow-sm">
            <CardHeader className="bg-gradient-to-r from-slate-50 to-gray-50 border-b">
              <CardTitle className="flex items-center gap-2">
                <Inbox className="w-5 h-5 text-orange-500" />
                받은 메일함 ({filteredAndSortedMails.length}/{mails.length}개)
              </CardTitle>
            </CardHeader>
            <CardContent className="p-0">
              <div className="divide-y">
                {filteredAndSortedMails.map((mail) => (
                  <div
                    key={mail.id}
                    onClick={() => handleMailClick(mail)}
                    className={`p-4 hover:bg-gray-50 transition-colors cursor-pointer ${
                      !mail.isRead ? "bg-blue-50/30" : ""
                    }`}
                  >
                    <div className="flex items-start gap-4">
                      {/* 읽음 표시 */}
                      <div className="flex-shrink-0 w-2 h-2 mt-2">
                        {!mail.isRead && (
                          <div className="w-2 h-2 bg-blue-500 rounded-full"></div>
                        )}
                      </div>

                      {/* 메일 내용 */}
                      <div className="flex-1 min-w-0">
                        <div className="flex items-center justify-between mb-1">
                          <span
                            className={`text-sm ${
                              mail.isRead
                                ? "text-gray-600"
                                : "text-gray-900 font-semibold"
                            }`}
                          >
                            {mail.from}
                          </span>
                          <div className="flex items-center gap-2">
                            {mail.hasAttachments && (
                              <Paperclip className="w-4 h-4 text-gray-400" />
                            )}
                            <span className="text-xs text-gray-500">
                              {formatDate(mail.date)}
                            </span>
                          </div>
                        </div>
                        <h3
                          className={`text-sm mb-1 truncate ${
                            mail.isRead ? "text-gray-700" : "text-gray-900 font-medium"
                          }`}
                        >
                          {mail.subject}
                        </h3>
                        <p className="text-xs text-gray-500 line-clamp-2">
                          {mail.preview}
                        </p>
                      </div>
                    </div>
                  </div>
                ))}
              </div>
            </CardContent>
          </Card>
        )}

        {/* 안내 정보 */}
        <Card className="bg-gradient-to-r from-green-50 to-emerald-50 border-green-200 shadow-sm">
          <CardHeader>
            <CardTitle className="text-lg flex items-center">
              <CheckCircle className="w-5 h-5 mr-2 text-green-600" />
              메일 수신 기능 완성! 🎉
            </CardTitle>
          </CardHeader>
          <CardContent>
            <p className="text-gray-700 mb-4">
              ✅ 구현 완료된 모든 기능:
            </p>
            <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
              <div>
                <p className="font-medium text-gray-800 mb-2">📬 기본 기능</p>
                <ul className="space-y-1 text-sm text-gray-600">
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>IMAP 프로토콜 메일 수신</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>메일 목록 표시</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>읽음/안읽음 상태</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>첨부파일 유무 표시</span>
                  </li>
                </ul>
              </div>
              <div>
                <p className="font-medium text-gray-800 mb-2">📄 상세보기</p>
                <ul className="space-y-1 text-sm text-gray-600">
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>HTML 본문 렌더링</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>텍스트 본문 보기</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>자동 읽음 처리</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>첨부파일 다운로드</span>
                  </li>
                </ul>
              </div>
              <div>
                <p className="font-medium text-gray-800 mb-2">🔍 고급 기능</p>
                <ul className="space-y-1 text-sm text-gray-600">
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>통합 검색 (제목/발신자/내용)</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>필터링 (읽음/첨부파일)</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>정렬 (날짜/발신자)</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>자동 새로고침 (30초)</span>
                  </li>
                </ul>
              </div>
              <div>
                <p className="font-medium text-gray-800 mb-2">🔒 보안</p>
                <ul className="space-y-1 text-sm text-gray-600">
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>XSS 방지 (DOMPurify)</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>비밀번호 암호화</span>
                  </li>
                  <li className="flex items-start">
                    <span className="text-green-500 mr-2">✓</span>
                    <span>안전한 파일명 생성</span>
                  </li>
                </ul>
              </div>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* 메일 상세 모달 */}
      <MailDetailModal
        isOpen={isDetailModalOpen}
        onClose={() => setIsDetailModalOpen(false)}
        accountId={selectedAccountId}
        mailId={selectedMailId}
        onMailRead={handleMailRead}
      />
    </div>
  );
}