import { useState, useMemo, useEffect } from "react";
import { Link, useSearchParams } from "react-router-dom";
import PageHeader from "@/components/common/PageHeader";
import SearchInput from "@/components/common/SearchInput";
import FilterDropdown from "@/components/common/FilterDropdown";
import FilterResetButton from "@/components/common/FilterResetButton";
import Pagination from "@/components/common/Pagination";
import EmptyState from "@/components/common/EmptyState";
import CopyButton from "@/components/common/CopyButton";
import MessageSlidePanel from "../components/MessageSlidePanel";
import { formatDate } from "@/utils/format";
import { MOCK_MESSAGES, SERVICE_FILTER_OPTIONS } from "../types";

const PAGE_SIZE = 10;

export default function MessageListPage() {
  const [searchParams, setSearchParams] = useSearchParams();

  // 필터 입력 상태
  const [search, setSearch] = useState("");
  const [serviceFilter, setServiceFilter] = useState("전체 서비스");
  const [currentPage, setCurrentPage] = useState(1);
  const [loading, setLoading] = useState(false);

  // 실제 적용될 필터 (조회 버튼 클릭 시 반영)
  const [appliedSearch, setAppliedSearch] = useState("");
  const [appliedService, setAppliedService] = useState("전체 서비스");

  // URL 쿼리 파라미터로 messageId가 넘어온 경우 자동 검색
  useEffect(() => {
    const messageId = searchParams.get("messageId");
    if (messageId) {
      setSearch(messageId);
      setAppliedSearch(messageId);
      setSearchParams({}, { replace: true });
    }
  }, []); // eslint-disable-line react-hooks/exhaustive-deps

  // 슬라이드 패널 상태
  const [panelOpen, setPanelOpen] = useState(false);
  const [selectedMessageId, setSelectedMessageId] = useState<string | null>(
    null
  );

  // 조회 버튼
  const handleQuery = () => {
    setLoading(true);
    setTimeout(() => {
      setAppliedSearch(search);
      setAppliedService(serviceFilter);
      setCurrentPage(1);
      setLoading(false);
    }, 400);
  };

  // 필터 초기화
  const handleReset = () => {
    setSearch("");
    setServiceFilter("전체 서비스");
    setAppliedSearch("");
    setAppliedService("전체 서비스");
    setCurrentPage(1);
  };

  // 필터링된 데이터
  const filtered = useMemo(() => {
    return MOCK_MESSAGES.filter((msg) => {
      // 검색 (메시지 ID / 제목)
      if (appliedSearch) {
        const q = appliedSearch.toLowerCase();
        if (
          !msg.messageId.toLowerCase().includes(q) &&
          !msg.title.toLowerCase().includes(q)
        ) return false;
      }
      // 서비스 필터
      if (
        appliedService !== "전체 서비스" &&
        msg.serviceName !== appliedService
      ) {
        return false;
      }
      return true;
    });
  }, [appliedSearch, appliedService]);

  // 페이지네이션
  const totalItems = filtered.length;
  const totalPages = Math.max(1, Math.ceil(totalItems / PAGE_SIZE));
  const paged = filtered.slice(
    (currentPage - 1) * PAGE_SIZE,
    currentPage * PAGE_SIZE
  );

  // 행 클릭 → 슬라이드 패널
  const handleRowClick = (messageId: string) => {
    setSelectedMessageId(messageId);
    setPanelOpen(true);
  };

  return (
    <div>
      <PageHeader
        title="메시지 목록"
        description="시스템에서 발송된 모든 메시지 내역을 관리합니다."
        action={
          <Link
            to="/messages/register"
            className="flex items-center justify-center gap-2 min-w-[154px] px-5 py-2.5 bg-[#2563EB] hover:bg-[#1d4ed8] text-white rounded-lg text-sm font-medium transition-colors shadow-sm"
          >
            <span className="material-symbols-outlined text-lg">add</span>
            새 메시지
          </Link>
        }
      />

      {/* 필터바 */}
      <div className="bg-white border border-gray-200 rounded-lg p-6 mb-6">
        <div className="flex items-end gap-4">
          <SearchInput
            value={search}
            onChange={setSearch}
            placeholder="검색어를 입력하세요"
            label="메시지 ID / 제목"
            disabled={loading}
          />
          <FilterDropdown
            label="서비스 구분"
            value={serviceFilter}
            options={SERVICE_FILTER_OPTIONS}
            onChange={setServiceFilter}
            className="w-[140px] flex-shrink-0"
            disabled={loading}
          />
          <FilterResetButton onClick={handleReset} disabled={loading} />
          <button
            onClick={handleQuery}
            disabled={loading}
            className="h-[38px] flex-shrink-0 bg-gray-800 hover:bg-gray-900 active:scale-95 text-white rounded-lg px-5 text-sm font-medium transition-all disabled:opacity-50 disabled:cursor-not-allowed"
          >
            조회
          </button>
        </div>
      </div>

      {/* 테이블 */}
      {loading ? (
        /* 로딩 스켈레톤 */
        <div className="bg-white border border-gray-200 rounded-lg overflow-hidden shadow-sm">
          <table className="w-full text-sm">
            <thead className="bg-gray-50 border-b border-gray-200">
              <tr>
                <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                  메시지 ID
                </th>
                <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                  메시지 제목
                </th>
                <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                  서비스
                </th>
                <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                  작성일
                </th>
              </tr>
            </thead>
            <tbody>
              {Array.from({ length: 5 }).map((_, i) => (
                <tr
                  key={i}
                  className={i < 4 ? "border-b border-gray-100" : ""}
                >
                  <td className="px-6 py-4 text-center">
                    <div className="h-4 w-20 rounded bg-gray-100 animate-pulse mx-auto" />
                  </td>
                  <td className="px-6 py-4">
                    <div className="h-4 w-48 rounded bg-gray-100 animate-pulse" />
                  </td>
                  <td className="px-6 py-4 text-center">
                    <div className="h-4 w-24 rounded bg-gray-100 animate-pulse mx-auto" />
                  </td>
                  <td className="px-6 py-4 text-center">
                    <div className="h-4 w-20 rounded bg-gray-100 animate-pulse mx-auto" />
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      ) : paged.length > 0 ? (
        <div className="bg-white border border-gray-200 rounded-lg overflow-hidden shadow-sm">
          <div className="overflow-x-auto">
            <table className="w-full">
              <thead className="bg-gray-50 border-b border-gray-200">
                <tr>
                  <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                    메시지 ID
                  </th>
                  <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                    메시지 제목
                  </th>
                  <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                    서비스
                  </th>
                  <th className="px-6 py-4 text-xs font-semibold uppercase text-gray-700 text-center">
                    작성일
                  </th>
                </tr>
              </thead>
              <tbody>
                {paged.map((msg, idx) => (
                  <tr
                    key={msg.messageId}
                    className={`${idx < paged.length - 1 ? "border-b border-gray-100" : ""} hover:bg-gray-50/50 transition-colors cursor-pointer`}
                    onClick={() => handleRowClick(msg.messageId)}
                  >
                    {/* 메시지 ID */}
                    <td className="px-6 py-4 text-center">
                      <div
                        className="flex items-center justify-center gap-2"
                        onClick={(e) => e.stopPropagation()}
                      >
                        <code className="text-sm text-gray-700 font-medium">
                          {msg.messageId}
                        </code>
                        <CopyButton text={msg.messageId} />
                      </div>
                    </td>
                    {/* 메시지 제목 */}
                    <td className="px-6 py-4">
                      <span className="text-sm text-gray-700 truncate max-w-xs block">
                        {msg.title}
                      </span>
                    </td>
                    {/* 서비스 */}
                    <td className="px-6 py-4 text-center">
                      <span className="text-sm text-gray-600">
                        {msg.serviceName}
                      </span>
                    </td>
                    {/* 작성일 */}
                    <td className="px-6 py-4 text-center">
                      <span className="text-sm text-gray-500">
                        {formatDate(msg.createdAt)}
                      </span>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>

          {/* 페이지네이션 */}
          <Pagination
            currentPage={currentPage}
            totalPages={totalPages}
            totalItems={totalItems}
            pageSize={PAGE_SIZE}
            onPageChange={setCurrentPage}
          />
        </div>
      ) : (
        <EmptyState
          icon="search_off"
          message="검색 결과가 없습니다"
          description="다른 검색어를 입력하거나 필터를 변경해보세요."
        />
      )}

      {/* 슬라이드 패널 */}
      <MessageSlidePanel
        isOpen={panelOpen}
        onClose={() => setPanelOpen(false)}
        messageId={selectedMessageId}
      />
    </div>
  );
}