import { useState, useCallback, useEffect } from "react";
import PageHeader from "@/components/common/PageHeader";
import DashboardFilter from "../components/DashboardFilter";
import type { DashboardFilterValues } from "../components/DashboardFilter";
import StatsCards from "../components/StatsCards";
import WeeklyChart from "../components/WeeklyChart";
import RecentMessages from "../components/RecentMessages";
import PlatformDonut from "../components/PlatformDonut";
import { fetchDashboard } from "@/api/dashboard.api";
import { formatNumber } from "@/utils/format";
import type { DashboardData } from "../types";

/** KPI → StatsCards props 변환 */
function mapCards(data: DashboardData) {
  const { kpi } = data;
  return [
    {
      label: "오늘 발송 수",
      value: formatNumber(kpi.total_sent),
      badge: { type: "trend" as const, value: `${Math.abs(kpi.sent_change_rate)}%` },
      link: "/statistics",
    },
    {
      label: "성공률",
      value: kpi.success_rate.toFixed(1),
      unit: "%",
      badge: { type: "icon" as const, icon: "check_circle", color: "bg-green-100 text-green-600" },
      link: "/statistics",
    },
    {
      label: "등록 기기 수",
      value: formatNumber(kpi.device_count),
      badge: { type: "icon" as const, icon: "devices", color: "bg-blue-50 text-primary" },
      link: "/devices",
    },
    {
      label: "활성 서비스",
      value: String(kpi.service_count),
      badge: { type: "icon" as const, icon: "grid_view", color: "bg-purple-50 text-purple-600" },
      link: "/services",
    },
  ];
}

/** daily_trend → WeeklyChart props 변환 */
function mapChart(data: DashboardData) {
  const trends = data.daily_trend;
  if (trends.length === 0) return [];

  const maxVal = Math.max(...trends.map((t) => Math.max(t.sent, t.success)), 1);
  const todayStr = new Date().toISOString().slice(0, 10);

  return trends.map((t) => {
    const isToday = t.date === todayStr;
    const mm = t.date.slice(5, 7);
    const dd = t.date.slice(8, 10);
    return {
      label: isToday ? "Today" : `${mm}.${dd}`,
      blue: 1 - t.sent / maxVal,      // Y축 비율 (0=최상단)
      green: 1 - t.success / maxVal,
      sent: formatNumber(t.sent),
      reach: formatNumber(t.success),
    };
  });
}

/** top_messages → RecentMessages props 변환 */
function mapMessages(data: DashboardData) {
  return data.top_messages.map((m) => ({
    template: m.message_name,
    targetCount: formatNumber(m.target_count),
    status: m.status as "완료" | "실패" | "진행" | "예약",
    sentAt: m.sent_at,
  }));
}

/** platform_ratio → PlatformDonut props 변환 */
function mapPlatform(data: DashboardData) {
  return {
    ios: data.platform_ratio.ios,
    android: data.platform_ratio.android,
  };
}

export default function DashboardPage() {
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(false);
  const [empty, setEmpty] = useState(false); // API 성공이나 데이터 없음
  const [cards, setCards] = useState<ReturnType<typeof mapCards> | undefined>();
  const [chart, setChart] = useState<ReturnType<typeof mapChart> | undefined>();
  const [messages, setMessages] = useState<ReturnType<typeof mapMessages> | undefined>();
  const [platform, setPlatform] = useState<ReturnType<typeof mapPlatform> | undefined>();

  // 필터 상태 보관 (초기 로드 + 조회 버튼)
  const [filter, setFilter] = useState<DashboardFilterValues>({
    dateStart: (() => {
      const d = new Date();
      d.setDate(d.getDate() - 30);
      return d.toISOString().slice(0, 10);
    })(),
    dateEnd: new Date().toISOString().slice(0, 10),
  });

  const loadDashboard = useCallback(async (f: DashboardFilterValues) => {
    setLoading(true);
    setError(false);
    setEmpty(false);
    try {
      const res = await fetchDashboard(
        { start_date: f.dateStart, end_date: f.dateEnd },
        f.serviceCode,
      );
      const d = res.data.data;

      // 데이터 비어있는지 판단
      const hasData =
        d.kpi.total_sent > 0 ||
        d.daily_trend.length > 0 ||
        d.top_messages.length > 0;

      if (!hasData) {
        setEmpty(true);
        return;
      }

      setCards(mapCards(d));
      setChart(mapChart(d));
      setMessages(mapMessages(d));
      setPlatform(mapPlatform(d));
    } catch {
      setError(true);
    } finally {
      setLoading(false);
    }
  }, []);

  // 초기 로드
  useEffect(() => {
    loadDashboard(filter);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  // 조회 버튼 핸들러
  const handleSearch = useCallback(
    (f: DashboardFilterValues) => {
      setFilter(f);
      loadDashboard(f);
    },
    [loadDashboard],
  );

  // 스켈레톤 표시 조건
  const showSkeleton = loading || error || empty || !cards;

  return (
    <>
      {/* 페이지 헤더 */}
      <PageHeader
        title="대시보드"
        description="서비스 발송 현황과 주요 지표를 한눈에 확인할 수 있습니다."
      />

      {/* 필터 */}
      <DashboardFilter onSearch={handleSearch} loading={loading} />

      {/* 데이터 영역 */}
      <div className="relative">
        <StatsCards cards={showSkeleton ? undefined : cards} loading={showSkeleton} />
        <WeeklyChart data={showSkeleton ? undefined : chart} loading={showSkeleton} />
        <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
          <RecentMessages messages={showSkeleton ? undefined : messages} loading={showSkeleton} />
          <PlatformDonut data={showSkeleton ? undefined : platform} loading={showSkeleton} />
        </div>

        {/* API 에러 오버레이 */}
        {error && !loading && (
          <div className="absolute inset-0 z-20 flex items-center justify-center bg-white/90 rounded-xl">
            <div className="text-center">
              <span
                className="material-symbols-outlined text-gray-400"
                style={{ fontSize: "48px" }}
              >
                cloud_off
              </span>
              <p className="mt-2 text-sm font-semibold text-gray-600">
                데이터를 불러올 수 없습니다
              </p>
              <p className="mt-1 text-xs text-gray-500">
                네트워크 상태를 확인하거나 다시 조회해 주세요
              </p>
            </div>
          </div>
        )}

        {/* 조회 결과 없음 오버레이 */}
        {empty && !loading && (
          <div className="absolute inset-0 z-20 flex items-center justify-center bg-white/90 rounded-xl">
            <div className="text-center">
              <span
                className="material-symbols-outlined text-gray-400"
                style={{ fontSize: "48px" }}
              >
                inbox
              </span>
              <p className="mt-2 text-sm font-semibold text-gray-600">
                조회된 데이터가 없습니다
              </p>
              <p className="mt-1 text-xs text-gray-500">
                기간이나 서비스를 변경하여 다시 조회해 주세요
              </p>
            </div>
          </div>
        )}
      </div>
    </>
  );
}