import { useQuery } from "@tanstack/react-query";
import {
  Activity,
  BarChart3,
  Database,
  ShieldCheck,
  Users,
} from "lucide-react";
import { type ReactNode, useMemo, useState } from "react";
import { RoleGuard } from "../../components/auth/RoleGuard";
import {
  type RPUsageDailyMetric,
  type RPUsagePeriod,
  type TenantSummary,
  fetchAdminOverviewStats,
  fetchAdminRPUsageDaily,
  fetchAllTenants,
} from "../../lib/adminApi";
import { t } from "../../lib/i18n";

type DailyPoint = {
  date: string;
  loginRequests: number;
  otherRequests: number;
};

type SeriesSummary = {
  key: string;
  tenantLabel: string;
  clientLabel: string;
  loginRequests: number;
  otherRequests: number;
  uniqueSubjects: number;
};

function summarizeDaily(rows: RPUsageDailyMetric[]): DailyPoint[] {
  const byDate = new Map<string, DailyPoint>();
  for (const row of rows) {
    const current =
      byDate.get(row.date) ??
      ({
        date: row.date,
        loginRequests: 0,
        otherRequests: 0,
      } satisfies DailyPoint);
    current.loginRequests += row.loginRequests;
    current.otherRequests += row.otherRequests;
    byDate.set(row.date, current);
  }
  return Array.from(byDate.values()).sort((a, b) =>
    a.date.localeCompare(b.date),
  );
}

function summarizeSeries(rows: RPUsageDailyMetric[]): SeriesSummary[] {
  const bySeries = new Map<string, SeriesSummary>();
  for (const row of rows) {
    const key = `${row.tenantId}:${row.clientId}`;
    const current =
      bySeries.get(key) ??
      ({
        key,
        tenantLabel: row.tenantName || row.tenantId || "-",
        clientLabel: row.clientName || row.clientId,
        loginRequests: 0,
        otherRequests: 0,
        uniqueSubjects: 0,
      } satisfies SeriesSummary);
    current.loginRequests += row.loginRequests;
    current.otherRequests += row.otherRequests;
    current.uniqueSubjects = Math.max(
      current.uniqueSubjects,
      row.uniqueSubjects,
    );
    bySeries.set(key, current);
  }
  return Array.from(bySeries.values())
    .sort(
      (a, b) =>
        b.loginRequests + b.otherRequests - (a.loginRequests + a.otherRequests),
    )
    .slice(0, 5);
}

function parseDateParts(date: string) {
  const parts = date.split("-");
  if (parts.length === 3) {
    return {
      year: Number(parts[0]),
      month: Number(parts[1]),
      day: Number(parts[2]),
      monthText: parts[1],
      dayText: parts[2],
    };
  }
  return null;
}

function getISOWeekNumber(year: number, month: number, day: number) {
  const date = new Date(Date.UTC(year, month - 1, day));
  const dayOfWeek = date.getUTCDay() || 7;
  date.setUTCDate(date.getUTCDate() + 4 - dayOfWeek);
  const yearStart = new Date(Date.UTC(date.getUTCFullYear(), 0, 1));
  return Math.ceil(((date.getTime() - yearStart.getTime()) / 86400000 + 1) / 7);
}

function getISOWeekThursday(year: number, month: number, day: number) {
  const date = new Date(Date.UTC(year, month - 1, day));
  const dayOfWeek = date.getUTCDay() || 7;
  date.setUTCDate(date.getUTCDate() + 4 - dayOfWeek);
  return date;
}

function formatPeriodLabel(date: string, period: RPUsagePeriod) {
  const parts = parseDateParts(date);
  if (!parts) {
    return date;
  }
  if (period === "month") {
    return `${parts.monthText}월`;
  }
  if (period === "week") {
    const weekNumber = String(
      getISOWeekNumber(parts.year, parts.month, parts.day),
    ).padStart(2, "0");
    const weekThursday = getISOWeekThursday(parts.year, parts.month, parts.day);
    const weekMonth = weekThursday.getUTCMonth() + 1;
    const weekDay = weekThursday.getUTCDate();
    const weekMonthText = String(weekMonth).padStart(2, "0");
    const weekOfMonth = Math.min(5, Math.max(1, Math.ceil(weekDay / 7)));
    return `${weekNumber}(${weekMonthText}월${weekOfMonth}주)`;
  }
  return `${parts.monthText}.${parts.dayText}`;
}

function OverviewMetric({
  icon,
  label,
  value,
}: {
  icon: ReactNode;
  label: string;
  value: string;
}) {
  return (
    <span className="inline-flex items-center gap-2 whitespace-nowrap text-sm">
      <span className="text-muted-foreground">{icon}</span>
      <span className="text-muted-foreground">{label}</span>
      <span className="font-semibold tabular-nums">{value}</span>
    </span>
  );
}

function RPUsageMixedChart({
  rows,
  filters,
  period,
}: {
  rows: RPUsageDailyMetric[];
  filters: ReactNode;
  period: RPUsagePeriod;
}) {
  const daily = summarizeDaily(rows);
  const series = summarizeSeries(rows);
  const chartWidth = 720;
  const chartHeight = 230;
  const padX = 48;
  const padTop = 32;
  const padBottom = 34;
  const innerWidth = chartWidth - padX * 2;
  const innerHeight = chartHeight - padTop - padBottom;
  const maxValue = Math.max(
    1,
    ...daily.map((point) => point.loginRequests + point.otherRequests),
    ...daily.map((point) => point.loginRequests),
  );
  const slot = daily.length > 0 ? innerWidth / daily.length : innerWidth;
  const barWidth = Math.min(28, Math.max(10, slot * 0.42));
  const y = (value: number) =>
    padTop + innerHeight - (value / maxValue) * innerHeight;
  const x = (index: number) => padX + slot * index + slot / 2;
  const linePoints = daily
    .map((point, index) => `${x(index)},${y(point.loginRequests)}`)
    .join(" ");

  return (
    <section className="space-y-3">
      <div className="flex flex-wrap items-center justify-between gap-3">
        <div className="flex items-center gap-2">
          <BarChart3 size={18} className="text-primary" />
          <h3 className="text-base font-semibold">
            회사별 앱별 로그인요청/기타 요청 현황
          </h3>
        </div>
        {filters}
      </div>

      {daily.length === 0 ? (
        <div className="flex min-h-[210px] items-center justify-center text-sm text-muted-foreground">
          표시할 RP 이용 집계가 없습니다.
        </div>
      ) : (
        <div className="overflow-x-auto">
          <svg
            role="img"
            aria-label="일 단위 RP 요청 현황"
            viewBox={`0 0 ${chartWidth} ${chartHeight}`}
            className="h-[235px] min-w-[720px] w-full"
          >
            <title>일 단위 RP 요청 현황</title>
            <g transform="translate(510 10)">
              <rect
                x="0"
                y="3"
                width="10"
                height="10"
                rx="2"
                className="fill-sky-500/70"
              />
              <text x="16" y="12" className="fill-muted-foreground text-[11px]">
                기타 요청
              </text>
              <line
                x1="78"
                x2="98"
                y1="8"
                y2="8"
                className="stroke-emerald-500"
                strokeWidth="3"
                strokeLinecap="round"
              />
              <text
                x="104"
                y="12"
                className="fill-muted-foreground text-[11px]"
              >
                로그인 요청
              </text>
            </g>
            {[0, 0.25, 0.5, 0.75, 1].map((ratio) => {
              const gridY = padTop + innerHeight * ratio;
              const label = Math.round(maxValue * (1 - ratio));
              return (
                <g key={ratio}>
                  <line
                    x1={padX}
                    x2={chartWidth - padX}
                    y1={gridY}
                    y2={gridY}
                    stroke="currentColor"
                    className="text-border"
                    strokeWidth="1"
                  />
                  <text
                    x={padX - 12}
                    y={gridY + 4}
                    textAnchor="end"
                    className="fill-muted-foreground text-[11px]"
                  >
                    {label}
                  </text>
                </g>
              );
            })}
            {daily.map((point, index) => {
              const center = x(index);
              const otherHeight =
                (point.otherRequests / maxValue) * innerHeight;
              return (
                <g key={point.date}>
                  <rect
                    x={center - barWidth / 2}
                    y={padTop + innerHeight - otherHeight}
                    width={barWidth}
                    height={otherHeight}
                    rx="3"
                    className="fill-sky-500/70"
                  />
                  <text
                    x={center}
                    y={chartHeight - 12}
                    textAnchor="middle"
                    className="fill-muted-foreground text-[11px]"
                  >
                    {formatPeriodLabel(point.date, period)}
                  </text>
                </g>
              );
            })}
            <polyline
              points={linePoints}
              fill="none"
              className="stroke-emerald-500"
              strokeWidth="3"
              strokeLinecap="round"
              strokeLinejoin="round"
            />
            {daily.map((point, index) => (
              <circle
                key={`${point.date}-login`}
                cx={x(index)}
                cy={y(point.loginRequests)}
                r="4"
                className="fill-emerald-500 stroke-background"
                strokeWidth="2"
              />
            ))}
          </svg>
        </div>
      )}

      {series.length > 0 && (
        <div className="grid gap-x-6 gap-y-2 border-t border-border/60 pt-2 text-xs md:grid-cols-2 xl:grid-cols-3">
          {series.map((item) => (
            <div key={item.key} className="flex min-w-0 items-center gap-2">
              <span className="truncate font-medium">{item.clientLabel}</span>
              <span className="truncate text-muted-foreground">
                {item.tenantLabel}
              </span>
              <span className="ml-auto whitespace-nowrap tabular-nums">
                로그인 {item.loginRequests.toLocaleString()} / 기타{" "}
                {item.otherRequests.toLocaleString()} / 사용자{" "}
                {item.uniqueSubjects.toLocaleString()}
              </span>
            </div>
          ))}
        </div>
      )}
    </section>
  );
}

function GlobalOverviewPage() {
  const [period, setPeriod] = useState<RPUsagePeriod>("day");
  const [tenantSearch, setTenantSearch] = useState("");
  const [selectedTenantId, setSelectedTenantId] = useState("");
  const usageDays = period === "day" ? 14 : period === "week" ? 84 : 90;
  const statsQuery = useQuery({
    queryKey: ["admin-overview-stats"],
    queryFn: fetchAdminOverviewStats,
    retry: false,
  });
  const tenantsQuery = useQuery({
    queryKey: ["admin-overview-tenant-options"],
    queryFn: () => fetchAllTenants(),
    retry: false,
  });
  const tenantOptions = useMemo(() => {
    const term = tenantSearch.trim().toLowerCase();
    return (tenantsQuery.data?.items ?? [])
      .filter(
        (tenant) => tenant.type === "COMPANY" || tenant.type === "ORGANIZATION",
      )
      .filter((tenant) => {
        if (!term) return true;
        return (
          tenant.name.toLowerCase().includes(term) ||
          tenant.slug.toLowerCase().includes(term) ||
          tenant.id.toLowerCase().includes(term)
        );
      });
  }, [tenantSearch, tenantsQuery.data?.items]);
  const usageQuery = useQuery({
    queryKey: ["admin-rp-usage-daily", usageDays, period, selectedTenantId],
    queryFn: () =>
      fetchAdminRPUsageDaily({
        days: usageDays,
        period,
        tenantId: selectedTenantId || undefined,
      }),
    retry: false,
  });
  const stats = statsQuery.data;
  const usageRows = usageQuery.data?.items ?? [];
  const metric = (value: number | undefined) =>
    value === undefined ? "-" : value.toLocaleString();
  const chartFilters = (
    <div className="flex flex-wrap items-center gap-2">
      <div className="flex h-8 items-center gap-1" aria-label="집계 단위">
        {[
          ["day", "일"],
          ["week", "주"],
          ["month", "월"],
        ].map(([value, label]) => (
          <button
            key={value}
            type="button"
            aria-pressed={period === value}
            onClick={() => setPeriod(value as RPUsagePeriod)}
            className={`h-8 rounded px-3 text-xs font-medium transition-colors ${
              period === value
                ? "bg-primary text-primary-foreground"
                : "bg-muted/60 hover:bg-muted"
            }`}
          >
            {label}
          </button>
        ))}
      </div>
      <input
        aria-label="조직 검색"
        value={tenantSearch}
        onChange={(event) => setTenantSearch(event.target.value)}
        placeholder="조직 검색"
        className="h-8 w-36 rounded border border-input bg-background px-2 text-xs outline-none focus-visible:ring-2 focus-visible:ring-ring sm:w-44"
      />
      <select
        aria-label="대상 조직"
        value={selectedTenantId}
        onChange={(event) => setSelectedTenantId(event.target.value)}
        className="h-8 w-40 rounded border border-input bg-background px-2 text-xs outline-none focus-visible:ring-2 focus-visible:ring-ring sm:w-52"
      >
        <option value="">전체 조직</option>
        {tenantOptions.map((tenant) => (
          <option key={tenant.id} value={tenant.id}>
            {tenant.name} ({tenant.slug})
          </option>
        ))}
      </select>
    </div>
  );

  return (
    <div className="space-y-4 animate-in fade-in duration-500">
      <div className="flex flex-wrap items-end justify-between gap-4">
        <div className="space-y-1">
          <h2 className="text-2xl font-semibold tracking-tight">
            {t("ui.admin.overview.title", "Dashboard")}
          </h2>
          <p className="text-sm text-muted-foreground">
            {t(
              "msg.admin.overview.description",
              "시스템 전반의 주요 현황을 확인하고 관리합니다.",
            )}
          </p>
        </div>
      </div>

      <div className="flex flex-wrap items-center gap-x-6 gap-y-2 border-y border-border/60 py-2">
        <RoleGuard roles={["super_admin"]}>
          <OverviewMetric
            icon={<Users size={14} />}
            label={t(
              "ui.admin.overview.summary.total_tenants",
              "전체 테넌트 수",
            )}
            value={metric(stats?.totalTenants)}
          />
          <OverviewMetric
            icon={<ShieldCheck size={14} />}
            label={t(
              "ui.admin.overview.summary.oidc_clients",
              "OIDC 클라이언트",
            )}
            value={metric(stats?.oidcClients)}
          />
        </RoleGuard>
        <OverviewMetric
          icon={<Activity size={14} />}
          label={t(
            "ui.admin.overview.summary.audit_events_24h",
            "24시간 이벤트",
          )}
          value={metric(stats?.auditEvents24h)}
        />
        <OverviewMetric
          icon={<Database size={14} />}
          label={t("ui.admin.overview.summary.policy_gate", "정책 상태")}
          value="Active"
        />
      </div>

      {usageQuery.isError ? (
        <section className="space-y-2">
          <div className="flex flex-wrap items-center justify-between gap-3">
            <h3 className="text-base font-semibold">
              회사별 앱별 로그인요청/기타 요청 현황
            </h3>
            {chartFilters}
          </div>
          <div className="text-sm text-muted-foreground">
            RP 이용 통계 Query API 응답을 확인할 수 없습니다. backend 재시작
            이후 `rp_usage_daily_aggregate`가 준비되면 이 영역에 일 단위
            그래프가 표시됩니다.
          </div>
        </section>
      ) : (
        <RPUsageMixedChart
          rows={usageRows}
          filters={chartFilters}
          period={period}
        />
      )}
    </div>
  );
}

export default GlobalOverviewPage;