import { CalendarCheck, CalendarX, Clock, TrendingUp } from "lucide-react"
import { getTranslations } from "next-intl/server"

import { Card } from "@/shared/components/ui/card"
import { cn } from "@/shared/lib/utils"
import type { ParentStudentAttendanceSummary } from "@/modules/parent/types"

type AggregateStats = {
  totalStudents: number
  avgPresentRate: number
  totalAbsent: number
  totalLate: number
}

/**
 * 聚合多个子女的考勤统计（纯函数，便于测试）。
 */
export function aggregateStats(
  summaries: ParentStudentAttendanceSummary[],
): AggregateStats {
  if (summaries.length === 0) {
    return { totalStudents: 0, avgPresentRate: 0, totalAbsent: 0, totalLate: 0 }
  }
  const totalStudents = summaries.length
  const sumRate = summaries.reduce(
    (sum, s) => sum + (s.stats.total > 0 ? s.stats.presentRate : 0),
    0,
  )
  const avgPresentRate = sumRate / totalStudents
  const totalAbsent = summaries.reduce((sum, s) => sum + s.stats.absent, 0)
  const totalLate = summaries.reduce((sum, s) => sum + s.stats.late, 0)
  return { totalStudents, avgPresentRate, totalLate, totalAbsent }
}

/**
 * 根据出勤率返回语气色调（纯函数，便于测试）。
 */
export function rateTone(rate: number): "good" | "warn" | "bad" {
  if (rate >= 95) return "good"
  if (rate >= 90) return "warn"
  return "bad"
}

const TONE_STYLES: Record<"good" | "warn" | "bad", string> = {
  good: "text-emerald-600",
  warn: "text-amber-600",
  bad: "text-destructive",
}

/**
 * 家长考勤页顶部的出勤率汇总卡片（RSC）。
 * 聚合所有子女的出勤率、缺勤、迟到总数，让家长一眼掌握整体情况。
 *
 * P2-8 修复：从 client component 降级为 RSC，使用 `getTranslations`。
 */
export async function ParentAttendanceRateCard({
  summaries,
}: {
  summaries: ParentStudentAttendanceSummary[]
}) {
  const t = await getTranslations("attendance")
  const stats = aggregateStats(summaries)
  if (stats.totalStudents === 0) return null

  const tone = rateTone(stats.avgPresentRate)
  const rateLabel =
    stats.avgPresentRate >= 95
      ? t("parent.rateExcellent")
      : stats.avgPresentRate >= 90
        ? t("parent.rateNeedsAttention")
        : t("parent.rateBelowStandard")

  return (
    <Card className="p-4" aria-label={t("parent.rateCardTitle")}>
      <div className="grid grid-cols-2 gap-3 sm:grid-cols-4">
        <div className="space-y-1">
          <div className="flex items-center gap-1 text-xs text-muted-foreground">
            <TrendingUp className="h-3 w-3" aria-hidden />
            {t("stats.attendanceRate")}
          </div>
          <div className={cn("text-2xl font-bold tabular-nums", TONE_STYLES[tone])}>
            {stats.avgPresentRate.toFixed(1)}%
          </div>
          <div className="text-xs text-muted-foreground">{rateLabel}</div>
        </div>

        <div className="space-y-1">
          <div className="flex items-center gap-1 text-xs text-muted-foreground">
            <CalendarCheck className="h-3 w-3" aria-hidden />
            {t("parent.children")}
          </div>
          <div className="text-2xl font-bold tabular-nums">{stats.totalStudents}</div>
          <div className="text-xs text-muted-foreground">{t("parent.linked")}</div>
        </div>

        <div className="space-y-1">
          <div className="flex items-center gap-1 text-xs text-muted-foreground">
            <CalendarX className="h-3 w-3" aria-hidden />
            {t("stats.absent")}
          </div>
          <div
            className={cn(
              "text-2xl font-bold tabular-nums",
              stats.totalAbsent > 0 && "text-destructive",
            )}
          >
            {stats.totalAbsent}
          </div>
          <div className="text-xs text-muted-foreground">{t("parent.thisPeriod")}</div>
        </div>

        <div className="space-y-1">
          <div className="flex items-center gap-1 text-xs text-muted-foreground">
            <Clock className="h-3 w-3" aria-hidden />
            {t("stats.late")}
          </div>
          <div
            className={cn(
              "text-2xl font-bold tabular-nums",
              stats.totalLate > 0 && "text-amber-600",
            )}
          >
            {stats.totalLate}
          </div>
          <div className="text-xs text-muted-foreground">{t("parent.thisPeriod")}</div>
        </div>
      </div>
    </Card>
  )
}