NextEdu/src/app/(dashboard)/teacher/grades/analytics/page.tsx

import type { JSX } from "react"
import Link from "next/link"
import { BarChart3, ArrowLeft } from "lucide-react"

import { Button } from "@/shared/components/ui/button"
import { EmptyState } from "@/shared/components/ui/empty-state"
import { getAuthContext } from "@/shared/lib/auth-guard"
import { getParam, type SearchParams } from "@/shared/lib/search-params"
import { getTeacherClasses } from "@/modules/classes/data-access"
import { getGrades } from "@/modules/school/data-access"
import { getSubjectOptions } from "@/modules/school/data-access"

import {
  getClassComparison,
  getGradeDistribution,
  getGradeTrend,
  getSubjectComparison,
} from "@/modules/grades/data-access-analytics"
import { GradeTrendChart } from "@/modules/grades/components/grade-trend-chart"
import { ClassComparisonChart } from "@/modules/grades/components/class-comparison-chart"
import { SubjectComparisonChart } from "@/modules/grades/components/subject-comparison-chart"
import { GradeDistributionChart } from "@/modules/grades/components/grade-distribution-chart"
import { AnalyticsFilters } from "@/modules/grades/components/analytics-filters"

export const dynamic = "force-dynamic"

export default async function GradeAnalyticsPage({
  searchParams,
}: {
  searchParams: Promise<SearchParams>
}): Promise<JSX.Element> {
  const sp = await searchParams
  const ctx = await getAuthContext()

  const classId = getParam(sp, "classId")
  const subjectId = getParam(sp, "subjectId")
  const gradeId = getParam(sp, "gradeId")

  const [classes, allGrades, allSubjects] = await Promise.all([
    getTeacherClasses(),
    getGrades(),
    getSubjectOptions(),
  ])

  if (classes.length === 0) {
    return (
      <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
        <div>
          <h1 className="text-2xl font-bold tracking-tight">Grade Analytics</h1>
          <p className="text-muted-foreground">
            Trend analysis, class comparisons, and score distributions.
          </p>
        </div>
        <EmptyState
          title="No classes"
          description="You don't have any classes yet."
          icon={BarChart3}
          className="border-none shadow-none"
        />
      </div>
    )
  }

  const targetClassId = classId ?? classes[0].id
  const targetSubjectId =
    subjectId && subjectId !== "all" ? subjectId : undefined
  const targetGradeId = gradeId ?? allGrades[0]?.id

  // Run analytics queries in parallel
  const [trend, distribution, subjectComparison, classComparison] =
    await Promise.all([
      getGradeTrend({
        classId: targetClassId,
        subjectId: targetSubjectId,
        scope: ctx.dataScope,
        currentUserId: ctx.userId,
      }),
      getGradeDistribution({
        classId: targetClassId,
        subjectId: targetSubjectId,
        scope: ctx.dataScope,
        currentUserId: ctx.userId,
      }),
      getSubjectComparison({
        classId: targetClassId,
        scope: ctx.dataScope,
      }),
      targetGradeId
        ? getClassComparison({
            gradeId: targetGradeId,
            subjectId: targetSubjectId ?? allSubjects[0]?.id ?? "",
            scope: ctx.dataScope,
          })
        : Promise.resolve([]),
    ])

  return (
    <div className="h-full flex-1 flex-col space-y-6 p-8 md:flex">
      <div className="flex flex-col justify-between gap-4 md:flex-row md:items-center">
        <div>
          <h1 className="text-2xl font-bold tracking-tight">Grade Analytics</h1>
          <p className="text-muted-foreground">
            Trend analysis, class comparisons, and score distributions.
          </p>
        </div>
        <Button asChild variant="outline">
          <Link href="/teacher/grades">
            <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
            Back to Grades
          </Link>
        </Button>
      </div>

      <AnalyticsFilters
        classes={classes.map((c) => ({ id: c.id, name: c.name }))}
        grades={allGrades.map((g) => ({ id: g.id, name: g.name }))}
        subjects={allSubjects.map((s) => ({ id: s.id, name: s.name ?? "Unknown" }))}
        currentClassId={targetClassId}
        currentSubjectId={subjectId ?? "all"}
        currentGradeId={targetGradeId ?? ""}
      />

      <div className="grid grid-cols-1 gap-6 lg:grid-cols-2">
        <GradeTrendChart data={trend} />
        <GradeDistributionChart data={distribution} />
        <SubjectComparisonChart data={subjectComparison} />
        <ClassComparisonChart data={classComparison} />
      </div>
    </div>
  )
}