import type { TeacherDashboardData, TeacherTodayScheduleItem } from "@/modules/dashboard/types"

import { TeacherClassesCard } from "./teacher-classes-card"
import { TeacherDashboardHeader } from "./teacher-dashboard-header"
import { TeacherHomeworkCard } from "./teacher-homework-card"
import { RecentSubmissions } from "./recent-submissions"
import { TeacherSchedule } from "./teacher-schedule"
import { TeacherStats } from "./teacher-stats"
import { TeacherGradeTrends } from "./teacher-grade-trends"

const toWeekday = (d: Date): 1 | 2 | 3 | 4 | 5 | 6 | 7 => {
  const day = d.getDay()
  return (day === 0 ? 7 : day) as 1 | 2 | 3 | 4 | 5 | 6 | 7
}

export function TeacherDashboardView({ data }: { data: TeacherDashboardData }) {
  const totalStudents = data.classes.reduce((sum, c) => sum + (c.studentCount ?? 0), 0)
  const todayWeekday = toWeekday(new Date())

  const classNameById = new Map(data.classes.map((c) => [c.id, c.name] as const))
  const todayScheduleItems: TeacherTodayScheduleItem[] = data.schedule
    .filter((s) => s.weekday === todayWeekday)
    .sort((a, b) => a.startTime.localeCompare(b.startTime))
    .map((s): TeacherTodayScheduleItem => ({
      id: s.id,
      classId: s.classId,
      className: classNameById.get(s.classId) ?? "Class",
      course: s.course,
      startTime: s.startTime,
      endTime: s.endTime,
      location: s.location ?? null,
    }))

  const submittedSubmissions = data.submissions.filter((s) => Boolean(s.submittedAt))
  const toGradeCount = submittedSubmissions.filter((s) => s.status === "submitted").length
  
  // Filter for submissions that actually need grading (status === "submitted")
  // If we have less than 5 to grade, maybe also show some recently graded ones?
  // For now, let's stick to "Needs Grading" as it's more useful.
  const submissionsToGrade = submittedSubmissions
    .filter(s => s.status === "submitted")
    .sort((a, b) => new Date(a.submittedAt!).getTime() - new Date(b.submittedAt!).getTime()) // Oldest first? Or Newest? Usually oldest first for queue.
    .slice(0, 6);

  // Calculate stats for the dashboard
  const activeAssignmentsCount = data.assignments.filter(a => a.status === "published").length
  
  const totalTrendScore = data.gradeTrends.reduce((acc, curr) => acc + curr.averageScore, 0)
  const averageScore = data.gradeTrends.length > 0 ? totalTrendScore / data.gradeTrends.length : 0

  const totalSubmissions = data.gradeTrends.reduce((acc, curr) => acc + curr.submissionCount, 0)
  const totalPotentialSubmissions = data.gradeTrends.reduce((acc, curr) => acc + curr.totalStudents, 0)
  const submissionRate = totalPotentialSubmissions > 0 ? (totalSubmissions / totalPotentialSubmissions) * 100 : 0

  return (
    <div className="flex h-full flex-col space-y-6 p-8">
      <TeacherDashboardHeader teacherName={data.teacherName} />

      <TeacherStats
        toGradeCount={toGradeCount}
        activeAssignmentsCount={activeAssignmentsCount}
        averageScore={averageScore}
        submissionRate={submissionRate}
      />

      <div className="grid gap-6 lg:grid-cols-12">
        <div className="flex flex-col gap-6 lg:col-span-8">
            <TeacherGradeTrends trends={data.gradeTrends} />
            <RecentSubmissions 
                submissions={submissionsToGrade} 
                title="Needs Grading"
                emptyTitle="All caught up!"
                emptyDescription="You have no pending submissions to grade."
            />
        </div>
        
        <div className="flex flex-col gap-6 lg:col-span-4">
            <TeacherSchedule items={todayScheduleItems} />
            <TeacherHomeworkCard assignments={data.assignments} />
            <TeacherClassesCard classes={data.classes} />
        </div>
      </div>
    </div>
  )
}