"use server"

import { requirePermission } from "@/shared/lib/auth-guard"
import { Permissions } from "@/shared/types/permissions"
import type { ActionState } from "@/shared/types/action-state"
import { handleActionError } from "@/shared/lib/action-utils"
import { getClassSchedule, getStudentClasses, getStudentSchedule, getTeacherClasses, getTeacherIdForMutations } from "@/modules/classes/data-access"
import {
  getHomeworkAssignments,
  getHomeworkSubmissions,
} from "@/modules/homework/data-access"
import { getStudentHomeworkAssignments } from "@/modules/homework/data-access-student"
import { getStudentDashboardGrades, getTeacherGradeTrends } from "@/modules/homework/stats-service"
import { getCurrentStudentUser, getUserBasicInfo } from "@/modules/users/data-access"
import { getParentDashboardData } from "@/modules/parent/data-access"

import { getAdminDashboardData } from "./data-access"
import type {
  AdminDashboardData,
  StudentDashboardProps,
  TeacherDashboardData,
} from "./types"
import type { ParentDashboardData } from "@/modules/parent/types"
import {
  computeTeacherMetrics,
  countStudentAssignments,
  sortUpcomingAssignments,
  toWeekday,
  filterTodaySchedule,
  type TeacherDashboardMetrics,
} from "./lib/dashboard-utils"

/**
 * 获取管理员仪表盘数据。
 * 权限：DASHBOARD_ADMIN_READ
 */
export async function getAdminDashboardAction(): Promise<ActionState<AdminDashboardData>> {
  try {
    const ctx = await requirePermission(Permissions.DASHBOARD_ADMIN_READ)
    const data = await getAdminDashboardData(ctx.dataScope)
    return { success: true, data }
  } catch (e) {
    return handleActionError(e)
  }
}

/**
 * 获取教师仪表盘数据（含派生指标）。
 * 权限：DASHBOARD_TEACHER_READ
 */
export async function getTeacherDashboardAction(): Promise<ActionState<TeacherDashboardData & {
  metrics: TeacherDashboardMetrics
}>> {
  try {
    await requirePermission(Permissions.DASHBOARD_TEACHER_READ)
    const teacherId = await getTeacherIdForMutations()

    const [classes, schedule, assignments, submissions, teacherProfile, gradeTrends] = await Promise.all([
      getTeacherClasses({ teacherId }),
      getClassSchedule({ teacherId }),
      getHomeworkAssignments({ creatorId: teacherId }),
      getHomeworkSubmissions({ creatorId: teacherId }),
      getUserBasicInfo(teacherId),
      getTeacherGradeTrends(teacherId),
    ])

    const metrics = computeTeacherMetrics(
      classes,
      schedule,
      assignments,
      submissions,
      gradeTrends,
      new Date(),
    )

    return {
      success: true,
      data: {
        classes,
        schedule,
        assignments,
        submissions,
        teacherName: teacherProfile?.name ?? "",
        gradeTrends,
        metrics,
      },
    }
  } catch (e) {
    return handleActionError(e)
  }
}

/**
 * 获取学生仪表盘数据（含派生指标）。
 * 权限：DASHBOARD_STUDENT_READ
 */
export async function getStudentDashboardAction(): Promise<ActionState<{
  student: { id: string; name: string } | null
  dashboardProps: Omit<StudentDashboardProps, "studentName"> | null
}>> {
  try {
    await requirePermission(Permissions.DASHBOARD_STUDENT_READ)
    const student = await getCurrentStudentUser()
    if (!student) {
      return { success: true, data: { student: null, dashboardProps: null } }
    }

    const [classes, schedule, assignments, grades] = await Promise.all([
      getStudentClasses(student.id),
      getStudentSchedule(student.id),
      getStudentHomeworkAssignments(student.id),
      getStudentDashboardGrades(student.id),
    ])

    const now = new Date()
    const stats = countStudentAssignments(assignments, now)
    const todayWeekday = toWeekday(now)
    const todayScheduleItems = filterTodaySchedule(schedule, todayWeekday)
    const upcomingAssignments = sortUpcomingAssignments(assignments, 6)

    return {
      success: true,
      data: {
        student: { id: student.id, name: student.name },
        dashboardProps: {
          enrolledClassCount: classes.length,
          dueSoonCount: stats.dueSoonCount,
          overdueCount: stats.overdueCount,
          gradedCount: stats.gradedCount,
          todayScheduleItems,
          upcomingAssignments,
          grades,
        },
      },
    }
  } catch (e) {
    return handleActionError(e)
  }
}

/**
 * 获取家长仪表盘数据。
 * 权限：DASHBOARD_PARENT_READ
 */
export async function getParentDashboardAction(): Promise<ActionState<{
  data: ParentDashboardData | null
  hasChildren: boolean
}>> {
  try {
    const ctx = await requirePermission(Permissions.DASHBOARD_PARENT_READ)

    // 非 admin 且 dataScope 非 children 类型时，无孩子数据
    if (
      ctx.dataScope.type !== "all" &&
      !(ctx.dataScope.type === "children" && ctx.dataScope.childrenIds.length > 0)
    ) {
      return { success: true, data: { data: null, hasChildren: false } }
    }

    const data = await getParentDashboardData(ctx.userId)
    return { success: true, data: { data, hasChildren: data.children.length > 0 } }
  } catch (e) {
    return handleActionError(e)
  }
}