// Attendance & class sessions

enum AttendanceStatus {
  PRESENT
  ABSENT
  EXCUSED
}

model ClassSession {
  id        String   @id @default(cuid())
  groupId   String
  startsAt  DateTime
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  group        Group         @relation(fields: [groupId], references: [id], onDelete: Cascade)
  attendances  Attendance[]
  slotReleases SlotRelease[]

  @@unique([groupId, startsAt])
  @@map("class_sessions")
}

model Attendance {
  id             String           @id @default(cuid())
  attendeeId     String
  classSessionId String
  status         AttendanceStatus
  markedAt       DateTime         @default(now())

  attendee     Attendee     @relation(fields: [attendeeId], references: [id], onDelete: Cascade)
  classSession ClassSession @relation(fields: [classSessionId], references: [id], onDelete: Cascade)

  @@unique([attendeeId, classSessionId])
  @@map("attendances")
}

model SlotRelease {
  id             String   @id @default(cuid())
  attendeeId     String
  classSessionId String
  isClaimed      Boolean  @default(false)
  createdAt      DateTime @default(now())

  attendee     Attendee     @relation(fields: [attendeeId], references: [id], onDelete: Cascade)
  classSession ClassSession @relation(fields: [classSessionId], references: [id], onDelete: Cascade)

  @@unique([attendeeId, classSessionId])
  @@map("slot_releases")
}