import type {
  NotificationItem,
  NotificationTimeGroup,
  NotificationVariant,
} from "@/lib/mock/notifications"
import { workspaceRole } from "@/lib/workspace-role"
import { STATUS_BADGE_TONE_CLASS, type StatusBadgeTone } from "@/lib/list-status-badges"

export type NotificationFilter = "all" | "unread"

const TIME_GROUP_LABEL: Record<NotificationTimeGroup, string> = {
  today: "Today",
  yesterday: "Yesterday",
  earlier: "Earlier",
}

const TIME_GROUP_ORDER: NotificationTimeGroup[] = ["today", "yesterday", "earlier"]

/** Role filter — mirrors `visibleWhatsNew` audience rules. */
export function visibleNotifications(
  items: readonly NotificationItem[],
): NotificationItem[] {
  const student = workspaceRole() === "student"
  return items.filter(item => {
    if (!item.audience) return true
    return item.audience === (student ? "student" : "staff")
  })
}

export function applyNotificationReadState(
  items: readonly NotificationItem[],
  readIds: readonly string[],
): NotificationItem[] {
  const readSet = new Set(readIds)
  return items.map(item => ({
    ...item,
    read: readSet.has(item.id) ? true : item.read,
  }))
}

export function filterNotifications(
  items: readonly NotificationItem[],
  filter: NotificationFilter,
): NotificationItem[] {
  if (filter === "unread") return items.filter(item => !item.read)
  return [...items]
}

export function groupNotificationsByTime(
  items: readonly NotificationItem[],
): { label: string; items: NotificationItem[] }[] {
  return TIME_GROUP_ORDER.flatMap(group => {
    const grouped = items.filter(item => item.timeGroup === group)
    if (grouped.length === 0) return []
    return [{ label: TIME_GROUP_LABEL[group], items: grouped }]
  })
}

export function notificationVariantTone(variant: NotificationVariant): StatusBadgeTone {
  if (variant === "success") return "success"
  if (variant === "warning") return "warning"
  return "info"
}

export function notificationVariantTint(variant: NotificationVariant): string {
  return STATUS_BADGE_TONE_CLASS[notificationVariantTone(variant)]
}