import type { TrackDTO, UserSummaryDTO } from './dto';

export const NOTIFICATION_TYPES = ['reaction', 'follow', 'share'] as const;
export type NotificationType = (typeof NOTIFICATION_TYPES)[number];

/** Which notifications get pushed to your phone/browser. */
export type NotificationPrefs = Record<NotificationType, boolean>;

export const NOTIFICATION_PREF_LABELS: Record<NotificationType, string> = {
  reaction: 'Reactions to your songs',
  follow: 'New followers',
  share: 'Songs sent to you',
};

/** Missing settings mean on. */
export const notificationPrefs = (stored: Partial<NotificationPrefs> | null | undefined): NotificationPrefs => ({
  reaction: stored?.reaction ?? true,
  follow: stored?.follow ?? true,
  share: stored?.share ?? true,
});

export interface NotificationDTO {
  id: string;
  type: NotificationType;
  actor: UserSummaryDTO;
  track: TrackDTO | null;
  emoji: string | null;
  message: string | null;
  read: boolean;
  createdAt: string;
}

export interface NotificationListDTO {
  notifications: NotificationDTO[];
  unread: number;
  /** Pass back as ?cursor= for older ones; null at the end. */
  nextCursor: string | null;
}

/** What a push or a row in the list says. */
export function notificationText(n: Pick<NotificationDTO, 'type' | 'actor' | 'track' | 'emoji' | 'message'>): {
  title: string;
  body: string;
} {
  const who = n.actor.displayName ?? n.actor.username;
  const song = n.track ? `${n.track.title} by ${n.track.artist}` : 'a song';
  switch (n.type) {
    case 'reaction':
      return { title: `${who} reacted ${n.emoji ?? ''}`.trim(), body: `to ${song}` };
    case 'follow':
      return { title: `${who} followed you`, body: 'Follow back to see what they play.' };
    case 'share':
      return { title: `${who} sent you a song`, body: n.message ? `${song}: “${n.message}”` : song };
  }
}

/** Where tapping it goes, as an app/web path. */
export function notificationPath(n: Pick<NotificationDTO, 'type' | 'actor' | 'track'>): string {
  if ((n.type === 'share' || n.type === 'reaction') && n.track) return `/t/${n.track.id}`;
  return `/u/${n.actor.username}`;
}