export interface Source {
  service: string;
  mode: 'public' | 'authenticated';
  viewerDid?: string;
}

export interface Author {
  did: string;
  handle: string;
  displayName: string;
  avatar?: string;
  pronouns?: string;
  following?: boolean;
  followedBy?: boolean;
}

export interface FeedReason {
  kind: 'repost' | 'pin' | 'unknown';
  by?: Author;
  indexedAt?: string;
  type?: string;
}

export interface FeedOccurrence {
  id: string;
  postUri: string;
  reason?: FeedReason;
  parentUri?: string;
  rootUri?: string;
}

export interface FeedOptions {
  limit?: number;
  cursor?: string;
}

export interface FeedEncounter {
  feedViewId: string;
  occurrenceId: string;
  postUri: string;
  reason?: FeedReason;
}

export type TargetKind = 'post' | 'profile' | 'link' | 'tag' | 'media' | 'occurrence' | 'author-feed';
export interface Target {
  kind: TargetKind;
  value: string;
  label: string;
  ownerUri?: string;
  index?: number;
}

export interface Facet {
  byteStart: number;
  byteEnd: number;
  text: string;
  targets: Target[];
  unsupported: string[];
}

export interface Media {
  kind: 'image' | 'video';
  url?: string;
  thumbnail?: string;
  alt?: string;
  width?: number;
  height?: number;
}

export interface LinkCard {
  uri: string;
  title: string;
  description: string;
  thumbnail?: string;
}

export interface PostNode {
  uri: string;
  cid?: string;
  availability: 'available' | 'not-found' | 'blocked' | 'unsupported';
  author?: Author;
  text?: string;
  createdAt?: string;
  indexedAt?: string;
  parentUri?: string;
  rootUri?: string;
  replies: string[];
  repliesFetched: boolean;
  facets: Facet[];
  media: Media[];
  quotes: string[];
  cards: LinkCard[];
  labels: string[];
  unsupported: string[];
  counts: { replies?: number; likes?: number; reposts?: number; quotes?: number };
}

export interface FeedSnapshot {
  kind: 'feed';
  feed: 'following' | 'author';
  fetchedAt: string;
  source: Source;
  actor?: Author;
  entries: FeedOccurrence[];
  nodes: PostNode[];
  limit: number;
  cursor?: string;
  requestCursor?: string;
  maxNodes: number;
  locallyTruncated: boolean;
  warnings: string[];
}

export interface ThreadSnapshot {
  kind: 'thread';
  requested: string;
  focusUri: string;
  fetchedAt: string;
  source: Source;
  nodes: PostNode[];
  /** Oldest available ancestor first; excludes focus. */
  ancestors: string[];
  replyOrder: 'source';
  limits: { depth: number; parentHeight: number; maxNodes: number };
  /** Local node omission is distinct from unknown remote coverage. */
  locallyTruncated: boolean;
  warnings: string[];
  encounter?: FeedEncounter;
}

export interface ProfileLabel {
  value: string;
  issuerDid: string;
  uri: string;
  cid?: string;
  negated?: boolean;
  createdAt?: string;
  expiresAt?: string;
  signature?: string;
}

export interface ProfileEnrichment {
  id: string;
  title: string;
  status: 'available' | 'absent' | 'unavailable' | 'unsupported';
  items: Array<{ label: string; value: string; uri?: string }>;
  source: {
    service: string;
    actorDid: string;
    fetchedAt: string;
    uri?: string;
    cid?: string;
  };
  note?: string;
}

export interface ProfileSnapshot {
  kind: 'profile';
  requested: string;
  fetchedAt: string;
  source: Source;
  author: Author;
  description?: string;
  banner?: string;
  website?: string;
  createdAt?: string;
  indexedAt?: string;
  associated?: Record<string, unknown>;
  verification?: Record<string, unknown>;
  pinnedPost?: { uri: string; cid: string };
  counts: { followers?: number; follows?: number; posts?: number };
  labels: Array<string | ProfileLabel>;
  warnings?: string[];
  enrichments?: ProfileEnrichment[];
}

export interface TargetSnapshot {
  kind: 'target';
  fetchedAt: string;
  source: Source;
  target: Target;
  /** Link/tag/media inspection is not an external article fetch. */
  note: string;
}

export type Snapshot = ThreadSnapshot | ProfileSnapshot | TargetSnapshot | FeedSnapshot;
export interface ReadingView {
  /** Monotonically allocated by the local store, never reused. */
  id: string;
  snapshot: Snapshot;
  refs: Record<string, Target>;
}

export interface SessionInfo {
  name: string;
  viewId: string | null;
  history: string[];
}

export interface ThreadOptions {
  depth?: number;
  parentHeight?: number;
  maxNodes?: number;
}

export interface ReaderOptions {
  service?: string;
  /** Explicit opt-in to existing OMP atproto env, never persisted. */
  authConfig?: string;
  pds?: string;
}

export interface Reader {
  readonly source: Source;
  thread(input: string, options?: ThreadOptions): Promise<ThreadSnapshot>;
  profile(actor: string): Promise<ProfileSnapshot>;
  following(options?: FeedOptions): Promise<FeedSnapshot>;
  authorFeed(actor: string, options?: FeedOptions): Promise<FeedSnapshot>;
}

export interface RenderFiles {
  html: string;
  text: string;
  json: string;
  images: string[];
}

export function targetKey(target: Target): string {
  return JSON.stringify([target.kind, target.value, target.ownerUri ?? null, target.index ?? null]);
}

export function refFor(view: ReadingView, kind: TargetKind, value: string): string | undefined {
  return Object.entries(view.refs).find(([, target]) => target.kind === kind && target.value === value)?.[0];
}