// GatewayClient — the typed facade the screens call. Both the real Connect/
// FlatBuffers transport and the in-memory mock implement it. Domain failures (the
// gateway's result_code) and edge failures (Connect error codes) are normalised
// into a thrown GatewayError carrying a stable `code` the UI maps to an i18n
// message.

import type {
  AccountRef,
  BlockList,
  BlockStatus,
  ChatMessage,
  EvalResult,
  FeedbackState,
  FriendCode,
  GameList,
  GameView,
  ExportUrl,
  GcgExport,
  History,
  HintResult,
  Invitation,
  InvitationSettings,
  ConfirmLinkResult,
  LinkResult,
  MatchResult,
  MoveResult,
  OutgoingList,
  Profile,
  ProfileUpdate,
  PushEvent,
  Session,
  StateView,
  Stats,
  Tile,
  Variant,
  WordCheckResult,
  Wallet,
  WalletOrder,
  Catalog,
} from './model';

/** GatewayError carries a stable code (the gateway result_code, or an edge code). */
export class GatewayError extends Error {
  readonly code: string;
  constructor(code: string, message?: string) {
    super(message ?? code);
    this.name = 'GatewayError';
    this.code = code;
  }
}

/** A tile the player is submitting (rack/blank already resolved to a letter). */
export interface PlacedTile {
  row: number;
  col: number;
  letter: string;
  blank: boolean;
}

/** Unsubscribe handle for the live stream. */
export type Unsubscribe = () => void;

export interface GatewayClient {
  // --- auth (unauthenticated) ---
  authTelegram(initData: string): Promise<Session>;
  /** Authenticate a VK Mini App launch: params is the signed vk_* launch query string (the gateway
   *  verifies its sign); displayName is the client-read VKWebAppGetUserInfo name (an unsigned,
   *  cosmetic seed for a brand-new account). */
  authVK(params: string, displayName: string): Promise<Session>;
  authGuest(locale?: string): Promise<Session>;
  /** Mint a server guest for a native local guest gaining the network (background reconciliation).
   *  Unlike foreground auth it bypasses the offline kill switch and never raises the terminal update
   *  overlay — a too-old client stays a local guest instead (the gate×offline rule, docs/ARCHITECTURE.md §2). */
  authGuestSilent(locale?: string): Promise<Session>;
  authEmailRequest(email: string, language: string, pwa: boolean): Promise<void>;
  authEmailLogin(email: string, code: string): Promise<Session>;
  /** Confirm a one-tap email deeplink token: a login returns a session to adopt; a
   *  link returns a status ('confirmed' | 'merge_required'). */
  confirmEmailLink(token: string): Promise<ConfirmLinkResult>;

  // --- profile / lists ---
  profileGet(): Promise<Profile>;
  /** The caller's current manual block. Exempt from the backend's suspension gate, so a blocked
   *  client can still fetch it to render the blocked screen. */
  blockStatus(): Promise<BlockStatus>;
  gamesList(): Promise<GameList>;

  // --- lobby ---
  /** Start a quick game: human auto-match, or an honest-AI game against a robot when vsAi. */
  lobbyEnqueue(variant: Variant, multipleWords: boolean, vsAi: boolean): Promise<MatchResult>;
  lobbyPoll(): Promise<MatchResult>;
  /** Leave the auto-match pool (idempotent); a cancelled quick-match must not stay queued. */
  lobbyCancel(): Promise<void>;

  // --- game ---
  // The play loop exchanges alphabet indices, so submit/evaluate/exchange/
  // check-word take the game's variant (to map letters<->indices via the cached alphabet
  // table), and gameState's includeAlphabet asks the server to embed that table.
  gameState(gameId: string, includeAlphabet: boolean): Promise<StateView>;
  gameHistory(gameId: string): Promise<History>;
  submitPlay(gameId: string, tiles: PlacedTile[], variant: Variant): Promise<MoveResult>;
  pass(gameId: string): Promise<MoveResult>;
  exchange(gameId: string, tiles: string[], variant: Variant): Promise<MoveResult>;
  resign(gameId: string): Promise<MoveResult>;
  hint(gameId: string): Promise<HintResult>;
  evaluate(gameId: string, tiles: PlacedTile[], variant: Variant, signal?: AbortSignal): Promise<EvalResult>;
  checkWord(gameId: string, word: string, variant: Variant): Promise<WordCheckResult>;
  complaint(gameId: string, word: string, note: string): Promise<void>;
  /** Hide a finished game from the caller's own lobby list; per-account, irreversible. */
  hideGame(gameId: string): Promise<void>;

  // --- dictionary (local move preview) ---
  /** Fetch the raw serialized dictionary blob for a (variant, version) pair. Session-gated;
   *  lets the client validate and score a move locally instead of a network round trip.
   *  opts.signal aborts a stalled download; opts.reload bypasses the browser HTTP cache (the
   *  debug reset, for testing a cold load). */
  fetchDict(variant: Variant, version: string, opts?: { signal?: AbortSignal; reload?: boolean }): Promise<ArrayBuffer>;
  /** Post the client's local move-preview adoption telemetry — a small batch of counter deltas,
   *  session-gated and fire-and-forget (never on the gameplay path). */
  reportLocalEval(counts: Record<string, number>): Promise<void>;

  // --- draft ---
  /** The player's server-persisted client-side composition (rack order + board tiles), so a
   *  reload or a second device resumes the same arrangement. The JSON is opaque to the
   *  gateway; the client owns the {rack_order, board_tiles} shape. */
  draftGet(gameId: string): Promise<string>;
  draftSave(gameId: string, json: string): Promise<void>;

  // --- chat ---
  chatPost(gameId: string, body: string): Promise<ChatMessage>;
  chatList(gameId: string): Promise<ChatMessage[]>;
  nudge(gameId: string): Promise<ChatMessage>;
  /** Acknowledge the caller has read the game's chat (sent when they open the move history
   *  or chat), so the backend clears their unread bits and records the read latency. */
  markChatRead(gameId: string): Promise<void>;

  // --- feedback ---
  /** feedbackSubmit sends a feedback message with an optional single attachment. */
  feedbackSubmit(body: string, attachment: Uint8Array | null, attachmentName: string, channel: string): Promise<void>;
  /** feedbackGet returns the feedback screen state and marks any pending reply delivered. */
  feedbackGet(): Promise<FeedbackState>;
  /** feedbackUnread reports whether an operator reply awaits delivery (the badge). */
  feedbackUnread(): Promise<boolean>;

  // --- wallet ---
  /** wallet returns the caller's chip segments and active benefits, visible in their current
   *  trusted execution context (view-only when the platform is untrusted or VK-iOS frozen). */
  wallet(): Promise<Wallet>;
  /** catalog returns the storefront for the caller's context: chip-priced values and the chip
   *  packs priced in the context's payment method. */
  catalog(): Promise<Catalog>;
  /** walletBuy spends chips on a chip-priced value and returns the updated wallet. Gate-checked
   *  server-side: an untrusted/frozen context or an insufficient balance is refused. */
  walletBuy(productId: string): Promise<Wallet>;
  /** walletOrder opens a money order to fund a chip pack and returns the provider launch URL the
   *  client opens; chips are credited later, by the verified server callback. Direct rail only. */
  walletOrder(productId: string): Promise<WalletOrder>;
  /** walletReward credits a watched rewarded video (VK ads) and returns the updated wallet. nonce is
   *  the per-view idempotency key. Client-attested + a server daily/hourly cap; a reached cap rejects
   *  with a domain code. */
  walletReward(nonce: string): Promise<Wallet>;

  // --- friends ---
  friendsList(): Promise<AccountRef[]>;
  friendsIncoming(): Promise<AccountRef[]>;
  /** Addressees the caller has already requested (pending or declined; cannot re-request),
   *  plus the per-game disguised-robot requests that keep the in-game 🤝 disabled by seat. */
  friendsOutgoing(): Promise<OutgoingList>;
  /** Send a friend request. A non-empty gameId marks an in-game request, so a disguised-robot
   *  opponent is recorded as a per-game request rather than against the shared robot account. */
  friendRequest(accountId: string, gameId?: string): Promise<void>;
  friendRespond(requesterId: string, accept: boolean): Promise<void>;
  friendCancel(accountId: string): Promise<void>;
  unfriend(accountId: string): Promise<void>;
  friendCodeIssue(): Promise<FriendCode>;
  friendCodeRedeem(code: string): Promise<AccountRef>;

  // --- blocks ---
  blocksList(): Promise<BlockList>;
  block(accountId: string, gameId?: string): Promise<void>;
  unblock(accountId: string): Promise<void>;

  // --- invitations ---
  invitationsList(): Promise<Invitation[]>;
  invitationCreate(inviteeIds: string[], settings: InvitationSettings): Promise<Invitation>;
  invitationAccept(invitationId: string): Promise<Invitation>;
  invitationDecline(invitationId: string): Promise<Invitation>;
  invitationCancel(invitationId: string): Promise<void>;

  // --- profile / stats / history ---
  profileUpdate(p: ProfileUpdate): Promise<Profile>;
  statsGet(): Promise<Stats>;
  exportGcg(gameId: string): Promise<GcgExport>;
  /** Mints a signed download URL for a finished game's artifact. dateLocale and the
   *  localized non-play labels (pass/exchange/resign/timeout, in that order) ride the
   *  URL so the server-rendered image matches the player's presentation. */
  exportUrl(gameId: string, kind: 'png' | 'gcg', dateLocale: string, actionLabels: string[], timeZone: string): Promise<ExportUrl>;

  // --- account linking & merge ---
  linkEmailRequest(email: string): Promise<void>;
  linkEmailConfirm(email: string, code: string): Promise<LinkResult>;
  linkEmailMerge(email: string, code: string): Promise<LinkResult>;
  linkTelegram(data: string): Promise<LinkResult>;
  linkTelegramMerge(data: string): Promise<LinkResult>;
  /** Link a VK identity from the web: the args are the PKCE outputs of the VK ID
   *  authorization callback, exchanged for the trusted vk id on the gateway. */
  linkVK(code: string, deviceId: string, codeVerifier: string): Promise<LinkResult>;
  linkVKMerge(code: string, deviceId: string, codeVerifier: string): Promise<LinkResult>;
  /** Detach a platform identity (kind 'telegram' | 'vk') from the account; email is never
   *  unlinked. Returns the refreshed link result (status 'unlinked'). */
  linkUnlink(kind: string): Promise<LinkResult>;
  /** Change the account's confirmed email: mail a code to the new address, then confirm
   *  to atomically switch (status 'changed'). A new address owned by another account is
   *  refused without disclosure. */
  changeEmailRequest(email: string): Promise<void>;
  changeEmailConfirm(email: string, code: string): Promise<LinkResult>;
  /** Start account deletion; the backend mails a code (method 'email') or asks for the
   *  typed phrase (method 'phrase'). */
  deleteRequest(): Promise<{ method: 'email' | 'phrase' }>;
  /** Confirm and perform account deletion with the mailed code or the typed phrase. */
  deleteConfirm(code: string, phrase: string): Promise<void>;

  // --- live stream ---
  subscribe(onEvent: (e: PushEvent) => void, onError?: (err: unknown) => void): Unsubscribe;

  /** Set or clear the bearer token used for authenticated calls and the stream. */
  setToken(token: string | null): void;
}

export type { GameView, Tile };
