/**
 * The injection store — where the consumer application plugs the real SDK in, and
 * where the emulation keeps the state that only exists because one wallet hosts every
 * identity: the injected `ng`/`useShape`, the registry dependencies, WHO is currently
 * connected, and the `CapRegistry` singleton keyed by that holder.
 *
 * **NO COUNTERPART at any layer, by construction.** Upstream nothing is injected: the
 * app imports the SDK, and "who am I" is the session — there is no current-user relay
 * because a wallet has exactly one user. This module is the shape of that absence, so
 * it belongs with the shared-wallet machinery and evaporates whole at migration.
 *
 * Extracted from `polyfill.ts` on 2026-08-03. Before that, every internal module
 * imported the published ENTRY to reach the config, which made the entry a dependency
 * of the code it publishes — cycles `polyfill` <-> `connect` and `polyfill` <-> `inbox`.
 * The entry now only re-exports; the internals import this module instead.
 */

import type { NgLike, UseShapeLike, Nuri, NuriLike, PrincipalId, ReadCap } from "../model/types";
import type { SharedWalletConfig } from "./access-gate";
import { toNuri } from "../model/nuri";
import type { RegistrySession } from "./account-registry";
import { CapRegistry } from "../emulated-verifier/caps";
import { resetPublicStoreFetches } from "../emulated-verifier/public-store";
import { setAccessLog } from "./access-log";
import { inspectOutbox } from "./outbox-log";
import { startConnect } from "../emulated-verifier/connect";
import { cancelScheduledInboxProcessing } from "../emulated-verifier/inbox-processor";
import { resetSharedWalletSession, sharedWalletSession } from "./session";

/**
 * How an identity id becomes the key a virtual user is filed under.
 *
 * The package's rule, not a consumer's choice (2026-08-12): `@Alice`, `alice ` and `ALICE`
 * are ONE person's space. It has to be one rule, because the identifier arrives from three
 * places — typed at the barrier, read back from the URL after the broker round-trip, read
 * from storage — and any of them keying differently silently opens a SECOND space whose
 * documents the first one cannot see.
 *
 * **NO COUNTERPART.** Upstream there is nothing to normalize: a wallet holds one user, and
 * `session_start` takes the id the wallet gives. This exists only because one wallet here
 * hosts everybody, and it disappears with them.
 */
export function normalizeIdentityId(id: string): string {
  return id.trim().replace(/^@/, "").toLowerCase();
}

/**
 * Dependencies of the storeRegistry (polyfill-era) — INTERNAL, and no longer an
 * application's business.
 *
 * The registry itself is generic (it knows only native scopes); these two say how to reach
 * the shared-wallet session and how to key an identity in the shim. An application used to
 * supply both through {@link EventuallyConfig}; the package owns them now (2026-08-12), and
 * this interface is the substitution path its OWN suites use — the unit fakes need a
 * synchronous session, and the e2e harness holds one the broker gave it directly.
 *
 * Internal is carried by the module, not by a comment: nothing here is re-exported from
 * `src/index.ts`, so the published entry cannot reach it. Removed at migration with the
 * whole shim.
 */
export interface StoreRegistryDeps {
  /** Resolve the current shared-wallet session (id + private-store anchor). */
  getSession: () => Promise<RegistrySession>;
  /** Normalize an identity id for shim keying. Default: {@link normalizeIdentityId}. */
  normalizeId?: (id: string) => string;
  /**
   * POINTER micro-guard budget. The account records now live in a subscribable
   * doc-shim (`did:ng:o:...`) reached through a well-known write-once POINTER triple
   * in the store-root graph. The doc-shim read is barrier-AUTHORITATIVE, so accounts
   * need NO retry (this replaces the deleted account-level `provisionRetry`). The
   * ONLY residual sync-lag window is the store-root pointer read itself — one
   * write-once triple. This bounded guard re-reads JUST that pointer a few times if a
   * fresh cold read misses it; it can never provision or fork an account (worst case:
   * a couple extra reads before an existing pointer is seen). Enable it where the REAL
   * broker is used (app + e2e). Left UNSET (the default) → `attempts: 1` = single
   * read, keeping the synchronous unit fakes fast and unchanged.
   */
  pointerGuard?: { attempts?: number; baseMs?: number; maxStepMs?: number };
}

/**
 * Everything the polyfill needs, in ONE call.
 *
 * It used to take two — `configure` for the SDK injection, `configureStoreRegistry` for
 * the session — because the two belonged to different internals. That is a reason the
 * library has, not one an application should pay for: from a caller's side both are
 * "here is what you need to run", and two bootstrap calls is one more thing to delete
 * at migration than there needs to be. Merged 2026-08-07; the registry's own wiring
 * function stays internal.
 *
 * ── Two fields left on 2026-08-12, and what left with them ────────────────
 * `getSession` and `normalizeId` were published, and both made an application build
 * something the target never asks it for:
 *
 *   - `getSession` — upstream a session is RETURNED (`init()`'s callback delivers it,
 *     `session_start` hands one back). An application that has to ASSEMBLE one out of
 *     `session_id` / `private_store_id` / … is coding against a shape with no successor.
 *     The package captures the event instead ({@link ../surface/lifecycle}.init) and holds
 *     the session ({@link ./session}).
 *   - `normalizeId` — the identities it normalizes are this package's own invention (one
 *     wallet, many virtual users). There is nothing upstream to normalize, so there was
 *     nothing for a consumer to decide; see {@link normalizeIdentityId}.
 *
 * Every consumer wrote the same plumbing for both, and the reference integration's copy
 * carried two defects at once. Both remain substitutable through {@link StoreRegistryDeps},
 * which the published entry cannot reach.
 */
export interface EventuallyConfig {
  /** The REAL `@ng-org/web` `ng` (injected to avoid a hard import / alias loop). */
  ng: NgLike;
  /** The REAL `@ng-org/orm` `useShape`. */
  useShape: UseShapeLike;
  /**
   * POINTER micro-guard budget — see {@link StoreRegistryDeps.pointerGuard}. Left unset
   * → a single read, which keeps the synchronous unit fakes fast.
   */
  pointerGuard?: { attempts?: number; baseMs?: number; maxStepMs?: number };
  /**
   * The shared wallet this deployment hands out, and what the access gate needs to do
   * it (`shared-wallet/access-gate.ts`). Absent → no gate; the caller sets the identity
   * itself. Disappears with the gate: upstream a user opens their own wallet.
   */
  sharedWallet?: SharedWalletConfig;
  /**
   * Turn on the OFF-by-default document access log (see {@link ./access-log}):
   * every real read/write is printed, prefixed by the active identity, to
   * diagnose the shared-wallet isolation leak. Also enablable without a code
   * change via the env var `NG_EVENTUALLY_ACCESS_LOG=1`. Default: false.
   */
  debugAccessLog?: boolean;
  /** REAL `@ng-org/web` `init` (lifecycle) — forwarded by the lib's `init()`. */
  init?: (...args: any[]) => any;
  /** REAL `@ng-org/orm` `initNg` (ORM signals) — forwarded by the lib's `initNg()`. */
  initNg?: (...args: any[]) => any;
}

let cfg: EventuallyConfig | null = null;
let currentUser: PrincipalId | null = null;
/**
 * What hands the page to the broker — the polyfill's `init()` reduced to a thunk, kept so a
 * page that comes BACK from the hand-over can run it AGAIN ({@link ./access-gate}).
 *
 * It lives here rather than in either module that uses it because it is made of the injected
 * `init` and the caller's arguments, and this is where the injection is: `init()` registers
 * it (`../surface/lifecycle.ts`), the barrier runs it when someone confirms a second time.
 * Kept for the life of the page — the return it exists for happens long after the call.
 */
let handOver: (() => void) | null = null;
/** Required fields of StoreRegistryDeps after defaults are applied. `pointerGuard`
 *  defaults to `{ attempts: 1 }` (single read) when the consumer leaves it unset. */
type ResolvedRegistryDeps = Required<
  Pick<StoreRegistryDeps, "getSession" | "normalizeId" | "pointerGuard">
>;
let registryDeps: ResolvedRegistryDeps | null = null;
/**
 * Does the registry reach the session through the package's OWN holder?
 *
 * {@link configure} points it there, and that is what every application gets. The library's
 * suites and the e2e harness substitute a route of their own
 * ({@link configureStoreRegistry}) and hold a session no `init()` of this package opened —
 * so "`init()` was never called, therefore no session can ever arrive" is a true statement
 * about the package's holder and about nothing else. Recorded at the wiring rather than
 * asked afterwards: the wiring WRAPS the injected thunk, so it can no longer be recognised.
 */
let ownSessionRoute = false;
/**
 * The map key of the current identity — deliberately NOT the raw id.
 *
 * A virtual user IS a shim account, and the shim keys accounts by the
 * consumer-injected `normalizeId` ("@Alice" and "alice" are ONE account, with one
 * set of scope documents). This record must key the same way, or a consumer that
 * spells its own id differently between two calls gets a SECOND record and stops
 * reading its own documents — the caps are filed under one spelling and looked up
 * under the other. Falls back to the raw id while the registry deps are not yet
 * configured (nothing can be filed before that anyway).
 */
function capsHolder(): PrincipalId | null {
  if (currentUser === null) return null;
  return registryDeps ? registryDeps.normalizeId(currentUser) : currentUser;
}

/**
 * The emulated cap registry — one record PER identity (per virtual user),
 * resolved through {@link capsHolder} on every call. So switching identity
 * SWITCHES heldByHolder (nothing to reset, nothing wiped); see `caps.ts`. Empty until
 * the first cap is issued, and while it is empty the read filter passes through
 * (no regression).
 */
let caps = new CapRegistry(capsHolder);

export function configure(c: EventuallyConfig): void {
  cfg = c;
  // Not taken from the config: an application never supplies its own identity — upstream
  // it comes FROM the wallet a person opened. Accepting one here would also let a caller
  // skip the barrier on a top-level page, which is the one thing it exists to prevent.
  currentUser = null;
  setAccessLog(c.debugAccessLog ?? false);
  // Wire the registry onto what the PACKAGE owns. Unconditional since 2026-08-12: there is
  // no longer anything for a caller to supply here, so there is no longer a case where
  // configuring the library leaves the registry half-wired. A suite that needs its own
  // session or key rule calls `configureStoreRegistry` AFTER this, and overrides it.
  configureStoreRegistry({
    getSession: sharedWalletSession,
    ...(c.pointerGuard ? { pointerGuard: c.pointerGuard } : {}),
  });
}

/** @internal — used by the SDK-shaped wrappers to reach the injected real SDK. */
export function getConfig(): EventuallyConfig {
  if (!cfg) throw new Error("[ng-eventually] configure() must be called before use");
  return cfg;
}

/** Reset the injected config back to un-configured (mainly for tests, so a
 *  suite that calls configure() can restore the not-configured guard state).
 *  The captured session goes with it: it arrived through the config's `init`, so leaving
 *  it behind would hand the next `configure()` the previous one's session. */
export function resetConfig(): void {
  cfg = null;
  currentUser = null;
  // Any deferred inbox drain still waiting goes with it: it would fire into a library that
  // no longer has an `ng` to read or write with, and report a failure about a session that
  // no longer exists. See `emulated-verifier/inbox-processor.ts`.
  cancelScheduledInboxProcessing();
  // The hand-over goes with it, for the same reason: it is made of the config's injected
  // `init`, so leaving it behind would let a revived barrier delegate to the PREVIOUS
  // application's SDK.
  handOver = null;
  resetSharedWalletSession();
}

/**
 * Remember how this page is handed to the broker. Called by the polyfill's `init()` on its
 * way through, before it delegates.
 *
 * @internal Never published: an application does not perform the hand-over, it calls `init`.
 */
export function rememberHandOver(delegate: () => void): void {
  handOver = delegate;
}

/**
 * The registered hand-over, or `null` when `init()` has never been called — in which case
 * nothing ever navigated, so there is no return from a hand-over to serve.
 *
 * @internal
 */
export function getHandOver(): (() => void) | null {
  return handOver;
}

/**
 * Wire the storeRegistry's dependencies. INTERNAL since 2026-08-07: an application
 * passes these to {@link configure}, which calls this. Still exported for the library's
 * own suites, which wire the registry alone.
 */
export function configureStoreRegistry(deps: StoreRegistryDeps): void {
  // Fire the outbox inspection (Volet 3 of the low-level data-path trace) once,
  // on the FIRST successful `getSession()` resolution — the most reliable
  // "a session is established" signal available: every low-level reader/writer
  // (store-registry, open-repo, read-model, subscribe, inbox) reaches its
  // session through this SAME injected `getSession`, so wrapping it HERE catches
  // the first success from whichever caller happens to run first, instead of
  // tying the probe to one particular call site. Only on SUCCESS (an error
  // propagates untouched, exactly as before) and only ONCE per
  // `configureStoreRegistry()` call (a fresh session config → a fresh check).
  let outboxInspected = false;
  const getSession = async (): Promise<RegistrySession> => {
    const session = await deps.getSession();
    if (!outboxInspected) {
      outboxInspected = true;
      inspectOutbox();
    }
    return session;
  };
  ownSessionRoute = deps.getSession === sharedWalletSession;
  registryDeps = {
    getSession,
    normalizeId: deps.normalizeId ?? normalizeIdentityId,
    // Default: single read (no re-read). Only the real-broker consumers (app + e2e)
    // opt into the bounded pointer micro-guard; unit fakes stay synchronous.
    pointerGuard: deps.pointerGuard ?? { attempts: 1 },
  };
}

/** @internal — used by the storeRegistry to reach its injected dependencies. */
export function getStoreRegistryDeps(): ResolvedRegistryDeps {
  if (!registryDeps) {
    throw new Error("[ng-eventually] configureStoreRegistry() must be called before use");
  }
  return registryDeps;
}

/** @internal — see {@link ownSessionRoute}. */
export function sessionRouteIsThePackages(): boolean {
  return ownSessionRoute;
}

/** Reset storeRegistry deps (mainly for tests). */
export function resetStoreRegistry(): void {
  registryDeps = null;
  ownSessionRoute = false;
}

/**
 * Record who is acting — and touch nothing else. Answers whether it CHANGED, which is
 * what decides whether there is any connecting to do.
 *
 * Split out of {@link setCurrentUser} so that the two things it did — naming the identity
 * and reaching for the session on its behalf — can be asked for separately. Only the
 * session-FREE half of signing in uses this one ({@link ./access-gate}.settleIdentity),
 * and that is the whole of why it exists: see the warning on {@link setCurrentUser}.
 *
 * @internal Never published. A consumer names its identity through the access gate.
 */
export function adoptCurrentUser(id: PrincipalId | null): boolean {
  const changed = currentUser !== id;
  currentUser = id;
  return changed;
}

/**
 * Set the current identity id — who the SDK is reading/writing as — **and connect it**.
 * In the target this is the wallet user established at wallet-import time; here the
 * consumer relays that id through this call so the read filter and the inbox `from` know
 * who is acting. Passing `null` clears it (no identity yet, e.g. during startup).
 *
 * ── This call REACHES THE SESSION, and a caller must know it ──────────────
 * "Fire-and-forget" says nothing about whether the session is touched — only about who
 * waits. The fired work asks `resolveAccount` on its first line, which awaits the
 * consumer's `getSession` thunk (`connect.ts` → `account-registry.ts:280`). So this
 * setter is unusable at any moment the session cannot yet answer, and calling it there is
 * not merely wasteful — it **poisons** the work: the thunk throws, `resolveAccount`
 * returns null, the run abandons before restoring anything, and it is that abandoned run
 * that the next `connectedUser()` JOINS instead of doing the work (`connect.ts:56`).
 * Nothing anywhere throws; a user simply cannot read what was shared with it.
 *
 * That is not hypothetical — it shipped. The reference application calls the polyfill's
 * `init()` from inside the executor that is still building its own `sessionReady`
 * promise, so the thunk could not answer, by construction. Whoever settles an identity
 * before a session can exist wants {@link adoptCurrentUser} and an awaited
 * `connectedUser()` later.
 *
 * Gated on the registry being configured, and that is not a test convenience: an
 * identity set before the registry is wired has nothing to restore and no inbox to
 * reach. The consumer's real sequence is `configureStoreRegistry` then `setCurrentUser`;
 * anything else can call `connectedUser()` explicitly.
 */
export function setCurrentUser(id: PrincipalId | null): void {
  const changed = adoptCurrentUser(id);
  // Connecting a user is what triggers inbox processing — the library's job, not
  // the app's. Fire-and-forget: this setter is synchronous and every consumer calls
  // it from synchronous code, so the work announces itself through the cap
  // registry's change signal instead of making callers await. See `connect.ts`.
  if (changed && id !== null && registryDeps !== null) startConnect();
}

export function getCurrentUser(): PrincipalId | null {
  return currentUser;
}

/** The emulated cap registry — what the current identity holds, plus the emulated
 *  public store. The read filter and the read-model consult it. */
export function getCaps(): CapRegistry {
  return caps;
}

/**
 * Do I hold this document's key?
 *
 * The only question the model admits. There is no "may principal P read D" anywhere
 * upstream and there cannot be: reading IS key possession, so a cap-introspection API
 * would have to invent an ACL the engine does not have (`docs/api-contract.md` § 10).
 *
 * Returns a BOOLEAN, not the cap. It used to hand the value back, and the only consumer
 * that used it did so to pass it to `share` — which now takes the document instead.
 * Nothing an application does requires holding a key: upstream it never sees one, the
 * verifier fills `ContactDetails.read_cap` itself. So the surface answers the question
 * and keeps the key.
 */
export function hasCap(nuri: NuriLike): boolean {
  return caps.capFor(toNuri(nuri, "hasCap")) !== undefined;
}

/**
 * Drop EVERY holder's caps (tests / a fresh wallet). This is **not** what an identity
 * change does: switching identity switches heldByHolder, it never wipes one — if it
 * wiped, durability would be a lie and per-session re-declaration would come back
 * under another name. Nothing in the library calls this on `setCurrentUser`.
 */
export function resetCaps(): void {
  // Clear IN PLACE rather than rebuilding: whoever subscribed to the registry's
  // change signal (`watchShape`) stays subscribed to the live instance instead of
  // silently holding a listener on an orphaned one.
  caps.clear();
  // …and forget which documents were already asked about, or the emulated public-store
  // fetch would answer from a memo taken before the wipe and hand back caps this
  // registry no longer holds.
  resetPublicStoreFetches();
}