import { withoutUnverifiedThinking } from "../model-thinking";
import type { CatalogPolicyInputs } from "../types";
import { type ResolveRoute, resolveCatalogAxes } from "./resolve";

/**
 * Rule-owned catalog-axis policy by model. Resolve once per process rather
 * than walking the static policy cascade on every accessor call. The key
 * mirrors the cascade target inputs — `providerType ?? provider`, api, the
 * logical id plus `requestModelId` (the wire id `policyModelId` resolves
 * unknown logical ids under), the reasoning flag, and the route's upstream;
 * identity-derived class/family/revision facts are a pure function of
 * provider + id. Bounded: one entry per distinct model and upstream.
 */
const catalogPolicyCache = new Map<string, Readonly<Record<string, unknown>>>();
const CATALOG_POLICY_CACHE_MAX = 8192;

/**
 * The `catalog` axis bag authored in the KDL cascade rules for a model (on one
 * upstream when `route` names it), memoized per distinct model. Frozen: the bag
 * is shared across callers, so it must stay read-only — extract the value you
 * need rather than handing it on.
 */
export function resolveCatalogPolicy(
	model: CatalogPolicyInputs,
	route?: ResolveRoute,
): Readonly<Record<string, unknown>> {
	const key = `${model.provider}\u0000${model.providerType ?? ""}\u0000${model.api}\u0000${model.id}\u0000${model.requestModelId ?? ""}\u0000${model.reasoning ? 1 : 0}\u0000${route?.upstream ?? ""}`;
	const cached = catalogPolicyCache.get(key);
	if (cached !== undefined) return cached;
	const policy = Object.freeze({ ...resolveCatalogAxes(withoutUnverifiedThinking(model), route) });
	if (catalogPolicyCache.size >= CATALOG_POLICY_CACHE_MAX) catalogPolicyCache.clear();
	catalogPolicyCache.set(key, policy);
	return policy;
}