/**
 * config-cache — Per-database LLM billing configuration cache
 *
 * Caches resolved billing function names per database_id.
 * Uses an LRU cache with TTL so config changes propagate within a bounded window
 * without requiring a server restart.
 *
 * Resolution flow:
 *   Billing config from `metaschema_modules_public.billing_module`
 *   (schema name + function names for record_usage, check_billing_quota)
 *
 * All queries run through the Graphile `withPgClient` callback, which gives us
 * a client connected to the tenant database with proper role settings.
 *
 * The LLM module config (provider, model, etc.) is already resolved by the
 * LlmModulePlugin at schema-build time. This cache handles the runtime-only
 * billing piece.
 */
/**
 * Generic pg client interface matching what Graphile's withPgClient provides.
 * Avoids a hard dependency on the `pg` package.
 */
export interface PgClient {
    query(sql: string, values?: unknown[]): Promise<{
        rows: Record<string, unknown>[];
    }>;
}
/**
 * Billing function metadata resolved from the billing_module metaschema table.
 */
export interface BillingConfig {
    /** Private schema containing the billing functions */
    privateSchema: string;
    /** Name of the record_usage function */
    recordUsageFunction: string;
    /** Name of the check_billing_quota function */
    checkBillingQuotaFunction: string;
    /** Public schema containing meters table */
    publicSchema: string;
}
/**
 * Inference log table metadata resolved from the inference_log_module.
 */
export interface InferenceLogConfig {
    /** Schema containing the usage_log_inference table */
    schema: string;
    /** Name of the inference log table */
    tableName: string;
}
/**
 * Per-database cached configuration for the LLM billing integration.
 */
export interface LlmBillingCacheEntry {
    /** Billing function references (null if billing_module not provisioned) */
    billing: BillingConfig | null;
    /** Inference log table references (null if inference_log_module not provisioned) */
    inferenceLog: InferenceLogConfig | null;
}
/**
 * Resolve billing config for a database.
 * Results are cached per database_id with a 5-minute TTL.
 *
 * @param pgClient - A client connected to the tenant database (from withPgClient)
 * @param databaseId - The database UUID
 */
export declare function getLlmBillingConfig(pgClient: PgClient, databaseId: string): Promise<LlmBillingCacheEntry>;
/**
 * Invalidate the cached config for a specific database (or all).
 */
export declare function invalidateLlmBillingConfig(databaseId?: string): void;
/**
 * Get cache stats for diagnostics.
 */
export declare function getLlmBillingCacheStats(): {
    size: number;
    max: number;
};