/**
 * Keeps the local mirror inside its byte budget, and keeps the blob store and
 * its index from drifting apart.
 *
 * Eviction order is cheapest-to-rebuild-last. Envelopes are small and are what
 * every listing needs, so they go last; attachment bytes are the heaviest and
 * the easiest to re-download, so they go first:
 *
 *   1. attachment blobs, least-recently-read first
 *   2. message bodies, least-recently-read first (envelopes stay)
 *   3. envelopes older than the configured window — last resort only
 *
 * Everything here is best-effort and safe to interrupt: the mirror is
 * regenerable, so a partial pass just means the next one finishes the job.
 */
import type BlobStore from './blob-store.js';
import type CacheStore from './store.js';
export interface BudgetResult {
    /** Bytes held (SQLite + blobs) before the pass. */
    usedBytesBefore: number;
    /** Bytes held after it. */
    usedBytesAfter: number;
    budgetBytes: number;
    evictedBlobs: number;
    evictedBodies: number;
    evictedMessages: number;
}
interface BudgetOptions {
    /**
     * Fraction of the budget to evict down to, so a cache sitting exactly at
     * the limit does not evict on every single cycle.
     */
    lowWaterRatio?: number;
    /** Envelopes older than this are evictable in the last-resort step. */
    windowDays?: number;
}
/**
 * Evict until the mirror is back under the low-water mark.
 *
 * @param maxSizeMb the configured budget; 0 disables enforcement entirely.
 */
export declare function enforceBudget(store: CacheStore, blobs: BlobStore, maxSizeMb: number, options?: BudgetOptions): Promise<BudgetResult>;
/**
 * Reconcile the blob store against its index in both directions: content no
 * row references is deleted, and rows whose content has vanished are dropped
 * so the next read re-downloads instead of failing.
 *
 * @returns how many orphaned blobs were removed.
 */
export declare function collectOrphans(store: CacheStore, blobs: BlobStore): Promise<number>;
export {};
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