/**
 * Forgen — Observability Store (Phase 1)
 *
 * solution_events 테이블에 matched/surfaced/acted_on 이벤트를 기록.
 * Fail-open: 모든 함수는 내부 오류를 삼키고 절대 throw 하지 않는다.
 */
export type EventType = 'matched' | 'surfaced' | 'acted_on';
export interface EmitOptions {
    ts?: number;
    sessionId?: string | null;
    solutionId: string;
    eventType: EventType;
    signalSource: string;
    signalScore?: number | null;
    meta?: Record<string, unknown>;
}
export interface SurfacedEvent {
    id: number;
    ts: number;
    sessionId: string | null;
    solutionId: string;
    signalSource: string;
    signalScore: number | null;
    meta: Record<string, unknown> | null;
}
export interface HitRateRow {
    solutionId: string;
    matched_30d: number;
    surfaced_30d: number;
    acted_30d: number;
    matched_90d: number;
    surfaced_90d: number;
    acted_90d: number;
    matched_180d: number;
    surfaced_180d: number;
    acted_180d: number;
    last_event_ts: number;
}
interface SqliteDb {
    exec(sql: string): void;
    prepare(sql: string): {
        run(...args: unknown[]): {
            lastInsertRowid: number;
        };
        get(...args: unknown[]): unknown;
        all(...args: unknown[]): unknown[];
    };
    close(): void;
}
/** solution_events 스키마 및 schema_version 초기화. idempotent. */
export declare function ensureObservabilitySchema(db: SqliteDb): void;
/** solution_events 에 이벤트를 기록한다. fail-open (throw 없음). */
export declare function emitSolutionEvent(opts: EmitOptions): void;
/** 특정 세션에서 지정 시간 window 내 surfaced 이벤트 조회. */
export declare function querySurfacedWithin(sessionId: string, minutesWindow: number): SurfacedEvent[];
/** 30/90/180일 hit-rate 집계. solutionId 지정 시 단일 솔루션만. */
export declare function queryHitRate(solutionId?: string): HitRateRow[];
export {};