import type { CompressionBlock, CompressionState, CoreMessage } from "acp-kernel";
import { type BlockSnapshot, type ShapeVariantName, type ShapeTarget, type SnapManifest, type SnapUserMessage } from "./snapcompact.js";
/** Minimal shape: pi AgentSessionModel exposes `input: string[]`. */
export interface VisionModelLike {
    input?: string[];
}
export interface SnapSettings {
    mode: "auto" | "on" | "off";
    variant?: ShapeVariantName;
    maxFrames: number;
    /** Newest N active blocks stay hot text; older ones are snap candidates. */
    hotBlocks: number;
    /** Auto-snap fires when unsnapped cold summaries sum to >= this many tokens. */
    thresholdTokens: number;
    midTurnEnabled: boolean;
    idleEnabled: boolean;
    idleTimeoutSeconds: number;
    /** Idle snap only runs when last observed usage >= this many tokens. */
    idleThresholdTokens: number;
}
/** Env ACP_SNAPCOMPACT=off|force overrides the configured mode (matches the
 *  official escape hatch). */
export declare function resolveSnapSettings(adapterConfig: object, env?: NodeJS.ProcessEnv): SnapSettings;
export declare function hasVision(model?: VisionModelLike): boolean;
/** Whether the PNG path may run at all. "on" without a vision model still
 *  returns true — callers dispatch to the text fallback when !hasVision. */
export declare function snapEnabled(settings: SnapSettings, model?: VisionModelLike): boolean;
export declare function summaryTokens(blocks: CompressionBlock[]): number;
/** Active blocks oldest-first. */
export declare function activeByAge(state: CompressionState): CompressionBlock[];
/** Cold = active blocks outside the hot window (newest hotBlocks stay text). */
export declare function coldBlocks(state: CompressionState, settings: SnapSettings): CompressionBlock[];
/** Cold blocks not yet rendered into frames. */
export declare function unsnappedCold(state: CompressionState, manifest: SnapManifest, settings: SnapSettings): CompressionBlock[];
/** Quality gate: auto-snap only when pending cold summaries are worth a
 *  render pass. Returns the blocks to snap, or null when under threshold. */
export declare function autoSnapCandidates(state: CompressionState, manifest: SnapManifest, settings: SnapSettings): CompressionBlock[] | null;
/** Blocks whose summaries are already imaged AND still active — their anchor
 *  compress tool-calls must be hidden so the summary text is not duplicated
 *  beside its frame. */
export declare function snappedView(state: CompressionState, manifest: SnapManifest): {
    blockIds: Set<string>;
    callIds: Set<string>;
};
/** Load, GC (drop batches whose blocks were consumed/deactivated), and cap.
 *  Cheap enough to run on every context event; only writes when changed. */
export declare function pruneManifest(sessionFile: string, state: CompressionState, settings: SnapSettings): SnapManifest;
export interface SnapRunResult {
    manifest: SnapManifest;
    added: number;
    blocks: BlockSnapshot[];
}
/** Build renderable snapshots: official-style scoped serialization of each
 *  block's original messages when available (frames then read like official
 *  archives), plain summary otherwise (idle maintenance has no messages). */
export declare function snapshotBlocks(blocks: CompressionBlock[], coreMessages: CoreMessage[] | null): BlockSnapshot[];
/** Render the given snapshots into frames (vision path). */
export declare function runSnap(options: {
    sessionFile: string;
    manifest: SnapManifest;
    blocks: BlockSnapshot[];
    settings: SnapSettings;
    model?: ShapeTarget;
}): Promise<SnapRunResult>;
export declare function snapAttachment(manifest: SnapManifest): SnapUserMessage | undefined;
/** Text-model fallback (/acp-snap on a non-vision model): direct the model to
 *  run tier-2 distillation over the cold blocks right now. */
export declare function distillDirective(blocks: CompressionBlock[]): string;
/** Manual /compact restoration: force the model to compress everything
 *  compressible immediately (plugin compression stays model-driven). */
export declare function compactDirective(): string;