/**
 * M1 — session-log projection: DSH surface events → acp-kernel CoreMessage.
 *
 * The ARC kernel is message-array based; DSH is event-log based. This module
 * is the bridge in the direction the engine needs (projectEvent /
 * eventsToCoreMessages). The reverse direction (CoreMessage[] → session
 * appends) is the M5 region transaction's job.
 * Mirrors billion-context-pi's `projectMessage`/`entriesToCoreMessages`
 * against DSH event shapes (see V-verification: SurfaceEventType =
 * 'user/message' | 'assistant/message' | 'tool/result').
 * @module billion-context-pi-dsh/messages
 */
import type { CoreMessage } from 'acp-kernel';
import type { SessionEvent } from '@deepseek-ai/dsh-session';
/**
 * Extract plain text from a DSH content block array or string.
 *
 * Recursive: a real DSH `tool-result` block is `{ type: 'tool-result',
 * toolCallId, content: ContentBlock[] }` — the inner `content` array holds
 * the actual `text` blocks, so a top-level-only walk would drop every tool
 * result from the projection (and with it the seq's ref assignment, breaking
 * compress boundary resolution). Nested arrays are flattened depth-first.
 */
export declare function extractText(content: unknown): string;
/**
 * Project one surface message event into CoreMessage(s).
 *  - user/message      → user text (verbatim content)
 *  - assistant/message → assistant text, or one CoreMessage per tool-call
 *  - tool/result       → tool result (toolName/toolCallId, role 'tool')
 * Non-surface events project to nothing.
 */
export declare function projectEvent(event: SessionEvent): CoreMessage[];
/** Project a session's message events into CoreMessage[] in log order. */
export declare function eventsToCoreMessages(events: readonly SessionEvent[]): CoreMessage[];
/** The surface-visible message events of a session, in model-visible order. */
export declare function surfaceEventsOf(session: import('@deepseek-ai/dsh-session').Session): SessionEvent[];
/**
 * ALL message-type events in log order — the visible surface PLUS everything
 * shadowed by compression. The ARC kernel deactivates any block whose consumed
 * message ids are absent from the array it is given (syncBlocks), and refuses
 * to anchor a block boundary that cannot find its messages, so T2/T3
 * distillation requires the full log, not just the visible surface.
 */
export declare function allLogMessages(session: import('@deepseek-ai/dsh-session').Session): CoreMessage[];
/** Extract the model-facing text of any surface message event. */
export declare function extractEventText(event: SessionEvent): string;