/**
 * Registry activity timestamps (T12512): "probed" and "opened" are different
 * facts and live in different columns.
 *
 * - `last_probed_at` — a health check, `nexus sync` or git state probe looked
 *   at the project. Says nothing about whether anyone uses it.
 * - `last_opened_at` — a real CLI command ran inside the project. Written at
 *   most once per {@link OPENED_WRITE_INTERVAL_MS}: a read decides, and only a
 *   stale value costs a primary-key update, so a read-only command does not
 *   take the write lock on every run.
 *
 * `last_seen` records identity and location writes to the registry row:
 * registration, a new or moved checkout, reconcile, rename and index stats.
 * It is NOT bumped on every command (the per-command encounter returns early
 * when the checkout is already current), so on its own it is not "last used".
 * Neither writer here touches it.
 *
 * ## Activity
 *
 * Any "recently active / recently used" decision reads ONE value:
 * {@link projectLastActivity} = max(`last_seen`, `last_opened_at`,
 * `last_probed_at`), or {@link projectLastActivitySql} in a query. Temp-project
 * GC, name disambiguation and the Studio project list all use it.
 *
 * @task T12512
 * @epic T12496
 */
import { type SQL } from 'drizzle-orm';
import type { NodeSQLiteDatabase } from 'drizzle-orm/node-sqlite';
/** Minimum interval between two `last_opened_at` writes for one project. */
export declare const OPENED_WRITE_INTERVAL_MS = 60000;
/** Registry timestamp columns that together make up a project's activity. */
export declare const ACTIVITY_COLUMNS: readonly ["last_seen", "last_opened_at", "last_probed_at"];
/**
 * Normalise a registry timestamp to ISO-8601 UTC so values written by
 * `datetime('now')` (`YYYY-MM-DD HH:MM:SS`, UTC) and by `toISOString()`
 * compare correctly.
 *
 * @param value - Stored timestamp, or `null`/`undefined`.
 * @returns An ISO-8601 string, or `null` when absent or unparseable.
 */
export declare function normalizeRegistryTimestamp(value: string | null | undefined): string | null;
/**
 * A project's last activity: the newest of `lastSeen`, `lastOpenedAt` and
 * `lastProbedAt` (T12512). The single accessor for "recently active".
 *
 * @param p - Registry timestamps (the camel-case `NexusProject` fields).
 * @returns The newest as ISO-8601, or `null` when none parses.
 * @example
 * ```ts
 * projectLastActivity({ lastSeen: '2026-01-01 00:00:00', lastOpenedAt: '2026-09-29T10:00:00.000Z' });
 * // '2026-09-29T10:00:00.000Z'
 * ```
 */
export declare function projectLastActivity(p: {
    lastSeen: string | null | undefined;
    lastOpenedAt?: string | null;
    lastProbedAt?: string | null;
}): string | null;
/**
 * SQL text for a project's last activity over `nexus_project_registry`
 * columns, for raw-SQL readers (Studio). Only the columns in `available` are
 * used, so a store not yet migrated (no `last_opened_at`) still reads.
 * Space-separated `datetime('now')` values are made comparable by `replace`.
 *
 * @param available - Column names present on the table.
 * @returns A SQL expression.
 */
export declare function projectLastActivitySqlText(available: ReadonlySet<string>): string;
/**
 * Drizzle SQL for a project's last activity (every column exists on a
 * migrated store). Order by it, descending, for "most recently active first".
 */
export declare const projectLastActivitySql: SQL<string>;
/** Registry handle subset the activity writers need. */
export type ProjectActivityHandle = Pick<NodeSQLiteDatabase, 'select' | 'update'>;
/**
 * Record that a health check, sync or git probe looked at these projects.
 *
 * @param db - Global registry handle.
 * @param projectIds - Probed project ids (duplicates are fine).
 * @param now - Probe instant.
 * @returns Number of registry rows updated.
 * @example
 * ```ts
 * markProjectsProbed(db, ['a1b2c3d4e5f6'], new Date());
 * ```
 */
export declare function markProjectsProbed(db: ProjectActivityHandle, projectIds: readonly string[], now?: Date): number;
/**
 * Record real CLI use of a project, unless it was recorded within the last
 * {@link OPENED_WRITE_INTERVAL_MS}.
 *
 * @param db - Global registry handle.
 * @param projectId - The project the command ran in.
 * @param now - Command instant.
 * @returns `written`, `throttled`, or `unregistered` (no registry row).
 * @example
 * ```ts
 * markProjectOpened(db, 'a1b2c3d4e5f6');
 * ```
 */
export declare function markProjectOpened(db: ProjectActivityHandle, projectId: string, now?: Date): 'written' | 'throttled' | 'unregistered';
//# sourceMappingURL=project-activity.d.ts.map