/**
 * Exodus pre-flight plan builder.
 *
 * `buildExodusPlan()` computes the full migration plan — source DB paths,
 * combined size, free-disk availability, staging directory — BEFORE any
 * writes occur. A `--dry-run` caller can print the plan and exit early.
 *
 * ## Disk pre-flight (AC8 · right-sized T11838)
 *
 * The original gate required `availableBytes >= 3 * totalSourceBytes` — an
 * over-estimate that blocked large-fleet migrations even with ample headroom:
 * exodus never holds 3× the SUM of every source on disk at once. It copies one
 * source into staging at a time (lock released before the next) and writes a
 * single consolidated cleo.db whose size approximates the sum of source ROW data.
 *
 * The right-sized requirement is therefore
 * `STAGING_HEADROOM_FACTOR * largestSourceBytes + consolidatedEstimate`, where
 * `consolidatedEstimate ≈ totalSourceBytes` ({@link computeRequiredBytes}). The
 * check uses `statvfs` via `node:fs.statfsSync()` (Node 18+).
 *
 * @task T11248 (E5 · SG-DB-SUBSTRATE-V2)
 * @task T11838 (right-sized preflight + optional staging copy for large sources)
 * @saga T11242
 */
import type { ExodusPlan, LegacyDbDescriptor } from './types.js';
/**
 * Headroom multiplier applied to the LARGEST single source when sizing the
 * staging-copy footprint. The staging dir only ever holds ONE source backup at a
 * time (its advisory lock is released before the next source is touched), so the
 * peak staging footprint is the largest source plus a small slack for the
 * write-then-rename journal + SQLite sidecars — hence `1.2×`, not `3×` of the SUM.
 *
 * @task T11838
 */
export declare const STAGING_HEADROOM_FACTOR: 1.2;
/**
 * Per-source byte threshold above which the full staging `copyFileSync` backup
 * is skipped (the source is archived, not deleted, on success). Sized at 256 MiB
 * — comfortably above the small project DBs (tasks/conduit/skills/signaldock are
 * sub-MB to low-MB) but below the large global stores (a multi-GB `brain.db` or
 * `nexus.db`) whose redundant full-file copy is the costly case T11838 removes.
 *
 * @task T11838
 */
export declare const STAGING_COPY_SKIP_THRESHOLD_BYTES: number;
/**
 * Compute the right-sized free-disk requirement for an exodus run (T11838).
 *
 * `STAGING_HEADROOM_FACTOR * largestSourceBytes` covers the peak staging-copy
 * footprint (one source at a time, plus slack), and `totalSourceBytes` is the
 * consolidated-cleo.db estimate (every source's row data lands there). The two
 * are additive because staging and the consolidated DB coexist on disk until the
 * sources are archived.
 *
 * @param totalSourceBytes   - Combined size of all source DB files in bytes.
 * @param largestSourceBytes - Size of the single largest source DB in bytes.
 * @returns The minimum free bytes the target filesystem must have.
 */
export declare function computeRequiredBytes(totalSourceBytes: number, largestSourceBytes: number): number;
/**
 * Derive the staging directory name from the current ISO-8601 timestamp.
 *
 * Pattern: `.cleo/exodus-staging-<YYYYMMDDTHHMMSSZ>`.
 * Colons are replaced with empty string (NTFS + shell-safe).
 */
export declare function deriveStagingDirName(): string;
/**
 * Build the complete exodus plan.
 *
 * This is a pure read operation — no files are created or modified.
 * Pass the result to `runExodusMigrate()` to execute the migration.
 *
 * @param cwd - Working directory used to resolve the project root. Defaults to
 *   `process.cwd()`.
 * @returns {@link ExodusPlan} describing sources, disk availability, and paths.
 *
 * @task T11248 (AC8 — disk pre-flight)
 * @task T11838 (right-sized: largest-source factor + consolidated estimate)
 */
export declare function buildExodusPlan(cwd?: string): ExodusPlan;
/**
 * Check whether all required source DBs exist.
 *
 * Returns `true` if at least one source file is present (partial sets are
 * acceptable — empty tables simply copy zero rows).
 */
export declare function sourcesPresent(sources: LegacyDbDescriptor[]): boolean;
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