import type { MigrationBlockConfig, MigrationConfig, ResolvedMigrationBlockTarget } from './migration-types.js';
/**
 * Describes the migration retrofit layout discovered in a project directory.
 *
 * Multi-block discovery wins when block targets are discovered under
 * `src/blocks/<slug>/block.json`.
 * Otherwise the runtime falls back to a supported single-block layout.
 */
export type DiscoveredMigrationLayout = {
    block: MigrationBlockConfig;
    mode: 'single';
} | {
    blocks: MigrationBlockConfig[];
    mode: 'multi';
};
/**
 * Synthesizes the implicit legacy migration block target for single-block projects.
 *
 * @param projectDir Project directory that may contain a legacy root migration layout.
 * @param blockName Optional configured block name used to prefer a matching legacy root target.
 * @returns The discovered single-block migration target keyed as `default`.
 */
export declare function createImplicitLegacyBlock(projectDir: string, blockName?: string): MigrationBlockConfig;
/**
 * Verifies that a project directory contains the files required for migration tooling.
 *
 * @param projectDir Project directory to validate.
 * @param blocks Optional block targets to validate directly instead of auto-discovering them.
 * @returns Nothing.
 * @throws Error When any required project file is missing.
 */
export declare function ensureAdvancedMigrationProject(projectDir: string, blocks?: MigrationBlockConfig[]): void;
/**
 * Detects the supported migration retrofit layout for `migrate init`.
 *
 * Multi-block targets under `src/blocks/<slug>` take precedence over
 * single-block layouts.
 * Returns the detected layout on success and throws an actionable error when no
 * supported first-party layout can be inferred.
 *
 * @param projectDir Project directory to inspect.
 * @returns The discovered migration layout.
 * @throws Error When no supported layout can be inferred.
 */
export declare function discoverMigrationInitLayout(projectDir: string): DiscoveredMigrationLayout;
/**
 * Resolves the configured migration block targets and their current artifacts.
 *
 * @param projectDir Project directory containing the migration workspace.
 * @param config Parsed migration configuration.
 * @returns The resolved block targets, including current block.json and manifest documents.
 */
export declare function resolveMigrationBlocks(projectDir: string, config: MigrationConfig): ResolvedMigrationBlockTarget[];
/**
 * Returns the discovered block name for a supported single-block project.
 *
 * Uses `discoverSingleBlockTarget(projectDir)` internally and throws when the
 * project directory does not resolve to a supported single-block migration
 * layout.
 */
export declare function readProjectBlockName(projectDir: string): string;