/**
 * Projection Engine for Lex Instructions
 *
 * Transforms canonical instruction content into host-specific files.
 * Pure transformation - no file I/O operations.
 */
import { CanonicalResult } from "./canonical-loader.js";
import { HostDetectionResult } from "./host-detection.js";
import { LexYaml } from "../config/lex-yaml-schema.js";
/**
 * Supported host types for projection
 */
export type HostType = "copilot" | "cursor";
/**
 * Configuration input for the projection engine
 */
export interface ProjectionConfig {
    /** Loaded canonical instruction content */
    canonical: CanonicalResult;
    /** Detected host targets in the repository */
    hosts: HostDetectionResult;
    /** Lex configuration with projection settings */
    config: LexYaml;
    /** Function to read existing file content (for determining action). If not provided, assumes files don't exist. */
    readFile?: (path: string) => string | null;
}
/**
 * Action to take for a projection
 * - create: File doesn't exist, will be created
 * - update: File exists, will be updated with new content
 * - skip: No action needed (content unchanged or host disabled)
 */
export type ProjectionAction = "create" | "update" | "skip";
/**
 * Result of projecting to a specific host
 */
export interface ProjectionResult {
    /** Target host type */
    host: HostType;
    /** Absolute path to the target file */
    path: string;
    /** Generated content for the file */
    content: string;
    /** Action to take */
    action: ProjectionAction;
}
/**
 * Generate projections for all enabled and available hosts
 *
 * This is a pure transformation function - it does not perform file I/O.
 * The caller is responsible for writing the generated content to files.
 *
 * @param config - Projection configuration with canonical content, hosts, and settings
 * @returns Array of projection results for each applicable host
 *
 * @example
 * ```ts
 * const projections = generateProjections({
 *   canonical: loadCanonicalInstructions(repoRoot),
 *   hosts: detectAvailableHosts(repoRoot),
 *   config: { version: 1 },
 *   readFile: (path) => fs.existsSync(path) ? fs.readFileSync(path, 'utf-8') : null
 * });
 *
 * for (const proj of projections) {
 *   if (proj.action !== 'skip') {
 *     fs.writeFileSync(proj.path, proj.content);
 *   }
 * }
 * ```
 */
export declare function generateProjections(config: ProjectionConfig): ProjectionResult[];
/**
 * Default file reader implementation using Node.js fs
 *
 * @param path - Path to read
 * @returns File content or null if file doesn't exist or can't be read
 */
export declare function defaultFileReader(path: string): string | null;