/**
 * File Feature Flag Provider
 *
 * File-based provider implementation supporting JSON and YAML configuration files.
 * This will be moved to @plyaz/core when the package structure is finalized.
 *
 * @fileoverview File provider implementation for feature flags
 * @version 1.0.0
 */
import type { FeatureFlag, FeatureFlagRule, FeatureFlagConfig, FeatureFlagValue, CreateFlagRequest } from '@plyaz/types';
import { FeatureFlagProvider } from '../provider';
/**
 * File-based feature flag provider supporting JSON and YAML formats.
 *
 * @class FileFeatureFlagProvider
 * @extends {FeatureFlagProvider}
 *
 * @example
 * ```typescript
 * const provider = new FileFeatureFlagProvider<FeatureFlagKey>({
 *   provider: 'file',
 *   fileConfig: {
 *     filePath: './config/feature-flags.json',
 *     format: 'json',
 *     shouldWatchForChanges: true,
 *   },
 *   isCacheEnabled: true,
 *   cacheTtl: 60,
 * }, FEATURES);
 *
 * await provider.initialize();
 * const isEnabled = await provider.isEnabled('AUTH_GOOGLE');
 * ```
 */
export declare class FileFeatureFlagProvider<FeatureFlagKey extends string> extends FeatureFlagProvider<FeatureFlagKey> {
    private fileWatcher?;
    private lastFileContent?;
    private fileCheckInterval?;
    private flags;
    private rules;
    /**
     * Creates a new file feature flag provider.
     *
     * @param config - Provider configuration with file settings
     * @param features - Record of feature flag keys to their default values
     */
    constructor(config: FeatureFlagConfig<FeatureFlagKey>, features: Record<FeatureFlagKey, FeatureFlagValue>);
    /**
     * Initializes the provider and sets up file watching if enabled.
     */
    initialize(): Promise<void>;
    /**
     * Fetches flags and rules from the configuration file.
     *
     * @protected
     * @returns Promise resolving to flags and rules from file
     */
    protected fetchData(): Promise<{
        flags: FeatureFlag<FeatureFlagKey>[];
        rules: FeatureFlagRule<FeatureFlagKey>[];
    }>;
    /**
     * Parses file content based on format.
     *
     * @private
     */
    private parseFileContent;
    /**
     * Handles errors for fetchData, including file creation and fallback.
     *
     * @private
     */
    private handleFetchDataError;
    /**
     * Type guard for NodeJS.ErrnoException.
     */
    private isFileNotFoundError;
    /**
     * Handles the case when the file is not found and fallback is enabled.
     */
    private handleFileNotFound;
    /**
     * Handles fallback to default flags and rules.
     */
    private handleFallbackToDefaults;
    /**
     * Validates the file provider configuration.
     *
     * @private
     * @throws Error if configuration is invalid
     */
    private validateConfig;
    /**
     * Resolves the file path, supporting relative and absolute paths.
     *
     * @private
     * @param filePath - The file path from configuration
     * @returns Resolved absolute file path
     */
    private resolveFilePath;
    /**
     * Parses JSON content.
     *
     * @private
     * @param content - File content
     * @returns Parsed data
     */
    private parseJSON;
    /**
     * Parses YAML content.
     *
     * @private
     * @param content - File content
     * @returns Parsed data
     */
    private parseYAML;
    /**
     * Validates the structure of file data.
     *
     * @private
     * @param data - Parsed file data
     */
    private validateFileData;
    private checkFlagsArray;
    private checkRulesArray;
    private validateFlags;
    private validateRules;
    /**
     * Creates a default configuration file with values from features.
     *
     * @private
     * @param filePath - Path where to create the file
     * @param format - File format (json or yaml)
     */
    private createDefaultFile;
    /**
     * Creates default flags from the features configuration.
     *
     * @private
     * @returns Array of default flags
     */
    private createDefaultFlags;
    /**
     * Sets up file watching for hot reload if enabled.
     *
     * @private
     */
    private setupFileWatcher;
    /**
     * Disposes of the file provider and stops file watching.
     */
    dispose(): void;
    /**
     * Refreshes the provider by fetching latest data from the file.
     * Overrides base class to store rules.
     *
     * @returns Promise that resolves when refresh is complete
     */
    refresh(): Promise<void>;
    /**
     * Creates a new feature flag and persists to file.
     *
     * @param data - Flag creation data
     * @returns The created feature flag
     */
    createFlag(data: CreateFlagRequest<FeatureFlagKey>): Promise<FeatureFlag<FeatureFlagKey>>;
    /**
     * Updates an existing feature flag and persists to file.
     *
     * @param key - Flag key to update
     * @param data - Partial flag data to update
     * @returns The updated feature flag
     */
    updateFlag(key: FeatureFlagKey, data: Partial<CreateFlagRequest<FeatureFlagKey>>): Promise<FeatureFlag<FeatureFlagKey>>;
    /**
     * Deletes a feature flag and persists to file.
     *
     * @param key - Flag key to delete
     */
    deleteFlag(key: FeatureFlagKey): Promise<void>;
    /**
     * Gets all rules for a specific flag.
     *
     * @param key - Flag key to get rules for
     * @returns Array of rules for the flag
     */
    getRules(key: FeatureFlagKey): Promise<FeatureFlagRule<FeatureFlagKey>[]>;
    /**
     * Gets all enabled rules.
     *
     * @returns Array of all enabled rules
     */
    getAllRules(): Promise<FeatureFlagRule<FeatureFlagKey>[]>;
    /**
     * Persists current flags and rules to file.
     *
     * @private
     */
    private persistToFile;
    /**
     * Infers the flag type from its value.
     *
     * @private
     */
    private inferFlagType;
    /**
     * Updates the features object and writes to file.
     * This allows updating the FEATURES at runtime and persisting to file.
     *
     * @param newFeatures - New features object to sync with
     */
    syncFeatures(newFeatures: Record<FeatureFlagKey, FeatureFlagValue>): Promise<void>;
    /**
     * Gets information about the file provider.
     *
     * @returns File provider information
     */
    getFileInfo(): {
        filePath?: string;
        resolvedPath?: string;
        format?: string;
        isWatchEnabled: boolean;
        isImplemented: boolean;
        lastModified?: Date;
    };
}
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