/**
 * @fileoverview Provides a utility class `IdGenerator` for creating customizable, prefixed unique identifiers,
 * and a standalone `generateUUID` function for generating standard UUIDs.
 * The `IdGenerator` supports entity-specific prefixes, custom character sets, and lengths.
 *
 * Note: Logging has been removed from this module to prevent circular dependencies
 * with the `requestContextService`, which itself uses `generateUUID` from this module.
 * This was causing `ReferenceError: Cannot access 'generateUUID' before initialization`
 * during application startup.
 * @module src/utils/security/idGenerator
 */
import { validationError } from '../../types-global/errors.js';
/**
 * Returns cryptographically secure random bytes using the Web Crypto API (`crypto.getRandomValues`).
 * Available in Node.js 19+, Cloudflare Workers, and browsers — no Node.js-specific imports needed.
 * @param count - Number of random bytes to generate.
 * @returns A `Uint8Array` of `count` random bytes.
 */
function getRandomBytes(count) {
    const bytes = new Uint8Array(count);
    crypto.getRandomValues(bytes);
    return bytes;
}
/**
 * A generic ID Generator class for creating and managing unique, prefixed identifiers.
 * Allows defining custom prefixes, generating random strings, and validating/normalizing IDs.
 */
export class IdGenerator {
    /**
     * Default character set for the random part of the ID.
     * @private
     */
    static DEFAULT_CHARSET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    /**
     * Default separator character between prefix and random part.
     * @private
     */
    static DEFAULT_SEPARATOR = '_';
    /**
     * Default length for the random part of the ID.
     * @private
     */
    static DEFAULT_LENGTH = 6;
    /**
     * Stores the mapping of entity types to their prefixes.
     * @private
     */
    entityPrefixes = {};
    /**
     * Stores a reverse mapping from prefixes (case-insensitive) to entity types.
     * @private
     */
    prefixToEntityType = {};
    /**
     * Constructs an `IdGenerator` instance.
     * @param entityPrefixes - An initial map of entity types to their prefixes.
     */
    constructor(entityPrefixes = {}) {
        // Logging removed to prevent circular dependency with requestContextService.
        this.setEntityPrefixes(entityPrefixes);
    }
    /**
     * Sets or updates the entity prefix configuration and rebuilds the internal reverse lookup map.
     * @param entityPrefixes - A map where keys are entity type names and values are their desired ID prefixes.
     */
    setEntityPrefixes(entityPrefixes) {
        // Logging removed.
        this.entityPrefixes = { ...entityPrefixes };
        this.prefixToEntityType = Object.entries(this.entityPrefixes).reduce((acc, [type, prefix]) => {
            acc[prefix.toLowerCase()] = type; // Store lowercase for case-insensitive lookup
            return acc;
        }, {});
    }
    /**
     * Retrieves a copy of the current entity prefix configuration.
     * @returns The current entity prefix configuration.
     */
    getEntityPrefixes() {
        return { ...this.entityPrefixes };
    }
    /**
     * Generates a cryptographically secure random string.
     * @param length - The desired length of the random string. Defaults to `IdGenerator.DEFAULT_LENGTH`.
     * @param charset - The character set to use. Defaults to `IdGenerator.DEFAULT_CHARSET`.
     * @returns The generated random string.
     */
    generateRandomString(length = IdGenerator.DEFAULT_LENGTH, charset = IdGenerator.DEFAULT_CHARSET) {
        let result = '';
        // Determine the largest multiple of charset.length that is less than or equal to 256
        // This is the threshold for rejection sampling to avoid bias.
        const maxValidByteValue = Math.floor(256 / charset.length) * charset.length;
        while (result.length < length) {
            const byteBuffer = getRandomBytes(1);
            const byte = byteBuffer[0];
            // If the byte is within the valid range (i.e., it won't introduce bias),
            // use it to select a character from the charset. Otherwise, discard and try again.
            if (byte !== undefined && byte < maxValidByteValue) {
                const charIndex = byte % charset.length;
                const char = charset[charIndex];
                if (char) {
                    result += char;
                }
            }
        }
        return result;
    }
    /**
     * Generates a unique ID, optionally prepended with a prefix.
     * @param prefix - An optional prefix for the ID.
     * @param options - Optional parameters for ID generation (length, separator, charset).
     * @returns A unique identifier string.
     */
    generate(prefix, options = {}) {
        // Logging removed.
        const { length = IdGenerator.DEFAULT_LENGTH, separator = IdGenerator.DEFAULT_SEPARATOR, charset = IdGenerator.DEFAULT_CHARSET, } = options;
        const randomPart = this.generateRandomString(length, charset);
        const generatedId = prefix ? `${prefix}${separator}${randomPart}` : randomPart;
        return generatedId;
    }
    /**
     * Generates a unique ID for a specified entity type, using its configured prefix.
     * @param entityType - The type of entity (must be registered).
     * @param options - Optional parameters for ID generation.
     * @returns A unique identifier string for the entity (e.g., "PROJ_A6B3J0").
     * @throws {McpError} If the `entityType` is not registered.
     */
    generateForEntity(entityType, options = {}) {
        const prefix = this.entityPrefixes[entityType];
        if (!prefix) {
            throw validationError(`Unknown entity type: ${entityType}. No prefix registered.`);
        }
        return this.generate(prefix, options);
    }
    /**
     * Validates if an ID conforms to the expected format for a specific entity type.
     * @param id - The ID string to validate.
     * @param entityType - The expected entity type of the ID.
     * @param options - Optional parameters used during generation for validation consistency.
     *                  The `charset` from these options will be used for validation.
     * @returns `true` if the ID is valid, `false` otherwise.
     */
    isValid(id, entityType, options = {}) {
        const prefix = this.entityPrefixes[entityType];
        const { length = IdGenerator.DEFAULT_LENGTH, separator = IdGenerator.DEFAULT_SEPARATOR, charset = IdGenerator.DEFAULT_CHARSET, // Use charset from options or default
         } = options;
        if (!prefix) {
            return false;
        }
        // Build regex character class from the charset
        // Escape characters that have special meaning inside a regex character class `[]`
        const escapedCharsetForClass = charset.replace(/[[\]\\^-]/g, '\\$&');
        const charsetRegexPart = `[${escapedCharsetForClass}]`;
        const pattern = new RegExp(`^${this.escapeRegex(prefix)}${this.escapeRegex(separator)}${charsetRegexPart}{${length}}$`);
        return pattern.test(id);
    }
    /**
     * Escapes special characters in a string for use in a regular expression.
     * @param str - The string to escape.
     * @returns The escaped string.
     * @private
     */
    escapeRegex(str) {
        return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
    }
    /**
     * Strips the prefix and separator from an ID string, returning only the random part.
     * If the separator does not appear in the string, the original ID is returned unchanged.
     * Handles edge cases where the separator character appears in the random part by
     * rejoining all parts after the first split.
     *
     * @param id - The full ID string (e.g., `"PROJ_A6B3J0"`).
     * @param separator - The separator character used in the ID. Defaults to `'_'`.
     * @returns The random part of the ID without the prefix (e.g., `"A6B3J0"`), or the
     *   original string if the separator is not present.
     *
     * @example
     * ```ts
     * idGenerator.stripPrefix('PROJ_A6B3J0');         // → 'A6B3J0'
     * idGenerator.stripPrefix('PROJ-A6B3J0', '-');    // → 'A6B3J0'
     * idGenerator.stripPrefix('NOPREFIXID');           // → 'NOPREFIXID'
     * ```
     */
    stripPrefix(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
        const parts = id.split(separator);
        return parts.length > 1 ? parts.slice(1).join(separator) : id; // Handle separators in random part
    }
    /**
     * Determines the entity type from an ID string by its prefix (case-insensitive).
     * @param id - The ID string (e.g., "PROJ_A6B3J0").
     * @param separator - The separator used in the ID. Defaults to `IdGenerator.DEFAULT_SEPARATOR`.
     * @returns The determined entity type.
     * @throws {McpError} If ID format is invalid or prefix is unknown.
     */
    getEntityType(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
        const parts = id.split(separator);
        if (parts.length < 2 || !parts[0]) {
            throw validationError(`Invalid ID format: ${id}. Expected format like: PREFIX${separator}RANDOMPART`);
        }
        const prefix = parts[0];
        const entityType = this.prefixToEntityType[prefix.toLowerCase()];
        if (!entityType) {
            throw validationError(`Unknown entity type for prefix: ${prefix}`);
        }
        return entityType;
    }
    /**
     * Normalizes an entity ID so that the prefix matches its registered casing and the random
     * part is uppercased. Delegates to {@link getEntityType} to resolve the canonical prefix.
     *
     * Note: Uppercasing the random part is correct for the default `A-Z0-9` charset. For custom
     * charsets that include lowercase or non-alphabetic characters, `toUpperCase()` may produce
     * unexpected results.
     *
     * @param id - The ID to normalize (e.g., `"proj_a6b3j0"`).
     * @param separator - The separator used in the ID. Defaults to `'_'`.
     * @returns The normalized ID with canonical prefix casing and uppercase random part
     *   (e.g., `"PROJ_A6B3J0"`).
     * @throws {McpError} With {@link JsonRpcErrorCode.ValidationError} if the entity type
     *   cannot be determined from the ID's prefix.
     *
     * @example
     * ```ts
     * idGenerator.setEntityPrefixes({ project: 'PROJ' });
     * idGenerator.normalize('proj_a6b3j0'); // → 'PROJ_A6B3J0'
     * idGenerator.normalize('PROJ_a6b3j0'); // → 'PROJ_A6B3J0'
     * ```
     */
    normalize(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
        const entityType = this.getEntityType(id, separator);
        const registeredPrefix = this.entityPrefixes[entityType];
        const idParts = id.split(separator);
        const randomPart = idParts.slice(1).join(separator);
        // Consider if randomPart.toUpperCase() is always correct for custom charsets.
        // For now, maintaining existing behavior.
        return `${registeredPrefix}${separator}${randomPart.toUpperCase()}`;
    }
}
/**
 * Default singleton instance of {@link IdGenerator}, initialized with no entity prefixes.
 * Call `idGenerator.setEntityPrefixes({ ... })` during application startup to register prefixes
 * before calling `generateForEntity` or `getEntityType`.
 */
export const idGenerator = new IdGenerator();
/**
 * Generates a standard Version 4 UUID using the Web Crypto API (`crypto.randomUUID()`).
 * Cross-runtime: works in Node.js 19+, Cloudflare Workers, and browsers.
 *
 * @returns A new UUID v4 string (e.g., `"110e8400-e29b-41d4-a716-446655440000"`).
 *
 * @example
 * ```ts
 * const id = generateUUID(); // → '110e8400-e29b-41d4-a716-446655440000'
 * ```
 */
export const generateUUID = () => crypto.randomUUID();
/**
 * Generates a short, human-readable request context ID in the format `XXXXX-XXXXX`
 * (two 5-character alphanumeric segments joined by a hyphen, e.g., `"A3K9Z-BQ72M"`).
 *
 * This function is self-contained — it does not call `IdGenerator` or any other module-level
 * export — specifically to avoid circular dependencies with `requestContextService`, which
 * itself calls this function during initialization.
 *
 * Uses rejection sampling against the Web Crypto API for uniform, bias-free character selection.
 *
 * @returns A 11-character string in `XXXXX-XXXXX` format suitable for request tracing.
 *
 * @example
 * ```ts
 * const reqId = generateRequestContextId(); // → 'A3K9Z-BQ72M'
 * ```
 */
export const generateRequestContextId = () => {
    /**
     * Generates a cryptographically secure random string of a given length from a given charset.
     * @param length The desired length of the string.
     * @param charset The characters to use for generation.
     * @returns The generated random string.
     */
    const generateSecureRandomString = (length, charset) => {
        let result = '';
        const maxValidByteValue = Math.floor(256 / charset.length) * charset.length;
        while (result.length < length) {
            const byteBuffer = getRandomBytes(1);
            const byte = byteBuffer[0];
            if (byte !== undefined && byte < maxValidByteValue) {
                const charIndex = byte % charset.length;
                const char = charset[charIndex];
                if (char) {
                    result += char;
                }
            }
        }
        return result;
    };
    const charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    const part1 = generateSecureRandomString(5, charset);
    const part2 = generateSecureRandomString(5, charset);
    return `${part1}-${part2}`;
};
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