'use strict';

var path = require('path');
var minimatch = require('minimatch');
var createDebug = require('debug');
var objectSchema = require('@humanwhocodes/object-schema');

/**
 * @fileoverview ConfigSchema
 * @author Nicholas C. Zakas
 */

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const NOOP_STRATEGY = {
    required: false,
    merge() {
        return undefined;
    },
    validate() { }
};

//------------------------------------------------------------------------------
// Exports
//------------------------------------------------------------------------------

/**
 * The base schema that every ConfigArray uses.
 * @type Object
 */
const baseSchema = Object.freeze({
    name: {
        required: false,
        merge() {
            return undefined;
        },
        validate(value) {
            if (typeof value !== 'string') {
                throw new TypeError('Property must be a string.');
            }
        }
    },
    files: NOOP_STRATEGY,
    ignores: NOOP_STRATEGY
});

/**
 * @fileoverview ConfigSchema
 * @author Nicholas C. Zakas
 */

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

/**
 * Asserts that a given value is an array.
 * @param {*} value The value to check.
 * @returns {void}
 * @throws {TypeError} When the value is not an array.
 */
function assertIsArray(value) {
    if (!Array.isArray(value)) {
        throw new TypeError('Expected value to be an array.');
    }
}

/**
 * Asserts that a given value is an array containing only strings and functions.
 * @param {*} value The value to check.
 * @returns {void}
 * @throws {TypeError} When the value is not an array of strings and functions.
 */
function assertIsArrayOfStringsAndFunctions(value, name) {
    assertIsArray(value);

    if (value.some(item => typeof item !== 'string' && typeof item !== 'function')) {
        throw new TypeError('Expected array to only contain strings and functions.');
    }
}

/**
 * Asserts that a given value is a non-empty array.
 * @param {*} value The value to check.
 * @returns {void}
 * @throws {TypeError} When the value is not an array or an empty array.
 */
function assertIsNonEmptyArray(value) {
    if (!Array.isArray(value) || value.length === 0) {
        throw new TypeError('Expected value to be a non-empty array.');
    }
}

//------------------------------------------------------------------------------
// Exports
//------------------------------------------------------------------------------

/**
 * The schema for `files` and `ignores` that every ConfigArray uses.
 * @type Object
 */
const filesAndIgnoresSchema = Object.freeze({
    files: {
        required: false,
        merge() {
            return undefined;
        },
        validate(value) {

            // first check if it's an array
            assertIsNonEmptyArray(value);

            // then check each member
            value.forEach(item => {
                if (Array.isArray(item)) {
                    assertIsArrayOfStringsAndFunctions(item);
                } else if (typeof item !== 'string' && typeof item !== 'function') {
                    throw new TypeError('Items must be a string, a function, or an array of strings and functions.');
                }
            });

        }
    },
    ignores: {
        required: false,
        merge() {
            return undefined;
        },
        validate: assertIsArrayOfStringsAndFunctions
    }
});

/**
 * @fileoverview ConfigArray
 * @author Nicholas C. Zakas
 */


//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const Minimatch = minimatch.Minimatch;
const minimatchCache = new Map();
const negatedMinimatchCache = new Map();
const debug = createDebug('@hwc/config-array');

const MINIMATCH_OPTIONS = {
    // matchBase: true,
    dot: true
};

const CONFIG_TYPES = new Set(['array', 'function']);

const FILES_AND_IGNORES_SCHEMA = new objectSchema.ObjectSchema(filesAndIgnoresSchema);

/**
 * Shorthand for checking if a value is a string.
 * @param {any} value The value to check.
 * @returns {boolean} True if a string, false if not. 
 */
function isString(value) {
    return typeof value === 'string';
}

/**
 * Asserts that the files and ignores keys of a config object are valid as per base schema.
 * @param {object} config The config object to check.
 * @returns {void}
 * @throws {TypeError} If the files and ignores keys of a config object are not valid.
 */
function assertValidFilesAndIgnores(config) {
    if (!config || typeof config !== 'object') {
        return;
    }
    const validateConfig = { };
    if ('files' in config) {
        validateConfig.files = config.files;
    }
    if ('ignores' in config) {
        validateConfig.ignores = config.ignores;
    }
    FILES_AND_IGNORES_SCHEMA.validate(validateConfig);
}

/**
 * Wrapper around minimatch that caches minimatch patterns for
 * faster matching speed over multiple file path evaluations.
 * @param {string} filepath The file path to match.
 * @param {string} pattern The glob pattern to match against.
 * @param {object} options The minimatch options to use.
 * @returns 
 */
function doMatch(filepath, pattern, options = {}) {

    let cache = minimatchCache;

    if (options.flipNegate) {
        cache = negatedMinimatchCache;
    }

    let matcher = cache.get(pattern);

    if (!matcher) {
        matcher = new Minimatch(pattern, Object.assign({}, MINIMATCH_OPTIONS, options));
        cache.set(pattern, matcher);
    }

    return matcher.match(filepath);
}

/**
 * Normalizes a `ConfigArray` by flattening it and executing any functions
 * that are found inside.
 * @param {Array} items The items in a `ConfigArray`.
 * @param {Object} context The context object to pass into any function
 *      found.
 * @param {Array<string>} extraConfigTypes The config types to check.
 * @returns {Promise<Array>} A flattened array containing only config objects.
 * @throws {TypeError} When a config function returns a function.
 */
async function normalize(items, context, extraConfigTypes) {

    const allowFunctions = extraConfigTypes.includes('function');
    const allowArrays = extraConfigTypes.includes('array');

    async function* flatTraverse(array) {
        for (let item of array) {
            if (typeof item === 'function') {
                if (!allowFunctions) {
                    throw new TypeError('Unexpected function.');
                }

                item = item(context);
                if (item.then) {
                    item = await item;
                }
            }

            if (Array.isArray(item)) {
                if (!allowArrays) {
                    throw new TypeError('Unexpected array.');
                }
                yield* flatTraverse(item);
            } else if (typeof item === 'function') {
                throw new TypeError('A config function can only return an object or array.');
            } else {
                yield item;
            }
        }
    }

    /*
     * Async iterables cannot be used with the spread operator, so we need to manually
     * create the array to return.
     */
    const asyncIterable = await flatTraverse(items);
    const configs = [];

    for await (const config of asyncIterable) {
        configs.push(config);
    }

    return configs;
}

/**
 * Normalizes a `ConfigArray` by flattening it and executing any functions
 * that are found inside.
 * @param {Array} items The items in a `ConfigArray`.
 * @param {Object} context The context object to pass into any function
 *      found.
 * @param {Array<string>} extraConfigTypes The config types to check.
 * @returns {Array} A flattened array containing only config objects.
 * @throws {TypeError} When a config function returns a function.
 */
function normalizeSync(items, context, extraConfigTypes) {

    const allowFunctions = extraConfigTypes.includes('function');
    const allowArrays = extraConfigTypes.includes('array');

    function* flatTraverse(array) {
        for (let item of array) {
            if (typeof item === 'function') {

                if (!allowFunctions) {
                    throw new TypeError('Unexpected function.');
                }

                item = item(context);
                if (item.then) {
                    throw new TypeError('Async config functions are not supported.');
                }
            }

            if (Array.isArray(item)) {

                if (!allowArrays) {
                    throw new TypeError('Unexpected array.');
                }

                yield* flatTraverse(item);
            } else if (typeof item === 'function') {
                throw new TypeError('A config function can only return an object or array.');
            } else {
                yield item;
            }
        }
    }

    return [...flatTraverse(items)];
}

/**
 * Determines if a given file path should be ignored based on the given
 * matcher.
 * @param {Array<string|() => boolean>} ignores The ignore patterns to check. 
 * @param {string} filePath The absolute path of the file to check.
 * @param {string} relativeFilePath The relative path of the file to check.
 * @returns {boolean} True if the path should be ignored and false if not.
 */
function shouldIgnorePath(ignores, filePath, relativeFilePath) {

    // all files outside of the basePath are ignored
    if (relativeFilePath.startsWith('..')) {
        return true;
    }

    return ignores.reduce((ignored, matcher) => {

        if (!ignored) {

            if (typeof matcher === 'function') {
                return matcher(filePath);
            }

            // don't check negated patterns because we're not ignored yet
            if (!matcher.startsWith('!')) {
                return doMatch(relativeFilePath, matcher);
            }

            // otherwise we're still not ignored
            return false;

        }

        // only need to check negated patterns because we're ignored
        if (typeof matcher === 'string' && matcher.startsWith('!')) {
            return !doMatch(relativeFilePath, matcher, {
                flipNegate: true
            });
        }

        return ignored;

    }, false);

}

/**
 * Determines if a given file path is matched by a config based on
 * `ignores` only.
 * @param {string} filePath The absolute file path to check.
 * @param {string} basePath The base path for the config.
 * @param {Object} config The config object to check.
 * @returns {boolean} True if the file path is matched by the config,
 *      false if not.
 */
function pathMatchesIgnores(filePath, basePath, config) {

    /*
     * For both files and ignores, functions are passed the absolute
     * file path while strings are compared against the relative
     * file path.
     */
    const relativeFilePath = path.relative(basePath, filePath);

    return Object.keys(config).length > 1 &&
        !shouldIgnorePath(config.ignores, filePath, relativeFilePath);
}


/**
 * Determines if a given file path is matched by a config. If the config
 * has no `files` field, then it matches; otherwise, if a `files` field
 * is present then we match the globs in `files` and exclude any globs in
 * `ignores`.
 * @param {string} filePath The absolute file path to check.
 * @param {string} basePath The base path for the config.
 * @param {Object} config The config object to check.
 * @returns {boolean} True if the file path is matched by the config,
 *      false if not.
 */
function pathMatches(filePath, basePath, config) {

    /*
     * For both files and ignores, functions are passed the absolute
     * file path while strings are compared against the relative
     * file path.
     */
    const relativeFilePath = path.relative(basePath, filePath);

    // match both strings and functions
    const match = pattern => {

        if (isString(pattern)) {
            return doMatch(relativeFilePath, pattern);
        }

        if (typeof pattern === 'function') {
            return pattern(filePath);
        }

        throw new TypeError(`Unexpected matcher type ${pattern}.`);
    };

    // check for all matches to config.files
    let filePathMatchesPattern = config.files.some(pattern => {
        if (Array.isArray(pattern)) {
            return pattern.every(match);
        }

        return match(pattern);
    });

    /*
     * If the file path matches the config.files patterns, then check to see
     * if there are any files to ignore.
     */
    if (filePathMatchesPattern && config.ignores) {
        filePathMatchesPattern = !shouldIgnorePath(config.ignores, filePath, relativeFilePath);
    }

    return filePathMatchesPattern;
}

/**
 * Ensures that a ConfigArray has been normalized.
 * @param {ConfigArray} configArray The ConfigArray to check. 
 * @returns {void}
 * @throws {Error} When the `ConfigArray` is not normalized.
 */
function assertNormalized(configArray) {
    // TODO: Throw more verbose error
    if (!configArray.isNormalized()) {
        throw new Error('ConfigArray must be normalized to perform this operation.');
    }
}

/**
 * Ensures that config types are valid.
 * @param {Array<string>} extraConfigTypes The config types to check.
 * @returns {void}
 * @throws {Error} When the config types array is invalid.
 */
function assertExtraConfigTypes(extraConfigTypes) {
    if (extraConfigTypes.length > 2) {
        throw new TypeError('configTypes must be an array with at most two items.');
    }

    for (const configType of extraConfigTypes) {
        if (!CONFIG_TYPES.has(configType)) {
            throw new TypeError(`Unexpected config type "${configType}" found. Expected one of: "object", "array", "function".`);
        }
    }
}

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

const ConfigArraySymbol = {
    isNormalized: Symbol('isNormalized'),
    configCache: Symbol('configCache'),
    schema: Symbol('schema'),
    finalizeConfig: Symbol('finalizeConfig'),
    preprocessConfig: Symbol('preprocessConfig')
};

// used to store calculate data for faster lookup
const dataCache = new WeakMap();

/**
 * Represents an array of config objects and provides method for working with
 * those config objects.
 */
class ConfigArray extends Array {

    /**
     * Creates a new instance of ConfigArray.
     * @param {Iterable|Function|Object} configs An iterable yielding config
     *      objects, or a config function, or a config object.
     * @param {string} [options.basePath=""] The path of the config file
     * @param {boolean} [options.normalized=false] Flag indicating if the
     *      configs have already been normalized.
     * @param {Object} [options.schema] The additional schema 
     *      definitions to use for the ConfigArray schema.
     * @param {Array<string>} [options.configTypes] List of config types supported.
     */
    constructor(configs, {
        basePath = '',
        normalized = false,
        schema: customSchema,
        extraConfigTypes = []
    } = {}
    ) {
        super();

        /**
         * Tracks if the array has been normalized.
         * @property isNormalized
         * @type boolean
         * @private
         */
        this[ConfigArraySymbol.isNormalized] = normalized;

        /**
         * The schema used for validating and merging configs.
         * @property schema
         * @type ObjectSchema
         * @private
         */
        this[ConfigArraySymbol.schema] = new objectSchema.ObjectSchema(
            Object.assign({}, customSchema, baseSchema)
        );

        /**
         * The path of the config file that this array was loaded from.
         * This is used to calculate filename matches.
         * @property basePath
         * @type string
         */
        this.basePath = basePath;

        assertExtraConfigTypes(extraConfigTypes);

        /**
         * The supported config types.
         * @property configTypes
         * @type Array<string>
         */
        this.extraConfigTypes = Object.freeze([...extraConfigTypes]);

        /**
         * A cache to store calculated configs for faster repeat lookup.
         * @property configCache
         * @type Map
         * @private
         */
        this[ConfigArraySymbol.configCache] = new Map();

        // init cache
        dataCache.set(this, {
            explicitMatches: new Map(),
            directoryMatches: new Map(),
            files: undefined,
            ignores: undefined
        });

        // load the configs into this array
        if (Array.isArray(configs)) {
            this.push(...configs);
        } else {
            this.push(configs);
        }

    }

    /**
     * Prevent normal array methods from creating a new `ConfigArray` instance.
     * This is to ensure that methods such as `slice()` won't try to create a 
     * new instance of `ConfigArray` behind the scenes as doing so may throw
     * an error due to the different constructor signature.
     * @returns {Function} The `Array` constructor.
     */
    static get [Symbol.species]() {
        return Array;
    }

    /**
     * Returns the `files` globs from every config object in the array.
     * This can be used to determine which files will be matched by a
     * config array or to use as a glob pattern when no patterns are provided
     * for a command line interface.
     * @returns {Array<string|Function>} An array of matchers.
     */
    get files() {

        assertNormalized(this);

        // if this data has been cached, retrieve it
        const cache = dataCache.get(this);

        if (cache.files) {
            return cache.files;
        }

        // otherwise calculate it

        const result = [];

        for (const config of this) {
            if (config.files) {
                config.files.forEach(filePattern => {
                    result.push(filePattern);
                });
            }
        }

        // store result
        cache.files = result;
        dataCache.set(this, cache);

        return result;
    }

    /**
     * Returns ignore matchers that should always be ignored regardless of
     * the matching `files` fields in any configs. This is necessary to mimic
     * the behavior of things like .gitignore and .eslintignore, allowing a
     * globbing operation to be faster.
     * @returns {string[]} An array of string patterns and functions to be ignored.
     */
    get ignores() {

        assertNormalized(this);

        // if this data has been cached, retrieve it
        const cache = dataCache.get(this);

        if (cache.ignores) {
            return cache.ignores;
        }

        // otherwise calculate it

        const result = [];

        for (const config of this) {

            /*
             * We only count ignores if there are no other keys in the object.
             * In this case, it acts list a globally ignored pattern. If there
             * are additional keys, then ignores act like exclusions.
             */
            if (config.ignores && Object.keys(config).length === 1) {

                /*
                 * If there are directory ignores, then we need to double up
                 * the patterns to be ignored. For instance, `foo` will also
                 * need `foo/**` in order to account for subdirectories.
                 */
                config.ignores.forEach(ignore => {

                    result.push(ignore);
                    
                    if (typeof ignore === 'string') {

                        // unignoring files won't work unless we unignore directories too
                        if (ignore.startsWith('!')) {

                            if (ignore.endsWith('/**')) {
                                result.push(ignore.slice(0, ignore.length - 3));
                            } else if (ignore.endsWith('/*')) {
                                result.push(ignore.slice(0, ignore.length - 2));
                            }
                        }

                        // directories should work with or without a trailing slash
                        if (ignore.endsWith('/')) {
                            result.push(ignore.slice(0, ignore.length - 1));
                            result.push(ignore + '**');
                        } else if (!ignore.endsWith('*')) {
                            result.push(ignore + '/**');
                        }

                    }
                });
            }
        }

        // store result
        cache.ignores = result;
        dataCache.set(this, cache);

        return result;
    }

    /**
     * Indicates if the config array has been normalized.
     * @returns {boolean} True if the config array is normalized, false if not.
     */
    isNormalized() {
        return this[ConfigArraySymbol.isNormalized];
    }

    /**
     * Normalizes a config array by flattening embedded arrays and executing
     * config functions.
     * @param {ConfigContext} context The context object for config functions.
     * @returns {Promise<ConfigArray>} The current ConfigArray instance.
     */
    async normalize(context = {}) {

        if (!this.isNormalized()) {
            const normalizedConfigs = await normalize(this, context, this.extraConfigTypes);
            this.length = 0;
            this.push(...normalizedConfigs.map(this[ConfigArraySymbol.preprocessConfig].bind(this)));
            this.forEach(assertValidFilesAndIgnores);
            this[ConfigArraySymbol.isNormalized] = true;

            // prevent further changes
            Object.freeze(this);
        }

        return this;
    }

    /**
     * Normalizes a config array by flattening embedded arrays and executing
     * config functions.
     * @param {ConfigContext} context The context object for config functions.
     * @returns {ConfigArray} The current ConfigArray instance.
     */
    normalizeSync(context = {}) {

        if (!this.isNormalized()) {
            const normalizedConfigs = normalizeSync(this, context, this.extraConfigTypes);
            this.length = 0;
            this.push(...normalizedConfigs.map(this[ConfigArraySymbol.preprocessConfig].bind(this)));
            this.forEach(assertValidFilesAndIgnores);
            this[ConfigArraySymbol.isNormalized] = true;

            // prevent further changes
            Object.freeze(this);
        }

        return this;
    }

    /**
     * Finalizes the state of a config before being cached and returned by
     * `getConfig()`. Does nothing by default but is provided to be
     * overridden by subclasses as necessary.
     * @param {Object} config The config to finalize.
     * @returns {Object} The finalized config.
     */
    [ConfigArraySymbol.finalizeConfig](config) {
        return config;
    }

    /**
     * Preprocesses a config during the normalization process. This is the
     * method to override if you want to convert an array item before it is
     * validated for the first time. For example, if you want to replace a
     * string with an object, this is the method to override.
     * @param {Object} config The config to preprocess.
     * @returns {Object} The config to use in place of the argument.
     */
    [ConfigArraySymbol.preprocessConfig](config) {
        return config;
    }

    /**
     * Determines if a given file path explicitly matches a `files` entry
     * and also doesn't match an `ignores` entry. Configs that don't have
     * a `files` property are not considered an explicit match.
     * @param {string} filePath The complete path of a file to check.
     * @returns {boolean} True if the file path matches a `files` entry
     *         or false if not.
     */
    isExplicitMatch(filePath) {

        assertNormalized(this);

        const cache = dataCache.get(this);

        // first check the cache to avoid duplicate work
        let result = cache.explicitMatches.get(filePath);

        if (typeof result == 'boolean') {
            return result;
        }

        // TODO: Maybe move elsewhere? Maybe combine with getConfig() logic?
        const relativeFilePath = path.relative(this.basePath, filePath);

        if (shouldIgnorePath(this.ignores, filePath, relativeFilePath)) {
            debug(`Ignoring ${filePath}`);

            // cache and return result
            cache.explicitMatches.set(filePath, false);
            return false;
        }

        // filePath isn't automatically ignored, so try to find a match

        for (const config of this) {

            if (!config.files) {
                continue;
            }

            if (pathMatches(filePath, this.basePath, config)) {
                debug(`Matching config found for ${filePath}`);
                cache.explicitMatches.set(filePath, true);
                return true;
            }
        }

        return false;
    }

    /**
     * Returns the config object for a given file path.
     * @param {string} filePath The complete path of a file to get a config for.
     * @returns {Object} The config object for this file.
     */
    getConfig(filePath) {

        assertNormalized(this);

        const cache = this[ConfigArraySymbol.configCache];

        // first check the cache for a filename match to avoid duplicate work
        let finalConfig = cache.get(filePath);

        if (finalConfig) {
            return finalConfig;
        }

        // next check to see if the file should be ignored

        // check if this should be ignored due to its directory
        if (this.isDirectoryIgnored(path.dirname(filePath))) {
            debug(`Ignoring ${filePath} based on directory pattern`);

            // cache and return result - finalConfig is undefined at this point
            cache.set(filePath, finalConfig);
            return finalConfig;
        }

        // TODO: Maybe move elsewhere?
        const relativeFilePath = path.relative(this.basePath, filePath);

        if (shouldIgnorePath(this.ignores, filePath, relativeFilePath)) {
            debug(`Ignoring ${filePath} based on file pattern`);

            // cache and return result - finalConfig is undefined at this point
            cache.set(filePath, finalConfig);
            return finalConfig;
        }

        // filePath isn't automatically ignored, so try to construct config

        const matchingConfigIndices = [];
        let matchFound = false;
        const universalPattern = /\/\*{1,2}$/;

        this.forEach((config, index) => {

            if (!config.files) {

                if (!config.ignores) {
                    debug(`Anonymous universal config found for ${filePath}`);
                    matchingConfigIndices.push(index);
                    return;
                }

                if (pathMatchesIgnores(filePath, this.basePath, config)) {
                    debug(`Matching config found for ${filePath} (based on ignores: ${config.ignores})`);
                    matchingConfigIndices.push(index);
                    return;
                }
                
                debug(`Skipped config found for ${filePath} (based on ignores: ${config.ignores})`);
                return;
            }

            /*
             * If a config has a files pattern ending in /** or /*, and the
             * filePath only matches those patterns, then the config is only
             * applied if there is another config where the filePath matches
             * a file with a specific extensions such as *.js.
             */

            const universalFiles = config.files.filter(
                pattern => universalPattern.test(pattern)
            );

            // universal patterns were found so we need to check the config twice
            if (universalFiles.length) {

                debug('Universal files patterns found. Checking carefully.');

                const nonUniversalFiles = config.files.filter(
                    pattern => !universalPattern.test(pattern)
                );

                // check that the config matches without the non-universal files first
                if (
                    nonUniversalFiles.length && 
                    pathMatches(
                        filePath, this.basePath,
                        { files: nonUniversalFiles, ignores: config.ignores }
                    )
                ) {
                    debug(`Matching config found for ${filePath}`);
                    matchingConfigIndices.push(index);
                    matchFound = true;
                    return;
                }

                // if there wasn't a match then check if it matches with universal files
                if (
                    universalFiles.length &&
                    pathMatches(
                        filePath, this.basePath,
                        { files: universalFiles, ignores: config.ignores }
                    )
                ) {
                    debug(`Matching config found for ${filePath}`);
                    matchingConfigIndices.push(index);
                    return;
                }

                // if we make here, then there was no match
                return;
            }

            // the normal case
            if (pathMatches(filePath, this.basePath, config)) {
                debug(`Matching config found for ${filePath}`);
                matchingConfigIndices.push(index);
                matchFound = true;
                return;
            }

        });

        // if matching both files and ignores, there will be no config to create
        if (!matchFound) {
            debug(`No matching configs found for ${filePath}`);

            // cache and return result - finalConfig is undefined at this point
            cache.set(filePath, finalConfig);
            return finalConfig;
        }

        // check to see if there is a config cached by indices
        finalConfig = cache.get(matchingConfigIndices.toString());

        if (finalConfig) {

            // also store for filename for faster lookup next time
            cache.set(filePath, finalConfig);

            return finalConfig;
        }

        // otherwise construct the config

        finalConfig = matchingConfigIndices.reduce((result, index) => {
            return this[ConfigArraySymbol.schema].merge(result, this[index]);
        }, {}, this);

        finalConfig = this[ConfigArraySymbol.finalizeConfig](finalConfig);

        cache.set(filePath, finalConfig);
        cache.set(matchingConfigIndices.toString(), finalConfig);

        return finalConfig;
    }

    /**
     * Determines if the given filepath is ignored based on the configs.
     * @param {string} filePath The complete path of a file to check.
     * @returns {boolean} True if the path is ignored, false if not.
     * @deprecated Use `isFileIgnored` instead.
     */
    isIgnored(filePath) {
        return this.isFileIgnored(filePath);
    }

    /**
     * Determines if the given filepath is ignored based on the configs.
     * @param {string} filePath The complete path of a file to check.
     * @returns {boolean} True if the path is ignored, false if not.
     */
    isFileIgnored(filePath) {
        return this.getConfig(filePath) === undefined;
    }

    /**
     * Determines if the given directory is ignored based on the configs.
     * This checks only default `ignores` that don't have `files` in the 
     * same config. A pattern such as `/foo` be considered to ignore the directory
     * while a pattern such as `/foo/**` is not considered to ignore the
     * directory because it is matching files.
     * @param {string} directoryPath The complete path of a directory to check.
     * @returns {boolean} True if the directory is ignored, false if not. Will
     *         return true for any directory that is not inside of `basePath`.
     * @throws {Error} When the `ConfigArray` is not normalized.
     */
    isDirectoryIgnored(directoryPath) {

        assertNormalized(this);

        const relativeDirectoryPath = path.relative(this.basePath, directoryPath)
            .replace(/\\/g, '/');

        if (relativeDirectoryPath.startsWith('..')) {
            return true;
        }

        // first check the cache
        const cache = dataCache.get(this).directoryMatches;

        if (cache.has(relativeDirectoryPath)) {
            return cache.get(relativeDirectoryPath);
        }

        const directoryParts = relativeDirectoryPath.split('/');
        let relativeDirectoryToCheck = '';
        let result = false;

        /*
         * In order to get the correct gitignore-style ignores, where an
         * ignored parent directory cannot have any descendants unignored,
         * we need to check every directory starting at the parent all
         * the way down to the actual requested directory.
         * 
         * We aggressively cache all of this info to make sure we don't
         * have to recalculate everything for every call.
         */
        do {

            relativeDirectoryToCheck += directoryParts.shift() + '/';

            result = shouldIgnorePath(
                this.ignores,
                path.join(this.basePath, relativeDirectoryToCheck),
                relativeDirectoryToCheck
            );

            cache.set(relativeDirectoryToCheck, result);

        } while (!result && directoryParts.length);

        // also cache the result for the requested path
        cache.set(relativeDirectoryPath, result);

        return result;
    }

}

exports.ConfigArray = ConfigArray;
exports.ConfigArraySymbol = ConfigArraySymbol;