/*
 Copyright (c) 2012, Yahoo! Inc.  All rights reserved.
 Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
 */

var async = require('async'),
    fileset = require('fileset'),
    fs = require('fs'),
    path = require('path'),
    seq = 0;

function filesFor(options, callback) {
    if (!callback && typeof options === 'function') {
        callback = options;
        options = null;
    }
    options = options || {};

    var root = options.root,
        includes = options.includes,
        excludes = options.excludes,
        realpath = options.realpath,
        relative = options.relative,
        opts;

    root = root || process.cwd();
    includes = includes && Array.isArray(includes) ? includes : [ '**/*.js' ];
    excludes = excludes && Array.isArray(excludes) ? excludes : [ '**/node_modules/**' ];

    opts = { cwd: root, nodir: true };
    seq += 1;
    opts['x' + seq + new Date().getTime()] = true; //cache buster for minimatch cache bug
    fileset(includes.join(' '), excludes.join(' '), opts, function (err, files) {
        if (err) { return callback(err); }
        if (relative) { return callback(err, files); }

        if (!realpath) {
            files = files.map(function (file) { return path.resolve(root, file); });
            return callback(err, files);
        }

        var realPathCache = module.constructor._realpathCache || {};

        async.map(files, function (file, done) {
            fs.realpath(path.resolve(root, file), realPathCache, done);
        }, callback);
    });
}

function matcherFor(options, callback) {

    if (!callback && typeof options === 'function') {
        callback = options;
        options = null;
    }
    options = options || {};
    options.relative = false; //force absolute paths
    options.realpath = true; //force real paths (to match Node.js module paths)

    filesFor(options, function (err, files) {
        var fileMap = {},
            matchFn;
        if (err) { return callback(err); }
        files.forEach(function (file) { fileMap[file] = true; });

        matchFn = function (file) { return fileMap[file]; };
        matchFn.files = Object.keys(fileMap);
        return callback(null, matchFn);
    });
}

module.exports = {
    filesFor: filesFor,
    matcherFor: matcherFor
};