var fs = require("fs");
var p = require("path");
var minimatch = require("minimatch");

function patternMatcher(pattern) {
    return function(path, stats) {
        var minimatcher = new minimatch.Minimatch(pattern, { matchBase: true });
        return (!minimatcher.negate || stats.isFile()) && minimatcher.match(path);
    };
}

function toMatcherFunction(ignoreEntry) {
    if (typeof ignoreEntry == "function") {
        return ignoreEntry;
    } else {
        return patternMatcher(ignoreEntry);
    }
}

function readdir(path, ignores, callback) {
    if (typeof ignores == "function") {
        callback = ignores;
        ignores = [];
    }

    if (!callback) {
        return new Promise(function(resolve, reject) {
            readdir(path, ignores || [], function(err, data) {
                if (err) {
                    reject(err);
                } else {
                    resolve(data);
                }
            });
        });
    }

    ignores = ignores.map(toMatcherFunction);

    var list = [];

    fs.readdir(path, function(err, files) {
        if (err) {
            return callback(err);
        }

        var pending = files.length;
        if (!pending) {
            // we are done, woop woop
            return callback(null, list);
        }

        files.forEach(function(file)
        {
            var filePath = p.join(path, file);
            fs.stat(filePath, function(_err, stats)
            {
                if (_err)
                {
                    //return callback(_err);
                    return callback(null, list);
                }
                else
                {

                    if (
                        ignores.some(function(matcher) {
                            return matcher(filePath, stats);
                        })
                    ) {
                        pending -= 1;
                        if (!pending) {
                            return callback(null, list);
                        }
                        return null;
                    }

                    if (stats.isDirectory()) {
                        readdir(filePath, ignores, function(__err, res) {
                            if (__err) {
                                return callback(__err);
                            }

                            list = list.concat(res);
                            pending -= 1;
                            if (!pending) {
                                return callback(null, list);
                            }
                        });
                    } else {
                        list.push(filePath);
                        pending -= 1;
                        if (!pending) {
                            return callback(null, list);
                        }
                    }
                }
            });
        });
    });
}

module.exports = readdir;