SearchTwitterUsername.groovy

def search(String fmt) {
    def alpha = ('a'..'z').join('')
    def num = ('0'..'9').join('')
    def alphanum = alpha + num
    def all = alphanum + '_'

    def checkList = fmt.collect {
        switch (it) {
        case 'A': return alpha
        case 'N': return num
        case '.': return alphanum
        case '+': return all
        default: return it
        }
    }

    checkAll('', checkList as List)
}


def checkAll(String id, List<String> checkList) {
    if (checkList?.size() > 0) {
        checkList[0].each {
            checkAll(id + it, (checkList.size() > 1) ? checkList[1..-1] : null)
        }
    } else {
        check(id)
    }
}


def check(String id) {
    try {
        Thread.sleep(1000)
        if (valid(id)) {
            println id
        }
    } catch (Exception e) {
        try {
            Thread.sleep(3000)
            if (valid(id)) {
                println id
            }
        } catch (Exception e2) {
            println 'E:' + id
        }
    }
}


def valid(String id) {
    def url = "https://twitter.com/users/username_available?username=${id}"
    def res = new URL(url).text
    return res.contains('"valid":true')
}

search(args[0] as String)