from sys import stdout
class progress_range:
    def __init__(self, total, progress_unit_str="#", bar_width=50):
        self.total = total
        self.bar_width = int(bar_width)
        self.step = bar_width/total
        self.current = -1
        self.progress_unit_str = progress_unit_str
        self.msg_format = "\r[{:" + str(int(bar_width)) + "}] {}/{}"

    def __iter__(self):
        return self

    def __next__(self):
        if self.current == (self.total - 1):
            raise StopIteration
        else:
            self.current += 1
            count = int(self.step*(self.current+1))
            bar = self.progress_unit_str * (count if count <= self.bar_width else self.bar_width)
            self.message = self.msg_format.format(bar, self.current+1, self.total)
            stdout.write(self.message)
            stdout.flush()
        return self.current

    def update(self, msg):
        update = "{} {}".format(self.message, msg)
        stdout.write(update)
        stdout.flush()