import time


class TimerError(Exception):
    """ Manage timer errors """

class Timer:

    def __init__(
        self,
        text_out = '{}: Elapsed time: {:0.4f} seconds',
        text_in = 'Start {}',
        text_tag = 'Time elapsed for {}: {:0.4f} seconds',
        text_total = 'Total recorded time: {:0.4f} seconds',
        logger=print,
    ):
        self._start_time = None
        self.name = None
        self.text_in = text_in
        self.text_out = text_out
        self.text_tag = text_tag
        self.text_total = text_total
        self.logger = logger
        self.timers = {}

    def start(self, name='General'):
        """Start a new timer"""
        
        self.name = name
        # if timer does not exists, initiate it
        if not name in self.timers:
            self.timers[self.name] = 0

        if self._start_time is not None:
            raise TimerError('Timer is running. Use .stop() to stop it')

        self.logger(self.text_in.format(self.name))
        self._start_time = time.perf_counter()

    def stop(self):
        """Stop the timer, and report the elapsed time"""
        if self._start_time is None:
            raise TimerError('Timer is not running. Use .start() to start it')

        elapsed_time = time.perf_counter() - self._start_time
        self._start_time = None
        
        if self.logger:
            self.logger(self.text_out.format(self.name, elapsed_time))
        
        if self.name:
            self.timers[self.name] += elapsed_time

    def get_time_by_tag(self, tag):
        if tag in self.timers:
            self.logger(self.text_tag.format(tag,self.timers[tag]))

    def get_total_time(self):
        total = 0
        for v in self.timers.values():
            total += v
        self.logger(self.text_total.format(total))