import os
import time
from threading import Thread


class LogWatcher:
    def __init__(self):
        self.active = True
        self.t = None
        self.filename = None
        self.file_error = False

    def follow(self, thefile):
        thefile.seek(0, 2)  # Go to the end of the file
        while self.active:
            line = thefile.readline()
            if not line:
                time.sleep(0.1)  # Sleep briefly
                continue
            yield line

    def run(self):
        while not os.path.exists(self.filename):
            time.sleep(1)
            if not self.active:
                self.file_error = True
                return
        logfile = open(self.filename)
        print(logfile.read())
        loglines = self.follow(logfile)
        for line in loglines:
            print(line, end='')

    def start(self, filename):
        self.filename = filename
        self.t = Thread(target=self.run)
        self.t.start()

    def stop(self):
        self.active = False
        self.t.join()
        if not self.file_error:
            # delete log file
            os.remove(self.filename)


log_watcher = LogWatcher()