#!/usr/bin/env python3


import os
import sys
import time
import signal
import subprocess
import re

# check for the venv
from lib import sanity_check
sanity_check.check_venv(__file__)

from typing import IO

# TODO: Convert this to use scripts/lib/queue_workers.py
TOOLS_DIR = os.path.dirname(os.path.abspath(__file__))
successful_worker_launches = [
    '[process_queue] 20 queue worker threads were launched',
]

def check_worker_launch(logfile_name):
    # type: (str) -> bool
    def check(content):
        # type: (str) -> bool
        flag = True
        for entry in successful_worker_launches:
            flag = flag and entry in content
        return flag

    failed = True
    log_output = []
    print("Polling logfile", end='')
    logfile = open(logfile_name, 'rb', buffering=0)
    # Attempt to poll the log file for 60 sec. to see if all worker threads are launched.
    for i in range(200):
        time.sleep(0.3)
        sys.stdout.write('.')
        sys.stdout.flush()
        new_data = logfile.read().decode()
        if new_data:
            log_output.append(new_data)

        if check(''.join(log_output)):
            failed = False
            break
    sys.stdout.write('\n')
    logfile.close()

    if not failed:
        print('Worker threads launched successfully')
    else:
        print('Error in server startup. Dumping logs')
        print(''.join(log_output))

    return failed

if __name__ == '__main__':
    print('\nStarting Development Server')
    logfile_name = '/tmp/run-dev-output'
    logfile = open(logfile_name, 'wb', buffering=0)
    args = ["{}/run-dev.py".format(TOOLS_DIR)]
    run_dev = subprocess.Popen(args, stdout=logfile, stderr=subprocess.STDOUT)

    failed = check_worker_launch(logfile_name)
    if failed:
        run_dev.send_signal(signal.SIGINT)
        run_dev.wait()
        logfile.close()
        sys.exit(1)

    # In dev. environment, queues are run through Django's autoreload code. The
    # autoreload code of Django works by looping over the files associated with
    # all the loaded modules. This loop is run after every 1 second. If the
    # file is found for the first time by the loop, it is assumed that the
    # file is new and is not modified between the time it is loaded and is
    # checked by the loop. This assumption is the source of a race condition.

    # We can either implement a more sensitive version of the loop or we can
    # just allow enough time to the Django loop to touch every file at least
    # once.
    time.sleep(1.3)
    # Removing all data from the server log file.
    logfile.truncate(0)
    logfile.seek(0)

    print("Attempting to modify a file")
    os.utime('zerver/lib/actions.py')
    failed = check_worker_launch(logfile_name)

    run_dev.send_signal(signal.SIGINT)
    run_dev.wait()
    logfile.close()
    if failed:
        sys.exit(1)