#!/usr/bin/env python3
#
# Copyright 2017 Ettus Research, a National Instruments Company
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
"""
Main executable for the USRP Hardware Daemon
"""
from __future__ import print_function
import sys
import time
import argparse
from gevent import signal
import usrp_mpm as mpm
import usrp_mpm.rpc_server
import usrp_mpm.discovery
from usrp_mpm.mpmtypes import SharedState
from usrp_mpm.sys_utils import watchdog

# pylint: disable=wrong-import-order
# We have to import threading here because it must be imported after
# gevent.monkey.patch_all is called in rpc_server.py.
# (imported in the usrp_mpm __init__.py)
from threading import Event, Thread

_PROCESSES = []
_KILL_EVENT = Event()
# This Global Variable is used by the Simulator to make the spawn_processes,
# and by extension the main method, exit without waiting for the simulator to stop.
# See process_manager.py:bootstrap() for more information.
JOIN_PROCESSES = True

def setup_arg_parser():
    """
    Create an arg parser
    """
    parser = argparse.ArgumentParser(description="USRP Hardware Daemon")
    parser.add_argument(
        '--no-logbuf',
        dest='use_logbuf',
        help="Do not send log messages to UHD",
        action="store_false",
    )
    parser.add_argument(
        '--daemon',
        help="Run as daemon",
        action="store_true",
    )
    parser.add_argument(
        '--init-only',
        help="Don't start the RPC server, terminate after running initialization",
        action="store_true",
    )
    parser.add_argument(
        '--override-db-pids',
        help="Provide a comma-separated list of daughterboard PIDs that are " \
             "used instead of whatever else the code may find",
        default=None
    )
    parser.add_argument(
        '--discovery-addr',
        help="Bind discovery socket to this address only. Defaults to all " \
             "addresses.",
        default="0.0.0.0",
    )
    parser.add_argument(
        '--default-args',
        help="Provide a comma-separated list of key=value pairs that are" \
             "used as defaults for device initialization.",
        default=None
    )
    parser.add_argument(
        '-v',
        '--verbose',
        help="Increase verbosity level",
        action="count",
        default=0
    )
    parser.add_argument(
        '-q',
        '--quiet',
        help="Decrease verbosity level",
        action="count",
        default=0
    )
    return parser

def parse_args():
    """
    Return a fully parse args object
    """
    args = setup_arg_parser().parse_args()
    args.default_args = args.default_args or ''
    try:
        args.default_args = {
            x.split('=')[0].strip(): x.split('=')[1].strip()
                                     if x.find('=') != -1 else ''
            for x in args.default_args.split(',')
            if len(x)
        }
    except IndexError:
        print("Could not parse default device args: `{}'".format(
            args.default_args))
    return args


def kill_time(sig, frame):
    """
    kill all processes by setting _KILL_EVENT
    to be used in a signal handler
    """
    _KILL_EVENT.set()

def kill_thread():
    """
    Kill all processes after _KILL_EVENT is triggered
    If all processes are properly terminated, this will exit
    """
    _KILL_EVENT.wait()
    log = mpm.get_main_logger().getChild('kill')
    for proc in _PROCESSES:
        proc.terminate()
        log.info("Terminating pid: {0}".format(proc.pid))
    for proc in _PROCESSES:
        proc.join()
    log.info("System exiting")
    sys.exit(0)

def init_only(log, default_args):
    """
    Run the full initialization immediately and return
    """
    # Create the periph_manager for this device
    # This call will be forwarded to the device specific implementation
    # e.g. in periph_manager/n3xx.py
    # Which implementation is called will be determined during
    # configuration with cmake (-DMPM_DEVICE).
    # mgr is thus derived from PeriphManagerBase
    # (see periph_manager/base.py)
    from usrp_mpm.periph_manager import periph_manager
    log.info("Spawning periph manager...")
    ctor_time_start = time.time()
    mgr = periph_manager(default_args)
    ctor_duration = time.time() - ctor_time_start
    log.info("Ctor Duration: {:.02f} s".format(ctor_duration))
    init_time_start = time.time()
    init_result = mgr.init(default_args)
    init_duration = time.time() - init_time_start
    if init_result:
        log.info("Initialization successful! Duration: {:.02f} s"
                 .format(init_duration))
    else:
        log.warning("Initialization failed! Duration: {:.02f} s"
                    .format(init_duration))
    log.info("Terminating on user request before launching RPC server.")
    mgr.deinit()
    return init_result

def spawn_processes(log, args):
    """
    Launch the subprocesses and hang until completion.
    """
    shared = SharedState()
    log.info("Spawning RPC process...")
    _PROCESSES.append(
        mpm.rpc_server.spawn_rpc_process(
            shared, mpm.mpmtypes.MPM_RPC_PORT, args.default_args))
    log.debug("RPC process has PID: %d", _PROCESSES[-1].pid)
    if watchdog.has_watchdog():
        watchdog.transfer_control(_PROCESSES[-1].pid)
    log.info("Spawning discovery process...")
    _PROCESSES.append(
        mpm.discovery.spawn_discovery_process(shared, args.discovery_addr)
    )
    log.debug("Discovery process has PID: %d", _PROCESSES[-1].pid)
    log.info("Processes launched. Registering signal handlers.")
    # Launch the kill thread
    # This is used because we cannot block in a signal handler,
    # meaning we cannot join threads
    Thread(target=kill_thread, daemon=False).start()
    signal.signal(signal.SIGTERM, kill_time)
    signal.signal(signal.SIGINT, kill_time)
    if JOIN_PROCESSES:
        for proc in _PROCESSES:
            proc.join()
    return True

def main():
    """
    Go, go, go!

    Main process loop.
    """
    args = parse_args()
    log = mpm.get_main_logger(
        use_logbuf=args.use_logbuf,
        log_default_delta=args.verbose-args.quiet
    ).getChild('main')
    version_string = mpm.__version__
    if mpm.__githash__:
        version_string += "-g" + mpm.__githash__
    log.info("Launching USRP/MPM, version: %s", version_string)
    if args.init_only:
        # If --init-only is provided, we force disable init during boot time so
        # we can properly time it in init_only().
        args.default_args['skip_boot_init'] = "1"
    if args.override_db_pids is not None:
        log.warning('Overriding daughterboard PIDs!')
        args.default_args['override_db_pids'] = args.override_db_pids
    if args.init_only:
        return init_only(log, args.default_args)
    return spawn_processes(log, args)

if __name__ == '__main__':
    sys.exit(not main())
