#!/usr/bin/env python3

################################################################################
# BSD LICENSE
#
# Copyright(c) 2019-2020 Intel Corporation. All rights reserved.
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# modification, are permitted provided that the following conditions
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#     notice, this list of conditions and the following disclaimer.
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#     contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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################################################################################

"""
Main module.
Parses command line arguments, sets up logging, initialises libpqos,
starts REST API server and runs main loop (AppQoS)
"""

import argparse
import multiprocessing
import signal
import syslog
import time

import cache_ops
import caps
import common
import log
import power
from rest import rest_server
import sstbf

class AppQoS:
    """
    Main logic.
    Loads config file.
    Applies initial Intel RDT and SST-BF configuration.
    Handles configuration changes.
    """


    def __init__(self):
        self.stop_event = multiprocessing.Event()


    def run(self, args):
        """
        Runs main loop.

        Parameters:
            args: command line arguments
        """

        # load config file
        try:
            common.CONFIG_STORE.from_file(args.config)
        except IOError as ex:
            log.error("Error reading from config file {}... ".format(args.config))
            log.error(ex)
            return
        except Exception as ex:
            log.error("Invalid config file {}... ".format(args.config))
            log.error(ex)
            return

        log.debug("Cores controlled: {}".\
            format(common.CONFIG_STORE.get_pool_attr('cores', None)))

        data = common.CONFIG_STORE.get_config()
        for pool in data['pools']:
            log.debug("Pool: {}/{} Cores: {}, Apps: {}".format(pool.get('name'),\
                pool.get('id'), pool.get('cores'), pool.get('apps')))

        # set initial SST-BF configuration
        if caps.sstbf_enabled():
            result = sstbf.init_sstbf()
            if result != 0:
                log.error("Failed to apply initial SST-BF configuration, terminating...")
                return

            log.info("SST-BF enabled, {}configured.".\
                format("not " if not sstbf.is_sstbf_configured() else ""))
            log.info("SST-BF HP cores: {}".format(sstbf.get_hp_cores()))
            log.info("SST-BF STD cores: {}".format(sstbf.get_std_cores()))
        else:
            log.info("SST-BF not enabled")

        # set initial SST-CP configuration if SST-BF is not configured
        if caps.sstcp_enabled():
            if sstbf.is_sstbf_configured():
                log.info("Power Profiles/SST-CP enabled, not configured, SST-BF is configured")
            else:
                log.info("Power Profiles/SST-CP enabled.")
                # set initial POWER configuration
                result = power.configure_power()
                if result != 0:
                    log.error("Failed to apply initial Power Profiles configuration,"\
                        " terminating...")
                    return
        else:
            log.info("Power Profiles/EPP not enabled")

        # set initial RDT configuration
        log.info("Configuring RDT")
        result = cache_ops.configure_rdt()
        if result != 0:
            log.error("Failed to apply initial RDT configuration, terminating...")
            return

        # set CTRL+C sig handler
        signal.signal(signal.SIGINT, self.signal_handler)

        self.event_handler()

        log.info("Terminating...")


    def event_handler(self):
        """
        Handles config_changed event
        """

        # rate limiting
        last_cfg_change_ts = 0
        min_time_diff = 1 / common.RATE_LIMIT

        while not self.stop_event.is_set():
            if common.CONFIG_STORE.is_config_changed():

                time_diff = time.time() - last_cfg_change_ts
                if time_diff < min_time_diff:
                    log.info("Rate Limiter, sleeping " \
                        + str(round((min_time_diff - time_diff) * 1000)) + "ms...")
                    time.sleep(min_time_diff - time_diff)

                log.info("Configuration changed, processing new config...")
                result = cache_ops.configure_rdt()
                if result != 0:
                    log.error("Failed to apply RDT configuration!")
                    break

                if caps.sstcp_enabled() and not sstbf.is_sstbf_configured():
                    result = power.configure_power()
                    if result != 0:
                        log.error("Failed to apply Power Profiles configuration!")
                        break

                last_cfg_change_ts = time.time()


    def signal_handler(self, _signum, _frame):
        """
        Handles CTR+C
        """

        print("CTRL+C...")
        self.stop_event.set()


def main():
    """
    Main entry point
    """

    # parse command line arguments
    parser = argparse.ArgumentParser()
    parser.add_argument('-c', '--config', metavar="PATH", default=common.CONFIG_FILENAME,
                        help="Configuration file path")
    parser.add_argument('--port', metavar=("PORT"), default=[5000], type=int, nargs=1,
                        help="REST API port")
    parser.add_argument('-V', '--verbose', action='store_true', help="Verbose mode")
    cmd_args = parser.parse_args()

    # configure syslog output
    syslog.openlog("AppQoS")

    if cmd_args.verbose:
        log.enable_verbose()

    # initialize libpqos/Intel RDT interface
    result = common.PQOS_API.init()
    if result != 0:
        log.error("libpqos initialization failed, Terminating...")
        return

    # initialize capabilities
    result = caps.caps_init()
    if result == 0:
        # initialize main logic
        app_qos = AppQoS()

        # start REST API server
        server = rest_server.Server()
        result = server.start("127.0.0.1", cmd_args.port[0], cmd_args.verbose)
        if result == 0:
            # run main logic
            app_qos.run(cmd_args)

            # stop REST API server
            server.terminate()
        else:
            log.error("Failed to start REST API server, Terminating...")
    else:
        log.error("Required capabilities not supported, Terminating...")

    # de-initialize libpqos
    common.PQOS_API.fini()


if __name__ == '__main__':
    main()