#!/usr/bin/python
import fileinput
import sys
import subprocess
from OmsConfigHostHelpers import write_omsconfig_host_telemetry, write_omsconfig_host_switch_event, write_omsconfig_host_log, stop_old_host_instances
from imp                  import load_source
from os.path              import dirname, isfile, join, realpath
from time                 import sleep
from fcntl                import flock, LOCK_EX, LOCK_UN, LOCK_NB
from sys                  import argv

pathToCurrentScript = realpath(__file__)
pathToCommonScriptsFolder = dirname(pathToCurrentScript)

DSCLogPath = join(pathToCommonScriptsFolder, 'nxDSCLog.py')
nxDSCLog = load_source('nxDSCLog', DSCLogPath)
LG = nxDSCLog.DSCLog
helperLibPath = join(pathToCommonScriptsFolder, 'helperlib.py')
helperlib = load_source('helperlib', helperLibPath)

omicli_path = join(helperlib.CONFIG_BINDIR, 'omicli')
dsc_host_base_path = helperlib.DSC_HOST_BASE_PATH
dsc_host_path = join(dsc_host_base_path, 'bin/dsc_host')
dsc_host_output_path = join(dsc_host_base_path, 'output')
dsc_host_lock_path = join(dsc_host_base_path, 'dsc_host_lock')
dsc_host_switch_path = join(dsc_host_base_path, 'dsc_host_ready')

LG().Log("DEBUG", "Starting script logic for " + argv[0]+ " runing with python " + str(sys.version_info))

if ("omsconfig" in helperlib.DSC_SCRIPT_PATH):
    write_omsconfig_host_switch_event(pathToCurrentScript, isfile(dsc_host_switch_path))

if ("omsconfig" in helperlib.DSC_SCRIPT_PATH) and (isfile(dsc_host_switch_path)):
    use_omsconfig_host = True
else:
    use_omsconfig_host = False

parameters = []
if use_omsconfig_host:
    parameters.append(dsc_host_path)
    parameters.append(dsc_host_output_path)
    parameters.append("TestConfiguration")
else:
    parameters.append(omicli_path)
    parameters.append("iv")
    parameters.append("<DSC_NAMESPACE>")
    parameters.append("{")
    parameters.append("MSFT_DSCLocalConfigurationManager")
    parameters.append("}")
    parameters.append("TestConfiguration")

stdout = ''
stderr = ''

if use_omsconfig_host:
    if isfile(dsc_host_lock_path):
        try:
            dschostlock_filehandle = None
            stop_old_host_instances(dsc_host_lock_path)

            # Open the dsc host lock file. This also creates a file if it does not exist
            dschostlock_filehandle = open(dsc_host_lock_path, 'w')
            print("Opened the dsc host lock file at the path '" + dsc_host_lock_path + "'")
            
            dschostlock_acquired = False

            # Acquire dsc host file lock
            for retry in range(10):
                try:
                    flock(dschostlock_filehandle, LOCK_EX | LOCK_NB)
                    write_omsconfig_host_log('dsc_host lock file is acquired by : TestConfiguration', pathToCurrentScript)
                    dschostlock_acquired = True
                    break
                except IOError:
                    write_omsconfig_host_log('dsc_host lock file not acquired. retry (#' + str(retry) + ') after 60 seconds...', pathToCurrentScript)
                    sleep(60)

            if dschostlock_acquired:
                p = subprocess.Popen(parameters, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                stdout, stderr = p.communicate()
                exit_code = p.wait()
                print(stdout)

                if (exit_code > 0):
                    write_omsconfig_host_log('dsc_host failed with code = ' + str(exit_code), pathToCurrentScript)
                    exit(exit_code)
            else:
                print("dsc host lock already acuired by a different process")
        finally:
            if (dschostlock_filehandle):
                # Release dsc host file lock
                flock(dschostlock_filehandle, LOCK_UN)

                # Close dsc host lock file handle
                dschostlock_filehandle.close()
    else:
        write_omsconfig_host_log('dsc_host lock file does not exist. Skipping this operation until next consistency hits.', pathToCurrentScript, 'WARNING')
else:
    p = subprocess.Popen(parameters, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = p.communicate()

print(stdout)
print(stderr)

LG().Log("DEBUG", "End of script logic for " +  argv[0] + " runing with python " + str(sys.version_info))