#!/usr/bin/env python
#
# $Id:$
#
# hd_pxi_disk_monitor.py
#
# This script helps make sure the PXI system is recording data
# on gluonraid1, signaling the alarm system if it is not.
#
# This can be run from any computer with /gluonraid1 mounted.
# Typically though, it should be run from gluonraid1 itself
# so we know where to look for the process in order to kill it.
# Run it from the HDOPS account like this:
#
#  > $DAQ_HOME/tools/raidutils/hd_pxi_disk_monitor.py
#
# This script will check that a recent ROOT file exists in the
# /raid/Users/pxi directory. It will update an EPICS heartbeat
# variable to which an alarm is attached. If this script stops
# running, or does not detect a recent ROOT file, the heartbeat
# stops and an alarm is raised.
#
# Because this is only needed when the solenoid is on, then the
# hearbeat is automatically updated if the solenoid current is
# reported as less then 100A by EPICS.
#
# The EPICS variable giving the directory to check is EPICS_PXI_DIR
# The EPICS variable to update as a heartbeat is given in EPICS_HEARTBEAT
# The EPICS variable to read the solenoid current from is EPICS_SOLENOID
# The period in which to check is PERIOD and is given in seconds
#
# If a directory is given on the command line using the "-d dir" 
# option then it is used and EPICS_PXI_DIR is ignored
#
# This file is kept under version control at the following location:
#
# https://halldsvn.jlab.org/repos/trunk/online/daq/tools/raidutils/hd_pxi_disk_monitor.py
#
#
#  --- RUN THIS ON GLUONRAID1 ---
#

import os
import sys
import time
import datetime
import getopt
from epics import caget, caput

PXI_DIR = '/gluonraid1/Users/pxi' # directory to check for ROOT files
VERBOSE = False

EPICS_PXI_DIR   = 'pxiroot:ctrl:file_dir'
EPICS_HEARTBEAT = 'pxiroot:ctrl:raid:heartbeat'
EPICS_SOLENOID  = 'HallD-PXI:Data:I_Shunt'
PERIOD  = 2 # seconds between checks (and heartbeats)

PXI_DIR_OVERRIDE = None

def Usage(err):
	print 'Usage:'
	print '   hd_pxi_disk_monitor.py [-v] [-p period_secs] [-d directory]'
	print ' '
	sys.exit(err)


# Parse command line arguments
try:
	opts, args = getopt.getopt(sys.argv[1:], 'p:d:vh', ['pause=','dir=','verbose','help'])
except getopt.GetoptError:
	Usage(2)

for opt,arg in opts:
	if opt in ("-h", "--help")    : Usage(0)
	if opt in ("-p", "--pause")   : PERIOD = int(arg)
	if opt in ("-d", "--dir")     : PXI_DIR_OVERRIDE = arg
	if opt in ("-v", "--verbose") : VERBOSE = True



# Loop forever
first_iteration = True
heartbeat = 0
while True:

	# Get directory to check from EPICS, allowing user to override
	if PXI_DIR_OVERRIDE==None:
		PXI_DIR = caget('pxiroot:ctrl:file_dir')
	else:
		PXI_DIR = PXI_DIR_OVERRIDE

	# If EPICS variable was not available, then PXI_DIR will be None
	if PXI_DIR==None: PXI_DIR='/could/not/get/dir/from/epics'

	# Make sure PXI_DIR exists
	if not os.path.exists(PXI_DIR) :
		print '-------------------------------------'
		print 'path "%s" does not exist!' % PXI_DIR
		print 'hd_pxi_disk_monitor.py exiting ..'
		print '-------------------------------------'
		break

	# Get list of root files in PXI_DIR
	files = [os.path.join(PXI_DIR, f) for f in os.listdir(PXI_DIR) if os.path.isfile(os.path.join(PXI_DIR, f))]
	rootfiles = [f for f in files if f.endswith('.root')]
	
	if len(rootfiles) >= 1 :

		# Find most recently modified rootfile
		t_latest = 0
		f_latest = 'none'
		for f in rootfiles:
			t = os.path.getmtime(f)
			if t>t_latest:
				t_latest = t
				f_latest = f

		# Time since modification in seconds
		t_diff = time.time() - t_latest

		# Solenoid current
		isolenoid = caget(EPICS_SOLENOID)
		if isolenoid == None : isolenoid = 199.0

		# Print info only on first iteration
		if first_iteration :
			print '-------------------------------------'
			print 'hd_pxi_disk_monitor.py starting'
			print ''
			print '         VERBOSE: %s' % VERBOSE
			print '          PERIOD: %d' % PERIOD
			print '         PXI_DIR: %s' % PXI_DIR
			print '  EPICS PV names: %s' % EPICS_SOLENOID
			print '                  %s' % EPICS_HEARTBEAT
			print 'newest root file: %s (%f minutes old)' % (f_latest, t_diff/60.0)
			print '       Isolenoid: %f' % isolenoid
			print '-------------------------------------'
			first_iteration = False


		# Update heartbeat if file is less than 30 minutes old
		# or solenoid is less than 100A
		if t_diff<30*60 or isolenoid<100.0:

			# Update heartbeat
			myheartbeat = caget(EPICS_HEARTBEAT)
			if myheartbeat == None:
				print 'Failed to read hearbeat value from EPICS variable: %s setting to %d' % (EPICS_HEARTBEAT, heartbeat)
			else:
				heartbeat = myheartbeat

			heartbeat += 1
			if heartbeat>1: heartbeat = 0
			caput(EPICS_HEARTBEAT, heartbeat)

		if VERBOSE :
			print '%s : %f min old' % (f_latest, t_diff/60.0)

	# Sleep
	time.sleep(PERIOD)