#!/usr/bin/python

"""
=====================================================
=                                                   =
=  D-BUS script for changing Piding status message  =
=                                                   =
=  v.4 / 2008-10-04 / Miljan Karadzic               =
=  WWW:    http://www.miljan.org/                   =
=  E-Mail: miljank@gmail.com                        =
=                                                   =
=  Released free under "I Don't Care" license       =
=                                                   =
=====================================================
"""

"""
- How to run program
====================

pidgin_status.py -m 'My new status message' sets status to '-> My new status message'
pidgin_status.py -s 'My Favorite Band - My Favorite Song' sets status to '_| My Favorite Band - My Favorite Song'
pidgin_status.py -f /home/myself/quote/my_favorite_quotes.txt sets message to a random line from specified file

- Daemon mode
=============

'-d' argument specifies that program should run in daemon mode. This means the program will go in background
and periodically change your status message. This is most useful with '-f' option (see above).

Additionally you can specify the time interval in which the status can be changed.
'-t 5' will change status every 5 minutes. Default time interval is 10 minutes.

To change message every 15 minutes to a random line from file /home/me/file.txt you would need to run this command.
pidgin_status.py -d -t 15 -f /home/me/file.txt

You can kill the daemon by running the program with '--stop' argument.
piding_status.py --stop
"""

import os, sys, dbus
from random import randint
from time import sleep
from optparse import OptionParser

# File where we store daemon PID
pid_file = "/var/tmp/pidgin_status.pid"

# Initialize command line parser
cmd_line = OptionParser ()

"""
Function:
  set_cmd_line_opts()
	Sets and parses command line arguments
	If all necessary parameters are not set it 
	will print error message and exit.
In:
  N/A
Out:
  opt
	Command line arguments
Calls:
  N/A
"""
def set_cmd_line_opts ():
	cmd_line.add_option ("-m", "--message", dest="message",
		             help="Status message.")
	cmd_line.add_option ("-s", "--song", dest="song",
			     help="Set status to song name.")
	cmd_line.add_option ("-f", "--file", dest="file",
		             help="File from which we read random line.")
	cmd_line.add_option ("-d", "--daemon", action="store_true",
		             dest="daemon", default=False,
		             help="Run program in the background.")
	cmd_line.add_option ("-t", "--time", type="int", dest="time", default="10",
		             help="Time frame for changing the status (in minutes).")
	cmd_line.add_option ("--stop", action="store_true", dest="stop",
			      default=False, help="Stop daemon.")
	
	(opt, args) = cmd_line.parse_args ()

	# Check if we have all necessary arguments
	if not opt.message and not opt.song and not opt.file and not opt.stop:
		cmd_line.error ("This program requires arguments. Please use -h for help.\n")
	opt.time = opt.time * 60

	return opt

"""
Function:
  get_dbus()
	We need pidgin D-BUS session and objects in order 
	to change status message.
In:
  N/A
Out:
  purple
	Pidgin D-BUS object
Calls:
  N/A
"""
def get_dbus ():
	bus = dbus.SessionBus()
	obj = bus.get_object("im.pidgin.purple.PurpleService", "/im/pidgin/purple/PurpleObject")
	purple = dbus.Interface(obj, "im.pidgin.purple.PurpleInterface")

	return purple

"""
Function:
  pidgin_status()
	Sets new status message.
	It uses old message type (available, away, etc) and sets new message.
In:
  message
	New message
  icon
	Icon type (music note or arrow)
  putple
	Pidgin D-BUS object
Out:
  N/A
Calls:
  N/A
"""
def pidgin_status(message, icon, purple):
        old_status = purple.PurpleSavedstatusGetCurrent()               # get current status
        status_type = purple.PurpleSavedstatusGetType(old_status)       # get current status type
        new_status = purple.PurpleSavedstatusNew("", status_type)       # create new status with old status type
        purple.PurpleSavedstatusSetMessage(new_status, icon + message)  # fill new status with status message
        purple.PurpleSavedstatusActivate(new_status)                    # activate new status

"""
Function:
  start_daemon()
	Detaches from the console and creates a standalone daemon.
	We need to fork two times to avoid creating zombie processes.
	PID number is written into the pid_file so we can easily stop the daemon latter.
In:
  N/A
Out:
  N/A
Calls:
  N/A
"""
def start_daemon ():
	try: 
		pid = os.fork() 
		if pid > 0:
			sys.exit(0) 
	except OSError, e: 
		sys.stderr.write("Fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
		sys.exit(1)


	os.chdir("/") 
	os.setsid() 
	os.umask(0) 

	try: 
		pid = os.fork() 
		if pid > 0:
			sys.exit(0) 
	except OSError, e: 
		sys.stderr.write("Fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
		sys.exit(1) 

	f = open (pid_file, "w")
	f.write (str(os.getpid()))
	f.close ()
	print "Daemon started."
	return (True)

"""
Function:
  stop_daemon()
	Reads PID from pid_file and tries to kill the daemon process.
In:
  N/A
Out:
  Bool
Calls:
  N/A
"""
def stop_daemon ():
	try:
		f = open (pid_file, "r")
		pid = f.readline ()
		f.close ()
	except IOError:
		print "PID file empty. Aborting..."
		return (False)

	try:
		i = os.kill (int(pid), 15)
		if i == None:
			os.remove (pid_file)
			print "Daemon stopped."
			return (True)

		print "Could not stop daemon."
		return (False)
	except:
		os.remove (pid_file)
		print "PID doesn't exist. Aborting..."
		return (False)

"""
Function:
  get_quote()
	Reads file, finds and returns random line
In:
  file
	File from which we should get the status message
Out:
  quote
	Random line from file
Calls:
  N/A
"""
def get_quote(file):                            # function reads a file and gets random line
        num_lines = 0
        rand_line = 0
        l = 0

        if os.path.isfile(file):                # is file really there
                f = open(file, "r")             # open the file
                for line in f:                  # go through the file and count the lines
                        num_lines += 1
        else:
                sys.exit(1)

        rand_line = randint(0, num_lines)       # get the random line
        f.seek(0)                               # go to the begining of the file
        for line in f:                          # loop on the file till we get to the correct line
                if l == rand_line:              # if line correct
                        quote = line.strip()    # get the line content
                        break
                else:
                        l += 1

        f.close()                               # close the file and return the line
        return quote

"""
Function:
  set_status()
	Determains what kind of message we need to set
	  - Song
	  - Quote from file
	  - "Normal" message
	and according to this sets proper icon and message value.
In:
  purple
	Pidgin D-BUS object
Out:
  N/A
Calls:
  pidgin_status()
	Function for setting the pidgin status message
"""
def set_status(purple):
	if opt.message:
		icon = u'\u21e8 '
		msg = opt.message
	elif opt.song:
		icon = u'\u266C '
		msg = opt.song
	elif opt.file:
		icon = u'\u21e8 '
		msg = get_quote (opt.file)

	pidgin_status (msg, icon, purple)

# Main program
if __name__ == "__main__":
	# Get command line options
	opt = set_cmd_line_opts ()

	# Get pidgin D-BUS session
	purple = get_dbus ()

	# Are we are called to stop the daemon?
	if opt.stop:
		# Stop the daemon and exit
		if stop_daemon ():
			sys.exit (0)
		else:
			sys.exit (17)

	# Should we go to daemon mode?
	if opt.daemon and start_daemon():
		# If yes, loop to infinity
		while (1):
			# Set new status
			set_status (purple)
			# and wait for the required time
			sleep (opt.time)
	# If not in daemon mode just set the status and exit
	else:
		set_status (purple)