#! /usr/bin/env python
# -*- coding: ISO-8859-15 -*-

# CupsOfTee : Tee for CUPS
#
# (c) 2005 Jerome Alet <alet@librelogiciel.com>
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
#
# $Id$
#
#

import sys
import os
import errno
import cStringIO
import shlex
import tempfile

class CupsBackend :
    """Base class for tools with no database access."""
    def __init__(self) :
        """Initializes the CUPS backend wrapper."""
        self.debug = 1
        
    def discoverOtherBackends(self) :    
        """Discovers the other CUPS backends.
        
           Executes each existing backend in turn in device enumeration mode.
           Returns the list of available backends.
        """
        # Unfortunately this method can't output any debug information
        # to stdout or stderr, else CUPS considers that the device is
        # not available.
        available = []
        (directory, myname) = os.path.split(sys.argv[0])
        tmpdir = tempfile.gettempdir()
        lockfilename = os.path.join(tmpdir, "%s..LCK" % myname)
        if os.path.exists(lockfilename) :
            lockfile = open(lockfilename, "r")
            pid = int(lockfile.read())
            lockfile.close()
            try :
                # see if the pid contained in the lock file is still running
                os.kill(pid, 0)
            except OSError, e :    
                if e.errno != errno.EPERM :
                    # process doesn't exist anymore
                    os.remove(lockfilename)
            
        if not os.path.exists(lockfilename) :
            lockfile = open(lockfilename, "w")
            lockfile.write("%i" % os.getpid())
            lockfile.close()
            allbackends = [ os.path.join(directory, b) \
                                for b in os.listdir(directory) 
                                    if os.access(os.path.join(directory, b), os.X_OK) \
                                        and (b != myname)] 
            for backend in allbackends :                            
                answer = os.popen(backend, "r")
                try :
                    devices = [line.strip() for line in answer.readlines()]
                except :    
                    devices = []
                status = answer.close()
                if status is None :
                    for d in devices :
                        # each line is of the form : 
                        # 'xxxx xxxx "xxxx xxx" "xxxx xxx"'
                        # so we have to decompose it carefully
                        fdevice = cStringIO.StringIO(d)
                        tokenizer = shlex.shlex(fdevice)
                        tokenizer.wordchars = tokenizer.wordchars + \
                                                        r".:,?!~/\_$*-+={}[]()#"
                        arguments = []
                        while 1 :
                            token = tokenizer.get_token()
                            if token :
                                arguments.append(token)
                            else :
                                break
                        fdevice.close()
                        try :
                            (devicetype, device, name, fullname) = arguments
                        except ValueError :    
                            pass    # ignore this 'bizarre' device
                        else :    
                            if name.startswith('"') and name.endswith('"') :
                                name = name[1:-1]
                            if fullname.startswith('"') and fullname.endswith('"') :
                                fullname = fullname[1:-1]
                            available.append('%s cupsoftee:%s "CupsOfTee+%s" "CupsOfTee managed %s"' \
                                                 % (devicetype, device, name, fullname))
            os.remove(lockfilename)
        return available
                        
    def fakePrint(self) :    
        """Fakes to print the job."""
        if os.environ.has_key("CUPS_SERVERROOT") and os.path.isdir(os.environ.get("CUPS_SERVERROOT", "")) :
            # Either the job's datas are on our stdin, or in a file
            if len(sys.argv) == 7 :
                self.InputFile = sys.argv[6]
            else :    
                self.InputFile = None
                
            # check that the DEVICE_URI environment variable's value is 
            # prefixed with "cupsoftee:" otherwise don't touch it.
            # If this is the case, we have to remove the prefix from 
            # the environment before launching the real backend in cupspykota
            device_uri = os.environ.get("DEVICE_URI", "")
            if device_uri.startswith("cupspykota:") :
                fulldevice_uri = device_uri[:]
                device_uri = fulldevice_uri[len("cupspykota:"):]
                if device_uri.startswith("//") :    # lpd (at least)
                    device_uri = device_uri[2:]
                os.environ["DEVICE_URI"] = device_uri   # TODO : side effect !
            # TODO : check this for more complex urls than ipp://myprinter.dot.com:631/printers/lp
            try :
                (backend, destination) = device_uri.split(":", 1) 
            except ValueError :    
                raise PyKotaToolError, "Invalid DEVICE_URI : %s\n" % device_uri
            while destination.startswith("/") :
                destination = destination[1:]
            checkauth = destination.split("@", 1)    
            if len(checkauth) == 2 :
                destination = checkauth[1]
            printerhostname = destination.split("/")[0].split(":")[0]
            return ("CUPS", \
                    printerhostname, \
                    os.environ.get("PRINTER"), \
                    sys.argv[2].strip(), \
                    sys.argv[1].strip(), \
                    inputfile, \
                    int(sys.argv[4].strip()), \
                    sys.argv[3], \
                    sys.argv[5], \
                    backend)
        
    def logDebug(self, message) :    
        """Logs something to debug output if debug is enabled."""
        if self.debug :
            sys.stderr.write("DEBUG: %s\n" % message)
            sys.stderr.flush()
            
    def logInfo(self, message, level="info") :        
        """Logs a message to CUPS' error_log file."""
        sys.stderr.write("%s: %s\n" % (level.upper(), message))
        sys.stderr.flush()

if __name__ == "__main__" :    
    # This is a CUPS backend, we should act and die like a CUPS backend
    wrapper = CupsBackend()
    if len(sys.argv) == 1 :
        print "\n".join(wrapper.discoverOtherBackends())
        sys.exit(0)                
    elif len(sys.argv) not in (6, 7) :    
        sys.stderr.write("ERROR: %s job-id user title copies options [file]\n"\
                              % sys.argv[0])
        sys.exit(1)
    else :    
        sys.stderr.write("ERROR: Not Yet !\n")
        sys.exit(1)