# Copyright (C) 2006, Red Hat, Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.

import os
import socket
import sys

import gobject

from sugar import env

def get_display_number():
    """Find a free display number trying to connect to 6000+ ports"""
    retries = 20
    display_number = 1
    display_is_free = False    

    while not display_is_free and retries > 0:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            s.connect(('127.0.0.1', 6000 + display_number))
            s.close()

            display_number += 1
            retries -= 1
        except:
            display_is_free = True

    if display_is_free:
        return display_number
    else:
        logging.error('Cannot find a free display.')
        sys.exit(0)

class Process:
    """Object representing one of the session processes"""

    def __init__(self, command):
        self._command = command
    
    def get_name(self):
        return self._command
    
    def start(self, standard_output=False):
        args = self._command.split()
        flags = gobject.SPAWN_SEARCH_PATH
        result = gobject.spawn_async(args, flags=flags,
                                     standard_output=standard_output)
        self.pid = result[0]
        self._stdout = result[2]

class MatchboxProcess(Process):
    def __init__(self):
        kbd_config = os.path.join(env.get_data_dir(), 'kbdconfig')
        options = '-kbdconfig %s ' % kbd_config

        options += '-use_titlebar no '
        options += '-theme olpc '

        command = 'matchbox-window-manager %s ' % options
        Process.__init__(self, command)
    
    def get_name(self):
        return 'Matchbox'

class XephyrProcess(Process):
    def __init__(self, width, height, fullscreen):
        self._display = get_display_number()
        cmd = 'Xephyr :%d -ac ' % (self._display)

        if fullscreen:
            cmd += ' -fullscreen '
        
        if width > 0 and height > 0:
            cmd += ' -screen %dx%d' % (width, height)

        Process.__init__(self, cmd)
        
    def get_name(self):
        return 'Xephyr'

    def start(self, standard_output=False):
        Process.start(self)
        os.environ['DISPLAY'] = ":%d" % (self._display)
        os.environ['SUGAR_XEPHYR_PID'] = '%d' % self.pid

class Emulator(object):
    """The OLPC emulator"""
    def __init__(self, width, height, fullscreen):
        self._fullscreen = fullscreen
        self._width = width
        self._height = height

    def start(self):
        try:
            process = XephyrProcess(self._width, self._height,
                                    self._fullscreen)
            process.start()
        except:
            print 'Cannot run the emulator. You need to install Xephyr'
            sys.exit(0)

        process = MatchboxProcess()
        process.start()