#!@PYTHON@
# -*- mode: Python; indent-tabs-mode: nil; -*-

import atexit
import datetime
import dbus
from dbus.mainloop.glib import DBusGMainLoop
import gobject
try:
    import json
except ImportError:
    try:
        import simplejson as json
    except ImportError:
        json = None
import optparse
import os
import random
import re
import shutil
import signal
import subprocess
import sys
import tempfile
import termios
import time
import errno

def show_version(option, opt_str, value, parser):
    print "GNOME Shell @VERSION@"
    sys.exit()

def get_running_session_environs():
    wanted_environment = ['DBUS_SESSION_BUS_ADDRESS', 'DISPLAY', 'XDG_DATA_DIRS',
                          'XAUTHORITY', 'XDG_SESSION_COOKIE', 'ORBIT_SOCKETDIR',
                          'SESSION_MANAGER']
    num_re = re.compile('^[0-9]+$')
    myuid = os.getuid()
    if not os.path.isdir('/proc'):
        return {}
    for filename in os.listdir('/proc'):
        if not num_re.match(filename):
            continue
        piddir = '/proc/' + filename
        try:
            stat = os.stat(piddir)
        except OSError, e:
            continue
        if not stat.st_uid == myuid:
            continue
        try:
            f = open(piddir + "/cmdline")
            command = f.read()
            f.close()
        except IOError, e:
            continue
        # /proc/cmdline is separated and terminated by NULs
        command = command.split("\x00")[0]
        command = os.path.basename(command)
        if command != 'gnome-session':
            continue
        try:
            f = open(os.path.join(piddir, 'environ'))
        except OSError, e:
            continue
        environ_data = f.read()
        f.close()
        # There's a trailing null at the last one, so remove the
        # empty string
        environs = environ_data.split('\0')[:-1]
        # Rumor has it the presence of just FOO (instead of FOO=bar)
        # represents a deleted environment variable
        environs = filter(lambda x: '=' in x, environs)
        # Turn it into a dictionary
        environs = dict(map(lambda x: x.split('=', 1), environs))
        result = {}
        for key in wanted_environment:
            if key in environs:
                result[key] = environs[key]
        return result

def start_shell():
    self_dir = os.path.dirname(os.path.abspath(sys.argv[0]))
    if os.path.exists(os.path.join(self_dir, 'gnome-shell-jhbuild.in')):
        running_from_source_tree = True
        top_dir = os.path.dirname(self_dir)
        typelib_dir = '@JHBUILD_TYPELIBDIR@:' + os.path.join(top_dir, "src")
        js_dir = os.path.join(top_dir, "js")
        data_dir = os.path.join(top_dir, "data")
    else:
        running_from_source_tree = False
        js_dir = os.path.join('@pkgdatadir@', 'js')
        typelib_dir = '@JHBUILD_TYPELIBDIR@'

    if os.environ.has_key('GI_TYPELIB_PATH'):
        typelib_dir = typelib_dir + ":" + os.environ.get('GI_TYPELIB_PATH')

    # Set up environment
    env = dict(os.environ)
    if running_from_source_tree:
        env.update({'GNOME_SHELL_JS'       : js_dir,
                    'GNOME_SHELL_BINDIR'   : self_dir,
                    'GNOME_SHELL_DATADIR'  : data_dir,
                    'GSETTINGS_SCHEMA_DIR' : data_dir })

    args = []
    if options.debug:
        debug_command = options.debug_command.split()
        if running_from_source_tree:
            args += [os.path.join(top_dir, 'libtool'), '--mode=execute']
        args += debug_command

    args.append(os.path.join(self_dir, 'gnome-shell-real'))
    if options.replace:
        args.append('--replace')
    if options.sync:
        args.append('--sync')
    return subprocess.Popen(args, env=env)

def run_shell():
    if options.debug:
        # Record initial terminal state so we can reset it to that
        # later, in case we kill gdb at a bad time
        termattrs = termios.tcgetattr(0);

    normal_exit = False

    if options.verbose:
        print "Starting shell"

    try:
        shell = start_shell()

        # Wait for shell to exit
        if options.verbose:
            print "Waiting for shell to exit"
        shell.wait()

    except KeyboardInterrupt, e:
        try:
            os.kill(shell.pid, signal.SIGKILL)
        except:
            pass
        shell.wait()
    finally:
        if shell is None:
            print "Failed to start shell"
        elif shell.returncode == 0:
            normal_exit = True
            if options.verbose:
                print "Shell exited normally"
        elif shell.returncode < 0:
            # Python has no mapping for strsignal; not worth using
            # ctypes for this.
            print "Shell killed with signal %d" % - shell.returncode
        else:
            # Normal reason here would be losing connection the X server
            if options.verbose:
                print "Shell exited with return code %d" % shell.returncode

        if options.debug:
            termios.tcsetattr(0, termios.TCSANOW, termattrs);

    return normal_exit


def restore_gnome():
    # Do imports lazily to save time and memory
    import gio
    import gconf

    # We don't want to start the new gnome-panel in the current
    # directory; $HOME is better for stuff launched from it
    os.chdir(os.path.expanduser("~"))

    def launch_component(gconf_path):
        client = gconf.client_get_default()
        component = client.get_string(gconf_path)

        if component == None or component == "":
            return False

        # See gnome-session/gsm-util.c:gsm_util_find_desktop_file_for_app_name()
        # The one difference is that we don't search the autostart directories,
        # and just search normal application search path. (Gio doesnt' know
        # how to search the autostart dirs, so we'd have to do that ourselves.)
        appinfo = None
        try:
            appinfo = gio.unix.DesktopAppInfo(component + ".desktop")
        except:
            try:
                appinfo = gio.unix.DesktopAppInfo("gnome-" + component + ".desktop")
            except:
                pass

        if appinfo:
            appinfo.launch()
            return True
        return False

    # GNOME2 fallback
    wm    = launch_component("/desktop/gnome/session/required_components/windowmanager")
    panel = launch_component("/desktop/gnome/session/required_components/panel")

    if not wm and not panel: # Probably GNOME3
        subprocess.Popen(['gnome-shell'])

# Main program

parser = optparse.OptionParser()
parser.add_option("-r", "--replace", action="store_true",
                  help="Replace the running metacity/gnome-panel")
parser.add_option("-g", "--debug", action="store_true",
                  help="Run under a debugger")
parser.add_option("", "--debug-command", metavar="COMMAND",
                  help="Command to use for debugging (defaults to 'gdb --args')")
parser.add_option("-v", "--verbose", action="store_true")
parser.add_option("", "--sync", action="store_true")
parser.add_option("", "--version", action="callback", callback=show_version,
                  help="Display version and exit")

options, args = parser.parse_args()

if args:
    parser.print_usage()
    sys.exit(1)

# Handle ssh logins
if 'DISPLAY' not in os.environ:
    running_env = get_running_session_environs()
    os.environ.update(running_env)

if options.debug_command:
    options.debug = True
elif options.debug:
    options.debug_command = "gdb --args"

# We only respawn the previous environment on abnormal exit;
# for a clean exit, we assume that gnome-shell was replaced with
# something else.
normal_exit = False

try:
    normal_exit = run_shell()
finally:
    if options.replace and not normal_exit:
        restore_gnome()

if normal_exit:
    sys.exit(0)
else:
    sys.exit(1)