#!/usr/bin/python
"""
dogtail-run-headless

Runs a dogtail script 
This script launches an X server using the virtual framebuffer, allowing
dogtail scripts to be run on headless servers. 
The server can currently use a minimal GNOME session, or just metacity.

Dogtail scripts are run in the current directory. After the script
terminates, so does the X server.
"""
__author__ = "Zack Cerza <zcerza@redhat.com>"

_usage = """
Usage: dogtail-run-headless <options> <script>

Options:

    -h, --help      Display this message.
    
    -g, --gnome     Use a GNOME session.
    
    -n, --none      Use a minimal session, consisting of just metacity.
    
    -k, --kde       Use a KDE session (not implemented).
"""

def usage():
    print _usage

import os
import sys
import gconf
gconfClient = gconf.client_get_default()

TRUE='true'
FALSE='false'

a11yGConfKey = '/desktop/gnome/interface/accessibility'

global a11yIsEnabled
global a11yWasEnabled
a11yWasEnabled = True

def makeSureGNOMEIsAccessible():
    global a11yIsEnabled, a11yWasEnabled
    a11yIsEnabled = gconfClient.get_bool(a11yGConfKey)
    a11yWasEnabled = a11yIsEnabled

    if not a11yIsEnabled:
        print "Temporarily enabling accessibility support for GNOME"
        gconfClient.set_bool(a11yGConfKey, True)
        a11yIsEnabled = gconfClient.get_bool(a11yGConfKey)

    return a11yIsEnabled

global xinitrc
xinitrc = None

def startXServer():
    def findFreeDisplay():
        import re
        tmp = os.listdir('/tmp')
        pattern = re.compile('\.X([0-9]+)-lock')
        numbers = []
        for file in tmp:
            match = re.match(pattern, file)
            if match: numbers.append(int(match.groups()[0]))
        if not numbers: return ':0'
        numbers.sort()
        return ':' + str(numbers[-1] + 1)
    
    server = os.popen('/usr/bin/which Xvfb 2>/dev/null')
    if not server:
        print "Cannot find Xvfb"
        sys.exit(EXIT_DEPS)
    server = server.readlines()[0].strip()

    client = xinitrc.name
    resolution = '1024x768x16'
    cmd = 'xinit %s -- %s %s -screen 0 %s -ac -noreset -shmem' % \
            (client, server, findFreeDisplay(), resolution)
    print cmd
    return os.system(cmd)
    
global exitCodeFile
exitCodeFile = None

def main(argv):
    import getopt
    EXIT_SYNTAX = 1
    EXIT_NOT_IMPL = 2
    EXIT_DEPS = 3

    shortOpts = "hgkn"
    longOpts = ['help', 'gnome', 'kde', 'none']
    try:
        opts, args = getopt.getopt(argv[1:], shortOpts, longOpts)
    except getopt.GetoptError:
        usage()
        return EXIT_SYNTAX
    if len(opts) == 0:
        usage()
        return EXIT_SYNTAX
        
    def stripOpt(opt):
        # take the '-' out of e.g. '-h'
        if len(opt) == 2: opt = opt[1]
        # take the '--' out of e.g. '--help'
        if len(opt) > 2: opt = opt[2:]
        return opt
    
    for opt, arg in opts:
        opt = stripOpt(opt)
        if opt in (shortOpts[0], longOpts[0]):
            usage()
            cleanup()
            return 0
        elif len(args) == 0:
            print "You must specify a script to execute in the headless session."
            print
            return EXIT_SYNTAX
        elif len(args) > 1:
            print "You may only specify one script to execute in the headless session."
            print
            print "Note: If you're trying to have dogtail-run-headless run a script using certain"
            print "environment values, use the following format (note the quotation marks):"
            print
            print '   dogtail-run-headless "VAR=value /path/to/script.py"'
            print
            return EXIT_SYNTAX
        else:
            script = args[0]
    
        pid = str(os.getpid())
        global exitCodeFile
        exitCodeFile = "/tmp/dogtail-headless-exitcode." + pid

        global xinitrc
        xinitrc = file("/tmp/dogtail-headless-xinitrc." + pid, 'w')
        xinitrc.write('#!/bin/sh\n')
        
        if opt in (shortOpts[1], longOpts[1]):
            # (Fake) GNOME session

            # Damn binaries, always ambling about the filesystem
            if os.path.exists('/usr/libexec/gnome-settings-daemon'):
                xinitrc.write('/usr/libexec/')
            xinitrc.write('gnome-settings-daemon &\n')
            xinitrc.write('gnome-panel &\n')
            xinitrc.write('nautilus -n &\n')
            xinitrc.write('metacity &\n')
            xinitrc.write('sleep 10\n')
            xinitrc.write('cd %s && dogtail-detect-session && sh -c "%s"; echo -n $? > %s\n' % (os.getcwdu(), script, exitCodeFile))
            xinitrc.close()

            makeSureGNOMEIsAccessible()
            startXServer()
            exitCode = int(file(exitCodeFile, 'r').read())
            return exitCode
            
        elif opt in (shortOpts[2], longOpts[2]):
            # KDE session
            print "Sorry, this is just a placeholder. KDE4 should support dogtail, and vice versa."
            cleanup()
            return EXIT_NOT_IMPL

        elif opt in (shortOpts[3], longOpts[3]):
            # No session
            xinitrc.write('metacity &\n')
            xinitrc.write('sleep 3\n')
            xinitrc.write('cd %s && sh -c "%s"; echo -n $? > %s\n' % (os.getcwdu(), script, exitCodeFile))
            xinitrc.close()
            
            makeSureGNOMEIsAccessible()
            startXServer()
            exitCode = int(file(exitCodeFile, 'r').read())
            return exitCode

def cleanup():
    if not a11yWasEnabled: gconfClient.set_bool(a11yGConfKey, False)
    if exitCodeFile:
        os.remove(exitCodeFile)
    if xinitrc:
        name = xinitrc.name
        xinitrc.close()
        os.remove(name)

if __name__ == "__main__":
    import traceback
    try: exitCode = main(sys.argv)
    except:
        exitCode = 254
        traceback.print_exc()
    try: 
        cleanup()
    except: traceback.print_exc()
    sys.exit(exitCode)