#!/usr/bin/python
# -*- coding: utf-8 -*-
# vim: set et ts=4:

# Filename:      grml-x
# Purpose:       wrapper for startx on grml [providing new xconfiguration tool]
# Authors:       grml-team (grml.org), (c) Christian Hofstaedtler <ch@grml.org>
# Bug-Reports:   see http://grml.org/bugs/
# License:       This file is licensed under the GPL v2.
###############################################################################

# Requires python 2.6 or, possibly, a newer version of python 2.X.

import fileinput, os, subprocess, sys, tempfile, time, traceback
from optparse import OptionParser

class Section(object):
    def __init__(self, name, identifier, data):
        self.name = name
        self.identifer = identifier
        self.data = data
        self.subsect = ""
    def __str__(self):
        s = "Section \"%s\"\n\tIdentifier \"%s\"\n" % (self.name, self.identifer)
        for k in self.data:
            v = self.data[k]
            if isinstance(v, list):
                v = '" "'.join(v)
            elif not isinstance(v, basestring): # int, others
                v = str(v)
            elif '-' in v: # sync range
                pass
            else:
                v = '"%s"' % v
            s += "\t%s %s\n" % (k, v)
        s += self.subsect
        s += 'EndSection\n'
        return s

def get_monitor_section(options, force):
    if not options.hsync and not options.vsync and not force:
        return None
    d = {}
    d['HorizSync'] = options.hsync or '28.0 - 96.0'
    d['VertRefresh'] = options.vsync or '50.0 - 60.0'
    return Section('Monitor', 'Monitor0', d)

def get_device_section(options):
    if not options.module:
        return None
    d = {}
    d['Driver'] = options.module
    d['VendorName'] = 'All'
    d['BoardName'] = 'All'
    return Section('Device', 'Card0', d)

def build_bootparams():
    lines = []
    def walk_bootparams_path(p):
        try:
            if not os.path.exists(p): return
            for root, dirs, files in os.walk(p):
                for name in files:
                    f = open(os.path.join(root, name))
                    lines.extend(f.readlines())
                    f.close()
        except:
            print 'W: Error while getting bootparams from %s' % p
    f = open('/proc/cmdline')
    lines.append(f.readline())
    f.close()
    walk_bootparams_path('/cdrom/bootparams')
    walk_bootparams_path('/live/image/bootparams')
    params = {}
    for p in ' '.join(lines).split(' '):
        if '=' in p:
            (k,v) = p.split('=', 1)
            params[k] = v
        else:
            params[p] = True
    return params

def detect_qemu():
    f = open('/proc/cpuinfo')
    x = ''.join(f.readlines())
    f.close()
    if 'QEMU' in x: return True
    return False

def get_program_output(args):
    p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, close_fds=True)
    return p.communicate()[0]

def run_program(args):
    subprocess.Popen(args, close_fds=True).wait()

def which(program):
    def is_exe(fpath):
        return os.path.exists(fpath) and os.access(fpath, os.X_OK)

    fpath, fname = os.path.split(program)
    if fpath:
        if is_exe(program):
            return program
    else:
        for path in os.environ["PATH"].split(os.pathsep):
            exe_file = os.path.join(path, program)
            if is_exe(exe_file):
                return exe_file

    return None

XORG_CONF_HEADER = "# Automatically generated by grml-x."
def check_old_xorg_conf(filename, overwrite):
    # True: no problem, we can create/overwrite the config file
    # False: pre-existing config file, and we are not to overwrite it
    if overwrite: return True
    if not os.path.exists(filename): return True
    try:
        f = file(filename, 'r')
        lines = f.readlines()
        f.close()
        return (not XORG_CONF_HEADER in lines)
    except IOError:
        return False

parser = OptionParser(usage="usage: %prog [options] [window-manager]")
parser.add_option("--nostart", action="store_false", dest="start_server", default=True,
                help="Don't start X server")
parser.add_option("--display", action="store", type="string", dest="display",
                help="Start X server on display DISPLAY")
parser.add_option("--hsync", action="store", type="string", dest="hsync",
                help="Force writing a HorizSync range")
parser.add_option("--vsync", action="store", type="string", dest="vsync",
                help="Force writing a VertRefresh range")
parser.add_option("--mode", action="store", type="string", dest="mode",
                help="Force a specific resolution")
parser.add_option("--module", action="store", type="string", dest="module",
                help="Force driver MODULE instead of Xorg autodetection")
parser.add_option("-o", action="store", type="string", dest="xorg_conf", default="/etc/X11/xorg.conf",
                help="Specify alternate xorg.conf file [default: %default]")
parser.add_option("-f", "--force", action="store_true", dest="overwrite", default=False,
                help="Overwrite xorg.conf if it exists [default: %default]")

parser.add_option("-t", "--tcp", action="store_true", dest="tcp", default=False,
                help="Enable TCP")

def main():
    (options, args) = parser.parse_args()
    bootparams = build_bootparams()

    if os.getuid() == 0 and options.start_server:
        print "W: running as root is unsupported and may not work."
        time.sleep(1)

    if not check_old_xorg_conf(options.xorg_conf, options.overwrite):
        print "E: Not overwriting existing %r without --force." % options.xorg_conf
        print "I: If you previously ran grml-x, use startx /usr/bin/x-window-manager"
        return 1

    if 'xmode' in bootparams and not options.mode: options.mode = bootparams['xmode']
    if 'xmodule' in bootparams and not options.module: options.module = bootparams['xmodule']

    force_monitor = False
    # cirrus driver for QEMU doesn't do 1024x768 without HorizSync set
    if detect_qemu(): force_monitor = True

    monitor = get_monitor_section(options, force_monitor)
    device = get_device_section(options)

    # build Screen section ourselves
    d = {}
    if monitor: d['Monitor'] = monitor.identifer
    if device: d['Device'] = device.identifer
    screen = Section('Screen', 'Screen0', d)
    if options.mode:
        d['DefaultColorDepth'] = 16
        for depth in [8, 15, 16, 24, 32]:
            screen.subsect += "SubSection \"Display\"\n\tDepth %d\n\tModes \"%s\"\t\nEndSubSection\n" % (depth, options.mode)

    xinitrc = '/home/brad/.xinitrc'
    if 'XINITRC' in os.environ: xinitrc = os.environ['XINITRC']
    xinitrc = os.path.expanduser(xinitrc)

    window_manager = 'x-window-manager'
    if len(args) == 1: window_manager = args[0]
    window_manager_path = which(window_manager)
    if not window_manager_path:
        print "E: Cannot find window manager %r, aborting." % window_manager
        return 2

    wm_exec = "exec %s\n" % window_manager_path
    if not os.path.exists(xinitrc):
        f = open(xinitrc, 'w')
        f.write("#!/bin/sh\n")
        f.write(wm_exec)
        f.close()
    else:
        f = open(xinitrc, 'r')
        lines = f.readlines()
        f.close()
        f = open(xinitrc, 'w')
        for line in lines:
            if line.strip().startswith('exec '): line = wm_exec
            f.write(line)
        os.fchmod(f.fileno(), 0750)
        f.close()

    # write new config
    if monitor or device or len(screen.data) > 0 or screen.subsect != '':
        try:
            f = tempfile.NamedTemporaryFile(delete=False)
            f.write(XORG_CONF_HEADER + "\n")
            f.write("# DO NOT MODIFY, YOUR CHANGES WILL BE LOST - OR REMOVE ALL HEADER LINES\n")
            f.write("# See man xorg.conf or /etc/X11/xorg.conf.example for more\n")
            if monitor: f.write(str(monitor))
            if device: f.write(str(device))
            f.write(str(screen))
            f.flush()
            os.fchmod(f.fileno(), 0644)
            run_program(['mv', '-f', f.name, options.xorg_conf])
        finally:
            f.close()

    if options.start_server:
        if options.tcp:
            startx = ['su', '-', 'brad', '-c', 'startx', xinitrc, '--']
        else:
            startx = ['su', '-', 'brad', '-c', 'startx', xinitrc, '--', '-nolisten', 'tcp']
        if options.display: startx.append(':' + options.display)
        print "Starting X: %r" % startx
        run_program(startx)

    return 0

if __name__ == '__main__':
    rc = 1
    try:
        rc = main()
    except Exception:
        print "E: Exception: ",
        traceback.print_exc()
    sys.exit(1)