#!/usr/bin/env python
"""Frontend for knoppix-customize. It automates setting a new language
and it allows to replace the logo image. It will take care that the file
size does not change.

The file size of a replacement logo must be samller that the original.
This program will pad smaller files and abort on larger files.
'ppmtolss16' is required for this.

The action is based on the program name:
 knxiso-setlang
 knxiso-setlogo

Installation:
Save this script as 'knxiso-setlang', then use
 ln -s knxiso-setlang knxiso-setlogo
to create a link.
'knoppix-customize' must be in the search PATH. (install it in /usr/local/bin)

Examples:
 knxiso-setlang knoppix.iso us
 knxiso-setlogo knoppix.iso logo.ppm
 pxctoppm <mylogo.pcx | knxiso-setlogo knoppix.iso -

 knxiso-setlogo -d knoppix.iso logo.ppm

That last example uses -d option to only simulate the write. It will not touch
the iso. It's recomended that you run this program on copies of the original
iso only.

Requires:
 knoppix-customize by Kester Habermann <kester@linuxtag.org>
 from http://hydra.hq.linuxtag.net/~kester/knoppix-customize/

Python license, Chris Liechti <cliechti@gmx.net>

This is experimental software. Use at your own risk.
"""

import os, re, sys

# helpers

#~ class Tempfile:
    #~ """Create a temporary file that can be used by external programs.
    #~ This is a proxy object taht can be used as file."""
    
    #~ def __init__(self):
        #~ """Create a random name and open the file"""
        #~ import tempfile
        #~ self.name = tempfile.mktemp()
        #~ self.file = open(self.name, 'w+b')

    #~ def __getattr__(self, name):
        #~ return getattr(self.file, name)

    #~ def __del__(self):
        #~ self.file.close()
        #~ os.unlink(self.name)

class ISO:
    """take an ISO image or disk image and allow file operations on it"""
    
    def __init__(self, filename, simulate = 0):
        self.name = filename
        self.simulate = simulate

    def readFile(self, name):
        fin = os.popen('knoppix-customize --image %s --action export_file --image_file %s --local_file -' % (self.name, name))
        data = fin.read()          #and read all the data
        fin.close()
        return data
    
    def writeFile(self, name, data):
        if self.simulate:
            sys.stdout.write('Would have written %d bytes to file %s.\n' % (len(data), name))
        else:
            fin, fout = os.popen2('knoppix-customize --image %s --action import_file --image_file %s --local_file -' % (self.name, name))
            fin.write(data)
            fin.close()
            fout.close()

    def getBootdisk(self):
        fin = os.popen('knoppix-customize --image %s --action export_floppy --local_file -' % (self.name,))
        data = fin.read()          #and read all the data
        fin.close()
        return data

# operations

def setlang(simulate):
    #incomplete list of languages supported by knoppix at boot param
    languages = ['de', 'bg', 'ch', 'cn', 'cs', 'cz', 'da', 'dk', 'es', 'fr', 'it', 'nl', 'pl', 'ru', 'sk', 'tr', 'tw', 'uk', 'us']
    if len(sys.argv) < 3:
        sys.stderr.write("""USAGE: knxiso-setlang imagename language
use knoppix-customize to set the language of a KNOPPIX ISO image or boot disk image.
supported languages (incomplete list):\n  %s\n""" % ', '.join(languages))
        sys.exit(1)
    
    isoname = sys.argv[1]
    language = sys.argv[2]
    sysconfig = "syslinux.cfg"
    
    if language not in languages:
        sys.stderr.write("warning: language not in builtin list. its possibly not supported.\n")
    iso = ISO(isoname, simulate)
    cfg = iso.readFile(sysconfig)
    origlen = len(cfg)
    cfg = re.sub(r'lang=(\w+)', 'lang=%s' % language, cfg)
    diffsize = len(cfg) - origlen
    if diffsize > 0:
        cfg = cfg.replace('##'+'#'*diffsize, '##', 1)   #use two char at min to not acidentaly uncomment a comment
    elif diffsize < 0:
        cfg = cfg.replace('##', '##'*(-diffsize), 1)    #use two char at min to not touch a comment
    iso.writeFile(sysconfig, cfg)

def setlogo(simulate):
    if len(sys.argv) < 3:
        sys.stderr.write("""USAGE: knxiso-setlogo imagename ppmlogo
use knoppix-customize to set the boot logo of a KNOPPIX ISO image or boot disk image.

Examples:
    knxiso-setlogo knoppix.iso logo.ppm
    pxctoppm <mylogo.pcx | knxiso-setlogo knoppix.iso -
""")
        sys.exit(1)
    
    isoname = sys.argv[1]
    newlogo = sys.argv[2]
    logofile = "logo.16"
    
    iso = ISO(isoname, simulate)
    logo = iso.readFile(logofile)
    origlen = len(logo)
    fin, fout = os.popen2('ppmtolss16', 'b', 1024*100)
    if newlogo == '-':
        fin.write(sys.stdin.read())
    else:
        fin.write(open(newlogo, 'rb').read())
    fin.close()
    logo = fout.read()
    paddsize = origlen - len(logo)
    if paddsize < 0:
        sys.stderr.write("\n")
        sys.exit(1)
    logo = logo + '\0'*paddsize         #pad
    iso.writeFile(logofile, logo)

def getfloppy(simulate):
    """extract the bootfloppy from the image"""
    if len(sys.argv) < 2:
        sys.stderr.write("""USAGE: knxiso-getfloppy imagename 
extract bootdisk from ISO image.

Examples:
    knxiso-getfloppy knoppix.iso
""")
        sys.exit(1)
    
    isoname = sys.argv[1]
    
    iso = ISO(isoname, simulate)
    floppy = iso.getBootdisk()
    sys.stdout.write(floppy)

# main entry

if __name__ == '__main__':
    #find out what operation, based on the executable name
    execname = os.path.basename(sys.argv[0]).lower().replace('.py', '')
    actions  = {
        'setlang':      setlang,
        'setlogo':      setlogo,
        'getfloppy':    getfloppy
    }
    simulate = '-d' in sys.argv
    if simulate:
        sys.argv.remove('-d')
    
    for action in actions.keys():
        opt = '--%s' % action
        if opt in sys.argv:
            sys.argv.remove(opt)
            break
    else:
        action = execname.split('-')[1]
    
    if actions.has_key(action):
        actions[action](simulate)           #execute action
    else:
        sys.stderr.write("Unknown operation. Possible values are: %s\n" % ', '.join(actions.keys()))