#!/usr/bin/env python

from optparse import OptionParser
import os
import re
import sys
import subprocess

tarball_url="http://gnuradio.org/releases/gnuradio/gr-howto-write-a-block-3.3git-651-g642252d8.tar.gz"

def open_tarball(tarball_name=None):
    """Return a readable fileobject that references the tarball.
    If tarball_name is None, download from the net
    """
    if tarball_name:
        return open(tarball_name, 'r')
    p = subprocess.Popen(["wget", "-O", "-", tarball_url],
                         close_fds=True, stdout=subprocess.PIPE)
    return p.stdout

def extract_and_rename_files(tarball, module_name):
    #  Requires GNU tar.
    tar_cmd = 'tar xz --strip-components=1 --transform="s/howto/%s/g"' % (module_name,)
    p = subprocess.Popen(tar_cmd, shell=True, stdin=tarball, close_fds=True)
    sts = os.waitpid(p.pid, 0)
    return sts == 0

def main():
    usage = "%prog: [options] new_module_name"
    description="Create a prototype 'out of tree' GNU Radio project"
    parser = OptionParser(usage=usage, description=description)
    parser.add_option("-T", "--tarball", type="string", default=None,
                      help="path to gr-howto-build-a-block gzipped tarball [default=<get from web>]")
    (options, args) = parser.parse_args()
    if len(args) != 1:
        parser.print_help()
        raise SystemExit,2
    module_name = args[0]
    if not re.match(r'[_a-z][_a-z0-9]*$', module_name):
        sys.stderr.write("module_name '%s' may only contain [a-z0-9_]\n" % (module_name))
        raise SystemExit, 1

    # Ensure there's no file or directory called <module_name>
    if os.path.exists(module_name):
        sys.stderr.write("A file or directory named '%s' already exists\n" % (module_name,))
        raise SystemExit, 1

    os.mkdir(module_name)
    os.chdir(module_name)

    ok = extract_and_rename_files(open_tarball(options.tarball), module_name)

    # rename file contents
    upper_module_name = module_name.upper()
    sed_cmd = 'sed -i -e "s/howto-write-a-block/%s/g" -e "s/howto/%s/g" -e "s/HOWTO/%s/g"' % (module_name, module_name, \
												upper_module_name)
    os.system('find . -type f -print0 | xargs -0 ' + sed_cmd)

    sys.stdout.write("""
Project '%s' is now ready to build.

  $ ./bootstrap
  $ ./configure --prefix=/home/[user]/install
  $ (make && make check && make install) 2>&1 | tee make.log

""" % (module_name,))

if __name__ == '__main__':
    main()