#!/usr/bin/python
# Copyright 2011, 2012, 2013  Lars Wirzenius
# Copyright 2012  Codethink Limited
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import cliapp
import crypt
import logging
import os
import re
import shutil
import subprocess
import tempfile


class VmDebootstrap(cliapp.Application):

    def add_settings(self):
        default_arch = 'amd64'

        self.settings.boolean(['verbose'], 'report what is going on')
        self.settings.string(['image'], 'put created disk image in FILE',
                             metavar='FILE')
        self.settings.bytesize(['size'],
                               'create a disk image of size SIZE (%default)',
                               metavar='SIZE',
                               default='1G')
        self.settings.string(['tarball'], "tar up the disk's contents in FILE",
                             metavar='FILE')
        self.settings.string(['mirror'],
                             'use MIRROR as package source (%default)',
                             metavar='URL',
                             default='http://cdn.debian.net/debian/')
        self.settings.string(['arch'], 'architecture to use (%default)',
                             metavar='ARCH',
                             default=default_arch)
        self.settings.string(['distribution'],
                             'release to use (%default)',
                             metavar='NAME',
                             default='stable')
        self.settings.string_list(['package'], 'install PACKAGE onto system')
        self.settings.string_list(['custom-package'],
                                  'install package in DEB file onto system '
                                    '(not from mirror)',
                                  metavar='DEB')
        self.settings.boolean(['no-kernel'], 'do not install a linux package')
        self.settings.boolean(['enable-dhcp'], 'enable DHCP on eth0')
        self.settings.string(['root-password'], 'set root password',
                             metavar='PASSWORD')
        self.settings.boolean(['lock-root-password'], 
                              'lock root account so they cannot login?')
        self.settings.string(['customize'],
                             'run SCRIPT after setting up system',
                             metavar='SCRIPT')
        self.settings.string(['hostname'],
                             'set name to HOSTNAME (%default)',
                             metavar='HOSTNAME',
                             default='debian')
        self.settings.string_list(['user'],
                                  'create USER with PASSWORD',
                                  metavar='USER/PASSWORD')
        self.settings.boolean(['serial-console'], 
                              'configure image to use a serial console')
        self.settings.boolean(['sudo'], 
                              'install sudo, and if user is created, add them '
                                'to sudo group')

    def process_args(self, args):
        if not self.settings['image'] and not self.settings['tarball']:
            raise cliapp.AppException('You must give disk image filename, '
                                      'or tarball filename')
        if self.settings['image'] and not self.settings['size']:
            raise cliapp.AppException('If disk image is specified, '
                                      'You must give image size.')

        self.remove_dirs = []
        self.mount_points = []

        try:
            if self.settings['image']:
                self.create_empty_image()
                self.partition_image()
                rootdev = self.setup_kpartx()
                self.mkfs(rootdev)
                rootdir = self.mount(rootdev)
            else:
                rootdir = self.mkdtemp()
            self.debootstrap(rootdir)
            self.set_hostname(rootdir)
            self.create_fstab(rootdir)
            self.install_debs(rootdir)
            self.set_root_password(rootdir)
            self.create_users(rootdir)
            self.remove_udev_persistent_rules(rootdir)
            self.setup_networking(rootdir)
            self.customize(rootdir)
            if self.settings['image']:
                self.install_extlinux(rootdev, rootdir)
            if self.settings['tarball']:
                self.create_tarball(rootdir)
        except BaseException, e:
            self.message('EEEK! Something bad happened...')
            self.cleanup_system()
            raise
        else:
            self.cleanup_system()

    def message(self, msg):
        logging.info(msg)
        if self.settings['verbose']:
            print msg

    def runcmd(self, argv, stdin='', ignore_fail=False, **kwargs):
        logging.debug('runcmd: %s %s' % (argv, kwargs))
        p = subprocess.Popen(argv, stdin=subprocess.PIPE, 
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE, 
                             **kwargs)
        out, err = p.communicate(stdin)
        if p.returncode != 0:
            msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
            logging.error(msg)
            if not ignore_fail:
                raise cliapp.AppException(msg)
        return out

    def mkdtemp(self):
        dirname = tempfile.mkdtemp()
        self.remove_dirs.append(dirname)
        logging.debug('mkdir %s' % dirname)
        return dirname
    
    def mount(self, device):
        self.message('Mounting %s' % device)
        mount_point = self.mkdtemp()
        self.runcmd(['mount', device, mount_point])
        self.mount_points.append(mount_point)
        logging.debug('mounted %s on %s' % (device, mount_point))
        return mount_point

    def create_empty_image(self):
        self.message('Creating disk image')
        self.runcmd(['qemu-img', 'create', '-f', 'raw', 
                     self.settings['image'],
                     str(self.settings['size'])])

    def partition_image(self):
        self.message('Creating partitions')
        self.runcmd(['parted', '-s', self.settings['image'],
                     'mklabel', 'msdos'])
        self.runcmd(['parted', '-s', self.settings['image'],
                     'mkpart', 'primary', '0%', '100%'])
        self.runcmd(['parted', '-s', self.settings['image'],
                     'set', '1', 'boot', 'on'])

    def setup_kpartx(self):
        out = self.runcmd(['kpartx', '-av', self.settings['image']])
        devices = [line.split()[2]
                   for line in out.splitlines()
                   if line.startswith('add map ')]
        if len(devices) != 1:
            raise cliapp.AppException('Surprising number of partitions')
        return '/dev/mapper/%s' % devices[0]

    def mkfs(self, device):
        self.message('Creating filesystem')
        self.runcmd(['mkfs', '-t', 'ext2', device])
    
    def debootstrap(self, rootdir):
        self.message('Debootstrapping')

        include = self.settings['package']

        if not self.settings['no-kernel']:
            if self.settings['arch'] == 'i386':
                kernel_arch = '686'
            else:
                kernel_arch = self.settings['arch']
            kernel_image = 'linux-image-2.6-%s' % kernel_arch
            include.append(kernel_image)

        if self.settings['sudo'] and 'sudo' not in include:
            include.append('sudo')

        args = ['debootstrap', '--arch=%s' % self.settings['arch']]
        if include: args.append('--include=%s' % ','.join(include))
        args += [self.settings['distribution'],
                 rootdir, self.settings['mirror']]
        self.runcmd(args)

    def set_hostname(self, rootdir):
        hostname = self.settings['hostname']
        with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
            f.write('%s\n' % hostname)
            
        etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
        with open(etc_hosts, 'r') as f:
            data = f.read()
        with open(etc_hosts, 'w') as f:
            for line in data.splitlines():
                if line.startswith('127.0.0.1'):
                    line += ' %s' % hostname
                f.write('%s\n' % line)

    def create_fstab(self, rootdir):
        fstab = os.path.join(rootdir, 'etc', 'fstab')
        with open(fstab, 'w') as f:
            f.write('proc /proc proc defaults 0 0\n')
            f.write('/dev/sda1 / ext4 errors=remount-ro 0 1\n')

    def install_debs(self, rootdir):
        if not self.settings['custom-package']:
            return
        self.message('Installing custom packages')
        tmp = os.path.join(rootdir, 'tmp', 'install_debs')
        os.mkdir(tmp)
        for deb in self.settings['custom-package']:
            shutil.copy(deb, tmp)
        filenames = [os.path.join('/tmp/install_debs', os.path.basename(deb))
                     for deb in self.settings['custom-package']]
        out, err, exit = \
            self.runcmd_unchecked(['chroot', rootdir, 'dpkg', '-i'] + filenames)
        logging.debug('stdout:\n%s' % out)
        logging.debug('stderr:\n%s' % err)
        out = self.runcmd(['chroot', rootdir, 
                     'apt-get', '-f', '--no-remove', 'install'])
        logging.debug('stdout:\n%s' % out)
        shutil.rmtree(tmp)

    def set_root_password(self, rootdir):
        if self.settings['root-password']:
            self.message('Setting root password')
            self.set_password(rootdir, 'root', self.settings['root-password'])
        elif self.settings['lock-root-password']:
            self.message('Locking root password')
            self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
        else:
            self.message('Give root an empty password')
            self.delete_password(rootdir, 'root')

    def create_users(self, rootdir):
        def create_user(user):
            self.runcmd(['chroot', rootdir, 'adduser', '--gecos', user,
                         '--disabled-password', user])
            if self.settings['sudo']:
                self.runcmd(['chroot', rootdir, 'adduser', user, 'sudo'])

        for userpass in self.settings['user']:
            if '/' in userpass:
                user, password = userpass.split('/', 1)
                create_user(user)
                self.set_password(rootdir, user, password)
            else:
                create_user(userpass)
                self.delete_password(rootdir, userpass)

    def set_password(self, rootdir, user, password):
        encrypted = crypt.crypt(password, '..')
        self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted, user])

    def delete_password(self, rootdir, user):
        self.runcmd(['chroot', rootdir, 'passwd', '-d', user])

    def remove_udev_persistent_rules(self, rootdir):
        self.message('Removing udev persistent cd and net rules')
        for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
            pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
            if os.path.exists(pathname):
                logging.debug('rm %s' % pathname)
                os.remove(pathname)
            else:
                logging.debug('not removing non-existent %s' % pathname)

    def setup_networking(self, rootdir):
        self.message('Setting up networking')
        
        f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
        f.write('auto lo\n')
        f.write('iface lo inet loopback\n')
        
        if self.settings['enable-dhcp']:
            f.write('\n')
            f.write('allow-hotplug eth0\n')
            f.write('iface eth0 inet dhcp\n')
            
        f.close()

    def install_extlinux(self, rootdev, rootdir):
        self.message('Installing extlinux')

        def find(pattern):
            dirname = os.path.join(rootdir, 'boot')
            basenames = os.listdir(dirname)
            logging.debug('find: %s' % basenames)
            for basename in basenames:
                if re.search(pattern, basename):
                    return os.path.join('boot', basename)
            raise cliapp.AppException('Cannot find match: %s' % pattern)

        kernel_image = find('vmlinuz-.*')
        initrd_image = find('initrd.img-.*')

        out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
                           '-s', 'UUID', rootdev])
        uuid = out.splitlines()[0].strip()

        conf = os.path.join(rootdir, 'extlinux.conf')
        logging.debug('configure extlinux %s' % conf)
        f = open(conf, 'w')
        f.write('''
default linux
timeout 1

label linux
kernel %(kernel)s
append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
%(extserial)s
''' % {
    'kernel': kernel_image,
    'initrd': initrd_image,
    'uuid': uuid,
    'kserial': 
        'console=ttyS0,115200' if self.settings['serial-console'] else '',
    'extserial': 'serial 0 115200' if self.settings['serial-console'] else '',
})
        f.close()
        
        if self.settings['serial-console']:
            logging.debug('adding getty to serial console')
            inittab = os.path.join(rootdir, 'etc/inittab')
            with open(inittab, 'a') as f:
                f.write('\nS0:23:respawn:/sbin/getty -L ttyS0 115200 vt100\n')

        self.runcmd(['extlinux', '--install', rootdir])
        self.runcmd(['sync'])
        import time; time.sleep(2)
        
    def cleanup_system(self):
        # Clean up after any errors.

        self.message('Cleaning up')

        if self.settings['image']:
            for mount_point in self.mount_points:
                self.runcmd(['umount', mount_point], ignore_fail=True)

            self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)
        
        for dirname in self.remove_dirs:
            shutil.rmtree(dirname)

    def customize(self, rootdir):
        script = self.settings['customize']
        if script:
            self.message('Running customize script %s' % script)
            with open('/dev/tty', 'w') as tty:
                cliapp.runcmd([script, rootdir], stdout=tty, stderr=tty)

    def create_tarball(self, rootdir):
        # Create a tarball of the disk's contents
        # shell out to runcmd since it more easily handles rootdir
        self.message('Creating tarball of disk contents')
        self.runcmd(['tar', '-cf', self.settings['tarball'], '-C', rootdir, '.'])


if __name__ == '__main__':
    VmDebootstrap().run()