#!/usr/bin/python3

import os
import sys
import glob
import subprocess
import tempfile
import shutil
import re
import functools

parameters = dict(
    release='testing',
    #mirror='http://fr.archive.ubuntu.com/ubuntu/',
    mirror='http://httpredir.debian.org/debian',
    arch='armhf',
    packages='''
        aptitude
        bash
        bash-completion
        bind9-host
        bmon
        busybox
        bzip2
        curl
        htop
        iftop
        ifupdown
        iotop
        iperf
        iproute2
        iptables
        iputils-ping
        less
        lftp
        locales
        ncdu
        ncurses-base
        ncurses-term
        net-tools
        netbase
        netcat
        nload
        openssh-client
        openssh-server
        psmisc
        python3
        ranger
        rsync
        screen
        sed
        socat
        strace
        tar
        tcpdump
        telnet
        tmux
        tree
        tzdata
        ubuntu-archive-keyring
        vim
        vim-nox
        vim-runtime
        w3m
        wget
        zsh
    '''.split(),
)


open8 = functools.partial(open, encoding='utf8')
numerical_sort = lambda y: [int(x) if x.isdigit() else x
                            for x in re.split('(\d+)', y)]


def join(item0, *items):
    return os.path.join(item0, *[p.lstrip('/') for p in items])


def mlstrip(s):
    return re.sub(r'^\s*', '', s, flags=re.MULTILINE)


def run(*l, **kw):
    print('run:', *l)
    return subprocess.run(*l, **kw)


def reexec_root():
    # run as root
    if os.geteuid() != 0:
        os.execvp("sudo", ["sudo"] + sys.argv)


def system_customization(rootdir):
    os.unlink(rootdir + '/etc/localtime')
    shutil.copy('files/zoneinfo', join(rootdir, 'etc/zoneinfo'))
    shutil.copy(rootdir + '/usr/share/zoneinfo/Europe/Paris',
                rootdir + '/etc/localtime')
    shutil.copy('files/interfaces', join(rootdir, 'etc/network/interfaces'))
    shutil.copy('files/hosts', join(rootdir, 'etc/hosts'))
    shutil.copy('files/hostname', join(rootdir, 'etc/hostname'))
    os.makedirs(rootdir + '/boot/firmware', mode=0o755)
    shutil.copy('files/fstab', join(rootdir, 'etc/fstab'))
    os.symlink('/lib/systemd/system/serial-getty@.service',
               join(rootdir, '/etc/systemd/system/getty.target.wants/serial-getty@ttyAMA0.service'))
    os.makedirs(rootdir + '/etc/systemd/system/serial-getty@ttyAMA0.service.d',
                mode=0o755)
    shutil.copy('files/autologin.conf', join(rootdir, '/etc/systemd/system/serial-getty@ttyAMA0.service.d/autologin.conf'))
    shutil.copy('files/keyboard', join(rootdir, 'etc/default/keyboard'))
    shutil.copy('files/locale', join(rootdir, 'etc/default/locale'))
    shutil.copy('files/vimrc', join(rootdir, 'etc/vim/vimrc'))
    shutil.copy('files/ubuntu.pref',    join(rootdir, 'etc/apt/preferences.d'))
    shutil.copy('files/ubuntu.sources', join(rootdir, 'etc/apt/sources.list.d'))
    shutil.copy('files/main.sources', join(rootdir, 'etc/apt/sources.list.d'))
    os.unlink(join(rootdir, 'etc/apt/sources.list'))
    shutil.copy('files/vg-copy-rpi',    join(rootdir, 'etc/kernel/postinst.d'))
    os.makedirs(join(rootdir, 'etc/kernel/postrm.d'), mode=0o755)
    os.symlink('../postinst.d/vg-copy-rpi',
               join(rootdir, 'etc/kernel/postrm.d/vg-copy-rpi'))

    open8(rootdir + '/etc/bash.bashrc', 'a').write(mlstrip(
        '''\

            # enable bash completion in interactive shells
            if ! shopt -oq posix; then
            if [ -f /usr/share/bash-completion/bash_completion ]; then
                . /usr/share/bash-completion/bash_completion
            elif [ -f /etc/bash_completion ]; then
                . /etc/bash_completion
            fi
            fi
            alias ls="ls --color=aut"
            alias l="ls -CF"
            alias ll="l -lh"
            alias la="l -a"
            alias e="vim"
            alias rm='rm -i'
            alias cp='cp -i'
            alias mv='mv -i'
            export PAGER=less
            export EDITOR=vim
            export VISUAL=vim
        '''))

    for locale in ['fr_FR', 'en_US', 'en_GB', 'en_DK', 'de_DE']:
        run([
            'localedef',
            '--prefix={}'.format(rootdir),
            '-f', 'UTF-8',
            '-i', locale,
            '{}.UTF-8'.format(locale)
            ], check=True)

    run(['chroot', rootdir, '/usr/bin/qemu-arm-static',
         '/usr/bin/apt', 'update'], check=True)
    run(['chroot', rootdir, '/usr/bin/qemu-arm-static',
         '/usr/bin/apt', 'install', '--no-install-recommends',
         '-yq', 'linux-image-raspi2'], check=True)


def main():
    reexec_root()
    rootdir = 'debootstrapdir'
    os.makedirs(rootdir, mode=0o755)
    print('debootstrapping...')
    run([
        'qemu-debootstrap',
        '--arch=' + parameters['arch'],
        '--include=' + ','.join(parameters['packages']),
        '--components=main,contrib',
        parameters['release'],
        rootdir,
        parameters['mirror'],
        ], check=True)
    print('doing system customization on debootstrapped system...')
    system_customization(rootdir)


if __name__ == '__main__':
    main()