#!/usr/bin/python3

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

# http://elinux.org/RPi_U-Boot

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
        linux-image-armmp-lpae
        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
        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 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')
    open8(rootdir + '/etc/zoneinfo', 'w').write('Europe/Paris\n')
    shutil.copy(rootdir + '/usr/share/zoneinfo/Europe/Paris',
                rootdir + '/etc/localtime')

    open8(rootdir + '/etc/network/interfaces', 'w').write(mlstrip(
        '''\
            auto lo
            iface lo inet loopback

            auto eth0
            iface eth0 inet dhcp
        '''))
    open8(rootdir + '/etc/hosts', 'w').write(mlstrip(
        '''\
            127.0.0.1 localhost localhost.localdomain debian

            # the following lines are desirable for IPv6 capable hosts
            ::1     localhost ip6-localhost ip6-loopback
            ff02::1 ip6-allnodes
            ff02::2 ip6-allrouters
        '''))
    open8(rootdir + '/etc/hostname', 'w').write('debian\n')
    os.makedirs(rootdir + '/boot/firmware', mode=0o755)
    open8(rootdir + '/etc/fstab', 'w').write(mlstrip(
        '''\
            # <device> <mount point> <type> <options> <dump>  <pass>
            /dev/mmcblk0p2 / ext4 errors=remount-ro,relatime 0 1
            /dev/mmcblk0p1 /boot/firmware vfat errors=remount-ro,relatime 0 2
        '''))

    # activate serial console
    run([
        'ln',
        '-s',
        '/lib/systemd/system/serial-getty@.service',
        rootdir + '/etc/systemd/system/getty.target.wants/serial-getty@ttyAMA0.service',
        ], check=True)
    os.makedirs(rootdir + '/etc/systemd/system/serial-getty@ttyAMA0.service.d',
                mode=0o755)
    open8(rootdir +
        '/etc/systemd/system/serial-getty@ttyAMA0.service.d/autologin.conf',
        'w').write(mlstrip(
        '''\
            [Service]
            ExecStart=
            ExecStart=-/sbin/agetty --autologin root --login-pause --noclear %I 115200,38400,9600 vt102
        '''))

    open8(rootdir + '/etc/default/keyboard', 'w').write(mlstrip(
        '''\
            XKBMODEL="pc105"
            XKBLAYOUT="fr"
            XKBVARIANT="bepo"
            XKBOPTIONS=""
        '''))

    open8(rootdir + '/etc/default/locale', 'w').write(mlstrip(
        '''\
            LANG="en_US.UTF-8"
            LC_TIME="en_DK.UTF-8"
            LC_PAPER="en_GB.UTF-8"
            LC_MEASUREMENT="en_GB.UTF-8"
        '''))

    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)

    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
        '''))

    open8(rootdir + '/etc/vim/vimrc', 'w').write(mlstrip(
        '''\
            set nocompatible

            au BufReadPost * if line("'\"") > 1 && line("'\"") <= line("$") | exe "normal! g'\"" | endif
            filetype plugin indent on
            set autoindent
            set background=dark
            set backspace=2
            set hidden
            set hlsearch
            set ignorecase
            set incsearch
            set laststatus=2
            set modelines=0
            set nobackup
            set nowritebackup
            set ruler
            set scrolloff=3
            set shiftwidth=4
            set showcmd
            set showmatch
            set statusline=%<%f%h%m%r%=%l,%c\ %P
            set ts=4
            set whichwrap=<,>,[,]
            set wildmode=list:full
            syntax on
        '''))


    #kernel_params  = 'ro text console=ttyAMA0,115200n8'
    #kernel_params += ' console=tty0 net.ifnames=0'
    #open8(rootdir + '/boot/grub/grub.cfg', 'w').write(mlstrip(
    #    '''\
    #        terminal_output console
    #        serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
    #        set default=0
    #        set timeout=3
    #        menuentry 'default' {{
    #            search --set=root --file /boot/grub/grub.cfg --hint hd0,gpt2
    #            linux /vmlinuz root=PARTUUID={rid} {kp}
    #            initrd /initrd.img
    #        }}
    #    '''.format(rid=rootpartuuid, kp=kernel_params)))


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


if __name__ == '__main__':
    main()