#!/bin/bash

PRJ_PATH=`pwd`

BOARD=imx6ull

TAR_PATH=${PRJ_PATH}/../tarball

# rootfs should be buildroot or stretch/buster/bullseye for debian system
ROOTFS=buildroot

ROOTFS_DIR=rootfs_${ROOTFS}
ARCH=armhf

# rootfs configuration
DEF_PASSWD=123456
DEF_HOSTNAME=${BOARD}

APT_UPDATE=0

EXTRA_APPS="vim net-tools network-manager tree file parted locales lsb-release tzdata  wireless-tools openssh-server"

set -u
set -e

trap 'ctrlC_handler' INT

function ctrlC_handler()
{
    echo "Ctrl+C is captured, do some clean work" 
    rm -f  ${ROOTFS_DIR}/usr/bin/qemu-arm-static
}

STAGE=0

function msg_banner()
{ 
    STAGE=`expr $STAGE + 1`
    
    echo ""
    echo "+---------------------------------------------+" 
    printf " Stage $STAGE: $1\n" 
    echo "+---------------------------------------------+"
    echo ""
}

function do_systools()
{
    msg_banner " install system tools"

    debootstrap --version > /dev/null 2>&1
    if [ $? == 0 ] ; then
       echo "system tools already installed, skip it"
       return ;
    fi

    apt install binfmt-support qemu qemu-user-static debootstrap debian-archive-keyring
}

function do_fetch()
{
    if [ ! -d ${ROOTFS_DIR} ] ; then
        if [ -s ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 ]  ; then 
            msg_banner " decompress ${ROOTFS_DIR}.tar.bz2 "
            mkdir -p ${ROOTFS_DIR}
            tar -xjf ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 -C ${ROOTFS_DIR}
            APT_UPDATE=1
        else 
            msg_banner " debootstrap fetch " 
            debootstrap --arch=${ARCH} --foreign ${ROOTFS} ${ROOTFS_DIR} http://ftp.cn.debian.org/debian/
            DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C chroot ${ROOTFS_DIR} debootstrap/debootstrap --second-stage
            APT_UPDATE=1
        fi
    else
       msg_banner "debain rootfs already fetch, skip it"
    fi

    if [ $APT_UPDATE == 0 ] ; then
        return ;
    fi

	msg_banner " debootstrap config "
    cp -f /usr/bin/qemu-arm-static ${ROOTFS_DIR}/usr/bin/
    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C chroot ${ROOTFS_DIR} dpkg --configure -a 
    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C chroot ${ROOTFS_DIR} apt update

	msg_banner " debootstrap apt install "
    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C chroot ${ROOTFS_DIR} apt install -y ${EXTRA_APPS}
    DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true LC_ALL=C LANGUAGE=C LANG=C chroot ${ROOTFS_DIR} sh -c "echo root:${DEF_PASSWD} | chpasswd"

    rm -f ${ROOTFS_DIR}/usr/bin/qemu-arm-static
}

function do_modify()
{
    msg_banner " modify rootfs environment"

    # update hostnmae and issue
    echo $DEF_HOSTNAME > ${ROOTFS_DIR}/etc/hostname
    echo "Debian GNU/Linux $ROOTFS \n \l, default password '$DEF_PASSWD'." > ${ROOTFS_DIR}/etc/issue

    # update dns server
    echo "nameserver 114.114.114.114" > ${ROOTFS_DIR}/etc/resolv.conf
    echo "nameserver 223.5.5.5" >> ${ROOTFS_DIR}/etc/resolv.conf

    # add ls alias for display with color
    grep "color=auto" ${ROOTFS_DIR}/etc/profile > /dev/null 2>&1
    if [ $? != 0 ] ; then
       echo "alias ls='ls --color=auto'" >> ${ROOTFS_DIR}/etc/profile
    fi

    # permit root ssh login
    grep "^PermitRootLogin" ${ROOTFS_DIR}/etc/ssh/sshd_config > /dev/null 2>&1
    if [ $? != 0 ] ; then
       echo "PermitRootLogin yes" >> ${ROOTFS_DIR}/etc/ssh/sshd_config
    fi
}

function do_pack()
{

    if [ -f ${ROOTFS_DIR}.tar.bz2 ] ; then
       msg_banner " rootfs already generate, skip it"
       return ;
   else
       msg_banner " generate rootfs packet "
    fi

    cd ${ROOTFS_DIR}

    tar -cjf ../${ROOTFS_DIR}.tar.bz2 *

    cd ${PRJ_PATH}
}

if [ $ROOTFS == buildroot -o $ROOTFS == yocto ]  ;then
    echo "INFO: $ROOTFS no need build."
    exit 0;
fi

if [ `id -u` != 0 ] ; then
   echo "ERRROR: This shell script must excuted as root privilege."
   exit 0;
fi

do_systools

do_fetch

set +e
do_modify

do_pack