#!/bin/bash

PRJ_PATH=`pwd`
PRJ_NAME=`basename ${PRJ_PATH}`

BOARD=igkboard

# SYSTEM  should be: buildroot, yocto or debian
# DISTRO  should be: 2021.02, hardknott, buster or bullseye
# SYSNAME should be: buildroot, yocto, buster or bullseye
SYSTEM=buildroot
DISTRO=2021.02
SYSNAME=buildroot

ROOTFS_DIR=rootfs_${SYSNAME}

TAR_PATH=${PRJ_PATH}/../tarball
DRV_PATH=${PRJ_PATH}/driver

# rootfs configuration
ARCH=armhf
DEF_USER=lingyun
DEF_PASSWD=12345
DEF_HOSTNAME=${BOARD}

APPS_CONF=extra_apps.json

set -u
set -e

trap 'exit_handler' EXIT
function exit_handler()
{
    rm -f  ${ROOTFS_DIR}/usr/bin/qemu-arm-static
    umount ${ROOTFS_DIR}/{sys,proc,dev/pts,dev} 2>/dev/null || true
}

STAGE=0
function msg_banner()
{
    STAGE=`expr $STAGE + 1`

    echo ""
    echo "+---------------------------------------------+"
    printf " Stage $STAGE: $1\n"
    echo "+---------------------------------------------+"
    echo ""
}

function do_unpack()
{
    if [ -d ${ROOTFS_DIR} ] ; then
        printf "\n\n -- ${ROOTFS_DIR} fetched already, skip it -- \n\n"
        return;
    fi

    if [ -s ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 ]  ; then
        printf "\n\n -- decompress ${ROOTFS_DIR}.tar.bz2 -- \n\n"
        mkdir -p ${ROOTFS_DIR}
        tar -xjf ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 -C ${ROOTFS_DIR}
    fi

    return;
}


# decompress rootfs packet or debootstrap fetch debian rootfs
function do_fetch()
{
    msg_banner " ${ROOTFS_DIR} do fetch "

    # try to decompress packet first.
    do_unpack

    # Yocto and buildroot rootfs decompress only
    if [ -d ${ROOTFS_DIR} ] ; then
        return ;
    else
        if [ $SYSTEM != "debian" ] ; then
            echo " ERROR: miss ${SYSTEM}(${DISTRO}) rootfs, exit now. "
            echo ""
            exit;
        fi
    fi

    # debootstrap fetch debian rootfs
    export DEBIAN_FRONTEND=noninteractive
    export DEBCONF_NONINTERACTIVE_SEEN=true
    export LC_ALL=C
    export LANGUAGE=C
    export LANG=C

    printf "\n\n -- debootstrap fetch start --\n\n"
    echo "debootstrap --arch=${ARCH} --foreign ${DISTRO} ${ROOTFS_DIR} http://ftp.cn.debian.org/debian/"
    debootstrap --arch=${ARCH} --foreign ${DISTRO} ${ROOTFS_DIR} http://ftp.cn.debian.org/debian/

    chroot ${ROOTFS_DIR} debootstrap/debootstrap --second-stage
    printf "\n\n -- debootstrap config start --\n\n"

    chroot ${ROOTFS_DIR} dpkg --configure -a
    printf "\n\n -- debootstrap fetch done -- \n\n"

    # Clear the MD5 value to install extra apps
    sed -i -e "s|.*md5apt.*|\t\"md5apt\":\"MD5_Auto_Generate_Here\"|g" $APPS_CONF
}


# Install extra apps defined in extra_apps.conf
function do_extra_apt()
{
    if [ ! -f $APPS_CONF ] ; then
        return ;
    fi

    extra_apps=$(eval jq -r .extra_debian_apps[] $APPS_CONF )
    md5_file=$(eval jq -r .md5apt $APPS_CONF)
    md5_calc=$(eval echo $extra_apps | md5sum | awk '{print $1}')

    if [ $md5_file == $md5_calc ] ; then
        printf "\n\n -- debootstrap apt install already, skip it! --\n\n"
        return ;
    fi

    msg_banner " debootstrap apt install "

    export DEBIAN_FRONTEND=noninteractive
    export DEBCONF_NONINTERACTIVE_SEEN=true
    export LC_ALL=C
    export LANGUAGE=C
    export LANG=C


    cp -f /usr/bin/qemu-arm-static ${ROOTFS_DIR}/usr/bin/
    mount -o bind /proc ${ROOTFS_DIR}/proc
    mount -o bind /dev ${ROOTFS_DIR}/dev
    mount -o bind /dev/pts ${ROOTFS_DIR}/dev/pts
    mount -o bind /sys ${ROOTFS_DIR}/sys

    chroot ${ROOTFS_DIR} apt update
    chroot ${ROOTFS_DIR} apt install -y ${extra_apps}

    umount ${ROOTFS_DIR}/{sys,proc,dev/pts,dev}


    sed -i -e "s|.*md5apt.*|\t\"md5apt\":\"$md5_calc\"|g" $APPS_CONF
    printf "\n\n -- debootstrap apt install done --\n\n"

    # modify root password
    chroot ${ROOTFS_DIR} sh -c "echo root:${DEF_PASSWD} | chpasswd"

    # add extra user account
    set +e
    grep "$DEF_USER" ${ROOTFS_DIR}/etc/passwd > /dev/null 2>&1
    if [ $? != 0 ] ; then
        printf "\n\n -- setup default user account --\n\n"
        chroot ${ROOTFS_DIR} sh -c "useradd -m -s /bin/bash ${DEF_USER}"
        chroot ${ROOTFS_DIR} sh -c "echo ${DEF_USER}:${DEF_PASSWD} | chpasswd"
        chroot ${ROOTFS_DIR} sh -c "usermod -G video,audio,sudo avnet"
        echo "${DEF_USER}    ALL=(ALL:ALL) NOPASSWD:ALL" >> ${ROOTFS_DIR}/etc/sudoers
    fi
    set -e
}

function install_file()
{
    if [ $# != 1 ] ; then
        return ;
    fi

    # parser the source file and destination install path
    src=`echo $1 | cut -d: -f1`
    dst=${ROOTFS_DIR}/`echo $1 | cut -d: -f2`

    echo "install $src => $dst"

    mkdir -p ${dst}

    # parser to get .tar.gz .tar.bz2 .tar.xz
    tar=`echo "${src#*.}"`

    case $tar in
        tar.gz)
            tar -xzf ${src} -C ${dst}
            ;;

        tar.bz2)
            tar -xjf ${src} -C ${dst}
            ;;

        tar.xz)
            tar -xJf ${src} -C ${dst}
            ;;

        *)
            rm -rf ${dst}/`basename ${src}`
            cp -rf ${src} ${dst}
            ;;

        esac
}

function do_install()
{
    # apt install extra packet for debian rootfs
    if [ $SYSTEM == "debian" ] ; then
        do_extra_apt
    fi

    # install common files for all the system
    for row in $( jq -r '.extra_common_files | keys[] as $k | "\($k):\(.[$k])"' $APPS_CONF ) ; do
        install_file $row
    done

    # install extra files for custom system
    jq_args=".extra_${SYSTEM}_files | keys[] as \$k | \"\(\$k):\(.[\$k])\""
    for row in $( jq -r "${jq_args}" $APPS_CONF ) ; do
        install_file $row
    done
}

function do_modify()
{
    msg_banner " modify rootfs environment"

    set +e

    # update hostnmae and issue
    echo "Welcome to LingYun IoT Gateway Kit Board GNU/Linux ${SYSTEM}(${DISTRO}) system, default password '$DEF_PASSWD'." > ${ROOTFS_DIR}/etc/issue
    echo $DEF_HOSTNAME > ${ROOTFS_DIR}/etc/hostname
    grep "$BOARD" ${ROOTFS_DIR}/etc/hosts > /dev/null 2>&1
    if [ $? != 0 ] ; then
       echo "127.0.0.1       ${BOARD}" >> ${ROOTFS_DIR}/etc/hosts
    fi

    # 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

    # update profile
    sed -i "s|PS1='# '|PS1='\\\u@\\\h:\\\w# '|g" ${ROOTFS_DIR}/etc/profile
    sed -i "s|PS1='$ '|PS1='\\\u@\\\h:\\\w$ '|g" ${ROOTFS_DIR}/etc/profile


    # add ls alias for display with color
    grep "^alias ls=" ${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
    sed -i "s|^#PermitRootLogin.*|PermitRootLogin yes|g" ${ROOTFS_DIR}/etc/ssh/sshd_config
    sed -i "s|^#PasswordAuthentication.*|PasswordAuthentication yes|g" ${ROOTFS_DIR}/etc/ssh/sshd_config

    # add vim alias for buildroot and yocto
    if [ $SYSTEM != "debian" ] ; then
        grep "alias vim=" ${ROOTFS_DIR}/etc/profile > /dev/null 2>&1
        if [ $? != 0 ] ; then
            echo "alias vim='vi'" >> ${ROOTFS_DIR}/etc/profile
        fi
    fi

    set -e

    printf "\n\n -- modify rootfs done --\n\n"
}

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}

    printf "\n\n -- generate rootfs packet done --\n\n"
}

function do_distclean()
{
    printf "\n\n -- do distclean in $PRJ_NAME --\n\n"

    rm -rf driver
    rm -rf $ROOTFS_DIR

    exit;
}

function do_rootfs()
{
    do_fetch
    do_install
    do_modify
    do_pack
}

function do_root()
{
    echo ""
    if [[ $1 == "yes" ]] && [ `id -u` != 0 ] ; then
        echo "ERROR: This action must run as root!"
        echo ""
        exit;
    elif [[ $1 != "yes" ]] && [ `id -u` == 0 ] ; then
        echo "ERROR: This action cannot run as root!"
        echo ""
        exit;
    fi
}

function do_usage()
{
    echo ""
    echo "Usage:"
    echo "   $0 [-b] [-c] [-h]"
    echo "       -b: download and build $PRJ_NAME"
    echo "       -c: clean all the source code"
    echo "       -h: show this help message"
    echo ""
    echo " WARNNING: This shell script must run as sudo"
    echo ""
    exit;
}

while getopts "bch" OPTNAME
do
    case "${OPTNAME}" in
        "b")
            break;
            ;;

        "c")
            do_root "yes"
            do_distclean
            ;;

        "*")
            do_usage
            ;;
    esac
done

do_root "yes"
do_rootfs