#!/bin/bash

# matter-chroot | MatterLinux chroot script
# MatterLinux 2023-2024 (https://matterlinux.xyz)

# 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 <https://www.gnu.org/licenses/>.

#############################
## import common functions ##
#############################
location="$(dirname "${0}")"
location="$(realpath "${location}")"
commonsh="$(echo "${location}" | sed 's/\/bin/\/lib/g')/mtsc-common.sh"

source "${commonsh}"

if [ "${?}" != "0" ]; then
  echo "Failed to import mtsc-common"
  exit 1
fi

####################
## util functions ##
####################
linkresolv(){
  if [ ! -f "${target}/etc/resolv.conf" ]; then
    ln -sf /run/systemd/resolve/resolv.conf "${target}/etc/resolv.conf"
  fi
}

chrt() {
  mount -t proc proc "${target}/proc"
  mount -t sysfs sysfs "${target}/sys"
  if [[ -d "${target}/sys/firmware/efi/efivars" ]]; then
    mount -t efivarfs efivarfs "${target}/sys/firmware/efi/efivars"
  fi

  mount -o bind /dev "${target}/dev"
  mount -t devpts none "${target}/dev/pts"
  mount --bind /run "${target}/run"
  linkresolv

  if [ -h "${target}/dev/shm" ]; then
    mkdir -p "${target}/$(readlink "${target}/dev/shm")"
  else
    mount -t tmpfs -o nosuid,nodev tmpfs "${target}/dev/shm"
  fi

  
  local prompt='\['$BOLD'\['$RED'(chroot)\['$RESET'\['$BOLD' \u@\h:\w#\['$RESET' '
  chroot "${target}" /usr/bin/env -i \
    HOME=/root                       \
    TERM="${TERM}"                   \
    PS1="${prompt}"                  \
    PATH=/usr/bin:/usr/sbin          \
    "$@"
  local ret_code=$?

  # kill procs that may prevent umount
  killall -9 keyboxd   2> /dev/null
  killall -9 dirmngr   2> /dev/null
  killall -9 gpg-agent 2> /dev/null

  umount "${target}/proc"
  mountpoint -q "${target}/sys/firmware/efi/efivars" && umount "${target}/sys/firmware/efi/efivars"
  umount "${target}/sys"

  umount "${target}/dev/pts"
  mountpoint -q "${target}/dev/shm" && umount "${target}/dev/shm"
  umount "${target}/dev"
  umount "${target}/run"

  return $ret_code
}

#################
## main script ##
#################
if [ "$EUID" -ne 0 ]; then
  error "Cannot chroot without root"
  exit 1
fi

if [ $# -eq 0 ]; then
  error "Please specify a directory"
  exit 1
fi

target="$(realpath "${1}")" 

if [ -f "${target}" ]; then
  error "${target} is a file"
  exit 1
fi

if [ ! -d "${target}" ]; then
  error "${target} does not exist"
  exit 1
fi 

if [ $# -gt 1 ]; then
  chrt ${@:2}
  exit $?
fi

chrt bash --noprofile --login
exit $?