#!/bin/sh

VERSION=0.1
CONFIG_DIR=/rodeo/configuration
OVERLAY_DIRECTORY=/rodeo/overlays
DEFAULT_OVERLAY_FILE=$CONFIG_DIR/included_overlays
MANAGED_DIRECTORIES_FILE=$CONFIG_DIR/managed_directories

fatal() {
  echo "Error: $1"
  exit 1
}

error () {
  echo "Error: $1"
}

info() {
  echo "$1"
}

debug() {
  [ "$RODEO_DEBUG" = "1" ] && info "$1"
}

warning() {
  echo "Warning: $1"
}

get_lower_dirs() {
  overlay_config="$1"
  dir="$2"
  while IFS="" read -r overlay || [ -n "$overlay" ]
  do
    if [ -f "$overlay" ]; then
      get_lower_dirs "$overlay" "$dir"
    else
      debug "Checking if $overlay has $dir"
      cd $OVERLAY_DIRECTORY || fatal "Failed to change directory"
      overlay_path="$(realpath "$overlay")"
      if [ -d "$overlay_path/$dir" ]; then
        debug "$overlay has $dir"
        if [ -z "$lowerdirs" ]; then
          lowerdirs="$overlay_path/$dir"
        else
          lowerdirs="$lowerdirs:$overlay_path/$dir"
        fi
      else
        debug "$overlay does not have $dir"
      fi
    fi
  done < "$overlay_config"
}

remount() {
  overlay_config=$DEFAULT_OVERLAY_FILE
  [ -n "$1" ] && overlay_config="$1"
  while IFS="" read -r dir || [ -n "$dir" ]
  do
    debug "Scanning for overlays to be mounted on /$dir"
    lowerdirs=""
    get_lower_dirs "$overlay_config" "$dir"
    umount "/$dir" || error "Unmounting of /$dir failed"
    if [ -z "$lowerdirs" ]; then
      warning "No overlay has $dir"
      mount --bind "/rodeo/root/$dir" "/$dir" || error "Bind-Mounting /$dir failed"
    else
      debug "Overlays to be mounted on /$dir: $lowerdirs"
      mount -t overlay overlay -o lowerdir="$lowerdirs",upperdir="/rodeo/root/$dir",workdir="/rodeo/tmp/$dir" "/$dir" || error "Overlay-Mounting /$dir failed"
    fi
  done < $MANAGED_DIRECTORIES_FILE
}

initial_mount() {
  overlay_config=$DEFAULT_OVERLAY_FILE
  [ -n "$1" ] && overlay_config="$1"
  while IFS="" read -r dir || [ -n "$dir" ]
  do
    debug "Scanning for overlays to be mounted on /$dir"
    lowerdirs=""
    get_lower_dirs "$overlay_config" "$dir"
    if [ -z "$lowerdirs" ]; then
      warning "No overlay has $dir"
      mount --bind "/rodeo/root/$dir" "/$dir" || error "Bind-Mounting /$dir failed"
    else
      debug "Overlays to be mounted on /$dir: $lowerdirs"
      mount -t overlay overlay -o lowerdir="$lowerdirs",upperdir="/rodeo/root/$dir",workdir="/rodeo/tmp/$dir" "/$dir" || error "Overlay-Mounting /$dir failed"
    fi
  done < $MANAGED_DIRECTORIES_FILE
}

transfer_directory() {
  dir="$1"
  mv "/$dir" "/rodeo/root/$dir"
  mkdir -p "/$dir" "/rodeo/tmp/$dir"
  echo "$dir" >> $MANAGED_DIRECTORIES_FILE
  info "Added $dir to the list of managed directories"
  initial_mount
}

shell() {
  target="$1"
  overlay_file=$DEFAULT_OVERLAY_FILE
  command="/bin/sh"
  [ -n "$2" ] && overlay_file="$2"
  [ -n "$3" ] && command="$3"
  [ ! -d "$target" ] && mkdir -p "$target"
  info "Mounting Base Filesystems"
  mount --bind / "$target"
  mount --bind /dev "$target/dev"
  mount --bind /sys "$target/sys"
  mount --bind /proc "$target/proc"
  info "Mounting Overlays"
  chroot "$target" /sbin/rodeo-overlay.sh initial-mount "$overlay_file"
  info "Executing $command"
  chroot "$target" "$command"
}

[ "$1" = "transfer-directory" ] && transfer_directory "$2"
[ "$1" = "remount" ] && remount "$2"
[ "$1" = "initial-mount" ] && initial_mount "$2"
[ "$1" = "shell" ] && shell "$2" "$3" "$4"