# Copyright 2012 Hewlett-Packard Development Company, L.P.
# All Rights Reserved.
# 
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

function mk_build_dir () {
  export TMP_BUILD_DIR=$(mktemp -t -d image.XXXXXXXX)
  [ $? -eq 0 ] || die "Failed to create tmp directory"
  trap cleanup EXIT
  echo Building in $TMP_BUILD_DIR
  export TMP_IMAGE_PATH=$TMP_BUILD_DIR/image
  export TMP_HOOKS_PATH=$TMP_BUILD_DIR/hooks
}

function save_image () {
    # TODO: this really should rename the old file
    if [ -f  $1 ] ; then
       echo "Old Image file Found REMOVING"
       rm -f $1
    fi

    cp $TMP_IMAGE_PATH $1
    rm -r $TMP_BUILD_DIR
    # All done!
    trap EXIT
    echo "Image file $1 created..."
}

function generate_hooks () {
  mkdir -p $TMP_HOOKS_PATH
  for _ELEMENT in $IMAGE_ELEMENT ; do 
    [ -d $ELEMENTS_DIR/$_ELEMENT ] || die "The element does not exist." ;
    cp -t $TMP_HOOKS_PATH -a $ELEMENTS_DIR/$_ELEMENT/* ;
  done
}

# Call the supplied break-in routine if the named point is listed in the break
# list.
# $1 the break point.
# $2.. what to call if a break is needed
function check_break () {
  if echo "$break" | egrep -e "(,|^)$1(,|$)" -q; then
    echo "Starting debug shell. Exit to resume building." >&2
    echo At stage $1 >&2
    shift
    "$@"
    echo "Resuming" >&2
  fi
}

# Check that a real element has been chosen (prevents foot-guns)
function check_element () {
  [ -d $TMP_HOOKS_PATH ] || generate_hooks
}

# Run a hook, looking for a regex in its stdout, and eval the matched lines.
# $1 is the hook to run
# $2 is the regex to look for
function eval_run_d () {
  local TEMP=`run_d $1`
  echo "$TEMP"
  if [ `echo "$TEMP" | grep -s "$2"` ]; then
      TEMP=`echo "$TEMP" | grep "$2"`
      eval "$TEMP"
  fi
}

# Usage: map_nbd $image
# Returns nbd device path
function map_nbd {
    (lsmod | grep '^nbd ') || sudo modprobe nbd max_part=16

    if [[ $(qemu-nbd --help | grep cache) == *writeback* ]] ; then 
        CACHE="--cache=writeback"
    else 
        echo "Warning: qemu-nbd without --cache=writeback is /slow/."
        CACHE=""
    fi
    NBD_DEV=
    for i in `seq 0 15`; do
        if [ ! -e /sys/block/nbd$i/pid ]; then
            NBD_DEV=/dev/nbd$i
            # Connect to nbd and wait till it is ready
            sudo qemu-nbd -c $NBD_DEV $CACHE $1
            if ! timeout 60 sh -c "while ! [ -e /sys/block/nbd$i/pid ]; do sleep 1; done"; then
                echo "Couldn't connect $NBD_DEV"
                exit 1
            fi
            break
        fi
    done
    if [ -z "$NBD_DEV" ]; then
        echo "No free NBD slots"
        exit 1
    fi
}

# Delete and unmount the working dir used in extracting kernel/initrd
function unmount_qcow_image () {
    sudo umount $WORK_DIR || true
    sudo qemu-nbd -d $NBD_DEV || true
    sudo rm -rf $WORK_DIR

    trap - SIGHUP SIGINT SIGTERM EXIT
}

function mount_qcow_image() {
    trap unmount_qcow_image SIGHUP SIGINT SIGTERM EXIT

    WORK_DIR=$(mktemp -d)
    map_nbd $1
    if [ -e "${NBD_DEV}p1" ]; then
       sudo mount ${NBD_DEV}p1 $WORK_DIR
    else
       sudo mount ${NBD_DEV} $WORK_DIR
    fi
}