#!/bin/bash

# This is a helper for the makefile rule to build a particular image
# from the preprocessed json manifest. It is a shellscript rather
# than just some make lines because some of the complexities just
# are painful to do in make.
#
# Features:
#
# * Knows what target to export based on the extensions.
# * Knows what the exported filename based on the extensions.
# * Supports building natively or in a VM via osbuildvm.
# * Runs only the minimal required commands as root, and
#   chowns the resulting files to the user
# * Supports exporting an extra ostree commit and pulling that
#   into an existing repo.

set -e

DEST="$1"
JSON="$2"
TARGET="$3"
IMAGETYPE="$4"
ARCH="$5"
EXTENSION="$6"

# Map extension => export pipeline name
declare -A EXPORT_BY_EXT
EXPORT_BY_EXT[img]=image
EXPORT_BY_EXT[oci.tar]=container
EXPORT_BY_EXT[qcow2]=qcow2
EXPORT_BY_EXT[repo]=ostree-commit
EXPORT_BY_EXT[rootfs]=rootfs
EXPORT_BY_EXT[ext4]=ext4
EXPORT_BY_EXT[tar]=tar

# Map extension to name of exported file by pipeline
declare -A EXPORT_FILE_BY_EXT
EXPORT_FILE_BY_EXT[img]=disk.img
EXPORT_FILE_BY_EXT[qcow2]=disk.qcow2
EXPORT_FILE_BY_EXT[oci.tar]=container.tar
EXPORT_FILE_BY_EXT[repo]=repo
EXPORT_FILE_BY_EXT[rootfs]=
EXPORT_FILE_BY_EXT[ext4]=rootfs.ext4
EXPORT_FILE_BY_EXT[tar]=rootfs.tar

EXPORT=${EXPORT_BY_EXT[${EXTENSION}]}
EXPORT_FILE=${EXPORT_FILE_BY_EXT[${EXTENSION}]}

HOST_ARCH=$(arch)
CURRENT_UIDGID="$(id -u):$(id -g)"

if [ $ARCH == $HOST_ARCH -a $VM == 0 ]; then
    SUDO="sudo"
    OSBUILD="sudo osbuild"
else
    SUDO=
    OSBUILD="osbuildvm/osbuildvm --arch=$ARCH"
fi

EXPORT_ARGS="--export $EXPORT"

CHECKPOINT_ARGS=
for CP in $CHECKPOINTS; do
    CHECKPOINT_ARGS="${CHECKPOINT_ARGS} --checkpoint ${CP}"
done

CHOWNARGS=
if [ $EXTENSION == repo ]; then
    CHOWNARGS=-R # Chown entire repo dir as it doesn't care about permissions
fi

EXPORTDIRS=$OUTPUTDIR/$EXPORT

# If OSTREE_REPO is set, and we're building an image that has an
# ostree commit, then we also export that commit to the repo specified
# by OSTREE_REPO.
ALSO_EXPORT_OSTREE=0
if [ "$OSTREE_REPO" != "" -a "$IMAGETYPE" == "ostree" ]; then
    ALSO_EXPORT_OSTREE=1
    if [ $EXPORT != "ostree-commit" ]; then
        EXPORT_ARGS="$EXPORT_ARGS --export ostree-commit"
        EXPORTDIRS="$EXPORTDIRS $OUTPUTDIR/ostree-commit"
    fi

    # Ensure we have a repo to export to
    ostree init --repo=$OSTREE_REPO --mode archive
fi

set -x

$SUDO rm -rf $EXPORTDIRS
mkdir -p $EXPORTDIRS # Own export dirs by user, not root

$OSBUILD $CHECKPOINT_ARGS --store $STOREDIR --output-directory $OUTPUTDIR $EXPORT_ARGS $OSBUILD_ARGS $JSON

if [ $ALSO_EXPORT_OSTREE == "1" ]; then
    ostree pull-local --repo=$OSTREE_REPO $OUTPUTDIR/ostree-commit/repo
fi

# Extract and chown exported file
rm -rf $DEST
$SUDO chown $CHOWNARGS $CURRENT_UIDGID $OUTPUTDIR/$EXPORT/$EXPORT_FILE
$SUDO mv $OUTPUTDIR/$EXPORT/$EXPORT_FILE $DEST

$SUDO rm -rf $EXPORTDIRS