#!/usr/bin/env bash

if [[ "${BASH_SOURCE[0]}" = "${0}" ]]
then
    set -euxo pipefail
    RUN_MAIN=yes
else
    RUN_MAIN=no
fi

PACKER_VERSION=1.8.6
INSTALL_DIR=/usr/local/bin
ARCH=amd64
PACKER_FILE=packer_${PACKER_VERSION}_linux_${ARCH}
UPSTREAM="https://github.com/mkaczanowski/packer-builder-arm"
UPGRADE="false"
BUILD_DIR="$(pwd)/build"
FORCE_DEPENDENCY_INSTALL="${FORCE_DEPENDENCY_INSTALL:-no}"

preflight () {
    if [ -z "$(command -v git)" -o "${FORCE_DEPENDENCY_INSTALL}" = "yes" ]
    then
        sudo apt-get update && sudo apt-get -y install git unzip qemu-user-static e2fsprogs dosfstools libarchive-tools xz-utils jq
    fi
    mkdir -p ${BUILD_DIR}
    pushd ${BUILD_DIR}
}

install_packer () {
    if [ -x ${INSTALL_DIR}/packer ]
    then
	return 0
    fi

    curl -LO https://releases.hashicorp.com/packer/${PACKER_VERSION}/${PACKER_FILE}.zip
    unzip ${PACKER_FILE}
    sudo mv packer ${INSTALL_DIR}/
    rm ${PACKER_FILE}.zip
}

install_packer_builder_arm () {
    if [ -x "${INSTALL_DIR}/packer-builder-arm" -a -z "${UPGRADE}" ]
    then
	    return 0
    fi

    if [ ! -d "${UPSTREAM##*/}" ]
    then
        git clone "${UPSTREAM}"
    fi

    pushd "${UPSTREAM##*/}"
    go mod download
    go build
    sudo mv packer-builder-arm ${INSTALL_DIR}/
    popd
}

cleanup () {
    popd
}

main () {
    preflight
    install_packer
    install_packer_builder_arm
    cleanup
}

if [[ "${RUN_MAIN}" = "yes" ]]
then
    main
fi