#!/usr/bin/env bash

set -e

# Clean up

rm -rf /var/lib/apt/lists/*

ACT_VERSION=${VERSION:-"latest"}

if [ "$(id -u)" -ne 0 ]; then

echo -e 'Script must be run as root. Use sudo, su, or add "USER root" to your Dockerfile before running this script.'

exit 1

fi

apt_get_update()

{

echo "Running apt-get update..."

apt-get update -y

}

# Checks if packages are installed and installs them if not

check_packages() {

if ! dpkg -s "$@" > /dev/null 2>&1; then

if [ "$(find /var/lib/apt/lists/* | wc -l)" = "0" ]; then

apt_get_update

fi

apt-get -y install --no-install-recommends "$@"

fi

}

export DEBIAN_FRONTEND=noninteractive

# Figure out correct version of a three part version number is not passed

find_version_from_git_tags() {

local variable_name=$1

local requested_version=${!variable_name}

if [ "${requested_version}" = "none" ]; then return; fi

local repository=$2

local prefix=${3:-"tags/v"}

local separator=${4:-"."}

local last_part_optional=${5:-"false"}

if [ "$(echo "${requested_version}" | grep -o "." | wc -l)" != "2" ]; then

local escaped_separator=${separator//./\\.}

local last_part

if [ "${last_part_optional}" = "true" ]; then

last_part="(${escaped_separator}[0-9]+)?"

else

last_part="${escaped_separator}[0-9]+"

fi

local regex="${prefix}\\K[0-9]+${escaped_separator}[0-9]+${last_part}$"

local version_list="$(git ls-remote --tags ${repository} | grep -oP "${regex}" | tr -d ' ' | tr "${separator}" "." | sort -rV)"

if [ "${requested_version}" = "latest" ] || [ "${requested_version}" = "current" ] || [ "${requested_version}" = "lts" ]; then

declare -g ${variable_name}="$(echo "${version_list}" | head -n 1)"

else

set +e

declare -g ${variable_name}="$(echo "${version_list}" | grep -E -m 1 "^${requested_version//./\\.}([\\.\\s]|$)")"

set -e

fi

fi

if [ -z "${!variable_name}" ] || ! echo "${version_list}" | grep "^${!variable_name//./\\.}$" > /dev/null 2>&1; then

echo -e "Invalid ${variable_name} value: ${requested_version}\nValid values:\n${version_list}" >&2

exit 1

fi

echo "${variable_name}=${!variable_name}"

}

# Install dependencies

check_packages ca-certificates curl git tar

architecture="$(uname -m)"

case $architecture in

x86_64) architecture="x86_64";;

aarch64 | armv8* | arm64) architecture="arm64";;

*) echo "(!) Architecture $architecture unsupported"; exit 1 ;;

esac

# Use a temporary locaiton for act archive

export TMP_DIR="/tmp/tmp-act"

mkdir -p ${TMP_DIR}

chmod 700 ${TMP_DIR}

# Install act

echo "(*) Installing act..."

find_version_from_git_tags ACT_VERSION https://github.com/nektos/act

ACT_VERSION="${ACT_VERSION#"v"}"

curl -sSL -o ${TMP_DIR}/act.tar.gz "https://github.com/nektos/act/releases/download/v${ACT_VERSION}/act_Linux_${architecture}.tar.gz"

tar -xzf "${TMP_DIR}/act.tar.gz" -C "${TMP_DIR}" act

mv ${TMP_DIR}/act /usr/local/bin/act

chmod 0755 /usr/local/bin/act

# Clean up

rm -rf /var/lib/apt/lists/*

echo "Done!"