#!/bin/bash

set -e
set -u
# Constants
TMP_DIR=$(mktemp -d)
STACK_CACHE_ROOT="/tmp/drycc/stack/cache"
STACK_DOWNLOAD_URL="${STACK_DOWNLOAD_URL:-https://download.drycc.cc/stacks}"

# OS Release
# shellcheck source=/dev/null
. /etc/os-release

function clean {
    # delay before exiting, so stdout/stderr flushes through the logging system
    rm -rf "${TMP_DIR}"
    sleep 3
}
trap clean EXIT

function main() {
    local name="${1:?name is required}"
    local version="${2:?version is required}"

    local os_name="${OS_NAME:-linux}"
    local os_arch="${OS_ARCH:-$(dpkg --print-architecture)}"
    local os_flavour="${OS_FLAVOUR:-${ID}-${VERSION_ID}}"

    local stack_path="/opt/drycc/${name}"
    local stack_name="${name}-${version}-${os_name}-${os_arch}-${os_flavour}"
    local stack_filename="${stack_name}".tar.gz
    local stack_download_url="${STACK_DOWNLOAD_URL}/${name}/${stack_filename}"

    echo "Downloading $stack_filename package"
    if [ -f "${STACK_CACHE_ROOT}/${stack_filename}" ]; then
        echo "${STACK_CACHE_ROOT}/${stack_filename} already exists, skipping download."
        cp "${STACK_CACHE_ROOT}/${stack_filename}" "${TMP_DIR}/${stack_filename}"
        rm "${STACK_CACHE_ROOT}/${stack_filename}"
    else
        curl --silent --show-error --fail "${stack_download_url}" -o "${TMP_DIR}/${stack_filename}"
    fi
    echo "Generate installation directory: ${stack_path}"
    if [ -d "${stack_path}" ]; then
        echo "Clean up the directory: ${stack_path}"
        rm -rf "${stack_path}"
    fi
    mkdir -p "${stack_path}"
    
    echo "Extract data to a temporary directory: ${TMP_DIR}"
    tar --directory "${TMP_DIR}" --extract --gunzip --file "${TMP_DIR}"/"${stack_filename}" --no-same-owner
    
    packages=$(tr '\t\n' ' ' < "${TMP_DIR}/meta/dependencies" | tr -s ' ')
    if [[ -n "${packages:+x}" ]]; then
        echo "Install system packages: ${packages}"
        install-packages "$packages"
    fi

    echo "Install stack: ${name} ${version}"
    "${TMP_DIR}"/meta/preinstall
    cp -rf "${TMP_DIR}"/data/* "${stack_path}"
    "${TMP_DIR}"/meta/postinstall
    echo "Stack installation completed"
}

main "$@"