#!/usr/bin/env bash
#
# Download, build and install an Archlinux's aur package
#
# Usage: $ aurinstall PACKAGE_SNAPSHOT_URL
#

set -o nounset
set -o errexit

declare -r AUR_BUILDS_DIR=$HOME/.aur_builds

function usage() {
    echo "Usage: $0 PACKAGE_SNAPSHOT_URL"
}

function _check_required_programs() {
    required=(tar wget makepkg)
    for p in ${required[@]}; do
        hash "${p}" 2>&- || \
            {
                echo >&2 " Required program \"${p}\" not installed or in search PATH.";
                exit 1;
            }
    done
}

function main() {
    if [[ $# -ne 1 ]] ; then
        usage;
        exit 1;
    fi

    local package_url=$1

    _check_required_programs

    mkdir -p $AUR_BUILDS_DIR
    cd $AUR_BUILDS_DIR

    # 1. Fetch snapshot
    # -nc skip if file exists
    wget -nc $package_url

    # 2. Extract files
    tar -xvf $(basename "$package_url")

    extracted_dir=`tar -xvf $(basename "$package_url") | head -1 | cut -f1 -d"/"`
    cd $extracted_dir

    # 3. Build and install
    # -i install, -s syncdeps, -L log, --noconfirm skip pacman confirmation
    makepkg -isL --noconfirm
}

main "$@"