#!/usr/bin/env bash
set -eu

version=0.7.1
tarball="shellcheck-v$version.linux.x86_64.tar.xz"
sha256=64f17152d96d7ec261ad3086ed42d18232fcb65148b44571b564d688269d36c8

check_version () {
    out="$(shellcheck --version 2>/dev/null)" && [[ "$out" = *"
version: $version
"* ]]
}

if ! check_version; then
    tmpdir="$(mktemp -d)"
    trap 'rm -r "$tmpdir"' EXIT
    cd "$tmpdir"
    wget -nv "https://github.com/koalaman/shellcheck/releases/download/v$version/$tarball"
    sha256sum -c <<< "$sha256 $tarball"
    tar -xJf "$tarball" --no-same-owner --strip-components=1 -C /usr/local/bin "shellcheck-v$version/shellcheck"
    check_version
fi