#!/bin/sh
set -eu

SOURCE_URL="${SOURCE_URL:-https://packages.element.io/desktop/install/linux/glibc-x86-64/element-desktop.tar.gz}"
OUTDIR="${1:-}"

if [ -z "$OUTDIR" ]; then
    echo "usage: $0 OUTDIR" >&2
    exit 1
fi

mkdir -p "$OUTDIR"

tmpdir="$(mktemp -d)"
cleanup() {
    rm -rf "$tmpdir"
}
trap cleanup EXIT INT TERM

archive="$tmpdir/element-desktop.tar.gz"
curl -fL "$SOURCE_URL" -o "$archive"

topdir="$(tar -tzf "$archive" | sed -n '1s#/##p')"
version="${topdir#element-desktop-}"

if [ -z "$version" ] || [ "$version" = "$topdir" ]; then
    echo "failed to derive version from archive root: $topdir" >&2
    exit 1
fi

dest="$OUTDIR/element-desktop-$version.tar.gz"
cp "$archive" "$dest"
printf '%s\n' "$version" > "$OUTDIR/.upstream-version"
printf '%s\n' "$dest"