#!/usr/bin/env bash

usage() {
    echo "Build and bundle Go releases with the current dir as the build dir."
    echo "Usage: $0 PACKAGE [ASSETS...]"
}

main() {
    set -eo pipefail
    [[ "$TRACE" ]] && set -x

    if [[ ! "$1" ]]; then
        usage
        exit 1
    fi

    if [[ ! "$GOOS" ]]; then
        export GOOS="linux"
        echo "Defaulting to GOOS=$GOOS"
    fi
    if [[ ! "$GOARCH" ]]; then
        export GOARCH="amd64"
        echo "Defaulting to GOARCH=$GOARCH"
    fi
    if [[ ! "$BUILDDIR" ]]; then
        export BUILDDIR="build"
        echo "Defaulting to BUILDDIR=$BUILDDIR"
    fi

    build "$@"
}

build() {
    local package="$1"; shift
    local assets="$@"

    local bin="$(basename $package)"
    local tarball="${bin}-${GOOS}_${GOARCH}.tgz"
    local outdir="$BUILDDIR/$bin"
    local tardir="$bin"
    if [ "$GOOS" == "windows" ]; then
        bin="$bin.exe"
    fi


    if [[ -d "$outdir" ]]; then
        echo "err: outdir already exists: $PWD/$outdir"
    fi
    mkdir -p "$outdir"

    go build -ldflags "$LDFLAGS" -o "$outdir/$bin" "$package"

    # Stage asset bundle
    if [[ "$assets" ]]; then
        ln -f $assets "$outdir"
    fi

    # Create tarball
    tar -C "$BUILDDIR" -czvf "$BUILDDIR/$tarball" "$tardir"

    # Cleanup
    rm -rf "$outdir"

    echo "Packaged: $tarball"
}

main "$@"