#!/usr/bin/env bash
set -euo pipefail

function host-goarch() {
	case "$(uname -m)" in
	x86_64|amd64)
		echo "amd64"
		;;
	aarch64|arm64)
		echo "arm64"
		;;
	*)
		echo ""
		;;
	esac
}

function require-command() {
	local command_name=$1
	if ! command -v "$command_name" >/dev/null 2>&1; then
		echo "missing required command: $command_name"
		return 1
	fi
}

function cpu_count() {
	if command -v nproc >/dev/null 2>&1; then
		nproc
	else
		getconf _NPROCESSORS_ONLN
	fi
}

function download() {
	local url=$1
	local output=$2
	if [ ! -f "$output" ]; then
		curl -fsSL "$url" -o "$output"
	fi
}

function prepare-dir() {
	local dir=$1
	rm -rf "$dir"
	mkdir -p "$dir"
}

function copy-tree() {
	local from_dir=$1
	local to_dir=$2
	rm -rf "$to_dir"
	mkdir -p "$to_dir"
	cp -a "$from_dir"/. "$to_dir"/
}

function copy-static-lib() {
	local pattern=$1
	local destination=$2
	local source_path=""

	source_path=$(find "$(dirname "$pattern")" -type f -name "$(basename "$pattern")" | head -n 1)
	if [ -z "$source_path" ]; then
		echo "missing static library: $pattern"
		return 1
	fi

	cp "$source_path" "$destination"
}

ROOT=$(cd "$(dirname "$0")/.." && pwd)
ARCH=${1:-$(host-goarch)}
HOST_ARCH=$(host-goarch)
LIBPCAP_VERSION=${LIBPCAP_VERSION:-1.10.5}
BROTLI_VERSION=${BROTLI_VERSION:-1.1.0}
WORKDIR=${WORKDIR:-"$ROOT/.third_party_build"}
DOWNLOAD_DIR="$WORKDIR/downloads"
SOURCE_DIR="$WORKDIR/sources"
BUILD_DIR="$WORKDIR/build"
LIBPCAP_URL="https://www.tcpdump.org/release/libpcap-${LIBPCAP_VERSION}.tar.gz"
BROTLI_URL="https://github.com/google/brotli/archive/refs/tags/v${BROTLI_VERSION}.tar.gz"

if [ -z "$ARCH" ]; then
	echo "unsupported host architecture: $(uname -m)"
	echo "usage: $0 [amd64|arm64]"
	exit 1
fi

if [ "$ARCH" != "amd64" ] && [ "$ARCH" != "arm64" ]; then
	echo "unsupported architecture: $ARCH"
	echo "supported architectures: amd64 arm64"
	exit 1
fi

if [ -n "$HOST_ARCH" ] && [ "$ARCH" != "$HOST_ARCH" ]; then
	echo "this helper only builds native Ubuntu 22.04 static libraries"
	echo "host arch: ${HOST_ARCH}, requested arch: ${ARCH}"
	exit 1
fi

for tool in curl tar make cmake gcc g++ ar ranlib; do
	require-command "$tool"
done

mkdir -p "$DOWNLOAD_DIR" "$SOURCE_DIR" "$BUILD_DIR"

echo "building third-party static libraries for ${ARCH} ..."
echo "workspace: $WORKDIR"

LIBPCAP_ARCHIVE="$DOWNLOAD_DIR/libpcap-${LIBPCAP_VERSION}.tar.gz"
BROTLI_ARCHIVE="$DOWNLOAD_DIR/brotli-${BROTLI_VERSION}.tar.gz"

download "$LIBPCAP_URL" "$LIBPCAP_ARCHIVE"
download "$BROTLI_URL" "$BROTLI_ARCHIVE"

LIBPCAP_SOURCE="$SOURCE_DIR/libpcap-${LIBPCAP_VERSION}"
BROTLI_SOURCE="$SOURCE_DIR/brotli-${BROTLI_VERSION}"
prepare-dir "$LIBPCAP_SOURCE"
prepare-dir "$BROTLI_SOURCE"

tar -xzf "$LIBPCAP_ARCHIVE" -C "$LIBPCAP_SOURCE" --strip-components=1
tar -xzf "$BROTLI_ARCHIVE" -C "$BROTLI_SOURCE" --strip-components=1

LIBPCAP_BUILD="$BUILD_DIR/libpcap-${ARCH}"
BROTLI_BUILD_SOURCE="$BUILD_DIR/brotli-source-${ARCH}"
BROTLI_BUILD_DIR="$BUILD_DIR/brotli-build-${ARCH}"
prepare-dir "$LIBPCAP_BUILD"
prepare-dir "$BROTLI_BUILD_SOURCE"
prepare-dir "$BROTLI_BUILD_DIR"

cp -a "$LIBPCAP_SOURCE"/. "$LIBPCAP_BUILD"/
cp -a "$BROTLI_SOURCE"/. "$BROTLI_BUILD_SOURCE"/

pushd "$LIBPCAP_BUILD" >/dev/null
./configure \
	--disable-shared \
	--enable-static \
	--without-dbus \
	--without-libnl \
	--without-bluetooth \
	--without-dag \
	--without-septel \
	--without-snf \
	--without-turbocap \
	--without-rdma \
	--without-netmap \
	CFLAGS="-O2 -fPIC"
make -j"$(cpu_count)"
popd >/dev/null

cmake -S "$BROTLI_BUILD_SOURCE" -B "$BROTLI_BUILD_DIR" \
	-DCMAKE_BUILD_TYPE=Release \
	-DBUILD_SHARED_LIBS=OFF \
	-DBROTLI_DISABLE_TESTS=ON \
	-DCMAKE_POSITION_INDEPENDENT_CODE=ON
cmake --build "$BROTLI_BUILD_DIR" --parallel "$(cpu_count)"

mkdir -p "$ROOT/libs/libpcap/${ARCH}"
mkdir -p "$ROOT/libs/libbrotli/${ARCH}"
mkdir -p "$ROOT/libs/libpcap/src"
mkdir -p "$ROOT/libs/libbrotli/src"

cp "$LIBPCAP_BUILD/libpcap.a" "$ROOT/libs/libpcap/${ARCH}/libpcap.a"
copy-tree "$LIBPCAP_BUILD" "$ROOT/libs/libpcap/src/libpcap"

copy-static-lib "$BROTLI_BUILD_DIR/libbrotlicommon*.a" "$ROOT/libs/libbrotli/${ARCH}/libbrotlicommon.a"
copy-static-lib "$BROTLI_BUILD_DIR/libbrotlidec*.a" "$ROOT/libs/libbrotli/${ARCH}/libbrotlidec.a"
copy-static-lib "$BROTLI_BUILD_DIR/libbrotlienc*.a" "$ROOT/libs/libbrotli/${ARCH}/libbrotlienc.a"
copy-tree "$BROTLI_SOURCE" "$ROOT/libs/libbrotli/src/brotli"

echo "done"
echo "generated:"
echo "  $ROOT/libs/libpcap/${ARCH}/libpcap.a"
echo "  $ROOT/libs/libbrotli/${ARCH}/libbrotlicommon.a"
echo "  $ROOT/libs/libbrotli/${ARCH}/libbrotlidec.a"
echo "  $ROOT/libs/libbrotli/${ARCH}/libbrotlienc.a"
echo ""
echo "next:"
echo "  cd \"$ROOT/build\" && ./build.sh linux ${ARCH} plus"