#!/usr/bin/env bash

function find-binary() {
	local candidate
	for candidate in "$@"; do
		if [ -z "$candidate" ]; then
			continue
		fi
		if [ -x "$candidate" ]; then
			echo "$candidate"
			return 0
		fi
		if command -v "$candidate" >/dev/null 2>&1; then
			command -v "$candidate"
			return 0
		fi
	done
	return 1
}

function host-goarch() {
	case "$(uname -m)" in
	x86_64|amd64)
		echo "amd64"
		;;
	aarch64|arm64)
		echo "arm64"
		;;
	i386|i486|i586|i686)
		echo "386"
		;;
	mips64)
		echo "mips64"
		;;
	mips64el)
		echo "mips64le"
		;;
	*)
		echo ""
		;;
	esac
}

function find-linux-static-toolchain() {
	local arch=$1
	local cc_bin=""
	local cxx_bin=""
	local host_arch

	host_arch=$(host-goarch)

	case "$arch" in
	amd64)
		cc_bin=$(find-binary \
			"/usr/local/gcc/x86_64-unknown-linux-gnu/bin/x86_64-unknown-linux-gnu-gcc" \
			"/usr/local/opt/musl-cross/bin/x86_64-linux-musl-gcc" \
			"x86_64-unknown-linux-gnu-gcc" \
			"x86_64-linux-musl-gcc" \
			"musl-gcc")
		cxx_bin=$(find-binary \
			"/usr/local/gcc/x86_64-unknown-linux-gnu/bin/x86_64-unknown-linux-gnu-g++" \
			"/usr/local/opt/musl-cross/bin/x86_64-linux-musl-g++" \
			"x86_64-unknown-linux-gnu-g++" \
			"x86_64-linux-musl-g++")
		if [ -z "$cc_bin" ] && [ "$host_arch" = "amd64" ]; then
			cc_bin=$(find-binary "gcc" "cc" "clang")
		fi
		if [ -z "$cxx_bin" ] && [ "$host_arch" = "amd64" ]; then
			cxx_bin=$(find-binary "g++" "c++" "clang++")
		fi
		;;
	386)
		cc_bin=$(find-binary "/usr/local/opt/musl-cross/bin/i486-linux-musl-gcc" "i486-linux-musl-gcc")
		cxx_bin=$(find-binary "/usr/local/opt/musl-cross/bin/i486-linux-musl-g++" "i486-linux-musl-g++")
		if [ -z "$cc_bin" ] && [ "$host_arch" = "386" ]; then
			cc_bin=$(find-binary "gcc" "cc" "clang")
		fi
		if [ -z "$cxx_bin" ] && [ "$host_arch" = "386" ]; then
			cxx_bin=$(find-binary "g++" "c++" "clang++")
		fi
		;;
	arm64)
		cc_bin=$(find-binary \
			"/usr/local/gcc/aarch64-unknown-linux-gnu/bin/aarch64-unknown-linux-gnu-gcc" \
			"/usr/local/opt/musl-cross/bin/aarch64-linux-musl-gcc" \
			"aarch64-unknown-linux-gnu-gcc" \
			"aarch64-linux-musl-gcc")
		cxx_bin=$(find-binary \
			"/usr/local/gcc/aarch64-unknown-linux-gnu/bin/aarch64-unknown-linux-gnu-g++" \
			"/usr/local/opt/musl-cross/bin/aarch64-linux-musl-g++" \
			"aarch64-unknown-linux-gnu-g++" \
			"aarch64-linux-musl-g++")
		if [ -z "$cc_bin" ] && [ "$host_arch" = "arm64" ]; then
			cc_bin=$(find-binary "gcc" "cc" "clang")
		fi
		if [ -z "$cxx_bin" ] && [ "$host_arch" = "arm64" ]; then
			cxx_bin=$(find-binary "g++" "c++" "clang++")
		fi
		;;
	mips64)
		cc_bin=$(find-binary "/usr/local/opt/musl-cross/bin/mips64-linux-musl-gcc" "mips64-linux-musl-gcc")
		cxx_bin=$(find-binary "/usr/local/opt/musl-cross/bin/mips64-linux-musl-g++" "mips64-linux-musl-g++")
		if [ -z "$cc_bin" ] && [ "$host_arch" = "mips64" ]; then
			cc_bin=$(find-binary "gcc" "cc" "clang")
		fi
		if [ -z "$cxx_bin" ] && [ "$host_arch" = "mips64" ]; then
			cxx_bin=$(find-binary "g++" "c++" "clang++")
		fi
		;;
	mips64le)
		cc_bin=$(find-binary "/usr/local/opt/musl-cross/bin/mips64el-linux-musl-gcc" "mips64el-linux-musl-gcc")
		cxx_bin=$(find-binary "/usr/local/opt/musl-cross/bin/mips64el-linux-musl-g++" "mips64el-linux-musl-g++")
		if [ -z "$cc_bin" ] && [ "$host_arch" = "mips64le" ]; then
			cc_bin=$(find-binary "gcc" "cc" "clang")
		fi
		if [ -z "$cxx_bin" ] && [ "$host_arch" = "mips64le" ]; then
			cxx_bin=$(find-binary "g++" "c++" "clang++")
		fi
		;;
	*)
		return 1
		;;
	esac

	if [ -z "$cc_bin" ]; then
		return 1
	fi
	if [ -z "$cxx_bin" ]; then
		cxx_bin="$cc_bin"
	fi

	echo "$cc_bin|$cxx_bin"
	return 0
}

function build() {
	ROOT=$(dirname "$0")
	NAME="edge-dns"
	VERSION=$(lookup-version "$ROOT"/../internal/const/const.go)
	DIST=$ROOT/"../dist/${NAME}"
	OS=${1}
	ARCH=${2}

	if [ -z "$OS" ]; then
		echo "usage: build.sh OS ARCH"
		exit
	fi
	if [ -z "$ARCH" ]; then
		echo "usage: build.sh OS ARCH"
		exit
	fi

	echo "checking ..."
	if ! command -v zip >/dev/null 2>&1; then
		echo "we need 'zip' command to compress files"
		exit 1
	fi

	echo "building v${VERSION}/${OS}/${ARCH} ..."
	ZIP="${NAME}-${OS}-${ARCH}-v${VERSION}.zip"

	echo "copying ..."
	if [ ! -d "$DIST" ]; then
		mkdir "$DIST"
		mkdir "$DIST"/bin
		mkdir "$DIST"/configs
		mkdir "$DIST"/logs
		mkdir "$DIST"/data
	fi

	cp "$ROOT"/configs/api_dns.template.yaml "$DIST"/configs

	echo "building ..."

	if [ "$OS" == "linux" ]; then
		TOOLCHAIN=$(find-linux-static-toolchain "$ARCH")
		if [ -z "$TOOLCHAIN" ]; then
			echo "could not find a static Linux toolchain for ${ARCH}"
			echo "install a musl toolchain before building edge-dns"
			exit 1
		fi

		CC_BIN=${TOOLCHAIN%|*}
		CXX_BIN=${TOOLCHAIN#*|}
		env CC="$CC_BIN" CXX="$CXX_BIN" GOOS="${OS}" GOARCH="${ARCH}" CGO_ENABLED=1 go build -trimpath -tags="plus" -o "$DIST"/bin/${NAME} -ldflags "-linkmode external -extldflags -static -s -w" "$ROOT"/../cmd/edge-dns/main.go
	else
		env GOOS="${OS}" GOARCH="${ARCH}" CGO_ENABLED=1 go build -trimpath -tags="plus" -o "$DIST"/bin/${NAME} -ldflags="-s -w" "$ROOT"/../cmd/edge-dns/main.go
	fi

	# check build result
	RESULT=$?
    if [ "${RESULT}" != "0" ]; then
    	exit 1
    fi

	# delete hidden files
	find "$DIST" -name ".DS_Store" -delete
	find "$DIST" -name ".gitignore" -delete

	echo "zip files"
	cd "${DIST}/../" || exit
	if [ -f "${ZIP}" ]; then
		rm -f "${ZIP}"
	fi
	zip -r -X -q "${ZIP}" ${NAME}/
	rm -rf ${NAME}
	cd - || exit

	echo "OK"
}

function lookup-version() {
	FILE=$1
	VERSION_DATA=$(cat "$FILE")
	re="Version[ ]+=[ ]+\"([0-9.]+)\""
	if [[ $VERSION_DATA =~ $re ]]; then
		VERSION=${BASH_REMATCH[1]}
		echo "$VERSION"
	else
		echo "could not match version"
		exit 1
	fi
}

build "$1" "$2"