#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright(c) 2023 Brian Witte

# define urls of the release tarballs
LIBBPF_URL="https://github.com/libbpf/libbpf/archive/refs/tags/v1.2.2.tar.gz"
BPFTOOL_URL="https://github.com/libbpf/bpftool/releases/download/v7.2.0/bpftool-libbpf-v7.2.0-sources.tar.gz"

# define where to extract the libraries
LIBBPF_DIR="libbpf"
BPFTOOL_DIR="bpftool"

# create directories
mkdir -p "$LIBBPF_DIR" "$BPFTOOL_DIR"

# download and extract libraries
echo "Fetching and extracting libbpf..."
curl -Ls "$LIBBPF_URL" | tar -xz -C "$LIBBPF_DIR" --strip-components=1

echo "Fetching and extracting bpftool..."
curl -Ls "$BPFTOOL_URL" | tar -xz -C "$BPFTOOL_DIR" --strip-components=1

echo "Libraries fetched and extracted successfully."

base=$PWD
cd bpftool/src && make && make install
cd $base
cd libbpf/src && make && make install

TOOLCHAIN_SCRIPT_BASE_DIR=$PWD


GCC_COMMIT_HASH=ac9c81dd76cfc34ed53402049021689a61c6d6e7
BINUTILS_COMMIT_HASH=8ea1e363b92243b0562e4a4a360a582e368884a8
GCC_BPF_PATCHES=false
PREFIX="$HOME/root-bpf"
BUILD_DIR="/tmp/root-bpf-build"


echo "Build directory set to: $BUILD_DIR"
echo "Prefix set to: $PREFIX"

mkdir -p "$BUILD_DIR"
cd "$BUILD_DIR"

install_dependencies() {
        echo "Installing necessary dependencies..."
        apt-get update
	if ! apt-get install -y \
		libgmp-dev \
		libmpfr-dev \
		libmpc-dev \
                texinfo \
                flex \
                bison \
		make \
		curl \
		git \
                file \
                gcc \
                g++ \
                gettext \
		libc6 \
		libzstd1 \
		zlib1g \
		libgmp10 \
		libmpc3 \
		libmpfr6 \
		libzstd1; then
		echo "Error installing dependencies. Aborting."
		exit 1
	fi
}

clone_repositories() {
	echo "Cloning GCC and Binutils repositories into $BUILD_DIR"

	if [ ! -d "$BUILD_DIR/gcc" ]; then
		echo "Cloning the GCC repository..."
		if ! git clone https://gcc.gnu.org/git/gcc.git "$BUILD_DIR/gcc"; then
			echo "Error cloning GCC repository. Aborting."
			exit 1
		fi
		if [ "$CI_MODE" = false ]; then
			(cd "$BUILD_DIR/gcc" && git checkout "$GCC_COMMIT_HASH")
		fi
	else
		echo "GCC repository already exists, skipping clone."
	fi

	if [ ! -d "$BUILD_DIR/binutils-gdb" ]; then
		echo "Cloning the Binutils repository..."
		if ! git clone https://sourceware.org/git/binutils-gdb.git "$BUILD_DIR/binutils-gdb"; then
			echo "Error cloning Binutils repository. Aborting."
			exit 1
		fi
		if [ "$CI_MODE" = false ]; then
			(cd "$BUILD_DIR/binutils-gdb" && git checkout "$BINUTILS_COMMIT_HASH")
		fi
	else
		echo "Binutils repository already exists, skipping clone."
	fi
}

apply_patches() {
	cd $TOOLCHAIN_SCRIPT_BASE_DIR
	echo "Applying patches..."
	patch_files=(gcc-bpf/0*.patch)

	# check if patch files are found
	if [ -f "${patch_files[0]}" ]; then
		for patch in "${patch_files[@]}"; do
			echo "Applying $patch"
			if ! patch -p1 -d "$BUILD_DIR" <"$patch"; then
				echo "Failed to apply patch: $patch"
				exit 1
			fi
		done
	else
		echo "No patch files found in gcc-bpf/ dir"
	fi
}

build_binutils() {
	echo "Building Binutils..."
	mkdir -p "$BUILD_DIR/binutils-build" && cd "$BUILD_DIR/binutils-build"
	echo $PWD
	if ! ../binutils-gdb/configure --target=bpf-unknown-none --prefix="$PREFIX"; then
		echo "Error running configure for Binutils. Aborting."
		exit 1
	fi
	# if ! make -j$(nproc); then
	if ! make -j16; then
		echo "Error compiling Binutils. Aborting."
		exit 1
	fi
	if ! make install; then
		echo "Error installing Binutils. Aborting."
		exit 1
	fi
	cd ..
}

build_gcc() {
	echo "Building GCC..."
	mkdir -p "$BUILD_DIR/gcc-build" && cd "$BUILD_DIR/gcc-build"
	if ! ../gcc/configure --target=bpf-unknown-none --prefix="$PREFIX" --disable-multilib --enable-languages=c; then
		echo "Error running configure for GCC. Aborting."
		exit 1
	fi
	#if ! make -j$(nproc); then
	if ! make -j16; then
		echo "Error compiling GCC. This step may take a while. Aborting."
		exit 1
	fi
	if ! make install; then
		echo "Error installing GCC. Aborting."
		exit 1
	fi
	cd ..
}

update_environment() {
	echo ""
	echo "Execute below in shell or add to .bashrc, .zshrc, etc."
	echo "export PATH=$PREFIX/bin:\$PATH"
	echo ""
}

verify_installation() {
	echo "Verifying installation..."
	if ! $PREFIX/bin/bpf-unknown-none-gcc --version; then
		echo "GCC installation verification failed. Aborting."
		exit 1
	fi
	if ! $PREFIX/bin/bpf-unknown-none-as --version; then
		echo "Binutils installation verification failed. Aborting."
		exit 1
	fi
	echo ""
	echo "GCC and Binutils successfully installed!"
}

# main program
install_dependencies
clone_repositories
if [ "$GCC_BPF_PATCHES" = true ]; then
	apply_patches
fi
build_binutils
build_gcc
verify_installation
update_environment

echo "Toolchain installation completed successfully."