#!/usr/bin/env sh

set -e

cd "$(dirname "$0")"

MAKE=make
NPROC=nproc
SUDO=sudo
TAGS=ctags
if [ "$(uname -s)" = "OpenBSD" ]; then
    NPROC="sysctl -n hw.ncpuonline"
    SUDO="doas"
    TAGS="ectags"
    export MAKE=gmake
    export CC="egcc"
    export CXX="eg++"
    export LDFLAGS=-Wl,-z,notext
fi

mode="${1}"
no_ask="${2}"

make_cross() {
    if [ ! -d "./cross/" ]; then
        if [ "$no_ask" != "-y" ]; then
            echo -n "Do you want to compile a cross compiler (this can take around 20 minutes)? [yn] "
            read -r answer
            if ! [ "$answer" != "${answer#[Yy]}" ]; then
                echo "The compilation of melvix requires a cross compiler!"
                exit 1
            fi
        fi

        # Create directory
        mkdir -p cross
        cd cross
        DIR=$(pwd)

        # Get sources
        mkdir "${DIR}/src" && cd "${DIR}/src"
        echo "Downloading..."
        curl "https://ftp.gnu.org/gnu/binutils/binutils-2.33.1.tar.gz" >binutils.tar.gz
        tar xzf binutils.tar.gz
        curl "https://ftp.gnu.org/gnu/gcc/gcc-9.2.0/gcc-9.2.0.tar.gz" >gcc.tar.gz
        tar xzf gcc.tar.gz

        # Prepare compiling
        mkdir -p "${DIR}/opt/bin"
        export PREFIX="${DIR}/opt"
        export TARGET=i686-elf
        export PATH="$PREFIX/bin:$PATH"

        if [ "$(uname -s)" = "OpenBSD" ]; then
            export with_gmp=/usr/local
            sed -i 's/-no-pie/-nopie/g' "${DIR}/src/gcc-9.2.0/gcc/configure"
        fi

        # Compile binutils
        mkdir "${DIR}/src/build-binutils" && cd "${DIR}/src/build-binutils"
        ../binutils-2.33.1/configure --target="$TARGET" --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
        $MAKE -j $($NPROC)
        $MAKE install

        # Compile GCC
        mkdir "${DIR}/src/build-gcc" && cd "${DIR}/src/build-gcc"
        ../gcc-9.2.0/configure --target="$TARGET" --prefix="$PREFIX" --disable-nls --enable-languages=c --without-headers
        $MAKE -j $($NPROC) all-gcc all-target-libgcc
        $MAKE install-gcc install-target-libgcc

        # Fix things
        if [ "$(uname -s)" = "OpenBSD" ]; then
            cd "${DIR}/opt/libexec/gcc/i686-elf/9.2.0/" && ln -sf liblto_plugin.so.0.0 liblto_plugin.so
        fi

        cd "${DIR}/.."
    fi
}

make_build() {
    mkdir -p build/

    # Build
    printf "\nBuilding...\n"
    $MAKE -j $($NPROC)

    # Create disk image
    dd if=/dev/zero of=build/disk.img bs=1k count=32k status=none
    if [ "$(uname -s)" = "OpenBSD" ]; then
        VND=$($SUDO vnconfig build/disk.img)
        (
            echo "e 0"
            echo 83
            echo n
            echo 0
            echo "*"
            echo "quit"
        ) | $SUDO fdisk -e $VND >/dev/null
        $SUDO mkfs.ext2 -F /dev/${VND}i >/dev/null
        $SUDO dd if=build/boot.bin of=/dev/${VND}i conv=notrunc status=none
    else
        $SUDO mke2fs -b 1024 -q build/disk.img
        dd if=build/boot.bin of=build/disk.img conv=notrunc status=none
    fi

    # Mount disk and copy files
    mkdir -p mnt/
    if [ "$(uname -s)" = "OpenBSD" ]; then
        $SUDO mount -t ext2fs /dev/${VND}i mnt/
    else
        $SUDO mount build/disk.img mnt/
    fi
    $SUDO cp -r build/load.bin mnt/load
    $SUDO cp -r build/example mnt/kernel
    $SUDO umount mnt/
    rm -rf mnt/

    if [ "$(uname -s)" = "OpenBSD" ]; then
        $SUDO vnconfig -u $VND
    fi
}

make_example() {
    qemu-system-i386 -d guest_errors -cpu max -serial stdio -m 256M -vga std -drive file=build/disk.img,format=raw,index=1,media=disk
}

if [ "${mode}" = "cross" ]; then
    make_cross
elif [ "${mode}" = "build" ]; then
    make_cross
    $MAKE clean
    make_build
elif [ "${mode}" = "example" ]; then
    make_cross
    $MAKE clean
    make_build
    make_example
fi