#!/bin/sh
set -eu

version_mes=0.22
version_mescc_tools=1.0.1
version_nyacc=0.99.3

version_linux=4.14
version_binutils=2.20.1
version_gcc=4.9.4
version_gmp=4.3.2
version_mpfr=2.4.2
version_mpc=1.0.3
version_musl=1.2.1
version_busybox=1.31.1

export MAKEFLAGS="-j${NPROC:-$(getconf _NPROCESSORS_ONLN)}"

system=system
dir_root="$PWD"
dir_sources="$dir_root/sources"
dir_install="$dir_root/$system"

mkdir -p build && cd build

rm -rf "mes-$version_mes"
tar xf "$dir_sources/mes-$version_mes.tar.gz"
( cd "mes-$version_mes"
    tar xf "$dir_sources/mescc-tools-Release_$version_mescc_tools.tar.gz"
    tar xf "$dir_sources/nyacc-$version_nyacc.tar.gz"
    mv "mescc-tools-Release_$version_mescc_tools" mescc-tools
    mv "nyacc-$version_nyacc" nyacc
    cp -a mescc-tools mescc-tools-target

    make -C mescc-tools M1 hex2 blood-elf COMMIT=
    export PATH="$PWD/mescc-tools/bin:$PATH"

    # First, we build a native mes, "mes-gcc".
    # This allows us to cross-build everything on systems that mes doesn't support.
    gcc -O2 -std=gnu99 -w -lrt -o mes-gcc -DMES_VERSION='""' -DSYSTEM_LIBC=1 -Iinclude \
        lib/mes/eputs.c \
        lib/mes/fdgetc.c \
        lib/mes/fdputc.c \
        lib/mes/fdputs.c \
        lib/mes/fdungetc.c \
        lib/mes/itoa.c \
        lib/mes/mes_open.c \
        lib/mes/ntoab.c \
        src/gc.c \
        src/hash.c \
        src/lib.c \
        src/math.c \
        src/mes.c \
        src/module.c \
        src/posix.c \
        src/reader.c \
        src/string.c \
        src/struct.c \
        src/vector.c

    # This version of mes messes doesn't have a proper getopt...
    # TODO: Fix this (somehow) and make the patch unnecessary.
    sed -i -e 's/ -nostdlib/ --nostdlib/' \
           -e 's/ -lc/ -l c/' \
        build-aux/bootstrap.sh.in

    # Use this to build mes and its libc for the target
    CC=true guile_site_dir="$PWD/nyacc/module" sh configure.sh --host=x86-linux-mes
    CC="$PWD/scripts/mescc" MES="$PWD/mes-gcc" sh bootstrap.sh

    # Install mes
    install -Dm755 bin/mes "$dir_install/mes/bin/mes"

    # Build tools with mes to obtain reproducible outputs
    make -C mescc-tools-target M1 hex2 blood-elf COMMIT= \
        CC="$PWD/scripts/mescc" MES="$PWD/mes-gcc" MES_PREFIX="../" \
        GUILE_LOAD_PATH="../module" CFLAGS='-L ../lib -L ../mescc-lib -l c+tcc'
    install -Dm755 mescc-tools-target/bin/M1 "$dir_install/mes/bin/M1"
    install -Dm755 mescc-tools-target/bin/hex2 "$dir_install/mes/bin/hex2"
    install -Dm755 mescc-tools-target/bin/blood-elf "$dir_install/mes/bin/blood-elf"
)

rm -rf "linux-$version_linux"
tar xf "$dir_sources/linux-$version_linux.tar.gz"
( cd "linux-$version_linux"
    make mrproper
    make ARCH=x86 INSTALL_HDR_PATH="$dir_install/sources/linux-headers" headers_install
    find "$dir_install/sources/linux-headers" -type f ! -name "*.h" -exec rm {} +
)

# Build static busybox with musl
rm -rf "busybox-$version_busybox"
tar xf "$dir_sources/busybox-$version_busybox.tar.bz2"
( cd "busybox-$version_busybox"
    tar xf "$dir_sources/binutils-${version_binutils}a.tar.bz2"
    mv "binutils-$version_binutils" binutils
    tar xf "$dir_sources/gcc-$version_gcc.tar.bz2"
    mv "gcc-$version_gcc" gcc
    tar xf "$dir_sources/gmp-$version_gmp.tar.bz2"
    mv "gmp-$version_gmp" gcc/gmp
    tar xf "$dir_sources/mpfr-$version_mpfr.tar.bz2"
    mv "mpfr-$version_mpfr" gcc/mpfr
    tar xf "$dir_sources/mpc-$version_mpc.tar.gz"
    mv "mpc-$version_mpc" gcc/mpc
    tar xf "$dir_sources/musl-$version_musl.tar.gz"
    mv "musl-$version_musl" musl

    prefix="$PWD/prefix"
    export PATH="$prefix/bin:$PATH"

    # Fix requirement for mktemp, so it works with coreutils-5.0
    if ! command -v mktemp 2> /dev/null; then
        sed -i -e 's@$(mktemp tmp.XXXXXXXXXX)@/tmp/tmp.trylink@' scripts/trylink
    fi

    # Building a specific version of binutils+GCC, to make the results reproducible...
    # GCC-4.6.4's results aren't reproducible across machines for some reason,
    #   so this bootstrap uses GCC-4.9.4. This increases the build time a little.
    ( cd binutils
        CFLAGS='-O2 -w' ./configure \
            --target=i686-bootstrap-linux-gnu \
            --prefix="$prefix" \
            --with-sysroot="$prefix" \
            --disable-nls \
            --disable-werror
        make
        make install
    )
    ( cd gcc
        mkdir build && cd build  # Build breaks without a build directory

        # Using --with-local-prefix=/ puts /include in the search path before
        #   /lib/gcc/.../include-fixed, avoiding some issues.
        CFLAGS='-O2 -w' CXXFLAGS='-O2 -w' MAKEINFO=true ../configure \
            --target=i686-bootstrap-linux-gnu \
            --prefix="$prefix" \
            --with-sysroot="$prefix" \
            --with-local-prefix=/ \
            --with-host-libstdcxx=-lsupc++ \
            --with-newlib \
            --without-headers \
            --disable-shared \
            --disable-threads \
            --disable-nls \
            --enable-languages=c
        make all-gcc all-target-libgcc
        make install-gcc install-target-libgcc
    )

    # Musl provides a very small libc, that can be linked statically.
    # It might be worthwhile to switch to uClibc in the future, as that's
    #   what's usually used for busybox. Might yield "cleaner" results.
    cp -a "$dir_install/sources/linux-headers" prefix
    ( cd musl
        ./configure \
            --host=i686-bootstrap-linux-gnu \
            --prefix="$PWD/../prefix" \
            --disable-shared
        make
        make install
    )

    cp "$dir_root/busybox-config" .config
    make CROSS_COMPILE=i686-bootstrap-linux-gnu- CONFIG_STATIC=y busybox

    install -Dm755 busybox "$dir_install/bin/busybox"
    install -Dm755 busybox_unstripped "$dir_install/bin/busybox_unstripped"
)

cd "$dir_install"

# Verify the built binaries
sha1sum -c "$dir_root/binaries.sha1"

# Pack it up
find bin mes sources \( -type f -o -type l \) ! -path bin/busybox_unstripped | LC_ALL=C sort | xargs tar --mtime=@0 --numeric-owner --owner=0 --group=0 -cf binaries.tar
gzip -nv binaries.tar

# Clean up
cd "$dir_root"
rm -rf build