# vim:set ft=sh:

git clone --depth=1 --recursive https://github.com/fosslinux/live-bootstrap
cd live-bootstrap
./rootfs.py -c --external-sources --cores $(nproc)
umount target/dev/shm  # double mounted?
umount target/dev/shm target/sys target/proc target/tmp

# Optional: back up the system
env -i chroot target tar --sort=name -cf /target.tar /
env -i chroot target bzip2 -9v /target.tar

# Goal:
# install cross compiler in /cross
# cross compiled system in /gentoo

mount -t proc proc target/proc
mount -t sysfs sysfs target/sys
mount -t devtmpfs devtmpfs target/dev
mount -t devpts devpts target/dev/pts
env -i chroot target
source /steps/env
cd /tmp

curl -LO https://github.com/ninja-build/ninja/archive/v1.11.1/ninja-1.11.1.tar.gz
curl -LO https://github.com/mesonbuild/meson/releases/download/1.4.1/meson-1.4.1.tar.gz
curl -LO http://gitweb.gentoo.org/proj/portage.git/snapshot/portage-3.0.65.tar.bz2
curl -LO https://github.com/plougher/squashfs-tools/archive/refs/tags/4.6.1/squashfs-tools-4.6.1.tar.gz
curl -LO http://distfiles.gentoo.org/snapshots/squashfs/gentoo-20240801.xz.sqfs

cat > portage.patch << 'EOF'
+++ b/lib/portage/util/compression_probe.py
@@ -1,13 +1,13 @@
 # Copyright 2015-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2

-import ctypes
 import errno
 import re


 from portage import _encodings, _unicode_encode
 from portage.exception import FileNotFound, PermissionDenied
+from portage.util._ctypes import ctypes

 _compressors = {
     "bzip2": {
@@ -49,7 +49,7 @@ _compressors = {
         # if the current architecture can support it, which is true when
         # sizeof(long) is at least 8 bytes.
         "decompress": "zstd -d"
-        + (" --long=31" if ctypes.sizeof(ctypes.c_long) >= 8 else ""),
+        + (" --long=31" if ctypes and ctypes.sizeof(ctypes.c_long) >= 8 else ""),
         "package": "app-arch/zstd",
     },
 }
EOF

tar xf ninja-1.11.1.tar.gz
cd ninja-1.11.1
./configure.py --bootstrap
install -m755 ninja /usr/bin
cd ..
rm -rf ninja-1.11.1

tar xf meson-1.4.1.tar.gz
cd meson-1.4.1
python setup.py install
cd ..
rm -rf meson-1.4.1

tar xf portage-3.0.65.tar.bz2
cd portage-3.0.65
patch -p1 -i ../portage.patch
meson setup build --prefix /usr
meson install -C build
cd ..
rm -rf portage-3.0.65

tar xf squashfs-tools-4.6.1.tar.gz
cd squashfs-tools-4.6.1
make -C squashfs-tools install \
    INSTALL_PREFIX=/usr \
    XZ_SUPPORT=1
cd ..
rm -rf squashfs-tools-4.6.1

unsquashfs gentoo-20240801.xz.sqfs
mkdir -p /var/db/repos
rm -rf /var/db/repos/gentoo
mv squashfs-root /var/db/repos/gentoo

# Configure portage
echo 'portage:x:250:250:portage:/var/tmp/portage:/bin/false' >> /etc/passwd
echo 'portage::250:portage' >> /etc/group

mkdir -p /etc/portage/make.profile
cat > /etc/portage/make.profile/make.defaults << 'EOF'
FEATURES="-news -sandbox -usersandbox -pid-sandbox -parallel-fetch"
BINPKG_COMPRESS="bzip2"
ARCH="x86"
ABI="$ARCH"
DEFAULT_ABI="$ARCH"
ACCEPT_KEYWORDS="$ARCH"
CHOST="i386-unknown-linux-musl"
LIBDIR_x86="lib/i386-unknown-linux-musl"
PKG_CONFIG_PATH="/usr/lib/i386-unknown-linux-musl/pkgconfig"
PYTHON_COMPAT_OVERRIDE="python3_11"
IUSE_IMPLICIT="kernel_linux elibc_glibc elibc_musl prefix prefix-guest"
USE="kernel_linux elibc_musl python_targets_python3_11"
EOF

# Install extra dependencies
FETCHCOMMAND="curl -o \"\${DISTDIR}/\${FILE}\" -L \"\${URI}\""
FETCHCOMMAND="$FETCHCOMMAND" MAKEOPTS=-j1 emerge -O1 dev-build/make
FETCHCOMMAND="$FETCHCOMMAND" emerge -O1 app-arch/lzip
FETCHCOMMAND="$FETCHCOMMAND" emerge -O1 net-misc/wget

# Fix "find" warnings in emerge
emerge -O1 sys-apps/findutils

# Set up python for dev-build/meson-format-array
py=python3.11
mkdir -p /usr/lib/python-exec/$py
ln -sv python3 /usr/lib/python-exec/$py/python
ln -svr /usr/bin/$py /usr/lib/python-exec/$py/python3
emerge -O1 dev-lang/python-exec

# Allow stripping binaries by installing "scanelf"
emerge -O1 dev-build/meson-format-array
emerge -O1 app-misc/pax-utils

# Install tooling around autoconf/automake for sys-devel/binutils and sys-devel/gcc
emerge -O1 sys-devel/gnuconfig sys-apps/gentoo-functions app-portage/elt-patches sys-devel/binutils-config sys-devel/gcc-config

# Install rsync for sys-kernel/linux-headers
emerge -O1 dev-build/autoconf dev-build/autoconf-wrapper
emerge -O1 dev-build/automake dev-build/automake-wrapper
emerge -O1 net-misc/rsync

# Set up cross compiler
mkdir -p /cross/etc/portage
ln -sf /etc/portage/make.profile /cross/etc/portage/make.profile
cat > /cross/etc/portage/make.conf << 'EOF'
USE="prefix multilib"
CTARGET="x86_64-bootstrap-linux-gnu"
LIBDIR_x86="lib"
LIBDIR_amd64="lib64"
DEFAULT_ABI="amd64"
MULTILIB_ABIS="amd64 x86"
EOF
mkdir -p /cross/etc/portage/env/sys-devel
cat > /cross/etc/portage/env/sys-devel/gcc << 'EOF'
EXTRA_ECONF='--with-sysroot=$EPREFIX/usr/$CTARGET'
EOF
cat > /cross/etc/portage/package.use << 'EOF'
sys-devel/gcc -sanitize
EOF
#EXTRA_EMAKE='MAKE=make MAKE+=libsuffix=../lib64'

# Set path for emerge builds
cat > /etc/env.d/50baselayout << 'EOF'
PATH=/cross/usr/bin:/usr/bin
ROOTPATH=/cross/usr/bin:/usr/bin
EOF
env-update

# TODO: Build sys-libs/glibc in /gentoo instead, to avoid extra rebuilding
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross emerge -O1 sys-devel/binutils
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross USE='headers-only' emerge -O1 sys-kernel/linux-headers
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross USE='headers-only -multilib' emerge -O1 sys-libs/glibc
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross USE='-cxx -fortran' emerge -O1 sys-devel/gcc
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross emerge -O1 sys-kernel/linux-headers
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross emerge -O1 sys-libs/glibc
PORTAGE_CONFIGROOT=/cross EPREFIX=/cross emerge -O1 sys-devel/gcc

# Get extra BDEPENDs for the final system
emerge -O1 dev-util/pkgconf  # dev-lang/python requires --keep-system-libs
emerge -O1 dev-libs/mpdecimal  # dev-lang/python (host)
emerge -O1 dev-libs/expat  # dev-lang/python (host)
# TODO: verify bzip2 dep
mv /bin/bzip2 /bin/bzip2-reference
ln -s bzip2-reference /bin/bzip2
emerge -O1 app-arch/bzip2  # dev-lang/python (build)
# TODO: move python build so we don't need python-exec hack
#       ... or switch to only using python3.11
USE='-*' emerge -O1 dev-lang/python  # cross compiling python programs needs same version
emerge -O1 dev-lang/python-exec-conf
USE='python_targets_python3_12' emerge -O1 dev-lang/python-exec

# Allow meson to still be ran despite python upgrade
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/gpep517
emerge -O1 app-arch/unzip
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/installer
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/flit-core
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/packaging
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/more-itertools
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/ordered-set
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/jaraco-text
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/jaraco-functools
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/jaraco-context
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/wheel
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-python/setuptools
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 dev-build/meson
PYTHON_COMPAT_OVERRIDE=python3_12 emerge -O1 sys-apps/portage

# Reconfigure cross toolchain for final system
cat > /cross/usr/lib/gcc/x86_64-bootstrap-linux-gnu/specs << 'EOF'
*link:
+ %{!shared:%{!static:%{!static-pie:-dynamic-linker %{m32:/lib/ld-linux.so.2;:/lib64/ld-linux-x86-64.so.2}}}}
EOF
for tool in gcc g++; do
rm -f /cross/usr/bin/x86_64-bootstrap-linux-gnu-$tool
cat > /cross/usr/bin/x86_64-bootstrap-linux-gnu-$tool << EOF
#!/bin/sh
exec /cross/usr/i386-unknown-linux-musl/x86_64-bootstrap-linux-gnu/gcc-bin/*/x86_64-bootstrap-linux-gnu-$tool --sysroot=/gentoo "\$@"
EOF
chmod +x /cross/usr/bin/x86_64-bootstrap-linux-gnu-$tool
done
# TODO: Do I need this?
cat > /cross/usr/bin/x86_64-bootstrap-linux-gnu-pkg-config << 'EOF'
#!/bin/sh
export PKG_CONFIG_SYSROOT_DIR=/gentoo
export PKG_CONFIG_LIBDIR=/gentoo/usr/lib64/pkgconfig
export PKG_CONFIG_PATH=/gentoo/usr/share/pkgconfig
export PKG_CONFIG_SYSTEM_INCLUDE_PATH=/gentoo/usr/include
export PKG_CONFIG_SYSTEM_LIBRARY_PATH=/gentoo/lib64:/gentoo/usr/lib64
exec pkg-config "$@"
EOF
chmod +x /cross/usr/bin/x86_64-bootstrap-linux-gnu-pkg-config

# Compile final system (hopefully)
# TODO: Try to get rid of CFLAGS_x86 override
mkdir -p /gentoo/etc/portage
ln -sf /var/db/repos/gentoo/profiles/default/linux/amd64/23.0 /gentoo/etc/portage/make.profile
cat > /gentoo/etc/portage/make.conf << 'EOF'
FEATURES="-news -sandbox -usersandbox -pid-sandbox -parallel-fetch"
BINPKG_COMPRESS="bzip2"
CBUILD="i386-unknown-linux-musl"
CHOST="x86_64-bootstrap-linux-gnu"
CFLAGS_x86=-m32
USE="-* build python_targets_$PYTHON_SINGLE_TARGET"
CONFIG_SITE="$PORTAGE_CONFIGROOT/etc/portage/config.site"
EOF
cat > /gentoo/etc/portage/config.site << 'EOF'
if [ "${CBUILD:-${CHOST}}" != "${CHOST}" ]; then
# Settings grabbed from crossdev
ac_cv_file__dev_ptmx=yes
ac_cv_file__dev_ptc=no
fi
EOF

# TODO: Build gcc with openmp (required by zstd)

PORTAGE_CONFIGROOT=/gentoo ROOT=/gentoo SYSROOT=/gentoo emerge -O1n \
    sys-apps/baselayout \
    sys-kernel/linux-headers \
    sys-libs/glibc \
    sys-devel/binutils \
    dev-libs/gmp \
    dev-libs/mpfr \
    dev-libs/mpc \
    sys-devel/gcc \
    \
    app-arch/bzip2 \
    app-arch/xz-utils \
    dev-libs/expat \
    dev-libs/libffi \
    dev-libs/mpdecimal \
    sys-apps/util-linux \
    sys-libs/libxcrypt \
    sys-libs/zlib \
    dev-lang/python:3.12 \
    \
    dev-lang/python-exec \
    sys-apps/portage \
    \
    sys-libs/ncurses \
    sys-libs/readline \
    app-shells/bash \
    \
    sys-apps/coreutils \
    sys-apps/findutils \
    app-arch/tar \
    app-arch/gzip \
    sys-apps/sed \
    sys-apps/grep \
    sys-devel/patch \
    sys-apps/gawk \
    dev-build/make

# TODO: Un-hardcode python 3.12
# TODO: Avoid gzip, sed and grep?

# Fetch some extra source code
DISTDIR=/gentoo/var/cache/distfiles \
PORTAGE_CONFIGROOT=/gentoo ROOT=/gentoo SYSROOT=/gentoo emerge -O1f \
    app-misc/ca-certificates \
    dev-lang/perl \
    dev-libs/openssl \
    dev-util/pkgconf \
    net-misc/wget

# From here you just chroot into /gentoo, clean /etc/portage (leaving only make.profile), install wget, and run "emerge -DN @world", untangling dependencies until it works
# TODO: Draw the rest of the fucking owl