#!/bin/bash

set -e pipefail

CC=gcc
LD=gcc
CFLAGS="-static -Oz -ffunction-sections -fdata-sections -fvisibility=hidden -fomit-frame-pointer -fno-merge-all-constants"
LDFLAGS="-static -Oz -ffunction-sections -fdata-sections -fvisibility=hidden -fomit-frame-pointer -Wl,--gc-sections -Wl,-O2 -Wl,-s"
ROOTFS=/tmp/initramfs

# Step 0: Cleanup
rm -rf ${ROOTFS}/*

# Step 1: Build musl
pushd musl
make distclean
CC=${CC} LD=${LD} CFLAGS="${CFLAGS}" LDFLAGS="${LDFLAGS}" \
  ./configure --enable-static --disable-shared --prefix=/usr
CC=${CC} LD=${LD} CFLAGS="${CFLAGS}" LDFLAGS="${LDFLAGS}" \
  make -j 24 VERBOSE=1

make install DESTDIR=${ROOTFS}
popd

# Step 2: Build tcc
pushd tcc
make distclean
./configure --enable-static --disable-shared --prefix=/usr \
	    --config-musl \
	    --extra-cflags="${CFLAGS} -I${ROOTFS}/usr/include" \
	    --extra-ldflags="${LDFLAGS} -L${ROOTFS}/usr/include" \
	    --includedir="/usr/include" \
	    --libpaths="/usr/lib" \
	    --tccdir="/usr/lib" \
	    --cc="${CC}"
echo '#define CONFIG_TCC_CRTPREFIX "/usr/lib"' >> config.h
CC="${CC}" \
  C_INCLUDE_PATH="${ROOTFS}/usr/include" \
  LIBRARY_PATH="${ROOTFS}/usr/lib" \
  CFLAGS="${CFLAGS}" LDFLAGS="${LDFLAGS}" \
  make -j 24 VERBOSE=1

make install DESTDIR=${ROOTFS}
popd

# Step 3: Build qemacs
pushd qemacs
make distclean
chmod 755 configure
CFLAGS="${CFLAGS} -I${ROOTFS}/usr/include -flto" \
      LDFLAGS="${LDFLAGS} -L${ROOTFS}/usr/lib -flto" \
      CC="${CC}" LD="${CC}" \
      ./configure --prefix=/usr/ --disable-x11 --disable-xv \
      --disable-xrender --disable-html --disable-png
CFLAGS="${CFLAGS} -I${ROOTFS}/usr/include -flto" \
      LDFLAGS="${LDFLAGS} -L${ROOTFS}/usr/lib -flto" \
      CC="${CC}" LD="${CC}" \
      make -j 24 VERBOSE=1
make install DESTDIR=${ROOTFS}
popd

# Step 4: Build busybox
pushd busybox
make distclean
cp ../bbconfig .config
sed -e "/CONFIG_PREFIX/s|=.*$|=\"${ROOTFS}\"|" -i .config
sed -e "/CONFIG_EXTRA_CFLAGS/s|=.*$|=\"${CFLAGS}\"|" -i .config
sed -e "/CONFIG_EXTRA_LDFLAGS/s|=.*$|=\"${LDFLAGS}\"|" -i .config
CFLAGS="${CFLAGS} -I${ROOTFS}/usr/include -flto" \
      LDFLAGS="${LDFLAGS} -L${ROOTFS}/usr/lib -flto" \
      CC="${CC}" LD="${CC}" \
      make -j 24 VERBOSE=1
make -j 24 install VERBOSE=1
popd

# Step 5: Cleanup the resulting env
rm -rf ${ROOTFS}/usr/share/{info,doc,man} ${ROOTFS}/usr/man

# Step 6: Prepare the cpio
fakeroot sh -c "
  cd ${ROOTFS} &&
  find . -print0 | cpio --null -ov --format=newc > ../base.cpio
"
mv "${ROOTFS}/../base.cpio" .