#!/bin/sh

if [ $(id -u) != 0 ]; then
    exec "${HOST_DIR}"/bin/fakeroot "$0" "$@"
fi

export PATH="${HOST_DIR}:${PATH}"

TARGET_DIR=$1
WORKDIR=$(mktemp -d)
OUTDIR="${WORKDIR}"/initramfs
LIB_CACHE="${WORKDIR}"/libs.cache
PKGDIR="${0%/*}"

trap 'rm -rf "${WORKDIR}"' INT QUIT TERM EXIT

cache_libs() {
    find \
        "${TARGET_DIR}"/usr/lib \
        "${TARGET_DIR}"/usr/lib64 \
        \( -type f -o -type l \) \
        -name '*.so*' \
        | sed "s@${TARGET_DIR}@@" \
        > "${LIB_CACHE}"
}

bin_install() {
    for arg; do
        arg=${arg#/}
        [ -e "${OUTDIR}/${arg}" ] && continue
        mkdir -p "${OUTDIR}/${arg%/*}"
        cp -a "${TARGET_DIR}/${arg}" "${OUTDIR}/${arg}"
        if [ -h "${TARGET_DIR}/${arg}" ]; then
            bin_install "$(realpath --relative-to "${TARGET_DIR}" "${TARGET_DIR}/${arg}")"
        elif [ -f "${TARGET_DIR}/${arg}" ]; then
            readelf --dynamic "${TARGET_DIR}/${arg}" \
                | awk '$2=="(NEEDED)"{gsub(/\[|\]/,"",$5); print $5}' \
                | while IFS= read -r lib; do
                    path="$(grep "${lib}"'$' "${LIB_CACHE}")"
                    if [ -z "${path}" ]; then
                        printf 'ERROR could not resolve shared library %s\n' "${lib}" >&2
                        return 1
                    fi
                    bin_install "${path}"
            done
        elif [ ! -e "${TARGET_DIR}/${arg}" ]; then
            printf 'ERROR could not find /%s to copy\n' "${arg}" >&2
            return 1
        fi
    done
}

mk_skel() {
    mkdir -p "${OUTDIR}"/dev
    mknod -m 0622 "${OUTDIR}"/dev/console c 5 1

    mkdir -p \
        "${OUTDIR}"/usr \
        "${OUTDIR}"/usr/bin \
        "${OUTDIR}"/usr/sbin \
        "${OUTDIR}"/usr/lib
    ln -s usr/bin "${OUTDIR}"/bin
    ln -s usr/sbin "${OUTDIR}"/sbin
    ln -s usr/lib "${OUTDIR}"/lib
    if [ -h "${TARGET_DIR}"/usr/lib64 ]; then
        cp -P "${TARGET_DIR}"/usr/lib64 "${OUTDIR}"/usr
    fi
    if [ -h "${TARGET_DIR}"/lib64 ]; then
        cp -P "${TARGET_DIR}"/lib64 "${OUTDIR}"
    fi
}

rm -rf "${OUTDIR}"

mk_skel || exit
cache_libs || exit

bin_install \
    /bin/cat \
    /bin/cp \
    /bin/ls \
    /bin/mkdir \
    /bin/mount \
    /bin/rm \
    /bin/sh \
    /bin/sort \
    /bin/tail \
    /bin/umount \
    /usr/bin/btrfs \
    /usr/bin/mkfs.btrfs \
    /usr/bin/mountpoint \
    /usr/bin/readlink \
    /usr/sbin/blkid \
    /usr/sbin/findfs \
    /usr/sbin/partx \
    /usr/sbin/sfdisk \
    /usr/sbin/switch_root \
    || exit

if [ -e "${TARGET_DIR}"/usr/bin/setfiles ]; then
    bin_install /usr/bin/setfiles || exit
fi

install "${PKGDIR}"/initramfs/initramfs-init.sh "${OUTDIR}"/init || exit
install "${PKGDIR}"/initramfs/init-storage.sh "${OUTDIR}"/usr/bin/init-storage || exit

mkdir -p "${TARGET_DIR}"/boot

(cd "${OUTDIR}" && find . -mindepth 1 \
    | LC_ALL=C sort \
    | cpio --reproducible --quiet -o -H newc \
    | zstd \
) > "${TARGET_DIR}"/boot/initramfs.img.zst