#!/usr/bin/env bash
# -*- coding: utf-8 -*-
# shellcheck source=./rebash/core.sh

declare -rg _mainmoddir="$(dirname "${BASH_SOURCE[0]}")/.." 2> /dev/null

declare -rg _supported_qcow_handlers=("xmount" "kernel")
# NOTE: expects 'qcow_handler' to be set in the environment, else
# will only build support for xmount
build_initialize_components() {
    _deps_base_dir="${_mainmoddir}/binaries"
    # We might want to move the "binaries" repos from the dnbd3-rootfs module to main repo one day...
    # TODO check for its existence using modinfo -k <kernel_version>
    if [[ ! -f "${_deps_base_dir}/dnbd3/build/dnbd3.ko" ]] || \
        [[ ! -f "${_deps_base_dir}/dnbd3/build/dnbd3-client" ]]; then
            logging.info "Could not find dnbd3, building it..."
            if ! CMAKE_FLAGS="-DKERNEL_DIR=${kernel_headers}" \
                build_compile_dnbd3 "${_deps_base_dir}/dnbd3/"; then
                    logging.error "Failed to build dnbd3."
                    return 1
            fi
    fi

    # process qcow handler
    logging.info "Supported handlers: ${_supported_qcow_handlers[*]}"
    IFS='|' _pattern="^(${_supported_qcow_handlers[*]})$" export _pattern
    if [ -z "$qcow_handler" ]; then
        logging.info "No qcow handler specified, will use xmount."
    elif [[ ! "$qcow_handler" =~ $_pattern ]] ; then
        logging.warn "Unknown qcow handler '$qcow_handler' - will use xmount"
    fi
    if [ -z "$qcow_handler" ] || [ "$qcow_handler" = "xmount" ]; then
        if [[ ! -f "${_deps_base_dir}/xmount/trunk/build/src/xmount" ]]; then
            logging.info "Could not find xmount binary, building it..."
            if ! build_compile_xmount "${_deps_base_dir}/xmount/"; then
                logging.error "Failed to build xmount binary."
                return 1
            fi
        fi
        if [[ ! -f "${_deps_base_dir}/qemu-xmount/libxmount_input_qemu.so" ]]; then
            logging.info "Could not find xmount qemu library, building it..."
            if ! build_compile_qemu_xmount "${_deps_base_dir}/qemu-xmount/"; then
                logging error "Failed to build xmount qemu library."
                return 1
            fi
        fi
    fi
    if [ "$qcow_handler" = "kernel" ]; then
        if [ ! -f "${_deps_base_dir}/kernel-qcow2-linux/drivers/block/loop/loop.ko" ] \
            || [ ! -f "${_deps_base_dir}/kernel-qcow2-linux/drivers/block/loop/loop_file_fmt_qcow.ko" ] \
            || [ ! -f "${_deps_base_dir}/kernel-qcow2-linux/drivers/block/loop/loop_file_fmt_raw.ko" ]; then
            logging.info "Could not find loop kernel modules, building them..."
            if ! build_compile_kernel_qcow "${_deps_base_dir}/kernel-qcow2-linux"; then
                logging.error "Failed to build qcow loop kernel modules."
                return 1
            fi
        fi
        if [ ! -f "${_deps_base_dir}/kernel-qcow2-util-linux/losetup" ]; then
            logging.info "Could not find losetup with qcow2 support, building it..."
            if ! build_compile_losetup_qcow "${_deps_base_dir}/kernel-qcow2-util-linux"; then
                logging.error "Failed to build losetup with qcow support."
                return 1
            fi
        fi
    fi

    # always compile this helper since it does not cost much to do so
    if [[ ! -f "${_deps_base_dir}/systemd-preserve-process-marker/systemd-preserve-process-marker" ]]; then
        logging.info "Could not find systemd-preserve-process-marker binary, building it ..."
        if ! build_compile_systemd_preserve_process_marker \
            "${_deps_base_dir}/systemd-preserve-process-marker/"; then
                    logging.error "Failed to build systemd-preserve-process-marker"
                    return 1
        fi
    fi
    logging.info "Compilation of dnbd3-rootfs dependencies succeeded."
    return 0
}

clean_components() {
    local __doc__='
    Removes all compiled kernel specific files.
    NOTE: This method is triggered manually and not supported by dracut itself.

    Example:

    `clean`
    '
    local _submoddir="${_mainmoddir}/binaries"
    build_clean_xmount "${_submoddir}/xmount/"
    build_clean_qemu_xmount "${_submoddir}/qemu-xmount/"
    build_clean_dnbd3 "${_submoddir}/dnbd3/"
    build_clean_losetup_qcow "${_submoddir}/kernel-qcow2-util-linux"
    build_clean_dnbd3 "${_submoddir}/dnbd3/"
    build_clean_systemd_preserve_process_marker \
        "${_submoddir}/systemd-preserve-process-marker/"
    return 0
}
# endregion

build_compile_qemu_xmount() {
    local __doc__='
    Compiles qemu libxmount.
    NOTE: expects xmount installation under
    $1/../xmount/trunk/build/release_build/

    Provides the following file:
    "$1/libxmount_input_qemu.so"

    Example:

    `build_compile_qemu_xmount /qemu_source /xmount/installation`
    '
    pushd "$1"
    local xmount_installation="../xmount/trunk/build/release_build/usr"
    [ ! -z "$2" ] && xmount_installation="$2"
    ./configure --enable-xmount-input --python="$(which python2)" \
        --extra-cflags="-std=gnu99" \
        --disable-werror \
        --extra-cflags="-fPIC" \
        --extra-cflags="-I${xmount_installation}/include" \
        --extra-cflags="-I${xmount_installation}/include/xmount" \
        --disable-fdt --target-list=""
    make -j libxmount_input_qemu.so
    local ret=$?
    popd
    return $ret
}
build_clean_qemu_xmount() {
    local __doc__='Clean the build of `build_compile_qemu_xmount`.'
    pushd "$1"
    make clean
    local ret=$?
    popd
    return $ret
}
build_compile_xmount() {
    local __doc__='
    Compiles xmount.

    Provides the xmount installation under:
    "$1/trunk/build/release_build/"

    Example:

    `build_compile_xmount /xmount_source /xmount_source/build /usr`
    '
    pushd "$1"

    local destination_directory="./release_build"
    [ ! -z "$2" ] && destination_directory="$2"
    local install_prefix="/usr"
    [ ! -z "$3" ] && install_prefix="$3"

    mkdir --parents trunk/build
    cd trunk/build || return 1
    cmake -DCMAKE_BUILD_TYPE=Release \
        -DCMAKE_INSTALL_PREFIX="$install_prefix" ..
    make -j
    make install DESTDIR="$destination_directory"
    local ret=$?
    popd
    return $ret
}
build_clean_xmount() {
    local __doc__='Clean the build of `build_compile_xmount`.'
    rm --recursive --force "$1/trunk/build"
}
build_compile_dnbd3() {
    local __doc__='
    Compiles dnbd3 kernel module and client.

    Provides the following file:
    "$1/build/dnbd3.ko"
    "$1/build/dnbd3-client"

    Examples:

    `build_compile_dnbd3 path/to/dnbd3/source/`

    Passing the kernel version to cmake:
    `CMAKE_FLAGS="-DKERNEL_VERSION=4.14.6-openslx+" \
        build_compile_dnbd3 path/to/dnbd3/source/`
    '
    pushd "$1"
    # NOTE: The generic way would be: "./build.sh" but this tries to build
    # more than we really need and takes more time.
    mkdir --parents build
    cd build
    # Inject CMAKE_FLAGS as a way to control how cmake is called,
    # e.g. to pass the kernel version
    cmake ${CMAKE_FLAGS} \
        -DBUILD_FUSE_CLIENT=OFF \
        -DBUILD_KERNEL_MODULE=ON \
        -DBUILD_SERVER=OFF \
        -DBUILD_STRESSTEST=OFF \
        ../
    make -j dnbd3 dnbd3-client
    local ret=$?
    popd
    return $ret
}
build_clean_dnbd3() {
    local __doc__='Clean the build of `build_compile_dnbd3`.'
    rm --recursive --force "$1/build"
    return $?
}
build_compile_kernel_qcow() {
    pushd "$1"
    # https://lab.ks.uni-freiburg.de/projects/kernel-qcow2/wiki
    if [ -z "$kernel_headers" ]; then
        logging.error "Kernel header directory not set, ignoring."
        return 1
    fi
    mkdir -p "${kernel_headers}/drivers/block/loop"
    for _file in \
        include/uapi/linux/loop.h \
        drivers/block/Kconfig \
        drivers/block/loop/loop_main.h \
        drivers/block/loop/loop_file_fmt.h \
        drivers/block/loop/Kconfig; do
            cp -f "${_file}" "${kernel_headers}/${_file}"
    done
    (
        set -o errexit
        make -C "$kernel_headers" CONFIG_BLK_DEV_LOOP=m \
            M=$(pwd)/drivers/block/loop loop.ko
        make -C "$kernel_headers" CONFIG_BLK_DEV_LOOP_FILE_FMT_RAW=m \
            M=$(pwd)/drivers/block/loop loop_file_fmt_raw.ko
        make -C "$kernel_headers" CONFIG_BLK_DEV_LOOP_FILE_FMT_QCOW=m \
            M=$(pwd)/drivers/block/loop loop_file_fmt_qcow.ko
    )
    local ret=$?
    popd
    return $ret
}
build_clean_kernel_qcow() {
    if [ -z "$kernel_headers" ]; then
        logging.error "Kernel header directory not set, ignoring."
        return 1
    fi
    pushd "$kernel_headers"
    make -C "$kernel_headers" M=$(pwd)/drivers/block/loop clean
    local ret=$?
    popd
    return $ret
}
build_compile_losetup_qcow() {
    pushd "$1"
    (
        set -o errexit
        ./autogen.sh
        ./configure
        make -j losetup
    )
    local ret=$?
    popd
    return $ret
}
build_clean_losetup_qcow() {
    pushd "$1"
    make clean
    local ret=$?
    popd
    return $ret
}
build_compile_systemd_preserve_process_marker() {
    local __doc__='
    Compiles simple c program.

    Examples:

    `build_compile_systemd_preserve_process_marker path/to/program/folder`
    '
    pushd "$1"
    make
    local ret=$?
    popd
    return $ret
}
build_clean_systemd_preserve_process_marker() {
    local __doc__='
    Clean the build of
    `build_compile_systemd_preserve_process_marker`.
    '
    pushd "$1"
    make clean
    local ret=$?
    popd
    return $ret
}
# region vim modline
# vim: set tabstop=4 shiftwidth=4 expandtab:
# vim: foldmethod=marker foldmarker=region,endregion:
# endregion