#!/bin/bash

check() {
    if ! type -f qemu-nbd >/dev/null; then
        echo "'qemu-nbd' not found on this system, install it to use this module."
        return 1
    fi
    if ! type -f qemu-img >/dev/null; then
        echo "'qemu-img' not found on this system, install it to use this module."
        return 1
    fi
    if ! type -f nbd-client >/dev/null; then
        echo "'nbd-client' not found on this system, install it to use this module."
        return 1
    else
        # check version
        local nbd_client_version="$(nbd-client --help 2>&1 | grep -oE '3\.[0-9]+')"
        local nbd_client_version_major="${nbd_client_version%.*}"
        local nbd_client_version_minor="${nbd_client_version#*.}"
        if [ "${nbd_client_version_major}" -ne 3 ]; then
            # nbd-client probably too old
            echo "The nbd-client major version is not 3, meaning its probably too old."
            return 1
        fi
        if [ "${nbd_client_version_minor}" -gt 8 ]; then
            # TODO check if ver = 3.9 has the same new syntax...
            echo "The nbd-client minor version is greater than 8. A new syntax has been
                    introduced starting with 3.10 which we do not support."
            return 1
        fi
        return 0
    fi
}

depends() {
    echo base network bash kernel-modules
    return 0
}

installkernel() {
    instmods ext4
}

install() {
    ### BINARIES
    #
    # busybox: cause we want lightweight tools
    inst "$moddir/binaries/busybox" /usr/bin/busybox
    # dnbd3-client: needed to mount remote dnbd3 filesystem.
    inst "$moddir/binaries/dnbd3-client" /usr/bin/dnbd3-client
    # A generic wrapper program to prepend a "@" to each process
    # spawned by given nested programs.
    inst "$moddir/binaries/systemd-preserve-process-marker" \
        /usr/bin/systemd-preserve-process-marker

    # NOTE: These modules are build again Kernel: 3.10.0-229.1.2.el7.x86_64
    # TODO: build these in check() !
    inst "$moddir/kernel_modules/dnbd3.ko" \
        /usr/lib/modules/current/extra/dnbd3.ko
    inst "$moddir/kernel_modules/nbd.ko" \
        /usr/lib/modules/current/extra/nbd.ko

    ### HOOKS
    ## HOOK cmdline
    # enables sysrq-shortcuts
    inst_hook cmdline 00 "$moddir/hooks/cmdline/enable-sysrq.sh"

    # expands the ip parameter in the kernel command line to
    # make it dracut-compatible
    # TODO: dracut still parses this incorrectly...
    inst_hook cmdline 10 "$moddir/hooks/cmdline/expand-kcl-ip.sh"

    # sets environment variables to tell dracut which device
    # holds the future root filesystem
    inst_hook cmdline 90 "$moddir/hooks/cmdline/mark-root-device.sh"

    ## HOOK pre-udev
    # loads the dnbd3/nbd kernel modules
    inst_hook pre-udev 00 "$moddir/hooks/pre-udev/load-dnbd3-nbd-modules.sh"

    ## HOOK pre-mount
    # this is the main hook where all the magic is triggered
    inst_hook pre-mount 10 "$moddir/hooks/pre-mount/mount-qcow.sh"

    ## HOOK mount
    # this simply mounts the prepared /dev/root to $NEWROOT
    # aka "the dracut way"
    inst_hook mount 10 "$moddir/hooks/mount/mount-root-device.sh"

    ## HOOK pre-pivot
    # this checks whether we found a partition suitable for
    # the future /tmp and if so, mounts it
    inst_hook pre-pivot 00 "$moddir/hooks/pre-pivot/mount-tmp.sh"

    ### SCRIPTS
    # the main magic script containing all the functions needed
    # to prepare the qcow2-based root filesystem
    inst "$moddir/scripts/setup-qcow2" /sbin/setup-qcow2

    # the script triggered by udev upon finding the right partitions
    inst "$moddir/scripts/prepare-disks" /sbin/prepare-disks

    # udev rules detecting 44, 45, 46 partitions and running
    # 'prepare-disks' to do then format/mount/use them
    inst "$moddir/udev/70-openslx-disk.rules" /etc/udev/rules.d/70-openslx-disk.rules

    # Debugging Uncomment this version if you need some useful debugging tools
    # in your iniramfs.
    inst_multiple lsblk ping ip ifconfig sshd htop tail head cat vim \
        touch sed lsmod insmod qemu-img sleep route wget find lsof strace \
        chroot switch_root pivot_root qemu-nbd mount nbd-client fdisk
    # Production:
    # inst_multiple insmod qemu-img qemu-nbd
    return 0
}