#!/usr/bin/env bash
# -*- coding: utf-8 -*-

# region header

# Copyright Torben Sickert (t.sickert["~at~"]gmail.com) 29.10.2015
#           Janosch Dobler (TODO) 29.10.2015

# License
# -------

# This library written by Torben Sickert and Janosch Dobler stand under a
# creative commons naming 3.0 unported license.
# see http://creativecommons.org/licenses/by/3.0/deed.de

# This tool provides a generic way to install systemd based remote linux
# initramfs.

# Examples
# --------

# Start install progress command (Assuming internet is available):
# >>> ./build_initramfs.sh

# Note that you only get very necessary output until you provide "--verbose" as
# commandline options.

# Dependencies
# ------------

# - bash (or any bash like shell)
# - cpio          - Copies files into or out of a cpio or tar archive. The
#                   archive can be another file on the disk, a magnetic tape,
#                   or a pipe.
# - git           - The stupid content tracker.
# - test          - Check file types and compare values (part of the shell).
# - shift         - Shifts the command line arguments (part of the shell).
# - echo          - Display a line of text (part of coreutils).
# - mktemp        - Create a temporary file or directory (part of coreutils).
# - cat           - Concatenate files and print on the standard output (part of
#                   coreutils).
# - rm            - Remove files or directories (part of coreutils).
# - sed           - Stream editor for filtering and transforming text.
# - gzip          - Compress or expand files.
# - curl          - Transfer a URL
# - tar           - The GNU version of the tar archiving utility.
# - make          - GNU make utility to maintain groups of programs.
# - cmake         - The "cmake" executable is the CMake command-line interface.
# - linux-headers - GNU make utility to maintain groups of programs.
# - grep          - Searches the named input files (or standard input if no
#                   files are named, or if a single hyphen-minus (-) is given
#                   as file name) for lines containing a match to the given
#                   PATTERN. By default, grep prints the matching lines.

# endregion

source $(dirname ${BASH_SOURCE[0]})/dnbd3-rootfs/scripts/rebash/core.sh
core.import logging
core.import utils
core.import exceptions

exceptions.init

# region properties

build_initramfs_verbose='no'
build_initramfs_debug='no'
build_initramfs_create_system_image='no'
build_initramfs_dependencies=(bash cpio git test shift echo mktemp cat rm sed \
    gzip curl tar grep make gcc cmake)
# TODO Check for:
# /usr/lib/x86_64-linux-gnu/libz.so ldconfig -p |grep libz.so
# for dnbd3

# endregion

# region functions

## region command line interface

function build_initramfs_print_usage_message() {
    # Prints a description about how to use this program.
    logging.cat << EOF
This program provides a generic way to install systemd based remote linux
initramfs.
EOF
}
function build_initramfs_print_usage_examples() {
    # Prints a description about how to use this program by providing examples.
    logging.cat << EOF
Start install progress:
>>> ./build_initramfs.sh
EOF
}
function build_initramfs_print_command_line_option_description() {
    # Prints descriptions about each available command line option.
    logging.cat << EOF
-h --help Shows this help message.

-v --verbose Tells you what is going on (default: "$build_initramfs_verbose").

-d --debug Gives you any output from all tools which are used
    (default: "$build_initramfs_debug").

-l --load-environment Simple load the install arch linux scope without
    doing anything else.

-c --create-system-image Creates a system image file for given path
    (default: "$build_initramfs_create_system_image").
EOF
}
function build_initramfs_print_help_message() {
    # Provides a help message for this module.
    logging.plain "\nUsage: $0 [options]\n"
    build_initramfs_print_usage_message "$@"
    logging.plain '\nExamples:\n'
    build_initramfs_print_usage_examples "$@"
    logging.plain -e '\nOption descriptions:\n'
    build_initramfs_print_command_line_option_description "$@"
    logging.plain
}
function build_initramfs_parse_command_line() {
    # Provides the command line interface and interactive questions.
    while true; do
        case "$1" in
            -h|--help)
                shift
                build_initramfs_print_help_message "$0"
                exit 0
                ;;
            -v|--verbose)
                shift
                build_initramfs_verbose='yes'
                logging.set_commands_log_level debug
                logging.set_log_level info
                ;;
            -d|--debug)
                shift
                build_initramfs_debug='yes'
                logging.set_commands_log_level debug
                logging.set_log_level debug
                ;;
            -c|--create-system-image)
                shift
                build_initramfs_create_system_image="$1"
                shift
                ;;

            '')
                break
                ;;
            *)
                logging.critical "Given argument: \"$1\" is not available."
                return 1
        esac
    done
    if [[ "$UID" != '0' ]]; then
        logging.critical \
            "You have to run this script as \"root\" not as \"${USER}\"."
        exit 2
    fi
    return 0
}

## endregion

function build_initramfs_initialize_dracut() {
    # Downloads and compiles dracut.
    #
    # Examples:
    #
    # >>> build_initramfs_initialize_dracut
    # ...
    mkdir dracut
    logging.info 'Download and extract dracut.'
    curl --location \
        https://www.kernel.org/pub/linux/utils/boot/dracut/dracut-043.tar.gz | \
        tar --extract --gzip --directory dracut --strip-components 1
    pushd dracut
    # NOTE: On virtualbox shared folder symlinks are not allowed.
    # NOTE: make the dracut-install binary (dracut-install resolves
    # dependencies etc.)
    logging.info 'Compiling dracut.'
    make install/dracut-install
    # NOTE: We have to copy the binary to current instead of symlinking them
    # since this feature isn't supported in shared virtual box machine folders.
    # If symlinks would be available we could simply use:
    # >>> make dracut-install
    cp install/dracut-install dracut-install
    popd
    return $?
}
function build_initramfs_create_qcow2_system() {
    # Packs current distribution in a qcow2 container.
    #
    # Examples:
    #
    # >>> build_initramfs_create_qcow2_system
    # TODO
    qemu-img create -f qcow2 "${CONTAINER_PATH}" "${QCOW_SIZE}"
    return $?
}

# endregion

# region controller

# TODO link dracut module if present in same folder or download if not present
# already.
# TODO write clean procedure (also clean dracut module).
# TODO check for existing kernel headers:
    # ubuntu: sudo apt-get install linux-headers-$(uname -r)

utils.dependency_check "${build_initramfs_dependencies[*]}"
if ! build_initramfs_parse_command_line "$@"; then
    build_initramfs_print_help_message "$0"
    exit 1
fi
logging.info 'Checking dracut.'
if ! [[ -d ./dracut ]]; then
    logging.info "Dracut isn't available yet loading it."
    build_initramfs_initialize_dracut
fi
build_initramfs__dracut_modules_source='../../dnbd3-rootfs'
build_initramfs__dracut_modules_target='dracut/modules.d/90dnbd3-rootfs'
if [[ ! -L "$build_initramfs__dracut_modules_target" || "$(readlink \
    "$build_initramfs__dracut_modules_target")" != \
    "$build_initramfs__dracut_modules_source" ]]
then
    logging.info \
        "Link dnbd3 plugin into dracut modules folder ($build_initramfs__dracut_modules_source -> $build_initramfs__dracut_modules_target)."
    ln --symbolic "$build_initramfs__dracut_modules_source" \
        "$build_initramfs__dracut_modules_target"
    # NOTE: If you copy we would have to recompile each binaries every time:
    # >>> cp --recursive --force --no-target-directory \
    # ...     "$(basename "$build_initramfs__dracut_modules_source")" \
    # ...     "$build_initramfs__dracut_modules_target"
fi
build_initramfs__loglevel=''
if [ "$build_initramfs_verbose" == 'yes' ]; then
    build_initramfs__loglevel='--verbose'
fi
build_initramfs__modules='dnbd3-rootfs'
if [ "$build_initramfs_debug" == 'yes' ]; then
    build_initramfs__loglevel="$build_initramfs__loglevel --stdlog 4"
    build_initramfs__modules="$build_initramfs__modules i18n terminfo"
fi
logging.info 'Build initramfs.'
dracut/dracut.sh --local $build_initramfs__loglevel --force --modules \
    "$build_initramfs__modules" --no-hostonly /boot/initramfs-test.img
logging.info 'All done!'

# endregion

# region vim modline

# vim: set tabstop=4 shiftwidth=4 expandtab:
# vim: foldmethod=marker foldmarker=region,endregion:

# endregion