#!/bin/sh
#
# Copyright © 2018 – 2019 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#


source /etc/os-release
release=$VERSION_ID

prefix_sudo=""
registry="registry.fedoraproject.org"
registry_candidate="candidate-registry.fedoraproject.org"
toolbox_prompt="🔹[\u@\h \W]\\$ "


is_integer()
{
    [ "$1" != "" ] && [ $1 -eq $1 2>&42 ]
    return $?
}


create()
(
    dbus_system_bus_address="unix:path=/var/run/dbus/system_bus_socket"
    tmpfs_size=$((64 * 1024 * 1024)) # 64 MiB
    working_container_name="fedora-toolbox-working-container-$(uuidgen --time)"

    if [ "$DBUS_SYSTEM_BUS_ADDRESS" != "" ]; then
        dbus_system_bus_address=$DBUS_SYSTEM_BUS_ADDRESS
    fi
    dbus_system_bus_path=$(echo $dbus_system_bus_address | cut --delimiter = --fields 2 2>&42)
    dbus_system_bus_path=$(readlink --canonicalize $dbus_system_bus_path 2>&42)

    echo "$0: checking if image $toolbox_image already exists" >&42

    if ! $prefix_sudo buildah inspect --type image $toolbox_image >/dev/null 2>&42; then
        echo "$0: trying to create working container $working_container_name" >&42
        echo "$0: looking for image localhost/$base_toolbox_image" >&42

        if ! $prefix_sudo buildah from \
                     --name $working_container_name \
                     localhost/$base_toolbox_image >/dev/null 2>&42; then
            echo "$0: looking for image $registry/$fgc/$base_toolbox_image" >&42

            if ! $prefix_sudo buildah from \
                         --name $working_container_name \
                         $registry/$fgc/$base_toolbox_image >/dev/null 2>&42; then
                echo "$0: failed to create working container"
                exit 1
            fi
        fi

        echo "$0: trying to configure working container $working_container_name" >&42

        if ! $prefix_sudo buildah run $working_container_name -- useradd \
                     --no-create-home \
                     --shell $SHELL \
                     --uid $UID \
                     --groups wheel \
                     $USER \
                     >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to create user $USER with UID $UID"
            exit 1
        fi

        if ! $prefix_sudo buildah run $working_container_name -- passwd -d $USER >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to remove password for user $USER"
            exit 1
        fi

        if ! $prefix_sudo buildah run $working_container_name -- passwd -d root >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to remove password for user root"
            exit 1
        fi

        if ! $prefix_sudo buildah config --volume $HOME $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure volume for $HOME"
            exit 1
        fi

        if ! $prefix_sudo buildah config --volume $XDG_RUNTIME_DIR $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure volume for $XDG_RUNTIME_DIR"
            exit 1
        fi

        if ! $prefix_sudo buildah config \
                     --volume $dbus_system_bus_path \
                     $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure volume for $dbus_system_bus_path"
            exit 1
        fi

        if ! $prefix_sudo buildah config --volume /dev/dri $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure volume for /dev/dri"
            exit 1
        fi

        if ! $prefix_sudo buildah config --user $USER $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure the default user as $USER"
            exit 1
        fi

        if ! $prefix_sudo buildah config --workingdir $HOME $working_container_name >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to configure the initial working directory to $HOME"
            exit 1
        fi

        echo "$0: trying to create image $toolbox_image" >&42

        if ! $prefix_sudo buildah commit --rm $working_container_name $toolbox_image >/dev/null 2>&42; then
            $prefix_sudo buildah rm $working_container_name >/dev/null 2>&42
            echo "$0: failed to create image $toolbox_image"
            exit 1
        fi

        echo "$0: created image $toolbox_image" >&42
    fi

    echo "$0: checking if container $toolbox_container already exists" >&42

    if $prefix_sudo podman inspect --type container $toolbox_container >/dev/null 2>&42; then
        echo "$0: container $toolbox_container already exists"
        exit 1
    fi

    total_ram=$(awk '( $1 == "MemTotal:" ) { print $2 }' /proc/meminfo 2>&42) # kibibytes
    if is_integer $total_ram; then
        tmpfs_size=$((total_ram*1024/2)) # bytes
    fi

    max_uid_count=65536
    max_minus_uid=$((max_uid_count-UID))
    uid_plus_one=$((UID+1))

    echo "$0: trying to create container $toolbox_container" >&42

    if ! $prefix_sudo podman create \
                 --group-add wheel \
                 --hostname toolbox \
                 --interactive \
                 --name $toolbox_container \
                 --network host \
                 --privileged \
                 --security-opt label=disable \
                 --tmpfs /dev/shm:size=$tmpfs_size \
                 --tty \
                 --uidmap $UID:0:1 \
                 --uidmap 0:1:$UID \
                 --uidmap $uid_plus_one:$uid_plus_one:$max_minus_uid \
                 --volume $HOME:$HOME \
                 --volume $XDG_RUNTIME_DIR:$XDG_RUNTIME_DIR \
                 --volume $dbus_system_bus_path:$dbus_system_bus_path \
                 --volume /dev/dri:/dev/dri \
                 $toolbox_image \
                 /bin/sh >/dev/null 2>&42; then
        echo "$0: failed to create container $toolbox_container"
        exit 1
    fi

    echo "$0: created container $toolbox_container" >&42
)


enter()
(
    shell_to_exec=/bin/bash

    echo "$0: trying to start container $toolbox_container" >&42

    if ! $prefix_sudo podman start $toolbox_container >/dev/null 2>&42; then
        echo "$0: failed to start container $toolbox_container"
        exit 1
    fi

    if [ "$DBUS_SYSTEM_BUS_ADDRESS" != "" ]; then
        set_dbus_system_bus_address="--env DBUS_SYSTEM_BUS_ADDRESS=$DBUS_SYSTEM_BUS_ADDRESS"
    fi

    echo "$0: looking for $SHELL in container $toolbox_container" >&42

    if $prefix_sudo podman exec $toolbox_container test -f $SHELL 2>&42; then
        shell_to_exec=$SHELL
    else
        echo "$0: $SHELL not found in $toolbox_container; using $shell_to_exec instead" >&42
    fi

    echo "$0: trying to exec $shell_to_exec in container $toolbox_container" >&42

    $prefix_sudo podman exec \
            --env COLORTERM=$COLORTERM \
            --env DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS \
            $set_dbus_system_bus_address \
            --env DESKTOP_SESSION=$DESKTOP_SESSION \
            --env DISPLAY=$DISPLAY \
            --env LANG=$LANG \
            --env SHELL=$SHELL \
            --env SSH_AUTH_SOCK=$SSH_AUTH_SOCK \
            --env TERM=$TERM \
            --env VTE_VERSION=$VTE_VERSION \
            --env XDG_CURRENT_DESKTOP=$XDG_CURRENT_DESKTOP \
            --env XDG_DATA_DIRS=$XDG_DATA_DIRS \
            --env XDG_MENU_PREFIX=$XDG_MENU_PREFIX \
            --env XDG_RUNTIME_DIR=$XDG_RUNTIME_DIR \
            --env XDG_SEAT=$XDG_SEAT \
            --env XDG_SESSION_DESKTOP=$XDG_SESSION_DESKTOP \
            --env XDG_SESSION_ID=$XDG_SESSION_ID \
            --env XDG_SESSION_TYPE=$XDG_SESSION_TYPE \
            --env XDG_VTNR=$XDG_VTNR \
            --interactive \
            --tty \
            $toolbox_container \
            /bin/sh -c 'cd "$1"; export PS1="$2"; shift 2; exec "$@"' \
                    /bin/sh \
                    "$PWD" \
                    "$toolbox_prompt" \
                    $shell_to_exec -l 2>&42
)


exit_if_extra_operand()
{
    if [ "$1" != "" ]; then
        echo "$0: extra operand '$1'"
        echo "Try '$0 --help' for more information."
        exit 1
    fi
}


exit_if_unrecognized_option()
{
    echo "$0: unrecognized option '$1'"
    echo "Try '$0 --help' for more information."
    exit 1
}


usage()
{
    echo "Usage: fedora-toolbox [--container <name>]"
    echo "                      [--release <release>]"
    echo "                      [-v | --verbose]"
    echo "                      create [--candidate-registry]"
    echo "                             [--image <name>]"
    echo "   or: fedora-toolbox [--container <name>]"
    echo "                      [--release <release>]"
    echo "                      [-v | --verbose]"
    echo "                      enter"
    echo "   or: fedora-toolbox --help"
}


exec 42>/dev/null

while [[ "$1" = -* ]]; do
    case $1 in
        --container )
            shift
            if [ "$1" = "" ]; then
                echo "$0: missing argument for '--container'"
                echo "Try '$0 --help' for more information."
                exit 1
            fi
            toolbox_container=$1
            ;;
        -h | --help )
            usage
            exit
            ;;
        --release )
            shift
            if [ "$1" = "" ]; then
                echo "$0: missing argument for '--release'"
                echo "Try '$0 --help' for more information."
                exit 1
            fi
            arg=$(echo $1 | sed 's/^F\|^f//' 2>&42)
            if ! is_integer $arg; then
                echo "$0: invalid argument for '--release'"
                echo "Try '$0 --help' for more information."
                exit 1
            fi
            if [ $arg -le 0 2>&42 ]; then
                echo "$0: invalid argument for '--release'"
                echo "Try '$0 --help' for more information."
                exit 1
            fi
            release=$arg
            ;;
        --sudo )
            prefix_sudo="sudo"
            ;;
        -v | --verbose )
            exec 42>&2
            ;;
        * )
            exit_if_unrecognized_option $1
    esac
    shift
done

fgc="f$release"
[ "$toolbox_container" = "" ] && toolbox_container="fedora-toolbox-$USER:$release"
base_toolbox_image="fedora-toolbox:$release"
toolbox_image="fedora-toolbox-$USER:$release"

if [ "$1" = "" ]; then
    echo "$0: missing command"
    echo "Try '$0 --help' for more information."
    exit 1
fi

op=$1
shift

case $op in
    create )
        while [[ "$1" = -* ]]; do
            case $1 in
                --candidate-registry )
                    registry=$registry_candidate
                    ;;
                --image )
                    shift
                    if [ "$1" = "" ]; then
                        echo "$0: missing argument for '--image'"
                        echo "Try '$0 --help' for more information."
                        exit 1
                    fi
                    toolbox_image=$1
                    ;;
                * )
                    exit_if_unrecognized_option $1
            esac
            shift
        done
        exit_if_extra_operand $1
        create
        exit
        ;;
    enter )
        while [[ "$1" = -* ]]; do
            case $1 in
                * )
                    exit_if_unrecognized_option $1
            esac
            shift
        done
        exit_if_extra_operand $1
        enter
        exit
        ;;
    * )
        echo "$0: unrecognized command '$op'"
        echo "Try '$0 --help' for more information."
        exit 1
esac