# Copyright (c) 2010-2016, Aneurin Price <aneurin.price@gmail.com>

# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.

__ZFS_CMD="/sbin/zfs"
__ZPOOL_CMD="/sbin/zpool"

# Disable bash's built-in hostname completion, as this makes it impossible to
# provide completions containing an @-sign, which is necessary for completing
# snapshot names. If bash_completion is in use, this will already be disabled
# and replaced with better completions anyway.
shopt -u hostcomplete

__zfs_get_commands()
{
    $__ZFS_CMD 2>&1 | awk '/^\t[a-z]/ {print $1}' | cut -f1 -d '|' | uniq
}

__zfs_get_properties()
{
    $__ZFS_CMD get 2>&1 | awk '$2 == "YES" || $2 == "NO" {print $1}'; echo all name space
}

__zfs_get_editable_properties()
{
    $__ZFS_CMD get 2>&1 | awk '$2 == "YES" {print $1"="}'
}

__zfs_get_inheritable_properties()
{
    $__ZFS_CMD get 2>&1 | awk '$3 == "YES" {print $1}'
}

__zfs_list_datasets()
{
    $__ZFS_CMD list -H -o name -s name -t filesystem,volume "$@"
}

__zfs_list_filesystems()
{
    $__ZFS_CMD list -H -o name -s name -t filesystem
}

__zfs_match_snapshot()
{
    local base_dataset="${cur%@*}"
    if [[ "$base_dataset" != "$cur" ]]
    then
        $__ZFS_CMD list -H -o name -s name -t snapshot -d 1 "$base_dataset"
    else
        if [[ "$cur" != "" ]] && __zfs_list_datasets "$cur" &> /dev/null
        then
            $__ZFS_CMD list -H -o name -s name -t filesystem,volume -r "$cur" | tail -n +2
            # We output the base dataset name even though we might be
            # completing a command that can only take a snapshot, because it
            # prevents bash from considering the completion finished when it
            # ends in the bare @.
            echo "$cur"
            echo "$cur@"
        else
            local datasets
            datasets="$(__zfs_list_datasets)"
            # As above
            echo "$datasets"
            if [[ "$cur" == */ ]]
            then
                # If the current command ends with a slash, then the only way
                # it can be completed with a single tab press (ie. in this pass)
                # is if it has exactly one child, so that's the only time we
                # need to offer a suggestion with an @ appended.
                local num_children
                # This is actually off by one as zfs list includes the named
                # dataset in addition to its children
                num_children=$(__zfs_list_datasets -d 1 "${cur%/}" 2> /dev/null | wc -l)
                if [[ $num_children != 2 ]]
                then
                    return 0
                fi
            fi
            echo "$datasets" | awk '{print $1 "@"}'
        fi
    fi
}

__zfs_match_snapshot_or_bookmark()
{
    local base_dataset="${cur%[#@]*}"
    if [[ "$base_dataset" != "$cur" ]]
    then
        if [[ $cur == *@* ]]
        then
            $__ZFS_CMD list -H -o name -s name -t snapshot -d 1 "$base_dataset"
        else
            $__ZFS_CMD list -H -o name -s name -t bookmark -d 1 "$base_dataset"
        fi
    else
        $__ZFS_CMD list -H -o name -s name -t filesystem,volume
        if [[ -e "$cur" ]] && $__ZFS_CMD list -H -o name -s name -t filesystem,volume "$cur" &> /dev/null
        then
            echo "$cur@"
            echo "$cur#"
        fi
    fi
}

__zfs_match_multiple_snapshots()
{
    local existing_opts
    existing_opts="$(expr "$cur" : '\(.*\)[%,]')"
    if [[ -e "$existing_opts" ]]
    then
        local base_dataset="${cur%@*}"
        if [[ "$base_dataset" != "$cur" ]]
        then
            local cur="${cur##*,}"
            if [[ $cur =~ ^%|%.*% ]]
            then
                # correct range syntax is start%end
                return 1
            fi
            local range_start
            range_start="$(expr "$cur" : '\(.*%\)')"
            # shellcheck disable=SC2016
            $__ZFS_CMD list -H -o name -s name -t snapshot -d 1 "$base_dataset" | sed 's$.*@$'"$range_start"'$g'
        fi
    else
        __zfs_match_snapshot_or_bookmark
    fi
}

__zfs_list_volumes()
{
    $__ZFS_CMD list -H -o name -s name -t volume
}

__zfs_argument_chosen()
{
    local word property
    for word in $(seq $((COMP_CWORD-1)) -1 2 2>/dev/null)
    do
        local prev="${COMP_WORDS[$word]}"
        if [[ ${COMP_WORDS[$word-1]} != -[tos] ]]
        then
            if [[ "$prev" == [^,]*,* ]] || [[ "$prev" == *[@:\#]* ]]
            then
                return 0
            fi
            for property in "$@"
            do
                if [[ $prev == "$property"* ]]
                then
                    return 0
                fi
            done
        fi
    done
    return 1
}

__zfs_complete_ordered_arguments()
{
    local list1=$1
    local list2=$2
    local cur=$3
    local extra=$4
    # shellcheck disable=SC2086
    if __zfs_argument_chosen $list1
    then
        mapfile -t COMPREPLY < <(compgen -W "$list2 $extra" -- "$cur")
    else
        mapfile -t COMPREPLY < <(compgen -W "$list1 $extra" -- "$cur")
    fi
}

__zfs_complete_multiple_options()
{
    local options=$1
    local cur=$2
    local existing_opts

    mapfile -t COMPREPLY < <(compgen -W "$options" -- "${cur##*,}")
    existing_opts=$(expr "$cur" : '\(.*,\)')
    if [[ -n "$existing_opts" ]]
    then
        COMPREPLY=( "${COMPREPLY[@]/#/${existing_opts}}" )
    fi
}

__zfs_complete_switch()
{
    local options=$1
    if [[ ${cur:0:1} == - ]]
    then
        mapfile -t COMPREPLY < <(compgen -W "-{$options}" -- "$cur")
        return 0
    else
        return 1
    fi
}

__zfs_complete_nospace()
{
    # Google indicates that there may still be bash versions out there that
    # don't have compopt.
    if type compopt &> /dev/null
    then
        compopt -o nospace
    fi
}

__zfs_complete()
{
    local cur prev cmd cmds
    COMPREPLY=()
    if type _get_comp_words_by_ref &> /dev/null
    then
        # Don't split on colon
        _get_comp_words_by_ref -n : -c cur -p prev -w COMP_WORDS -i COMP_CWORD
    else
        cur="${COMP_WORDS[COMP_CWORD]}"
        prev="${COMP_WORDS[COMP_CWORD-1]}"
    fi
    cmd="${COMP_WORDS[1]}"

    if [[ ${prev##*/} == zfs ]]
    then
        cmds=$(__zfs_get_commands)
        mapfile -t COMPREPLY < <(compgen -W "$cmds -?" -- "$cur")
        return 0
    fi

    case "${cmd}" in
        bookmark)
            if __zfs_argument_chosen
            then
                mapfile -t COMPREPLY < <(compgen -W "${prev%@*}# ${prev/@/#}" -- "$cur")
            else
                mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
            fi
            ;;
        clone)
            case "${prev}" in
                -o)
                    mapfile -t COMPREPLY < <(compgen -W "$(__zfs_get_editable_properties)" -- "$cur")
                    __zfs_complete_nospace
                    ;;
                *)
                    if ! __zfs_complete_switch "o,p"
                    then
                        if __zfs_argument_chosen
                        then
                            mapfile -t COMPREPLY < <(compgen -W "$(__zfs_list_datasets)" -- "$cur")
                        else
                            mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                        fi
                    fi
                    ;;
            esac
            ;;
        get)
            case "${prev}" in
                -d)
                    mapfile -t COMPREPLY < <(compgen -W "" -- "$cur")
                    ;;
                -t)
                    __zfs_complete_multiple_options "filesystem volume snapshot bookmark all" "$cur"
                    ;;
                -s)
                    __zfs_complete_multiple_options "local default inherited temporary received none" "$cur"
                    ;;
                -o)
                    __zfs_complete_multiple_options "name property value source received all" "$cur"
                    ;;
                *)
                    if ! __zfs_complete_switch "H,r,p,d,o,t,s"
                    then
                        # shellcheck disable=SC2046
                        if __zfs_argument_chosen $(__zfs_get_properties)
                        then
                            mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                        else
                            __zfs_complete_multiple_options "$(__zfs_get_properties)" "$cur"
                        fi
                    fi
                    ;;
            esac
            ;;
        inherit)
            if ! __zfs_complete_switch "r"
            then
                __zfs_complete_ordered_arguments "$(__zfs_get_inheritable_properties)" "$(__zfs_match_snapshot)" "$cur"
            fi
            ;;
        list)
            case "${prev}" in
                -d)
                    mapfile -t COMPREPLY < <(compgen -W "" -- "$cur")
                    ;;
                -t)
                    __zfs_complete_multiple_options "filesystem volume snapshot bookmark all" "$cur"
                    ;;
                -o)
                    __zfs_complete_multiple_options "$(__zfs_get_properties)" "$cur"
                    ;;
                -s|-S)
                    mapfile -t COMPREPLY < <(compgen -W "$(__zfs_get_properties)" -- "$cur")
                    ;;
                *)
                    if ! __zfs_complete_switch "H,r,d,o,t,s,S"
                    then
                        mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                    fi
                    ;;
            esac
            ;;
        promote)
            mapfile -t COMPREPLY < <(compgen -W "$(__zfs_list_filesystems)" -- "$cur")
            ;;
        rollback)
            if ! __zfs_complete_switch "r,R,f"
            then
                mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
            fi
            ;;
        send)
            if ! __zfs_complete_switch "D,n,P,p,R,v,e,L,i,I"
            then
                if __zfs_argument_chosen
                then
                    mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                else
                    if [[ $prev == -*i* ]]
                    then
                        mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot_or_bookmark)" -- "$cur")
                    else
                        mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                    fi
                fi
            fi
            ;;
        snapshot)
            case "${prev}" in
                -o)
                    mapfile -t COMPREPLY < <(compgen -W "$(__zfs_get_editable_properties)" -- "$cur")
                    __zfs_complete_nospace
                    ;;
                *)
                    if ! __zfs_complete_switch "o,r"
                    then
                        mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
                        __zfs_complete_nospace
                    fi
                    ;;
            esac
            ;;
        set)
            __zfs_complete_ordered_arguments "$(__zfs_get_editable_properties)" "$(__zfs_match_snapshot)" "$cur"
            __zfs_complete_nospace
            ;;
        upgrade)
            case "${prev}" in
                -a|-V|-v)
                    mapfile -t COMPREPLY < <(compgen -W "" -- "$cur")
                    ;;
                *)
                    if ! __zfs_complete_switch "a,V,v,r"
                    then
                        mapfile -t COMPREPLY < <(compgen -W "$(__zfs_list_filesystems)" -- "$cur")
                    fi
                    ;;
            esac
            ;;
        destroy)
            if ! __zfs_complete_switch "d,f,n,p,R,r,v"
            then
                __zfs_complete_multiple_options "$(__zfs_match_multiple_snapshots)" "$cur"
                __zfs_complete_nospace
            fi
            ;;
        *)
            mapfile -t COMPREPLY < <(compgen -W "$(__zfs_match_snapshot)" -- "$cur")
            ;;
    esac
    if type __ltrim_colon_completions &> /dev/null
    then
        __ltrim_colon_completions "$cur"
    fi
    return 0
}

__zpool_get_commands()
{
    $__ZPOOL_CMD 2>&1 | awk '/^\t[a-z]/ {print $1}' | uniq
}

__zpool_get_properties()
{
    $__ZPOOL_CMD get 2>&1 | awk '$2 == "YES" || $2 == "NO" {print $1}'; echo all
}

__zpool_get_editable_properties()
{
    $__ZPOOL_CMD get 2>&1 | awk '$2 == "YES" {print $1"="}'
}

__zpool_list_pools()
{
    $__ZPOOL_CMD list -H -o name
}

__zpool_complete()
{
    local cur prev cmd cmds pools
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"
    cmd="${COMP_WORDS[1]}"

    if [[ ${prev##*/} == zpool ]]
    then
        cmds=$(__zpool_get_commands)
        mapfile -t COMPREPLY < <(compgen -W "$cmds" -- "$cur")
        return 0
    fi

    case "${cmd}" in
        get)
            __zfs_complete_ordered_arguments "$(__zpool_get_properties)" "$(__zpool_list_pools)" "$cur"
            return 0
            ;;
        import)
            if [[ $prev == -d ]]
            then
                _filedir -d
            else
                mapfile -t COMPREPLY < <(compgen -W "$(__zpool_list_pools) -d" -- "$cur")
            fi
            return 0
            ;;
        set)
            __zfs_complete_ordered_arguments "$(__zpool_get_editable_properties)" "$(__zpool_list_pools)" "$cur"
            __zfs_complete_nospace
            return 0
            ;;
        add|attach|clear|create|detach|offline|online|remove|replace)
            pools="$(__zpool_list_pools)"
            # shellcheck disable=SC2086
            if __zfs_argument_chosen $pools
            then
                _filedir
            else
                mapfile -t COMPREPLY < <(compgen -W "$pools" -- "$cur")
            fi
            return 0
            ;;
        *)
            mapfile -t COMPREPLY < <(compgen -W "$(__zpool_list_pools)" -- "$cur")
            return 0
            ;;
    esac

}

complete -F __zfs_complete zfs
complete -F __zpool_complete zpool
