#
# Wrap the builtin history command to provide additional functionality.
#
function __fish_unexpected_hist_args --no-scope-shadowing
    if test -n "$search_mode"
        or set -q show_time[1]
        printf (_ "%ls: you cannot use any options with the %ls command\n") $cmd $hist_cmd >&2
        return 0
    end
    if set -q argv[1]
        printf (_ "%ls: %ls expected %d args, got %d\n") $cmd $hist_cmd 0 (count $argv) >&2
        return 0
    end
    return 1
end

function history --description "display or manipulate interactive command history"
    set -l cmd history
    set -l options --exclusive 'c,e,p' --exclusive 'S,D,M,V,X'
    set -a options h/help c/contains e/exact p/prefix
    set -a options C/case-sensitive R/reverse z/null 't/show-time=?' 'n#max'
    # The following options are deprecated and will be removed in the next major release.
    # Note that they do not have usable short flags.
    set -a options S-search D-delete M-merge V-save X-clear
    argparse -n $cmd $options -- $argv
    or return

    if set -q _flag_help
        __fish_print_help history
        return 0
    end

    set -l hist_cmd
    set -l show_time
    set -l max_count
    set -l search_mode
    set -q _flag_max
    set max_count -n$_flag_max

    set -q _flag_with_time
    and set -l _flag_show_time $_flag_with_time
    if set -q _flag_show_time[1]
        set show_time --show-time=$_flag_show_time
    else if set -q _flag_show_time
        set show_time --show-time
    end

    set -q _flag_prefix
    and set -l search_mode --prefix
    set -q _flag_contains
    and set -l search_mode --contains
    set -q _flag_exact
    and set -l search_mode --exact

    if set -q _flag_delete
        set hist_cmd delete
    else if set -q _flag_save
        set hist_cmd save
    else if set -q _flag_clear
        set hist_cmd clear
    else if set -q _flag_search
        set hist_cmd search
    else if set -q _flag_merge
        set hist_cmd merge
    end

    # If a history command has not already been specified check the first non-flag argument for a
    # command. This allows the flags to appear before or after the subcommand.
    if not set -q hist_cmd[1]
        and set -q argv[1]
        if contains $argv[1] search delete merge save clear
            set hist_cmd $argv[1]
            set -e argv[1]
        end
    end

    if not set -q hist_cmd[1]
        set hist_cmd search # default to "search" if the user didn't specify a subcommand
    end

    switch $hist_cmd
        case search # search the interactive command history
            test -z "$search_mode"
            and set search_mode --contains

            if isatty stdout
                set -l pager less
                set -q PAGER
                and echo $PAGER | read -at pager

                # If the user hasn't preconfigured less with the $LESS environment variable,
                # we do so to have it behave like cat if output fits on one screen. Prevent the
                # screen from clearing on quit, so there is something to see if it exits.
                # These are two of the options `git` sets through $LESS before starting the pager.
                not set -qx LESS
                and set -x LESS --quit-if-one-screen --no-init
                not set -qx LV # ask the pager lv not to strip colors
                and set -x LV -c

                builtin history search $search_mode $show_time $max_count $_flag_case_sensitive $_flag_reverse $_flag_null -- $argv | $pager
            else
                builtin history search $search_mode $show_time $max_count $_flag_case_sensitive $_flag_reverse $_flag_null -- $argv
            end

        case delete # interactively delete history
            # TODO: Fix this to deal with history entries that have multiple lines.
            set -l searchterm $argv
            if not set -q argv[1]
                read -P"Search term: " searchterm
            end

            if test -z "$search_mode"
                set search_mode --contains
            end

            if test $search_mode = --exact
                builtin history delete $search_mode $_flag_case_sensitive $searchterm
                return
            end

            # TODO: Fix this so that requesting history entries with a timestamp works:
            #   set -l found_items (builtin history search $search_mode $show_time -- $argv)
            set -l found_items
            set found_items (builtin history search $search_mode $_flag_case_sensitive --null -- $searchterm | string split0)
            if set -q found_items[1]
                set -l found_items_count (count $found_items)
                for i in (seq $found_items_count)
                    printf "[%s] %s\n" $i $found_items[$i]
                end
                echo ""
                echo "Enter nothing to cancel the delete, or"
                echo "Enter one or more of the entry IDs separated by a space, or"
                echo "Enter \"all\" to delete all the matching entries."
                echo ""
                read --local --prompt "echo 'Delete which entries? > '" choice
                echo ''

                if test -z "$choice"
                    printf "Cancelling the delete!\n"
                    return
                end

                if test "$choice" = all
                    printf "Deleting all matching entries!\n"
                    for item in $found_items
                        builtin history delete --exact --case-sensitive -- $item
                    end
                    builtin history save
                    return
                end

                for i in (string split " " -- $choice)
                    if test -z "$i"
                        or not string match -qr '^[1-9][0-9]*$' -- $i
                        or test $i -gt $found_items_count
                        printf "Ignoring invalid history entry ID \"%s\"\n" $i
                        continue
                    end

                    printf "Deleting history entry %s: \"%s\"\n" $i $found_items[$i]
                    builtin history delete --exact --case-sensitive -- "$found_items[$i]"
                end
                builtin history save
            end

        case save # save our interactive command history to the persistent history
            __fish_unexpected_hist_args $argv
            and return 1

            builtin history save -- $argv

        case merge # merge the persistent interactive command history with our history
            __fish_unexpected_hist_args $argv
            and return 1

            builtin history merge -- $argv

        case clear # clear the interactive command history
            __fish_unexpected_hist_args $argv
            and return 1

            printf (_ "If you enter 'yes' your entire interactive command history will be erased\n")
            read --local --prompt "echo 'Are you sure you want to clear history? (yes/no) '" choice
            if test "$choice" = yes
                builtin history clear -- $argv
                and printf (_ "Command history cleared!\n")
            else
                printf (_ "You did not say 'yes' so I will not clear your command history\n")
            end

        case '*'
            printf "%ls: unexpected subcommand '%ls'\n" $cmd $hist_cmd
            return 2
    end
end