shellfu-bash-saturnin/src/libexec/saturnin-menu

#!/bin/bash

. "$(ffoom path)" || exit 3

ffoo import inigrep
ffoo import pretty

usage() {
    mkusage "[-g generator_cmd] [-s selector_cmd] [-c consumer_cmd] [name]"
}

SATURNIN_MENU_MNAME=""
SATURNIN_MENU_GENERATOR=""
SATURNIN_MENU_SELECTOR=""
SATURNIN_MENU_SELECT_ARGS=""
SATURNIN_MENU_CONSUMER=""

load_parts() {
    #
    # Load mandatory parts for menu name $1
    #
    local mname

    # last chance to get mname
    test -n "$SATURNIN_MENU_MNAME" \
     || SATURNIN_MENU_MNAME="$(get_mname)" \
     || usage
    mname="$SATURNIN_MENU_MNAME"

    # check that menu item exists
    inigrep -s "menu.$mname" | grep -q . \
     || die "no such menu: $mname"

    test -n "$SATURNIN_MENU_GENERATOR" \
     || SATURNIN_MENU_GENERATOR="$(get_generator)"  \
     || die "cannot find generator for menu: $mname"

    test -n "$SATURNIN_MENU_SELECTOR" \
     || SATURNIN_MENU_SELECTOR="$(get_selector)" \
     || die "cannot find selector for menu: $mname"

    test -n "$SATURNIN_MENU_SELECT_ARGS" \
     || SATURNIN_MENU_SELECT_ARGS="$(get_select_args)"

    test -n "$SATURNIN_MENU_CONSUMER" \
     || SATURNIN_MENU_CONSUMER="$(get_consumer)" \
     || die "cannot find consumer for menu: $mname"
}

get_mname() {
    #
    # Take from global INI default
    #
    inigrep -1 -p menu._default_.name | grep .
}

get_generator() {
    #
    # Obtain and echo generator for menu $mname
    #
    # First, look for 'generator' key in menu definition,
    # then for items as 'item' keys at the same place,
    # finally default 'generator'.
    #
    inigrep -1 -p "menu.$mname.generator" | grep . \
     && return 0
    inigrep -p "menu.$mname.item" | grep -m 1 -q . \
     && echo "inigrep -p menu.$mname.item" \
     && return 0
    inigrep -1 -p "menu._default_.generator" | grep . \
     && return 0
    return 1
}

get_selector() {
    #
    # Obtain and echo selector for menu $mname
    #
    # First, look for 'selector' key in menu definition,
    # then a default 'selector'.
    #
    inigrep -1 -p "menu.$mname.selector" | grep . \
     && return 0
    inigrep -1 -p "menu._default_.selector" | grep .
}

get_select_args() {
    #
    # Obtain and echo selector args for menu $mname
    #
    # First, look for 'select_args' key in menu definition,
    # then a default 'select_args'.
    #
    inigrep -1 -p "menu.$mname.select_args" | grep . \
     && return 0
    inigrep -1 -p "menu._default_.select_args"
}

get_consumer() {
    #
    # Obtain and echo consumer args for menu $mname
    #
    # First, look for 'consumer' key in menu definition,
    # then a default 'consumer'.
    #
    inigrep -1 -p "menu.$mname.consumer" | grep . \
     && return 0
    inigrep -1 -p "menu._default_.consumer" | grep .
}

do_generate() {
    #
    # Generate menu items
    #
    bash -n <<<"$SATURNIN_MENU_GENERATOR" \
     || die "syntax errors in generator: $SATURNIN_MENU_GENERATOR"
    eval "$SATURNIN_MENU_GENERATOR"
}

do_select() {
    #
    # Bring up selection UI
    #
    bash -n <<<"$SATURNIN_MENU_SELECTOR" \
     || die "syntax errors in selector: $SATURNIN_MENU_SELECTOR"
    eval "$SATURNIN_MENU_SELECTOR $SATURNIN_MENU_SELECT_ARGS"
}


do_consume() {
    #
    # Process the selected item(s)
    #
    bash -n <<<"$SATURNIN_MENU_CONSUMER" \
     || die "syntax errors in consumer: $SATURNIN_MENU_CONSUMER"
    eval "$SATURNIN_MENU_CONSUMER"
}

while true; do case "$1" in
    -g) SATURNIN_MENU_GENERATOR="$2"; shift; shift ;;
    -s) SATURNIN_MENU_SELECTOR="$2"; shift; shift ;;
    -c) SATURNIN_MENU_CONSUMER="$2"; shift; shift ;;
    -*) usage ;;
    "") usage ;;
    *)  SATURNIN_MENU_MNAME="$1"; shift; break ;;
esac done

load_parts

debug -v SATURNIN_MENU_MNAME \
         SATURNIN_MENU_GENERATOR \
         SATURNIN_MENU_SELECTOR \
         SATURNIN_MENU_SELECT_ARGS \
         SATURNIN_MENU_CONSUMER

do_generate | do_select | do_consume