#!/bin/bash

# Purpose: A pretty GUI frontend to eselect, using zenity
# Author: Donnie Berkholz <dberkholz@gentoo.org>
# TODO:
#   Support additional types of eselect module besides single

# Supported modules, and how they act
# "single" is a single-choice type
MODULES=(
	emacs:single
	esd:single
	opengl:single
	profile:single
)

# Attempt to run a command
# On failure, present an error message and return failure
try() {
	local COMMAND=$@

	OUTPUT=$(${COMMAND} 2>&1) && echo ${OUTPUT} && return 0

	zenity \
		--error \
		--text="
Failed command:
${COMMAND}

Output:
${OUTPUT}"

	return 1
}

# Present a radio-button list for eselect modules that take a single choice
# and show the active choice in the third field of 'list' output
# Run the chosen eselect command
do_choice_single() {
	local i=0 line MODULE=$1 ZENITY_OPTIONS
	declare -a E_OPTIONS

	while read line; do
		E_OPTIONS[i]=${line}
		(( i++ ))
	done < <(eselect --no-color ${MODULE} list | grep '\[[0-9]*\]')

	# Build options list
	local STATUS CHOICE
	declare -a E_OPTION_LINE
	for (( j=0; j<${#E_OPTIONS[@]}; j++ )); do
		set ${E_OPTIONS[j]}
		shift

		# If the selection's active
		if [[ ${!#} = \* ]]; then
			STATUS="TRUE"
			# Strip the '*' off the end
			set ${@:0:$(($#-1))}
		else
			STATUS="FALSE"
		fi
		ALL="$@"

		# Replace spaces with underscores for zenity
		# Hopefully no eselect output uses underscores
		ZENITY_OPTIONS="${ZENITY_OPTIONS} ${STATUS} ${ALL// /_}"
	done

	ZENITY_COMMAND="zenity \
		--list --radiolist \
		--column="choice" --column="${MODULE}" \
		${ZENITY_OPTIONS}"

	CHOICE=$(try ${ZENITY_COMMAND})
	[[ $? -ne 0 ]] && return 1
	# Restore underscores to spaces so we can match properly
	CHOICE=${CHOICE//_/ }

	local CHOICENUM
	for (( k=0; k<${#E_OPTIONS[@]}; k++ )); do
		# It's k+1 because eselect numbers start at 1, not 0
		[[ ${E_OPTIONS[k]} = *${CHOICE}* ]] && CHOICENUM=$((k+1))
	done

	try eselect ${MODULE} set ${CHOICENUM}
}

# Asks user to select an available module and runs it
pick_module() {
	declare -a MODNAMES
	MODNAMES=${MODULES[@]/:*}

	local MOD ZENITY_OPTIONS
	for MOD in ${MODNAMES}; do
		# Make sure the module's installed, and it has selections available
		if eselect --no-color list-modules | grep -q "\<${MOD}\>" \
			&& eselect --no-color ${MOD} list | grep -q '\[[0-9]*\]'; then
			ZENITY_OPTIONS="${ZENITY_OPTIONS} FALSE ${MOD}"
		fi
	done

	local ZENITY_COMMAND="zenity \
		--list --radiolist \
		--column="choice" --column="module" \
		${ZENITY_OPTIONS}"

	local CHOICE=$(try ${ZENITY_COMMAND})
	[[ $? -ne 0 ]] && return 1

	# Find type, given a known module
	local MODULE
	for MODULE in ${MODULES[@]}; do
		MOD=${MODULE/:*}
		if [[ ${MOD} = ${CHOICE} ]]; then
			TYPE=${MODULE/*:}
			break
		fi
	done

	echo "Running do_choice_${TYPE} ${MOD}"
	do_choice_${TYPE} ${MOD} || return 1
}

main() {
	if [[ ${UID} -ne 0 ]]; then
		zenity \
			--error \
			--text="You must run ${0##*/} as root."
		exit 1
	fi

	# Keep asking till they don't want to do any more configuration
	while pick_module; do
		true
	done
}

# We need to match '*' because eselect uses that for active selections,
# so turn off globbing
set -o noglob

main

set +o noglob