#!/bin/sh
#
# Purpose {{{
# This script will …
#   1. …
# …
#
# 2021-11-27
# }}}
# Vars {{{
readonly PROGNAME=$(basename "${0}")
readonly PROGDIR=$(readlink -m $(dirname "${0}"))
readonly ARGS="${*}"
readonly NBARGS="${#}"
[ -z "${DEBUG}" ] && DEBUG=1
## Export DEBUG for sub-script
export DEBUG

# Default values for some vars
readonly MY_VAR_XY_DEFAULT="666"

## Colors
readonly PURPLE='\033[1;35m'
readonly RED='\033[0;31m'
readonly RESET='\033[0m'
readonly COLOR_DEBUG="${PURPLE}"
## Rofi colors
readonly BLACK="#000000"
readonly BLUE="#0094cc"
# }}}
usage() {                                                       # {{{

	cat <<- EOF
usage: $PROGNAME [-d|-h]

Try to give a description…

EXAMPLES :
    - Apply my script to…
        ${PROGNAME}

OPTIONS :
    -d,--debug
        Enable debug messages.

    -h,--help
        Print this help message.

	EOF

}
# }}}
debug_message() {                                               # {{{

	local_message="${1}"

	## Print message if DEBUG is enable (=0)
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6b\e[m\n' "DEBUG − ${PROGNAME} : ${local_message}"

	return 0
}
# }}}
error_message() {                                               # {{{

	local_error_message="${1}"
	local_error_code="${2}"

	## Print message if DEBUG is enable (=0)
	[ "${DEBUG}" -eq "0" ] && printf '%b\n' "ERROR − ${PROGNAME} : ${RED}${local_error_message}${RESET}"

	exit "${local_error_code:=66}"
}
# }}}
define_vars() {                                                 # {{{

	## Temp file vars {{{
	readonly pa_sink_list_path="/tmp/${PROGNAME}.list"
	## }}}

}
# }}}
is_command_absent() {                                           # {{{

	local_command_absent_cmd="${1}"

	## A command is absent by default
	return_command_absent="0"

	if [ "$(command -v ${local_command_absent_cmd})" ]; then
		debug_message "is_command_absent − \
${RED}${local_command_absent_cmd}${COLOR_DEBUG} seems present on this host."
		return_command_absent="1"
	else
		debug_message "is_command_absent − \
${RED}${local_command_absent_cmd}${COLOR_DEBUG} is not available on this host."
		return_command_absent="0"
	fi

	return "${return_command_absent}"

}
# }}}
get_pulseaudio_sink_list() {                                    # {{{

	## Return False by default
	return_get_pulseaudio_sink_list="1"

	debug_message "get_pulseaudio_sink_list − \
Create or empty ${RED}${pa_sink_list_path}${COLOR_DEBUG} file to store pulseaudio sinks."
	true > "${pa_sink_list_path}"

	## Get sinks list with pactl (index and description)
	## Merge every two lines
	if pactl list sinks | \
	grep --only-matching --perl-regexp '((?<=Sink #)[[:digit:].]*|(?<=Description: ).*)' | \
	paste --delimiters=" "  - - > "${pa_sink_list_path}"; then
		if [ -s "${pa_sink_list_path}" ]; then
			debug_message "get_pulseaudio_sink_list − \
PulseAudio sinks list successfully created (see ${pa_sink_list_path} file)."
			return_get_pulseaudio_sink_list="0"
		else
			debug_message "get_pulseaudio_sink_list − \
Error, the PulseAudio sinks list is empty (${pa_sink_list_path} file)."
			return_get_pulseaudio_sink_list="1"
		fi
	else
		debug_message "get_pulseaudio_sink_list − \
Error in ${RED}pacmd list-sinks${COLOR_DEBUG} command."
		return_get_pulseaudio_sink_list="1"
	fi

	return "${return_get_pulseaudio_sink_list}"

}
# }}}
choose_pulseaudio_sink() {                                      # {{{

	## Return False by default
	return_choose_pulseaudio_sink="1"

	debug_message "choose_pulseaudio_sink − \
Display PulseAudio sinks list with rofi to select one."

	choosen_sink=$(rofi -location 2 -lines 4 -no-auto-select -i -dmenu -p "Choose new default output sink for PulseAudio" -color-enabled -color-normal "${BLACK},${BLUE},${BLACK},${BLUE},${BLACK}" -color-window "${BLACK},${BLACK}" < "${pa_sink_list_path}")
	choosen_sink_index=$(printf -- '%s' "${choosen_sink}" | cut --delimiter=" " --field=1)
	choosen_sink_description=$(printf -- '%s' "${choosen_sink}" | cut --delimiter=" " --field=2-)

	## If no sink was selected (empty var)
	if [ -z "${choosen_sink_index}" ]; then
		debug_message "choose_pulseaudio_sink − \
Choosen sink var is ${RED}empty${COLOR_DEBUG}."
		return_choose_pulseaudio_sink="1"
	else
		debug_message "choose_pulseaudio_sink − \
PulseAudio choosen sink is ${RED}${choosen_sink_description}${COLOR_DEBUG} (index: ${RED}${choosen_sink_index}${COLOR_DEBUG})."
		return_choose_pulseaudio_sink="0"
	fi

	return "${return_choose_pulseaudio_sink}"

}
# }}}
set_default_pulseaudio_sink() {                                 # {{{

	## Return False by default
	return_set_default_pulseaudio_sink="1"

	debug_message "set_default_pulseaudio_sink − \
Try to set ${RED}${choosen_sink_description}${COLOR_DEBUG} (index: ${RED}${choosen_sink_index}${COLOR_DEBUG}) default PulseAudio sink."

	if pactl set-default-sink "${choosen_sink_index}"; then
		debug_message "set_default_pulseaudio_sink − \
${RED}${choosen_sink_description}${COLOR_DEBUG} is now the default output device."
		return_set_default_pulseaudio_sink="0"
	else
		debug_message "set_default_pulseaudio_sink − \
Error with ${RED}pacmd set-default-sink${COLOR_DEBUG} command."
		return_set_default_pulseaudio_sink="1"
	fi

	return "${return_set_default_pulseaudio_sink}"

}
# }}}

main() {                                                        # {{{

	## If rofi command is absent from the system {{{
	### Exit
	is_command_absent "rofi" \
		&& exit 0
	## }}}
	## If pacmd command is absent from the system {{{
	### Exit
	is_command_absent "pacmd" \
		&& exit 0
	## }}}

	## Define all vars
	define_vars

	## Try to get the sinks list {{{
	### OR Exit with error message
	get_pulseaudio_sink_list \
		|| error_message "Can't get the PulseAudio sinks list. Please use --debug option." 1
	## }}}
	## Choose a sink with rofi {{{
	### OR Exit with error message
	choose_pulseaudio_sink \
		|| error_message "Can't get the PulseAudio sinks list. Please use --debug option." 2
	## }}}
	## Set default output sink/device for PulseAudio {{{
	### OR Exit with error message
	set_default_pulseaudio_sink \
		|| error_message "Can't set the selected sink (${choosen_sink_description}) as default output sink/device. Please use --debug option." 3
	## }}}

}
# }}}

# Manage arguments                                                # {{{
# This code can't be in a function due to argument management

if [ ! "${NBARGS}" -eq "0" ]; then

	manage_arg="0"

	## If the first argument is not an option
	if ! printf -- '%s' "${1}" | grep -q -E -- "^-+";
	then
		## Print help message and exit
		printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
		printf '%b\n' "---"
		usage

		exit 1
	fi

	# Parse all options (start with a "-") one by one
	while printf -- '%s' "${1}" | grep -q -E -- "^-+"; do

	case "${1}" in
		-d|--debug )                          ## debug
			DEBUG=0
			;;
		-h|--help )                           ## help
			usage
			## Exit after help informations
			exit 0
			;;
		#-v|--var )                            ## Define var with given arg
			### Move to the next argument
			#shift
			### Define var
			#readonly my_var_xy="${1}"
			#;;
		* )                                   ## unknow option
			printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
			printf '%b\n' "---"
			usage
			exit 1
			;;
	esac

	debug_message "Arguments management − \
${RED}${1}${COLOR_DEBUG} option managed."

	## Move to the next argument
	shift
	manage_arg=$((manage_arg+1))

	done

	debug_message "Arguments management − \
${RED}${manage_arg}${COLOR_DEBUG} argument(s) successfully managed."
else
	debug_message "Arguments management − \
No arguments/options to manage."
fi

# }}}

main

exit 255