#!/bin/sh

# Uncomment the following line to get debug info
#set -x

SELF="$(basename ${0})"
LAUNCHER_FILE="$HOME/Launchers/launcher.txt"
FRONTEND_FILE="$HOME/.frontend"
PREVENT_LAUNCHER_FILE="/mnt/prevent_launcher"
DISABLE_FRONTEND_FILE="/mnt/disable_frontend"
DEFAULT_FRONTEND=retrofe
LOCK_FILE="/var/lock/frontend.lock"
REBOOTING_FILE="/run/rebooting"
LAST_OPK_FILE="/mnt/last_opk"

# Convert old launcher file to new frontend
if [ -f "${LAUNCHER_FILE}" ]; then
    mv "${LAUNCHER_FILE}" "${FRONTEND_FILE}"
    rm -rf $(dirname "${LAUNCHER_FILE}") 2>/dev/null
fi

# Convert old prevent launcher file to new frontend disable file
if [ -f "${PREVENT_LAUNCHER_FILE}" ]; then
    mv "${PREVENT_LAUNCHER_FILE}" "${DISABLE_FRONTEND_FILE}"
fi

usage() {
    >&2 echo "Usage: ${SELF} init"
    >&2 echo "       ${SELF} get"
    >&2 echo "       ${SELF} set gmenu2x|retrofe|none"
    exit 1
}

set_frontend() {
    mkdir -p "$(dirname "$FRONTEND_FILE")"
    local frontend=$(get_frontend)
    local new_frontend="${1}"
    echo "Setting frontend: ${new_frontend}"
    if [ "${new_frontend}" = "none" ]; then
		touch "${DISABLE_FRONTEND_FILE}"
    else
		rm -f "${DISABLE_FRONTEND_FILE}"
    fi
    if [ "${frontend}" != "none" ]; then
		pkill "${frontend}"
    fi
    echo "${new_frontend}" > "${FRONTEND_FILE}"
}

get_frontend() {
    local frontend=$(cat "${FRONTEND_FILE}" 2>/dev/null | head -1)

    # Check if not empty
    if [ "x${frontend}" = "x" ]; then
		frontend="${DEFAULT_FRONTEND}"
		echo "${frontend}" > "${FRONTEND_FILE}"
    fi

    # Return frontend name
    echo "${frontend}"
}

init_frontend() {
    if [ -f "${LOCK_FILE}" ]; then
		>&2 echo "${LOCK_FILE} already exists"
		exit 1
    fi
    touch "${LOCK_FILE}"

    # Then loop to launch the frontend indefinitely
    while true; do
	
		# Check if frontend disable file is present
		if [ -f "${DISABLE_FRONTEND_FILE}" ]; then
		    echo "${DISABLE_FRONTEND_FILE} file found, not starting frontend" 
		    sleep 5
		else

		    # Umount any remaining OPK, if any
		    umount /opk >/dev/null 2>&1
		    rm -f "${LAST_OPK_FILE}"

		    # Launch selected frontend
	    	local frontend="$(get_frontend)"
		    case "${frontend}" in
			gmenu2x|retrofe)
			    "${frontend}"&
			    ;;

			none)
			    echo "no frontend" 
			    sleep 5
			    ;;

			*)
			    DEFAULT_FRONTEND=retrofe
			    echo "Unrecognized frontend: $frontend, setting $DEFAULT_FRONTEND"
			    set_frontend "${DEFAULT_FRONTEND}"
			    ;;
		    esac

		    # Record the PID into a file, wait for the process to
		    # terminate and erase the recorded PID
		    pid record $!
		    wait $!
		    pid erase

		    # In case retrofe/opkrun quits with errors, clear graphic VT
		    termfix_all

		    # In case retrofe/opkrun quits with errors, reset default key mapping
		    keymap default
		fi

		# Prevent 100% CPU usage
		sleep 0.5

		# Exit if console rebooting
		if [ -f "${REBOOTING_FILE}" ]; then
	    	break
		fi
    done

    # Remove lock file and exit
    rm "${LOCK_FILE}"
}

# Check number of arguments
if [ ${#} -lt 1 -o ${#} -gt 2 ]; then
    usage
fi

case "${1}" in
    set)
	if [ ${#} -ne 2 ]; then
	    usage
	fi
	set_frontend "${2}"
	;;

    get)
	if [ ${#} -ne 1 ]; then
	    usage
	fi
	get_frontend
	;;

    init)
	if [ ${#} -ne 1 ]; then
	    usage
	fi
	init_frontend
	;;

    *)
	usage
	;;
esac
exit 0
