MQTT_HOST=your-mqtt-server.lan
MQTT_PORT=1883
MQTT_USER=username
MQTT_PASSWORD=password
MQTT_BASE_TOPIC=batocera/$(hostname)

SERVICE_NAME=$(basename "$0" .${0##*.})
ES_EVENTS=(game-start game-end game-selected system-selected theme-changed settings-changed controls-changed config-changed quit reboot shutdown sleep wake achievements screensaver-start screensaver-stop)


###############################################################################
# Publish an event message to the MQTT broker as JSON dictionary.
#
# The first argument is the subtopic to publish to (source/event_name)
# The remaining arguments are converted to a list of strings, which
# is stored in the 'data' field of the message
# An ISO-formatted 'timestamp' field is automatically added to the message
#
# Only executes if this service is enabled
###############################################################################
publish() {
    if [[ " $(/usr/bin/batocera-settings-get system.services) " == *" $SERVICE_NAME "* ]]; then
        subtopic="$1"
        shift
        # Initialize an empty JSON array
        data='['
        # Iterate over the remaining arguments
        for arg in "$@"; do
            # Convert each argument to a JSON string and append it to the array
            data+="$(jq -Rn --arg arg "$arg" '$arg'),"
        done
        # Remove the trailing comma and close the JSON array
        data="${data%,}]"
        mosquitto_pub -h "$MQTT_HOST" -p "$MQTT_PORT" -u "$MQTT_USER" -P "$MQTT_PASSWORD" -t "$MQTT_BASE_TOPIC/$subtopic" -m '{"data": '"$data"', "timestamp": "'"$(date --iso-8601=ns)"'"}' -r
    fi
}

###############################################################################
# Start the MQTT service.
# - Installs any missing support files
# - Publishes a system startup event
###############################################################################
start() {
    install
    publish "system/startup"
}

###############################################################################
# Stop the MQTT service.
# - Publishes a system shutdown event
###############################################################################
stop() {
    publish "system/shutdown"
}

###############################################################################
# Create scripts that capture events and publish them to the MQTT broker.
###############################################################################
install() {
    # EmulationStation events
    for event in ${ES_EVENTS[@]}; do
        script_dir="/userdata/system/configs/emulationstation/scripts/$event"
        mkdir -p "$script_dir"
        script="$script_dir/$SERVICE_NAME.sh"
        if [[ -f "$script" ]]; then
            echo "WARNING: Skipping installation of '$script', as it already exists"
            continue
        fi
        echo "Installing '$script'"
        cat <<-EOF > "$script"
#!/bin/bash
/userdata/system/services/$SERVICE_NAME publish "emulationstation/$event" "\$@"
EOF
    chmod +x "$script"
    done

    # Game events
    script="/userdata/system/scripts/$SERVICE_NAME.sh"
    echo "Installing '$script'"
    cat <<-EOF > "$script"
#!/bin/bash
/userdata/system/services/$SERVICE_NAME publish "game/\$1" "\${@:2}"
EOF
}

###############################################################################
# Delete scripts that capture events and publish them to the MQTT broker.
###############################################################################
uninstall() {
    # Delete EmulationStation event scripts, and remove event directories if empty
    for event in ${ES_EVENTS[@]}; do
        script_dir="/userdata/system/configs/emulationstation/scripts/$event"
        script="$script_dir/$SERVICE_NAME.sh"
        echo "Deleting '$script'"
        rm "$script"
        if [ -z "$(ls -A "$script_dir")" ]; then
            echo "Deleting empty directory '$script_dir'"
            rm -rf "$script_dir"
        fi
    done

    # Delete Game event script
    script="/userdata/system/scripts/$SERVICE_NAME.sh"
    echo "Deleting '$script'"
    rm "$script"
}

###############################################################################
# Script entrypoint
###############################################################################
if [ $# -eq 0 ]; then
    echo "ERROR: No arguments provided"
    echo "Usage: $SERVICE_NAME publish|start|stop|install|uninstall [args]"
    exit 1
fi
if [[ $(type -t "$1") == function ]]; then
    FUNCTION="$1"
    shift
    $FUNCTION "$@"
else
    echo "ERROR: '$1' is not defined"
    echo "Usage: $SERVICE_NAME publish|start|stop|install|uninstall [args]"
    exit 1
fi