enum MabniAIAction {
    //% block="stop"
    Stop = 1,
    //% block="forward"
    Forward = 2,
    //% block="turn left"
    Left = 3,
    //% block="turn right"
    Right = 4
}

/** Local AI results from Mabni AI Maker. Image inference runs on the computer. */
//% color="#8463C4" icon="\uf0eb" weight=87 block="AI Maker"
namespace mabniAI {
    let started = false;
    let action = MabniAIAction.Stop;
    let motorPermission = false;
    let lastMessage = 0;
    let sensorStreaming = false;
    const eventSource = 14567;

    function update(next: MabniAIAction): void {
        if (action !== next) {
            action = next;
            control.raiseEvent(eventSource, next);
        }
    }

    /** Start the local USB bridge. Silence or lost communication requests a stop. */
    //% blockId=mabni_ai_start block="start offline AI USB bridge"
    //% weight=100
    export function start(): void {
        if (started) return;
        started = true;
        serial.redirectToUSB();
        serial.setBaudRate(BaudRate.BaudRate115200);
        serial.onDataReceived(serial.delimiters(Delimiters.NewLine), function () {
            let line = serial.readUntil(serial.delimiters(Delimiters.NewLine)).trim();
            lastMessage = control.millis();
            if (line === "HELLO") {
                motorPermission = false;
                update(MabniAIAction.Stop);
                serial.writeLine("READY:MABNI-AI:1");
            } else if (line === "ARM") {
                update(MabniAIAction.Stop);
                motorPermission = true;
            } else if (line === "DISARM") {
                motorPermission = false;
                update(MabniAIAction.Stop);
            } else if (line === "SENSORON") {
                sensorStreaming = true;
            } else if (line === "SENSOROFF") {
                sensorStreaming = false;
            } else {
                update(line === "F" ? MabniAIAction.Forward : line === "L" ? MabniAIAction.Left : line === "R" ? MabniAIAction.Right : MabniAIAction.Stop);
            }
        });
        basic.forever(function () {
            if (control.millis() - lastMessage > 1100) update(MabniAIAction.Stop);
            if (sensorStreaming) serial.writeLine("D," + input.acceleration(Dimension.X) + "," + input.acceleration(Dimension.Y) + "," + input.acceleration(Dimension.Z));
            basic.pause(100);
        });
    }

    /** Run blocks when the locally trained model changes its action. */
    //% blockId=mabni_ai_on_action block="on AI %which"
    //% weight=90
    export function onAction(which: MabniAIAction, handler: () => void): void {
        control.onEvent(eventSource, which, handler);
    }

    /** Motor signals stay disabled until the adult wiring check is enabled in AI Maker. */
    //% blockId=mabni_ai_motor_permission block="AI motor outputs enabled"
    //% weight=30
    export function motorsEnabled(): boolean { return motorPermission; }

    /** Read the latest action. An uncertain prediction sends stop. */
    //% blockId=mabni_ai_current block="current AI action"
    //% weight=20
    export function currentAction(): MabniAIAction { return action; }
}