Source: cloudservermodel.js

import PreProcess from './preprocess.js';
import PostProcess from './postprocess.js';
import AsyncQueue from './asyncqueue.js';
import Mutex from './mutex.js';
import DGError from './dgerror.js';
import { parser } from './helpers/customParser.js';
import { loadMsgpack } from './msgpack.min.js';
import { loadSocketIo } from './socket.io.esm.min.js';

// Load msgpack library if needed
if (typeof msgpack === 'undefined') {
    console.log('cloudservermodel.js: Loading msgpack library');
    loadMsgpack();
}
// Load socketio library if needed
if (typeof io === 'undefined') {
    console.log('cloudservermodel.js: Loading socket.io library');
    loadSocketIo();
}


// Socketio client API:
//     Socket Class: Fundamental class for interacting with the server, belonging to a certain namespace and using an underlying Manager for communication.

// Events
//     'connect': Fired upon connection and reconnection.
//     'connect_error': Fired upon connection failure.
//     'disconnect': Fired upon disconnection.

// Attributes
//     socket.active: Indicates if the socket will automatically try to reconnect.
//     socket.connected: Indicates if the socket is currently connected to the server.
//     socket.disconnected: Indicates if the socket is currently disconnected from the server.
//     socket.id: Unique identifier for the socket session, set after the connect event.
//     socket.io: Reference to the underlying Manager.
//     socket.recovered: Indicates if the connection state was successfully recovered during the last reconnection.

// Methods
//     socket.close(): Synonym for socket.disconnect().
//     socket.compress(value): Sets a modifier for event emission to determine if the data will be compressed.
//     socket.connect(): Manually connects or reconnects the socket.
//     socket.disconnect(): Manually disconnects the socket.
//     socket.emit(eventName[, ...args][, ack]): Emits an event to the socket with the specified name and arguments.
//     socket.emitWithAck(eventName[, ...args]): Promised-based version of emitting and expecting an acknowledgment from the server.
//     socket.listeners(eventName): Returns the array of listeners for the specified event.
//     socket.listenersAny(): Returns the list of registered catch-all listeners.
//     socket.listenersAnyOutgoing(): Returns the list of registered catch-all listeners for outgoing packets.
//     socket.off([eventName][, listener]): Removes the specified listener from the listener array for the event.
//     socket.offAny([listener]): Removes all catch-all listeners or a specified listener.
//     socket.offAnyOutgoing([listener]): Removes all catch-all listeners for outgoing packets or a specified listener.
//     socket.on(eventName, callback): Registers a new handler for the specified event.
//     socket.onAny(callback): Registers a new catch-all listener.
//     socket.onAnyOutgoing(callback): Registers a new catch-all listener for outgoing packets.
//     socket.once(eventName, callback): Adds a one-time listener function for the specified event.
//     socket.open(): Synonym for socket.connect().
//     socket.prependAny(callback): Registers a new catch-all listener added to the beginning of the listeners array.
//     socket.prependAnyOutgoing(callback): Registers a new catch-all listener for outgoing packets added to the beginning of the listeners array.
//     socket.send([...args][, ack]): Sends a message event.
//     socket.timeout(value): Sets a modifier for a subsequent event emission to set a callback with an error if no acknowledgment is received within the given time.



/**
 * @class
 * @classdesc This class handles interactions with a cloud server for running inference.<br>
 * It uses socket.io for communication with the server uses internal queues to provide results in order.<br>
 * Use this class to send image data to the server, retrieve predictions, and manage model parameters.<br>
 * Internally, it connects through socketio as soon as the model instance is created. It only disconnects when the `cleanup` method is called.<br>
 * @example <caption>Usage:</caption>
 * let model = zoo.loadModel('model_name', {});
 * - Use the `predict` method for inference with individual data items or `predict_batch` for multiple items.
 * let result = await model.predict(someImage);
 * for await (let result of model.predict_batch(someDataGeneratorFn)) { ... }
 */
class CloudServerModel {
    /**
     * Do not call the constructor directly. Use the `loadModel` method of an AIServerZoo instance to create an AIServerModel.
     * @constructor
     * @param {Object} options - Options for initializing the model.
     * @param {string} options.modelName - The name of the model to load.
     * @param {string} options.serverUrl - The URL of the server to connect to.
     * @param {Object} options.modelParams - The parameters for the model.
     * @param {string} options.token - The authentication token for the model.
     * @param {number} [options.max_q_len=80] - The maximum length of the internal queues.
     * @param {function} [options.callback=null] - The callback function to call when results are available.
     * @param {Array<string>} [options.labels=null] - The labels for the model.
     * @param {Object} [additionalParams=null] - Additional parameters for the model.
    */
    constructor({ modelName, serverUrl, modelParams, token, max_q_len = 80, callback = null, labels = null }, additionalParams) {
        console.log(
            'CloudServerModel: Entered constructor.',
            'Parameters:',
            'modelName=', modelName,
            'serverUrl=', serverUrl,
            'modelParams=', modelParams,
            'token=', token,
            'max_q_len=', max_q_len,
            'callback=', callback,
            'labels=', labels,
            'additionalParams=', additionalParams
        );

        this.debugLogsEnabled = true;

        this.modelName = modelName;
        this.serverUrl = serverUrl;
        this.modelParams = modelParams;
        this.token = token;
        this.max_q_len = max_q_len;
        this.callback = callback;
        this.labels = labels;
        this.additionalParams = additionalParams;
        this.dirty = false;
        this.preProcessor = null;
        this.postProcessor = null;
        this.configParamsDirty = true;
        this.initialized = false;
        this.infoQ = new AsyncQueue(max_q_len, 'infoQ');
        this.resultQ = new AsyncQueue(max_q_len, 'resultQ');
        this.poison = false;
        this.finishedSettingAdditionalParams = false;
        this.initMemberValues();
        this.initializeSocket();

        this.lastProcessedMessage = Promise.resolve();
        this.mutex = new Mutex();

        // temporary variable to store current connection state.
        // instead: use this.socket.connected?
        this.socketConnected = false;

        this.inputFrameNumber = 0; // Current frame number, increments for each frame sent to the server.

        this.unorderedResults = new Map();
        this.expectedFrameNo = 0; // Keep track of the next expected frame number

        this.MAX_SOCKET_WAIT_MS = 10000; // Max Time to wait for the socket connection to be opened before error.
    }


    /// Initialize some member values from modelParams
    initMemberValues() {
        if (this.modelParams && this.modelParams["MODEL_PARAMETERS"] && this.modelParams["MODEL_PARAMETERS"].length > 0) {
            const parameters = this.modelParams["MODEL_PARAMETERS"][0];
            const preProcessParams = this.modelParams["PRE_PROCESS"][0];

            this.modelPath = parameters.ModelPath;

            // NCHW info is either under 'MODEL_PARAMETERS' or 'PRE_PROCESS'
            if (parameters.ModelInputN) {
                this.modelInputN = parameters.ModelInputN;
                this.modelInputC = parameters.ModelInputC;
                this.modelInputH = parameters.ModelInputH;
                this.modelInputW = parameters.ModelInputW;
            } else if (preProcessParams.InputN) {
                this.modelInputN = preProcessParams.InputN;
                this.modelInputC = preProcessParams.InputC;
                this.modelInputH = preProcessParams.InputH;
                this.modelInputW = preProcessParams.InputW;
            } else {
                throw new DGError("Model Parameters don't contain input height / width.", "MISSING_PARAMS", { parameters, preProcessParams }, "Ensure model parameters include input height and width.", "Check the model's documentation to provide the required input height and width parameters.");
            }
        }

        // Set internal parameters to default, only if the additionalParams weren't handled yet.
        if (!this.finishedSettingAdditionalParams) {
            // Internal model pre/post processing and inference parameters, initially set to defaults.
            // Display Parameters
            this._overlayColor = [255, 0, 0];
            this._overlayLineWidth = 2;
            this._overlayShowLabels = true;
            this._overlayShowProbabilities = false;
            this._overlayAlpha = 0.75;
            this._overlayFontScale = 1.0;

            // Input Handling Parameters
            this._inputLetterboxFillColor = [0, 0, 0];
            this._inputPadMethod = 'letterbox';
            this._saveModelImage = false;
            this._inputCropPercentage = 1.0;
        }
        // Assign additional parameters, using our set/get functions. Try to overwrite them by these values, and
        // warn the user if that parameter doesn't exist.
        // Only do this ONCE: prior to websocket opening.
        if (this.additionalParams !== null && this.additionalParams !== undefined && !this.finishedSettingAdditionalParams) {
            for (const [key, value] of Object.entries(this.additionalParams)) {
                console.log('initMemberValues(): Setting additional param key', key, 'and value', value);

                // Check for the existence of a setter for 'key'
                const descriptor = Object.getOwnPropertyDescriptor(Object.getPrototypeOf(this), key);
                const hasSetter = descriptor && typeof descriptor.set === 'function';

                if (hasSetter) {
                    try {
                        console.log('Invoking setter to set', key, 'to', value);
                        this[key] = value; // invoke the setter for 'key'
                        console.log('Now, the value for', key, 'is:', this[key]);
                    } catch (error) {
                        console.warn(`Error using setter for '${key}': ${error.message}`);
                    }
                } else {
                    console.warn(`Setter for '${key}' does not exist or cannot be used.`);
                }
            }
        }
        this.finishedSettingAdditionalParams = true;

        // Now set dirty to false.
        // Dirty is set to true when these are modified even if model isn't initialized
        // yet, so we set it back to false, so we don't reinitialize the websocket connection for no reason.
        this.dirty = false;
    }
    /**
     * Predicts the result for a given image. <br>
     * 
     * @example If callback is provided:
     * Onresult handler will invoke the callback directly when the result arrives.
     * 
     * @example If callback is not provided:
     * The function waits for the resultQ to get a result, then returns it.
     * let result = await model.predict(someImage);
     * 
     * @async
     * @param {Blob|File|string|HTMLImageElement|HTMLVideoElement|HTMLCanvasElement|ArrayBuffer|TypedArray|ImageBitmap} imageFile
     * @param {string} [info=performance.now()] - Unique frame information provided by user (such as frame num). Used for matching results back to input images within callback.
     * @param {boolean} [bypassPreprocessing=false] - Whether to bypass preprocessing. Used to send Blob data directly to the socket without any preprocessing.
     * @returns {Promise<Object>} The prediction result.
     */
    async predict(imageFile, info = '_DEFAULT_FRAME_INFO_', bypassPreprocessing = false) {
        let unlockedAlready = true; // only allow one mutex unlock operation per function call.

        // passthrough if the error flag is enabled.
        if (this.poison) return;
        // Outer try catch finally block for handling unexpected errors with cleanup code (e.g. release mutex)
        try {
            // Check if the model needs to be reloaded
            if (this.dirty) {
                this.log('predict(): dirty flag caught. modelParams object prior to reset:', this.modelParams);
                await this.handleDirtyFlag();
            }

            // Generate unique info from the imageFile here if needed
            if (info == '_DEFAULT_FRAME_INFO_') {
                info = `frame_${performance.now()}`;
            }

            // Instantly push the frame info to infoQ
            await this.infoQ.push({ info });

            // Attempt to lock the mutex with a timeout
            const mutexLockPromise = this.mutex.lock();
            const mutexTimeout_ms = 10000;
            const mutexTimeoutPromise = this.timeoutPromise(mutexTimeout_ms, () => this.mutex.cancelLock(mutexLockPromise));

            // Wait for either the mutex to be acquired, or for the timeout to occur
            await Promise.race([
                mutexLockPromise.then(() => { mutexTimeoutPromise.cancel(); }), // Lock acquired
                mutexTimeoutPromise // Timeout
            ]).catch(error => {
                throw new DGError("Error during mutex lock / mutex timeout unlock: " + error, "MUTEX_LOCK_TIMEOUT_ERROR", {}, "An error occurred while acquiring the mutex lock.", error);
            });

            unlockedAlready = false; // Set to false, so that now we are allowed to call unlock

            if (bypassPreprocessing) {
                // Ensure that the imageFile is a Blob
                if (!(imageFile instanceof Blob)) {
                    throw new DGError("predict(): Bypassed image must be a Blob.", "INVALID_BYPASSED_IMAGE", {}, "An error occurred during image preprocessing.", "Please check the image and try again.");
                }
                // Attach fake transformationDetails to infoQ.
                let fakeTransformationDetails = {
                    scaleX: 1.0,
                    scaleY: 1.0,
                    offsetX: 0,
                    offsetY: 0
                };
                await this.infoQ.update(
                    item => item.info === info,
                    { transformationDetails: fakeTransformationDetails, imageFrame: null }
                );
                // Directly send the image to the socket.
                await this.waitForSocketConnection(); // Timeout error here will be caught in outer trycatch
                this.log('predict(): Sending bypassed image to socket with info:', info);
                this.predictEmit(imageFile, info);
            } else {
                // Validate / send the image frame
                await this.validateAndSendFrame(imageFile, info);
            }

            this.mutex.unlock();
            unlockedAlready = true;

            if (this.callback == null) {
                return await this.resultQ.pop(); // does not instantly complete the try block. waits for the Promise to resolve before returning the resolved value
            }

        } catch (error) {
            this.poison = true; // Set the error flag.
            throw new DGError("An error occurred during predict:" + error, "PREDICT_ERROR", { error }, "An error occurred during predict.");
        } finally {
            if (!unlockedAlready) this.mutex.unlock();
        }
    }

    // helper function to emit the predict event to the socket
    // imageFile: blob
    // frameInfo: frame info, not used yet
    async predictEmit(imageFile, frameInfo) {
        /**
            The packet sent in Python is a tuple with two elements: the packed data and a string representation of the frame number
    
            data_packed = msgpack.packb(data if isinstance(data, list) else [data])
            packet = (b"0" + data_packed, str(self._input_frame_number))
            try:
                self._sio.emit("predict", packet)
         */

        //-------------------------------------------------------------------------------------
        // Flow: First we prepare a packet with the image data and the frame number.
        // The image data IS packed with a 0 prefix.
        // Then, it goes to the custom encoder serialization to get encoded AGAIN.

        // Example emit() input: (Before the final custom encoder serialization):
        // From python: {'type': 2, 'data': ['predict', b'0\x91\xc5\xb82\xff\xd8\xff\xe0\x00\x10JFIF\x0... 9f\xff\xd9', '0'], 'nsp': '/'}
        // So, the final packet sent to server is encoded with the custom encoder.
        //-------------------------------------------------------------------------------------
        // emit() input: 
        // Create a final packet that will be: 
        // [packetName, packedImage, String(frameNum)];

        // 1. Grab the fixed-length raw binary data buffer from the imageFile
        // 2. Pack this binary data with msgpack
        const arrayBuffer = await imageFile.arrayBuffer();
        // eslint-disable-next-line no-undef
        const codec = msgpack.createCodec({
            binarraybuffer: true,
            uint8array: true
        });
        // eslint-disable-next-line no-undef
        let packedImage = msgpack.encode([arrayBuffer], { codec: codec });


        // packedImage is now a Uint8Array: 
        // array-like view of underlying raw binary data buffer. Values are 0-255 and we can now manipulate this object.

        // 2.5. Deep clone the Uint8Array.
        // packedImage = structuredClone(packedImage);

        // 3. Prepend binary form of the ASCII character 0.
        const newArray = new Uint8Array(packedImage.length + 1);
        newArray[0] = 48; // ASCII 0
        newArray.set(packedImage, 1);

        // 4. Prepare final data type from the Uint8Array
        let finalData = newArray.buffer; // For ArrayBuffer

        // Emitting the packet
        try {
            // When the emit method is called, the Encoder class's encode method is used to encode the packet.
            // The customDumps function is called to serialize the packet using msgpack.
            // emit() -> Encoder.encode() -> customDumps()
            // debugger;
            this.socket.emit("predict", finalData, String(this.inputFrameNumber)); // --> data will be Array(3)["predict", ArrayBuffer, "0"]
            // this.socket.compress(false).emit("predict", packedImage, String(this.inputFrameNumber));
            // console.log('Called socket emit');
        } catch (error) {
            console.error('Transport error while sending packet to socket:', error);
            // transport error will be caught on reconnect..
        } finally {
            this.inputFrameNumber += 1;
        }
    }

    async validateAndSendFrame(imageFile, info) {
        // Input frame validation / conversion
        let imageFrame = await this.validateAndConvertInputFrame(imageFile);

        if (this.configParamsDirty || !this.preProcessor || !this.postProcessor) {
            await this.initPrePostProcessors();
        }

        await this.preprocessAndSend(imageFrame, info);
    }

    async preprocessAndSend(imageFrame, info = null) {
        try {
            if (!imageFrame || !this.modelInputW || !this.modelInputH) {
                throw new DGError("preprocessAndSend(): missing input parameters.", "MISSING_INPUT_PARAMETERS_ERROR", {}, "An error occurred during image preprocessing.", "Please check the input and try again.");
            }

            const startTime = performance.now();  // PERFORMANCE LOGGING
            const { blob: resizedBlob, transformationDetails } = await this.preProcessor.resizeImage(imageFrame);
            this.log('resizeImage() took:', performance.now() - startTime, 'ms.'); // PERFORMANCE LOGGING

            if (!transformationDetails.scaleX || !transformationDetails.scaleY) {
                throw new DGError("Scale factors are missing after resizeImage()", "MISSING_SCALE_FACTORS_ERROR", {}, "An error occurred during image preprocessing.", "Please check the image and try again.");
            }

            if (typeof transformationDetails.offsetX === 'undefined' || typeof transformationDetails.offsetY === 'undefined') {
                throw new DGError("Offset values are missing after resizeImage()", "MISSING_OFFSET_VALUES_ERROR", {}, "An error occurred during image preprocessing.", "Please check the image and try again.");
            }

            if (!resizedBlob) {
                throw new DGError("preprocessAndSend(): resizedBlob is null or undefined", "RESIZED_BLOB_NULL_ERROR", {}, "An error occurred during image preprocessing.", "Please check the image and try again.");
            }

            if (imageFrame instanceof HTMLVideoElement) {
                imageFrame = null;
            }
            if (this._saveModelImage) {
                await this.infoQ.update(
                    item => item.info === info,
                    { transformationDetails, imageFrame: imageFrame, modelImage: resizedBlob }
                );
            } else {
                await this.infoQ.update(
                    item => item.info === info,
                    { transformationDetails, imageFrame: imageFrame }
                );
            }

            await this.waitForSocketConnection(); // Timeout error here will be caught in outer trycatch
            this.log('preprocessAndSend(): Sending blob to socket with info:', info);
            this.predictEmit(resizedBlob, info);
        } catch (error) {
            this.poison = true; // Set the error flag.
            throw new DGError("preprocessAndSend(): Failed to preprocess the image:" + error, "PREPROCESS_IMAGE_FAILED", { error }, "Failed to preprocess the image.");
        }
    }

    /**
     * Predicts results for a batch of data. Will yield results if a callback is not provided.
     * @async
     * @generator
     * 
     * @example The function asynchronously processes results. If a callback is not provided, it will yield results.
     * for await (let result of model.predict_batch(data_source)) { console.log(result); }
     * @param {AsyncIterable} data_source - An async iterable data source.
     * @param {boolean} [bypassPreprocessing=false] - Whether to bypass preprocessing.
     * @yields {Object} The prediction result.
     */
    async *predict_batch(data_source, bypassPreprocessing = false) {
        if (this.poison) return;
        try {
            if (this.dirty) {
                this.log('predict_batch(): dirty flag caught. modelParams object prior to reset:', this.modelParams);
                await this.handleDirtyFlag();
            }

            for await (let [data, info] of data_source) {
                await this.infoQ.push({ info });

                if (bypassPreprocessing) {
                    if (!(data instanceof Blob)) {
                        throw new DGError("predict_batch(): Bypassed image must be a Blob.", "INVALID_BYPASSED_IMAGE", {}, "An error occurred during image preprocessing.", "Please check the image and try again.");
                    }
                    let fakeTransformationDetails = {
                        scaleX: 1.0,
                        scaleY: 1.0,
                        offsetX: 0,
                        offsetY: 0
                    };
                    await this.infoQ.update(
                        item => item.info === info,
                        { transformationDetails: fakeTransformationDetails, imageFrame: null }
                    );
                    await this.waitForSocketConnection();
                    this.predictEmit(data, info);
                } else {
                    await this.validateAndSendFrame(data, info);
                }

                if (this.callback == null) {
                    if (!this.resultQ.empty()) {
                        yield await this.resultQ.pop();
                    }
                }
            }

            if (this.callback == null) {
                while (!this.infoQ.empty() || !this.resultQ.empty()) {
                    yield await this.resultQ.pop();
                }
            }
        } catch (error) {
            this.poison = true; // Set the error flag.
            throw new DGError('An error occurred during predict_batch:' + error, "PREDICT_BATCH_ERROR", { error }, "An error occurred during predict_batch.");
        }
    }


    async initializePreProcessor() {
        if (!this.initialized) await this.waitFor(() => this.initialized);
        this.log('(re)setting preprocessor...');
        this.preProcessor = null;
        this.preProcessor = new PreProcess(this.modelParams, this.constructOverlayConfig());
    }

    async initializePostProcessor() {
        if (!this.initialized) await this.waitFor(() => this.initialized);
        this.log('(re)setting postprocessor...');
        this.postProcessor = null;
        this.postProcessor = new PostProcess(this.modelParams, this.constructOverlayConfig());
    }

    async initPrePostProcessors() {
        await this.initializePreProcessor();
        await this.initializePostProcessor();
        this.configParamsDirty = false;
    }

    // Constructs a config from all of the internal parameters. This is passed to pre/post processors
    // Compiles every internal parameter settable by user
    constructOverlayConfig() {
        return {
            labels: this.labels,
            overlayColor: this._overlayColor,
            overlayLineWidth: this._overlayLineWidth,
            overlayShowLabels: this._overlayShowLabels,
            overlayShowProbabilities: this._overlayShowProbabilities,
            overlayAlpha: this._overlayAlpha,
            overlayFontScale: this._overlayFontScale,
            inputLetterboxFillColor: this._inputLetterboxFillColor,
            inputPadMethod: this._inputPadMethod,
            saveModelImage: this._saveModelImage,
            inputCropPercentage: this._inputCropPercentage
        };
    }

    async initializeSocket() {
        console.log('cloudservermodel.js: Entered initializeSocket()');
        const nameParts = this.modelName.split("/");

        console.log('initializeSocket(): Constructing io object.');
        try {
            // Debug: connect to cs2.
            // this.serverUrl = 'https://cs2.degirum.com';
            // this.token = '....';

            let path = "/api/v2/socket.io";
            // Socket init:
            // eslint-disable-next-line no-undef
            this.socket = io(this.serverUrl, {
                parser: parser,
                reconnection: false,
                path: path,
                transports: ['websocket'],
                timeout: 5000,
                auth: {
                    token: this.token,
                    organization: nameParts[0],
                    zoo: nameParts[1],
                    model: nameParts[2],
                    model_params: JSON.stringify(this.modelParams),
                    frame_queue_depth: this.max_q_len,
                    inference_timeout_s: 100.0
                }
            });
            // console.log('Socket io() constructor params:');
            // console.log('serverUrl:', this.serverUrl);
            // console.log('parser:', parser);
            // console.log('reconnection:', false);
            // console.log('path:', "/api/v2/socket.io");
            // console.log('transports:', ['websocket']);
            // console.log('timeout:', 5000);
            // console.log('auth:', {
            //     token: this.token,
            //     organization: nameParts[0],
            //     zoo: nameParts[1],
            //     model: nameParts[2],
            //     model_params: JSON.stringify(this.modelParams),
            //     frame_queue_depth: this.max_q_len,
            //     inference_timeout_s: 100.0
            // });

            // After initialization, server sends us something like: {'type': 0, 'data': {'sid': 'XNBVcBDMVBc_kjDSFH3'}, 'nsp': '/'}

            // console.log('SocketIO Protocol number:', io.protocol); // undefined???

            // Manager object events (this.socket.io)
            this.socket.io.on("reconnect", (attempt) => {
                console.log('socket.io: Reconnected to the server. Attempt:', attempt);
            });

            this.socket.io.on("error", (error) => {
                console.log('socket.io: Error connecting to the server:', error);
            });

            this.socket.io.on("reconnect_attempt", (attempt) => {
                console.log('socket.io: Reconnect attempt:', attempt);
            });

            this.socket.io.on("reconnect_error", (error) => {
                console.log('socket.io: Reconnect error:', error);
            });

            this.socket.io.on("reconnect_failed", () => {
                console.log('socket.io: Reconnect failed.');
            });


            // Socket object events (this.socket)

            this.socket.on("connect", () => {
                console.log('socket: Connected to the server.');
                this.socketConnected = true;
            });

            this.socket.on("connect_error", (error) => {
                if (this.socket.active) {
                    // temporary failure, the socket will automatically try to reconnect
                    console.log('socket: Connection error, will automatically try to reconnect:', error);
                } else {
                    // the connection was denied by the server
                    // in that case, `socket.connect()` must be manually called in order to reconnect
                    console.log('socket: Connection error, must manually reconnect:', error);
                }
            });

            this.socket.on("disconnect", (reason, details) => {
                console.log('socket: Disconnected from the server. Reason:', reason, 'Details:', details);
                this.socketConnected = false;

                if (this.socket.active) {
                    // temporary failure, the socket will automatically try to reconnect
                    console.log('socket: Connection error, will automatically try to reconnect:', reason);
                } else {
                    // the connection was denied by the server
                    // in that case, `socket.connect()` must be manually called in order to reconnect
                    console.log('socket: Connection error, must manually reconnect:', reason);
                }
            });

            this.socket.on("predict_result", (data, frame_no) => {
                this.handlePredictResult(data, frame_no);
            });

            // Log all engine packets
            this.socket.io.engine.on('packet', packet => {
                if (!packet.type === 'ping') console.log('socket.io.engine: packet received:', packet);

                // the packet.data is an ArrayBuffer
                // let's try to decode that packet
                // let data = packet.data;
                // if (data instanceof ArrayBuffer) {
                //     let decoded = msgpack.decode(new Uint8Array(data));
                //     console.log('Decoded packet data:', decoded);
                // }
            });


            // Catch all engine packets with the .type === 'open'
            this.socket.io.engine.on('open', () => {
                console.log('SocketIO engine open packet received');
                // debug log
                if (this.socket.connected) { console.log('this.socket.connected is true.'); }
                else { console.log('this.socket.connected is false.'); }
            });

            this.initialized = true;
        } catch (error) {
            console.error('CloudServerModel: Error initializing socket:', error);
            throw new DGError("Failed to initialize socket: " + error, "SOCKET_INIT_ERROR", { error }, "Failed to initialize socket.");
        }
    }


    /////////////////// Internal Parameter Setters / Getters  ///////////////////
    // Internal parameters can be set / get without explicit getter / setter calling:
    // model.overlayShowLabels = false;  // This actually calls the setter method
    // console.log(model.overlayShowLabels);  // This calls the getter method

    // labelWhitelist
    set labelWhitelist(value) {
        if (!Array.isArray(value)) {
            throw new TypeError("labelWhitelist should be an array of strings. e.g. ['cat', 'dog'].");
        }
        for (const label of value) {
            if (typeof label !== 'string') {
                throw new TypeError("All items in labelWhitelist must be strings. e.g. ['cat', 'dog'].");
            }
        }
        this._labelWhitelist = value;
    }

    get labelWhitelist() {
        return this._labelWhitelist;
    }

    // labelBlacklist
    set labelBlacklist(value) {
        if (!Array.isArray(value)) {
            throw new TypeError("labelBlacklist should be an array of strings. e.g. ['cat', 'dog'].");
        }
        for (const label of value) {
            if (typeof label !== 'string') {
                throw new TypeError("All items in labelBlacklist must be strings. e.g. ['cat', 'dog'].");
            }
        }
        this._labelBlacklist = value;
    }

    get labelBlacklist() {
        return this._labelBlacklist;
    }


    /////////////////// Display Parameters ///////////////////

    // overlayColor
    set overlayColor(value) {
        if (!Array.isArray(value)) {
            throw new TypeError("overlayColor should be an array.");
        }
        // Validate if it's a list of [R, G, B] triplets or just a single triplet
        const isValidTriplet = (triplet) => {
            return Array.isArray(triplet) &&
                triplet.length === 3 &&
                triplet.every(color => typeof color === 'number' && color >= 0 && color <= 255);
        };

        if (!isValidTriplet(value)) {
            if (!value.every(isValidTriplet)) {
                throw new TypeError("overlayColor should either be a single [R, G, B] triplet or a list of such triplets.");
            }
        }
        this.configParamsDirty = true;
        this._overlayColor = value;
    }
    get overlayColor() {
        return this._overlayColor;
    }

    // overlayLineWidth
    set overlayLineWidth(value) {
        if (typeof value !== 'number' || value <= 0) {
            throw new TypeError("overlayLineWidth should be a positive number.");
        }
        this.configParamsDirty = true;
        this._overlayLineWidth = value;
    }
    get overlayLineWidth() {
        return this._overlayLineWidth;
    }

    // overlayShowLabels
    set overlayShowLabels(value) {
        if (typeof value !== 'boolean') {
            throw new TypeError("overlayShowLabels should be a boolean value.");
        }
        this.configParamsDirty = true;
        this._overlayShowLabels = value;
    }
    get overlayShowLabels() {
        return this._overlayShowLabels;
    }

    // overlayShowProbabilities
    set overlayShowProbabilities(value) {
        if (typeof value !== 'boolean') {
            throw new TypeError("overlayShowProbabilities should be a boolean value.");
        }
        this.configParamsDirty = true;
        this._overlayShowProbabilities = value;
    }
    get overlayShowProbabilities() {
        return this._overlayShowProbabilities;
    }

    // overlayAlpha
    set overlayAlpha(value) {
        if (typeof value !== 'number' || value < 0 || value > 1) {
            throw new TypeError("overlayAlpha should be a number between 0 and 1.");
        }
        this.configParamsDirty = true;
        this._overlayAlpha = value;
    }
    get overlayAlpha() {
        return this._overlayAlpha;
    }

    // overlayFontScale
    set overlayFontScale(value) {
        if (typeof value !== 'number' || value <= 0) {
            throw new TypeError("overlayFontScale should be a positive number.");
        }
        this.configParamsDirty = true;
        this._overlayFontScale = value;
    }
    get overlayFontScale() {
        return this._overlayFontScale;
    }

    /////////////////// Input Handling Parameters ///////////////////

    // inputLetterboxFillColor
    set inputLetterboxFillColor(value) {
        // Validation for single [R, G, B] triplet
        if (!Array.isArray(value) ||
            value.length !== 3 ||
            !value.every(color => typeof color === 'number' && color >= 0 && color <= 255)) {
            throw new TypeError("inputLetterboxFillColor should be a single [R, G, B] triplet.");
        }
        this.configParamsDirty = true;
        this._inputLetterboxFillColor = value;
    }
    get inputLetterboxFillColor() {
        return this._inputLetterboxFillColor;
    }

    // inputPadMethod
    set inputPadMethod(value) {
        if (typeof value !== 'string' ||
            !["stretch", "letterbox", "crop-first", "crop-last"].includes(value)) {
            throw new TypeError("inputPadMethod should be one of 'stretch', 'letterbox', 'crop-first', or 'crop-last'.");
        }
        this.configParamsDirty = true;
        this._inputPadMethod = value;
    }
    get inputPadMethod() {
        return this._inputPadMethod;
    }

    // saveModelImage
    set saveModelImage(value) {
        if (typeof value !== 'boolean') {
            throw new TypeError("saveModelImage should be a boolean value.");
        }
        this.configParamsDirty = true;
        this._saveModelImage = value;
    }
    get saveModelImage() {
        return this._saveModelImage;
    }

    // inputCropPercentage
    set inputCropPercentage(value) {
        if (typeof value !== 'number' || value < 0 || value > 1) {
            throw new TypeError("inputCropPercentage should be a number between 0 and 1.");
        }
        this.configParamsDirty = true;
        this._inputCropPercentage = value;
    }
    get inputCropPercentage() {
        return this._inputCropPercentage;
    }

    /////////////////// Inference Parameters ///////////////////
    // These just wrap setModelParameter() with input handling

    // cloudToken
    set cloudToken(value) {
        if (typeof value !== 'string') {
            throw new TypeError("cloudToken should be a string.");
        }
        this.setModelParameter('CloudToken', value);
    }
    get cloudToken() {
        return this.getModelParameter('CloudToken');
    }

    // cloudURL
    set cloudURL(value) {
        console.log('Setting cloudURL:', value);
        if (typeof value !== 'string') {
            throw new TypeError("cloudURL should be a string.");
        }
        this.setModelParameter('CloudURL', value);

        // Parse the URL and reconstruct it without the path (patch for HttpServer not expecting a path)
        // try {
        //     const urlObj = new URL(value);
        //     const urlWithoutPath = urlObj.origin; // origin includes protocol and host
        //     this.setModelParameter('CloudURL', urlWithoutPath);
        // } catch (e) {
        //     throw new DGError("Invalid URL provided.", "INVALID_URL", {}, "Invalid URL provided.");
        // }
    }

    get cloudURL() {
        return this.getModelParameter('CloudURL');
    }

    // outputConfidenceThreshold
    set outputConfidenceThreshold(value) {
        if (typeof value !== 'number' || value < 0 || value > 1) {
            throw new TypeError("outputConfidenceThreshold should be a number between 0 and 1.");
        }
        this.setModelParameter('OutputConfThreshold', value);
    }
    get outputConfidenceThreshold() {
        return this.getModelParameter('OutputConfThreshold');
    }

    // outputMaxDetections
    set outputMaxDetections(value) {
        if (typeof value !== 'number' || !Number.isInteger(value)) {
            throw new TypeError("outputMaxDetections should be an integer.");
        }
        this.setModelParameter('MaxDetections', value);
    }
    get outputMaxDetections() {
        return this.getModelParameter('MaxDetections');
    }

    // outputMaxDetectionsPerClass
    set outputMaxDetectionsPerClass(value) {
        if (typeof value !== 'number' || !Number.isInteger(value)) {
            throw new TypeError("outputMaxDetectionsPerClass should be an integer.");
        }
        this.setModelParameter('MaxDetectionsPerClass', value);
    }
    get outputMaxDetectionsPerClass() {
        return this.getModelParameter('MaxDetectionsPerClass');
    }

    // outputMaxClassesPerDetection
    set outputMaxClassesPerDetection(value) {
        if (typeof value !== 'number' || !Number.isInteger(value)) {
            throw new TypeError("outputMaxClassesPerDetection should be an integer.");
        }
        this.setModelParameter('MaxClassesPerDetection', value);
    }
    get outputMaxClassesPerDetection() {
        return this.getModelParameter('MaxClassesPerDetection');
    }

    // outputNmsThreshold
    set outputNmsThreshold(value) {
        if (typeof value !== 'number' || value < 0 || value > 1) {
            throw new TypeError("outputNmsThreshold should be a number between 0 and 1.");
        }
        this.setModelParameter('OutputNMSThreshold', value);
    }
    get outputNmsThreshold() {
        return this.getModelParameter('OutputNMSThreshold');
    }

    // outputPoseThreshold
    set outputPoseThreshold(value) {
        if (typeof value !== 'number' || value < 0 || value > 1) {
            throw new TypeError("outputPoseThreshold should be a number between 0 and 1.");
        }
        this.setModelParameter('OutputConfThreshold', value);  // set OutputConfThreshold with the value (not pose threshold)
    }
    get outputPoseThreshold() {
        return this.getModelParameter('OutputConfThreshold');
    }

    // outputPostprocessType
    set outputPostprocessType(value) {
        const validValues = ["Classification", "Detection", "DetectionYolo", "PoseDetection", "HandDetection", "FaceDetect", "Segmentation", "BodyPix", "Python", "None"];
        if (typeof value !== 'string' || !validValues.includes(value)) {
            throw new TypeError("outputPostprocessType should be one of the specified valid string values.");
        }
        this.setModelParameter('OutputPostprocessType', value);
    }
    get outputPostprocessType() {
        return this.getModelParameter('OutputPostprocessType');
    }

    // outputTopK
    set outputTopK(value) {
        if (typeof value !== 'number' || !Number.isInteger(value)) {
            throw new TypeError("outputTopK should be an integer.");
        }
        this.setModelParameter('OutputTopK', value);
    }
    get outputTopK() {
        return this.getModelParameter('OutputTopK');
    }

    // outputUseRegularNms
    set outputUseRegularNms(value) {
        if (typeof value !== 'boolean') {
            throw new TypeError("outputUseRegularNms should be a boolean.");
        }
        this.setModelParameter('UseRegularNMS', value);
    }
    get outputUseRegularNms() {
        return this.getModelParameter('UseRegularNMS');
    }

    // Helper function to wait for up to 1 second for some condition
    waitFor(conditionFunction, timeout = 1000, interval = 10) {
        const poll = resolve => {
            if (conditionFunction()) resolve();
            else if (timeout > 0) setTimeout(() => poll(resolve), interval);
            else throw new DGError("Timed out waiting.", "WAIT_TIMEOUT", {}, "Timed out waiting.");
        };

        return new Promise(poll);
    }

    // Return the modelParams JSON object - FROM THE CLASS
    async getModelParameters() {
        if (this.socket && this.modelParams) {
            return (this.modelParams);
        } else {
            throw new DGError("Model parameters are not yet initialized for this model!", "MODEL_PARAMETERS_NOT_INITIALIZED", {}, "Model parameters are not yet initialized for this model!");
        }
    }

    // Setter for updating a key withing modelParams and setting the dirty flag
    // Designed to only modify leaf nodes with primitive values in the JSON
    async setModelParameter(key, value) {
        this.log('setModelParameter(). Attempting to update:', key, 'to value:', value);
        let updated = false;
        try {
            // Ensure modelParams exists
            if (!this.modelParams) {
                throw new DGError("Model parameters are not initialized!", "MODEL_PARAMETERS_NOT_INITIALIZED", {}, "Model parameters are not initialized. Please initialize the model parameters before updating.");
            }
            // Check for top-level key
            if (Object.prototype.hasOwnProperty.call(this.modelParams, key)) {
                this.log('Top-level key found! Updating key to:', value);
                this.modelParams[key] = value;

                this.dirty = true;
                updated = true;
            } else if (key === 'CloudToken' || key === 'CloudURL') { // TEMPORARY PATCH - Cloud doesn't return FULL model params like our websocket does, so we manually add cloudURL/token if missing
                // We don't need to update cloud token / URL for params to pass to IO.
                // They are empty when constructing socket io instance.
                // this.modelParams[key] = value;

                this.dirty = true;
                updated = true;

            } else {
                // Try setting the value for each top-level key
                for (const topLevelKey in this.modelParams) {
                    if (this.modelParams[topLevelKey] && this.modelParams[topLevelKey][0] && Object.prototype.hasOwnProperty.call(this.modelParams[topLevelKey][0], key)) {
                        this.log('Key found! Updating key to:', value);
                        // Updating local copy of model params is now done on confirmation message from websocket in initializeSocket()

                        // Need to update local copy anyway, even if it will be overwritten by next lazy reload upon predict()
                        // This is so querying the model params after user changes parameter without performing inference
                        // will yield expected new model params, not old unchanged params object
                        this.log('setModelParameter(): Updating local modelParams copy, setting', this.modelParams[topLevelKey][0][key], 'to', value);
                        this.modelParams[topLevelKey][0][key] = value;

                        this.dirty = true;
                        updated = true;
                        break;
                    }
                }
            }
        } catch (error) {
            throw new DGError(`Failed to set a parameter: ${error}`, "SET_PARAMETER_FAILED", {}, "Failed to set a parameter.");
        }

        // If not updated, log an error
        if (!updated) {
            throw new DGError(`Failed to update the parameter. Key "${key}" not found!`, "UPDATE_PARAMETER_FAILED", { key }, `Failed to update the parameter "${key}". Please make sure the key exists.`);
        }
    }

    // Get model parameter from the modelParams JSON associated with this Model instance.
    getModelParameter(key) {
        this.log('Entered getModelParameter(). Querying value for key:', key);

        if (!this.modelParams) {
            throw new DGError("Model parameters are not initialized!", "MODEL_PARAMETERS_NOT_INITIALIZED", {}, "Model parameters are not initialized. Please initialize the model parameters before querying.");
        }

        // Check for top-level key
        if (Object.prototype.hasOwnProperty.call(this.modelParams, key)) {
            this.log('Top-level key found. Value:', this.modelParams[key]);
            return this.modelParams[key];
        } else {
            // Check in nested structures
            for (const topLevelKey in this.modelParams) {
                if (this.modelParams[topLevelKey] && this.modelParams[topLevelKey][0] && Object.prototype.hasOwnProperty.call(this.modelParams[topLevelKey][0], key)) {
                    this.log('Key found in nested structure. Value:', this.modelParams[topLevelKey][0][key]);
                    return this.modelParams[topLevelKey][0][key];
                }
            }
        }

        throw new DGError(`Failed to get the parameter. Key "${key}" not found!`, "GET_PARAMETER_FAILED", { key }, `Failed to get the parameter "${key}". Please make sure the key exists.`);
    }

    // Method to grab a read only copy of modelParams
    modelInfo() {
        return JSON.parse(JSON.stringify(this.modelParams));
    }

    // Method to return label dictionary
    labelDictionary() {
        return this.labels;
    }


    // Let's say user loaded a model and later requested to change a parameter.
    // If socket.io connection already established, we need to reset the connection in order to 
    // tell the server about the new parameter
    // Close and reinitialize the socket.io connection
    async resetSocket() {
        console.log('cloudservermodel.js: Entered resetSocket()');
        if (this.socketConnected) this.socket.disconnect();
        this.socketConnected = false;

        // Reinitialize the socket (this.modelParams has modifications which will be applied upon reinit)
        await this.initializeSocket();

        // Reset dirty flag
        this.dirty = false;
    }

    async handleDirtyFlag() {
        this.log('handleDirtyFlag(): dirty flag caught. modelParams object prior to reset:', this.modelParams);
        if (this.infoQ.empty() && this.resultQ.empty()) {
            this.resetSocket();
        } else {
            await new Promise(resolve => {
                const checkQueuesEmptyAndReset = () => {
                    if (this.infoQ.empty() && this.resultQ.empty()) {
                        if (this.infoQ.hasEventListener('onPop')) {
                            this.infoQ.removeEventListener('onPop', checkQueuesEmptyAndReset);
                        }
                        if (this.resultQ.hasEventListener('onPop')) {
                            this.resultQ.removeEventListener('onPop', checkQueuesEmptyAndReset);
                        }
                        this.resetSocket();
                        resolve();
                    }
                };
                this.infoQ.addEventListener('onPop', checkQueuesEmptyAndReset);
                this.resultQ.addEventListener('onPop', checkQueuesEmptyAndReset);
            });
        }
    }

    async handlePredictResult(data, frame_no) {
        console.log('cloudservermodel.js: Got result from socket:', data);

        // Store the result in the unorderedResults map
        this.unorderedResults.set(frame_no, data);

        // Process any available results in order
        this.processOrderedResults();
    }

    async processOrderedResults() {
        while (this.unorderedResults.has(this.expectedFrameNo)) {
            console.log('processOrderedResults(): Processing frame:', this.expectedFrameNo, 'from unorderedResults map.');

            let data = this.unorderedResults.get(this.expectedFrameNo);
            this.unorderedResults.delete(this.expectedFrameNo);

            if (!this.initialized) return;
            if (this.poison) return;
            if (!data) {
                throw new DGError('processOrderedResults(): Prediction result data is null or undefined.', 'DATA_NULL_ERROR', {}, 'Prediction result data is null or undefined.');
            }

            let info, transformationDetails, imageFrame, modelImage, combinedResult;

            const errorMsg = this.errorCheck(data);
            if (errorMsg) {
                this.poison = true;
                throw new DGError(`Error caught in result object: ${errorMsg}`, "RESULT_ERROR", { error: errorMsg }, "Error caught in result object.");
            }

            if (this._saveModelImage) {
                ({ info, transformationDetails, imageFrame, modelImage } = await this.infoQ.pop());
            } else {
                ({ info, transformationDetails, imageFrame } = await this.infoQ.pop());
            }

            // Logic for filtering objects based on labelWhitelist and labelBlacklist
            if (this._labelWhitelist || this._labelBlacklist) {
                // dummy check: Does this model even have labels?
                if (!this.labels) {
                    console.warn('labelWhitelist/labelBlacklist is set but this model does not have a label dictionary. Ignoring the labelWhitelist/labelBlacklist.');
                } else {
                    // whitelist set and blacklist set
                    if (this._labelWhitelist && this._labelBlacklist) {
                        const filteredData = data.filter(item => this._labelWhitelist.includes(item.label) && !this._labelBlacklist.includes(item.label));
                        data = filteredData;
                    }
                    // whitelist set, blacklist not set
                    else if (this._labelWhitelist) {
                        const filteredData = data.filter(item => this._labelWhitelist.includes(item.label));
                        data = filteredData;
                    }
                    // blacklist set, whitelist not set
                    else {
                        const filteredData = data.filter(item => !this._labelBlacklist.includes(item.label));
                        data = filteredData;
                    }
                }
            }

            data.scaleX = transformationDetails.scaleX;
            data.scaleY = transformationDetails.scaleY;
            data.offsetX = transformationDetails.offsetX;
            data.offsetY = transformationDetails.offsetY;
            const resultArray = [data, info];
            if (this._saveModelImage) {
                combinedResult = { result: resultArray, imageFrame, modelImage };
            } else {
                combinedResult = { result: resultArray, imageFrame };
            }
            if (this.callback == null) {
                this.resultQ.push(combinedResult);
            } else {
                this.callback(combinedResult, info);
            }
            this.expectedFrameNo++; // Increment to expect the next frame
        }
    }

    /**
     * Overlay the result onto the image frame and display it on the canvas.
     * @async
     * @param {Object} combinedResult - The result object combined with the original image frame. This is directly received from `predict` or `predict_batch`
     * @param {string|HTMLCanvasElement} outputCanvasName - The canvas to draw the image onto. Either the canvas element or the ID of the canvas element.
     * @param {boolean} [justResults=false] - Whether to show only the result overlay without the image frame.
     */
    async displayResultToCanvas(combinedResult, outputCanvasName, justResults = false) {
        this.log('Entered displayResultToCanvas()');

        // Handle incorrect / empty result object
        if (!combinedResult || !combinedResult.result) {
            throw new DGError('displayResultToCanvas(): Invalid or empty result object, returning', "INVALID_RESULT_OBJECT", {}, "Invalid or empty result object. Please make sure the result object is valid.");
        }

        // If !combinedResult.imageFrame then it means the input was a video element
        // allow it, just set justResults to true
        if (!combinedResult.imageFrame) {
            justResults = true;
            this.log('displayResultToCanvas(): No imageFrame found in combinedResult most likely due to video element inference. Setting justResults to true.');
        }

        const { result, imageFrame } = combinedResult;  // Destructure to extract result and imageFrame

        let canvas;
        // Input validation for outputCanvasName
        if (!outputCanvasName || typeof outputCanvasName !== 'string' || outputCanvasName.trim() === '') {
            // also accept HTMLCanvasElement 
            if (!(outputCanvasName instanceof HTMLCanvasElement)) {
                throw new DGError('Invalid outputCanvasName parameter', "INVALID_OUTPUT_CANVAS_NAME", {}, "Invalid outputCanvasName parameter. Please provide a valid outputCanvasName.");
            } else {
                canvas = outputCanvasName;
            }
        }
        if (!canvas) {
            canvas = document.getElementById(outputCanvasName);
        }

        try {
            // Check result for errors
            const errorMsg = this.errorCheck(result);
            if (errorMsg) {
                throw new DGError(`Error in result: ${errorMsg}`, "RESULT_ERROR", { errorMsg }, "Error in result. Please check the result for errors.");
            }
            // letterbox details attached to result already in onmessage
            this.postProcessor.displayResultToCanvas(imageFrame, result, canvas, justResults);
        } catch (error) {
            throw new DGError("Error in parsing result: ", "PARSE_RESULT_ERROR", {}, "Error in parsing result.");
        }
    }


    async validateAndConvertInputFrame(image) {
        if (!image) {
            throw new DGError('validateAndConvertInputFrame(): Image must be provided.', "INVALID_IMAGE_INPUT", {}, "Image must be provided.");
        }
        // Directly passthrough for these image types, as they can be directly used with our resizeImage() implementation:
        // HTMLImageElement
        // SVGImageElement
        // HTMLVideoElement
        // HTMLCanvasElement
        // ImageBitmap
        // OffscreenCanvas
        if (image instanceof HTMLImageElement || image instanceof SVGImageElement || image instanceof HTMLVideoElement || image instanceof HTMLCanvasElement || image instanceof ImageBitmap || image instanceof OffscreenCanvas) {
            return image;
        }
        // For Blob, ImageData, and File types, we use createImageBitmap()
        if (image instanceof Blob || image instanceof ImageData) {
            // Blob and ImageData are valid input types, but we need to convert them to an ImageBitmap
            const imageBitmap = await createImageBitmap(image);
            return imageBitmap;
        }

        if (image instanceof File) {
            // Check if the file is an image
            if (!image.type.startsWith('image/')) {
                throw new DGError('validateAndConvertInputFrame(): input image is a File but is not an image.', "INVALID_IMAGE_INPUT", {}, "File is not an image.");
            }
            // Convert the File to an ImageBitmap
            const imageBitmap = await createImageBitmap(image);
            return imageBitmap;
        }

        // Handle Data URLs, image URLs, base64 strings, ArrayBuffers, and typed arrays
        if (typeof image === 'string') {
            // Data URL
            if (image.startsWith('data:')) {
                return await this.convertDataUrlToImageBitmap(image);
            }
            try {
                // TODO: Need some more robust way to validate URLs...
                new URL(image);  // This will throw an error if `image` is not a valid URL
                // if (image.startsWith('http')) 
            } catch (error) {
                // If here, the string is neither a Data URL nor a valid URL, so it should be a base64 string
                return await this.convertBase64ToImageBitmap(image);
            }
            // Fetching image from URL
            return await this.convertImageURLToImageBitmap(image);
        }

        if (image instanceof ArrayBuffer) {
            return await this.convertArrayBufferToImageBitmap(image);
        }

        if (image instanceof Uint8Array || image instanceof Uint16Array || image instanceof Float32Array) {
            return await this.convertTypedArrayToImageBitmap(image);
        }

        throw new DGError('Invalid image input type, it is: ' + typeof (image), "INVALID_IMAGE_INPUT", {}, "Invalid image input type.");
    }

    async convertDataUrlToImageBitmap(dataUrl) {
        if (!dataUrl.startsWith('data:')) {
            throw new DGError('Invalid data URL: ' + dataUrl, "INVALID_DATA_URL", {}, "Invalid data URL.");
        }
        const response = await fetch(dataUrl);
        const blob = await response.blob();
        return await createImageBitmap(blob);
    }

    async convertImageURLToImageBitmap(imageUrl) {
        try {
            new URL(imageUrl); // Validates the URL
            const response = await fetch(imageUrl);
            const blob = await response.blob();
            return await createImageBitmap(blob);
        } catch (error) {
            throw new DGError('Invalid image URL: ' + imageUrl + ' : ' + error, "INVALID_IMAGE_URL", { error }, "Invalid image URL.");
        }
    }

    async convertBase64ToImageBitmap(base64) {
        try {
            const byteString = atob(base64);
            const ab = new ArrayBuffer(byteString.length);
            const ia = new Uint8Array(ab);
            for (let i = 0; i < byteString.length; i++) {
                ia[i] = byteString.charCodeAt(i);
            }
            let blob = new Blob([ab], { type: 'image/jpeg' });
            return await createImageBitmap(blob);
        } catch (error) {
            throw new DGError('Invalid base64 string: ' + base64 + ' : ' + error, "INVALID_BASE64_STRING", { error }, "Invalid base64 string.");
        }
    }

    async convertArrayBufferToImageBitmap(arrayBuffer) {
        if (!(arrayBuffer instanceof ArrayBuffer)) {
            throw new DGError('Invalid ArrayBuffer input: ' + arrayBuffer, "INVALID_ARRAY_BUFFER", {}, "Invalid ArrayBuffer input.");
        }
        const blob = new Blob([arrayBuffer]);
        return await createImageBitmap(blob);
    }

    async convertTypedArrayToImageBitmap(typedArray) {
        if (!(typedArray instanceof Uint8Array)) {
            throw new DGError('Invalid Uint8Array input: ' + typedArray, "INVALID_TYPED_ARRAY", {}, "Invalid Uint8Array input.");
        }
        const blob = new Blob([typedArray.buffer]);
        return await createImageBitmap(blob);
    }

    errorCheck(response) {
        // console.log('Entered errorCheck with result:', JSON.stringify(response));

        if (!response)
            return new DGError("response JSON is null!", "RESPONSE_JSON_NULL", {}, "Response JSON is null!");
        // Check for the success flag
        if (Object.prototype.hasOwnProperty.call(response, 'success')) {
            if (!response.success) {
                let msg = Object.prototype.hasOwnProperty.call(response, 'msg') ? response.msg : "unspecified error";
                return new DGError(msg, "RESPONSE_ERROR", { msg }, "Error in response.");
            }
        }

        // also add check for the string '[ERROR]' inside the first 25 characters of the stringified response
        if (JSON.stringify(response).substring(0, 25).includes('[ERROR]')) {
            // We have to parse the response to get the error message as well
            return new DGError("Error in response: " + response, "RESPONSE_ERROR", { response }, "Error in response.");
        }
        return ""; // no error
    }

    waitForSocketConnection() {
        return new Promise((resolve, reject) => {
            resolve();

            // TODO: test this.
            // use this.waitFor() to wait for the socket to connect
            // this.waitFor(() => this.socket.connected, this.MAX_SOCKET_WAIT_MS, 100)
            //     .then(() => resolve())
            //     .catch(error => reject(new DGError("Socket connection timeout: " + error, "SOCKET_CONNECTION_TIMEOUT", { error }, "Socket connection timeout.")))
        });
    }

    // Utility method for timeout which also handles cancellation
    // Specifically used for mutex lock timeouts
    timeoutPromise(duration, onCancel) {
        let timeoutId;
        const promise = new Promise((resolve, reject) => {
            timeoutId = setTimeout(() => {
                reject(new DGError('Mutex lock timeout exceeded', "MUTEX_LOCK_TIMEOUT", {}, "Mutex lock timeout exceeded."));
                onCancel();
            }, duration);
        });
        // Attach the cancel method
        promise.cancel = () => {
            clearTimeout(timeoutId);
        };
        return promise;
    }

    log(...args) {
        if (this.debugLogsEnabled) {
            console.log(...args);
        } else {
            console.warn('Debug logs are disabled. Enable them by setting debugLogsEnabled to true.');
        }
    }

    /**
     * Cleanup the model and release all resources.
     * Internally, it does the following:
     * - Sets the poison flag to stop further inferences
     * - Disconnects the socket
     * - Clears the async queues
     * - Nullifies references
     * - Resets internal states and flags
     * Call this method when you are done using the model to free up resources
     * @async
     */
    async cleanup() {
        // Set poison flag to stop further inferences
        this.poison = true;

        // Close connection
        if (this.socket) {
            this.socket.disconnect();
        }

        // Clear Async Queues
        await this.infoQ.clear();
        await this.resultQ.clear();

        // Nullify references
        this.preProcessor = null;
        this.postProcessor = null;
        this.mutex = null;
        this.infoQ = null;
        this.resultQ = null;

        // Reset internal states and flags
        this.initialized = false;
    }
}

export default CloudServerModel;