class GraphicsEngineAssignment {
    constructor(graphicsEngine = null, graphicsEngineOutput = null) {
        this._graphicsEngineName = null;
        this._graphicsEngineFullTypeName = null;
        this._graphicsEnginePlatformName = null;
        this._graphicsEngine = null;
        this._engineId = null;

        this._output = null;
        this._outputId = null;
        this._outputName = null;

        this._language = null;

        this._graphicsEngineUpdatedHandlers = new Set();
        this._outputUpdatedHandlers = new Set();

        this._propertyChangedHandlers = new Set();

        this.UpdateGraphicsEngineAndOutput(graphicsEngine, graphicsEngineOutput);
    }

    SubscribeGraphicsEngineUpdated(handler) {
        this._graphicsEngineUpdatedHandlers.add(handler);
    }

    UnsubscribeGraphicsEngineUpdated(handler) {
        this._graphicsEngineUpdatedHandlers.delete(handler);
    }

    SubscribeOutputUpdated(handler) {
        this._outputUpdatedHandlers.add(handler);
    }

    UnsubscribeOutputUpdated(handler) {
        this._outputUpdatedHandlers.delete(handler);
    }

    _invokeHandlers(handlers) {
        for (const handler of [...handlers]) {
            handler(this, {});
        }
    }

    get OutputName() {
        return this._outputName;
    }

    set OutputName(value) {
        this._outputName = value;
    }

    get GraphicsEngineName() {
        return this._graphicsEngineName;
    }

    set GraphicsEngineName(value) {
        this._graphicsEngineName = value;
    }

    get EngineId() {
        return this._engineId;
    }

    set EngineId(value) {
        this._engineId = value;
    }

    get OutputId() {
        return this._outputId;
    }

    set OutputId(value) {
        this._outputId = value;
    }

    get GraphicsEngineFullTypeName() {
        return this._graphicsEngineFullTypeName;
    }

    set GraphicsEngineFullTypeName(value) {
        this._graphicsEngineFullTypeName = value;
    }

    get GraphicsEnginePlatformName() {
        return this._graphicsEnginePlatformName;
    }

    set GraphicsEnginePlatformName(value) {
        this._graphicsEnginePlatformName = value;
    }

    get Language() {
        return this._language;
    }

    set Language(value) {
        this._language = value;
    }

    get GraphicsEngine() {
        return this._graphicsEngine;
    }

    get Output() {
        return this._output;
    }

    get IsGraphicsEngineMissing() {
        return this.GraphicsEngine == null;
    }

    get IsOutputMissing() {
        return this.Output == null;
    }

    get IsValid() {
        return !this.IsOutputMissing && !this.IsGraphicsEngineMissing;
    }

    UpdateGraphicsEngineAndOutput(graphicsEngine, output) {
        this._updateGraphicsEngine(graphicsEngine);
        this._updateOutput(output);
    }

    _updateOutput(output) {
        if (this.Output === output) {
            return;
        }

        this._output = output;

        if (this.Output != null) {
            this.OutputName = this.Output.Name;
            this.OutputId = this.Output.Id;
        }

        this._invokeHandlers(this._outputUpdatedHandlers);
    }

    _updateGraphicsEngine(graphicsEngine) {
        if (this.GraphicsEngine === graphicsEngine) {
            return;
        }

        this._graphicsEngine = graphicsEngine;

        if (this.GraphicsEngine != null) {
            this.GraphicsEngineName = this.GraphicsEngine.Name;
            this.GraphicsEngineFullTypeName = this.GraphicsEngine.constructor?.fullTypeName ?? this.GraphicsEngine.constructor?.name ?? null;
            this.GraphicsEnginePlatformName = this.GraphicsEngine.PlatformName;
            this.EngineId = this.GraphicsEngine.Id;
        }

        this._invokeHandlers(this._graphicsEngineUpdatedHandlers);
    }
}