import { Tools } from "../Misc/tools";
import { Observable } from "../Misc/observable";
import { Scene } from "../scene";
import { Engine } from "../Engines/engine";

// declare INSPECTOR namespace for compilation issue
declare var INSPECTOR: any;
declare var BABYLON: any;
// load the inspector using require, if not present in the global namespace.

/**
 * Interface used to define scene explorer extensibility option
 */
export interface IExplorerExtensibilityOption {
    /**
     * Define the option label
     */
    label: string;
    /**
     * Defines the action to execute on click
     */
    action: (entity: any) => void;
}

/**
 * Defines a group of actions associated with a predicate to use when extending the Inspector scene explorer
 */
export interface IExplorerExtensibilityGroup {
    /**
     * Defines a predicate to test if a given type mut be extended
     */
    predicate: (entity: any) => boolean;
    /**
     * Gets the list of options added to a type
     */
    entries: IExplorerExtensibilityOption[];
}

/**
 * Interface used to define the options to use to create the Inspector
 */
export interface IInspectorOptions {
    /**
     * Display in overlay mode (default: false)
     */
    overlay?: boolean;
    /**
     * HTML element to use as root (the parent of the rendering canvas will be used as default value)
     */
    globalRoot?: HTMLElement;
    /**
     * Display the Scene explorer
     */
    showExplorer?: boolean;
    /**
     * Display the property inspector
     */
    showInspector?: boolean;
    /**
     * Display in embed mode (both panes on the right)
     */
    embedMode?: boolean;
    /**
     * let the Inspector handles resize of the canvas when panes are resized (default to true)
     */
    handleResize?: boolean;
    /**
     * Allow the panes to popup (default: true)
     */
    enablePopup?: boolean;
    /**
     * Allow the panes to be closed by users (default: true)
     */
    enableClose?: boolean;
    /**
     * Optional list of extensibility entries
     */
    explorerExtensibility?: IExplorerExtensibilityGroup[];
    /**
     * Optional URL to get the inspector script from (by default it uses the babylonjs CDN).
     */
    inspectorURL?: string;
    /**
     * Optional initial tab (default to DebugLayerTab.PROPERTIES)
     */
    initialTab?: DebugLayerTab.PROPERTIES;
}

declare module "../scene" {
    export interface Scene {
        /**
         * @hidden
         * Backing field
         */
        _debugLayer: DebugLayer;

        /**
         * Gets the debug layer (aka Inspector) associated with the scene
         * @see http://doc.babylonjs.com/features/playground_debuglayer
         */
        debugLayer: DebugLayer;
    }
}
Object.defineProperty(Scene.prototype, "debugLayer", {
    get: function(this: Scene) {
        if (!this._debugLayer) {
            this._debugLayer = new DebugLayer(this);
        }
        return this._debugLayer;
    },
    enumerable: true,
    configurable: true
});

/**
 * Enum of inspector action tab
 */
export enum DebugLayerTab {
    /**
     * Properties tag (default)
     */
    PROPERTIES = 0,
    /**
     * Debug tab
     */
    DEBUG = 1,
    /**
     * Statistics tab
     */
    STATISTICS = 2,
    /**
     * Tools tab
     */
    TOOLS = 3,
    /**
     * Settings tab
     */
    SETTINGS = 4
}

/**
 * The debug layer (aka Inspector) is the go to tool in order to better understand
 * what is happening in your scene
 * @see http://doc.babylonjs.com/features/playground_debuglayer
 */
export class DebugLayer {
    /**
     * Define the url to get the inspector script from.
     * By default it uses the babylonjs CDN.
     * @ignoreNaming
     */
    public static InspectorURL = `https://unpkg.com/babylonjs-inspector@${Engine.Version}/babylon.inspector.bundle.js`;

    private _scene: Scene;

    private BJSINSPECTOR = this._getGlobalInspector();

    private _onPropertyChangedObservable?: Observable<{ object: any, property: string, value: any, initialValue: any }>;
    /**
     * Observable triggered when a property is changed through the inspector.
     */
    public get onPropertyChangedObservable() {
        if (this.BJSINSPECTOR && this.BJSINSPECTOR.Inspector) {
            return this.BJSINSPECTOR.Inspector.OnPropertyChangedObservable;
        }

        if (!this._onPropertyChangedObservable) {
            this._onPropertyChangedObservable = new Observable<{ object: any, property: string, value: any, initialValue: any }>();
        }

        return this._onPropertyChangedObservable;
    }

    /**
     * Instantiates a new debug layer.
     * The debug layer (aka Inspector) is the go to tool in order to better understand
     * what is happening in your scene
     * @see http://doc.babylonjs.com/features/playground_debuglayer
     * @param scene Defines the scene to inspect
     */
    constructor(scene: Scene) {
        this._scene = scene;
        this._scene.onDisposeObservable.add(() => {
            // Debug layer
            if (this._scene._debugLayer) {
                this._scene._debugLayer.hide();
            }
        });
    }

    /** Creates the inspector window. */
    private _createInspector(config?: Partial<IInspectorOptions>) {
        if (this.isVisible()) {
            return;
        }

        if (this._onPropertyChangedObservable) {
            for (var observer of this._onPropertyChangedObservable!.observers) {
                this.BJSINSPECTOR.Inspector.OnPropertyChangedObservable.add(observer);
            }
            this._onPropertyChangedObservable.clear();
            this._onPropertyChangedObservable = undefined;
        }

        const userOptions: IInspectorOptions = {
            overlay: false,
            showExplorer: true,
            showInspector: true,
            embedMode: false,
            handleResize: true,
            enablePopup: true,
            ...config
        };

        this.BJSINSPECTOR = this.BJSINSPECTOR || this._getGlobalInspector();

        this.BJSINSPECTOR.Inspector.Show(this._scene, userOptions);
    }

    /**
     * Select a specific entity in the scene explorer and highlight a specific block in that entity property grid
     * @param entity defines the entity to select
     * @param lineContainerTitle defines the specific block to highlight
     */
    public select(entity: any, lineContainerTitle?: string) {
        if (this.BJSINSPECTOR) {
            this.BJSINSPECTOR.Inspector.MarkLineContainerTitleForHighlighting(lineContainerTitle);
            this.BJSINSPECTOR.Inspector.OnSelectionChangeObservable.notifyObservers(entity);
        }

    }

    /** Get the inspector from bundle or global */
    private _getGlobalInspector(): any {
        // UMD Global name detection from Webpack Bundle UMD Name.
        if (typeof INSPECTOR !== 'undefined') {
            return INSPECTOR;
        }

        // In case of module let s check the global emitted from the Inspector entry point.
        if (typeof BABYLON !== 'undefined' && typeof BABYLON.Inspector !== 'undefined') {
            return BABYLON;
        }

        return undefined;
    }

    /**
     * Get if the inspector is visible or not.
     * @returns true if visible otherwise, false
     */
    public isVisible(): boolean {
        return this.BJSINSPECTOR && this.BJSINSPECTOR.Inspector.IsVisible;
    }

    /**
     * Hide the inspector and close its window.
     */
    public hide() {
        if (this.BJSINSPECTOR) {
            this.BJSINSPECTOR.Inspector.Hide();
        }
    }

    /**
      * Launch the debugLayer.
      * @param config Define the configuration of the inspector
      * @return a promise fulfilled when the debug layer is visible
      */
    public show(config?: IInspectorOptions): Promise<DebugLayer> {
        return new Promise((resolve, reject) => {
            if (typeof this.BJSINSPECTOR == 'undefined') {
                const inspectorUrl = config && config.inspectorURL ? config.inspectorURL : DebugLayer.InspectorURL;

                // Load inspector and add it to the DOM
                Tools.LoadScript(inspectorUrl, () => {
                    this._createInspector(config);
                    resolve(this);
                });
            } else {
                // Otherwise creates the inspector
                this._createInspector(config);
                resolve(this);
            }
        });
    }
}