import { Observer, Observable } from "../Misc/observable";
import { Nullable } from "../types";
import { PointerInfo, PointerEventTypes } from "../Events/pointerEvents";
import { Scene, IDisposable } from "../scene";
import { Node } from "../node";
import { AbstractMesh } from "../Meshes/abstractMesh";
import { _TimeToken } from "../Instrumentation/timeToken";
import { _DepthCullingState, _StencilState, _AlphaState } from "../States/index";
import { UtilityLayerRenderer } from "../Rendering/utilityLayerRenderer";
import { Color3 } from "../Maths/math";
import { SixDofDragBehavior } from "../Behaviors/Meshes/sixDofDragBehavior";

import { Gizmo } from "./gizmo";
import { RotationGizmo } from "./rotationGizmo";
import { PositionGizmo } from "./positionGizmo";
import { ScaleGizmo } from "./scaleGizmo";
import { BoundingBoxGizmo } from "./boundingBoxGizmo";

/**
 * Helps setup gizmo's in the scene to rotate/scale/position meshes
 */
export class GizmoManager implements IDisposable {
    /**
     * Gizmo's created by the gizmo manager, gizmo will be null until gizmo has been enabled for the first time
     */
    public gizmos: { positionGizmo: Nullable<PositionGizmo>, rotationGizmo: Nullable<RotationGizmo>, scaleGizmo: Nullable<ScaleGizmo>, boundingBoxGizmo: Nullable<BoundingBoxGizmo> };
    /** When true, the gizmo will be detached from the current object when a pointer down occurs with an empty picked mesh */
    public clearGizmoOnEmptyPointerEvent = false;
    /** Fires an event when the manager is attached to a mesh */
    public onAttachedToMeshObservable = new Observable<Nullable<AbstractMesh>>();
    private _gizmosEnabled = { positionGizmo: false, rotationGizmo: false, scaleGizmo: false, boundingBoxGizmo: false };
    private _pointerObserver: Nullable<Observer<PointerInfo>> = null;
    private _attachedMesh: Nullable<AbstractMesh> = null;
    private _boundingBoxColor = Color3.FromHexString("#0984e3");
    private _defaultUtilityLayer: UtilityLayerRenderer;
    private _defaultKeepDepthUtilityLayer: UtilityLayerRenderer;
    /**
     * When bounding box gizmo is enabled, this can be used to track drag/end events
     */
    public boundingBoxDragBehavior = new SixDofDragBehavior();
    /**
     * Array of meshes which will have the gizmo attached when a pointer selected them. If null, all meshes are attachable. (Default: null)
     */
    public attachableMeshes: Nullable<Array<AbstractMesh>> = null;
    /**
     * If pointer events should perform attaching/detaching a gizmo, if false this can be done manually via attachToMesh. (Default: true)
     */
    public usePointerToAttachGizmos = true;

    /**
     * Instatiates a gizmo manager
     * @param scene the scene to overlay the gizmos on top of
     */
    constructor(private scene: Scene) {
        this._defaultKeepDepthUtilityLayer = new UtilityLayerRenderer(scene);
        this._defaultKeepDepthUtilityLayer.utilityLayerScene.autoClearDepthAndStencil = false;
        this._defaultUtilityLayer = UtilityLayerRenderer.DefaultUtilityLayer;

        this.gizmos = { positionGizmo: null, rotationGizmo: null, scaleGizmo: null, boundingBoxGizmo: null };

        // Instatiate/dispose gizmos based on pointer actions
        this._pointerObserver = scene.onPointerObservable.add((pointerInfo) => {
            if (!this.usePointerToAttachGizmos) {
                return;
            }
            if (pointerInfo.type == PointerEventTypes.POINTERDOWN) {
                if (pointerInfo.pickInfo && pointerInfo.pickInfo.pickedMesh) {
                    var node: Nullable<Node> = pointerInfo.pickInfo.pickedMesh;
                    if (this.attachableMeshes == null) {
                        // Attach to the most parent node
                        while (node && node.parent != null) {
                            node = node.parent;
                        }
                    } else {
                        // Attach to the parent node that is an attachableMesh
                        var found = false;
                        this.attachableMeshes.forEach((mesh) => {
                            if (node && (node == mesh || node.isDescendantOf(mesh))) {
                                node = mesh;
                                found = true;
                            }
                        });
                        if (!found) {
                            node = null;
                        }
                    }
                    if (node instanceof AbstractMesh) {
                        if (this._attachedMesh != node) {
                            this.attachToMesh(node);
                        }
                    } else {
                        if (this.clearGizmoOnEmptyPointerEvent) {
                            this.attachToMesh(null);
                        }
                    }
                } else {
                    if (this.clearGizmoOnEmptyPointerEvent) {
                        this.attachToMesh(null);
                    }
                }
            }
        });
    }

    /**
     * Attaches a set of gizmos to the specified mesh
     * @param mesh The mesh the gizmo's should be attached to
     */
    public attachToMesh(mesh: Nullable<AbstractMesh>) {
        if (this._attachedMesh) {
            this._attachedMesh.removeBehavior(this.boundingBoxDragBehavior);
        }
        this._attachedMesh = mesh;
        for (var key in this.gizmos) {
            var gizmo = <Nullable<Gizmo>>((<any>this.gizmos)[key]);
            if (gizmo && (<any>this._gizmosEnabled)[key]) {
                gizmo.attachedMesh = mesh;
            }
        }
        if (this.boundingBoxGizmoEnabled && this._attachedMesh) {
            this._attachedMesh.addBehavior(this.boundingBoxDragBehavior);
        }
        this.onAttachedToMeshObservable.notifyObservers(mesh);
    }

    /**
     * If the position gizmo is enabled
     */
    public set positionGizmoEnabled(value: boolean) {
        if (value) {
            if (!this.gizmos.positionGizmo) {
                this.gizmos.positionGizmo = new PositionGizmo(this._defaultUtilityLayer);
            }
            this.gizmos.positionGizmo.attachedMesh = this._attachedMesh;
        } else if (this.gizmos.positionGizmo) {
            this.gizmos.positionGizmo.attachedMesh = null;
        }
        this._gizmosEnabled.positionGizmo = value;
    }
    public get positionGizmoEnabled(): boolean {
        return this._gizmosEnabled.positionGizmo;
    }
    /**
     * If the rotation gizmo is enabled
     */
    public set rotationGizmoEnabled(value: boolean) {
        if (value) {
            if (!this.gizmos.rotationGizmo) {
                this.gizmos.rotationGizmo = new RotationGizmo(this._defaultUtilityLayer);
            }
            this.gizmos.rotationGizmo.attachedMesh = this._attachedMesh;
        } else if (this.gizmos.rotationGizmo) {
            this.gizmos.rotationGizmo.attachedMesh = null;
        }
        this._gizmosEnabled.rotationGizmo = value;
    }
    public get rotationGizmoEnabled(): boolean {
        return this._gizmosEnabled.rotationGizmo;
    }
    /**
     * If the scale gizmo is enabled
     */
    public set scaleGizmoEnabled(value: boolean) {
        if (value) {
            this.gizmos.scaleGizmo = this.gizmos.scaleGizmo || new ScaleGizmo(this._defaultUtilityLayer);
            this.gizmos.scaleGizmo.attachedMesh = this._attachedMesh;
        } else if (this.gizmos.scaleGizmo) {
            this.gizmos.scaleGizmo.attachedMesh = null;
        }
        this._gizmosEnabled.scaleGizmo = value;
    }
    public get scaleGizmoEnabled(): boolean {
        return this._gizmosEnabled.scaleGizmo;
    }
    /**
     * If the boundingBox gizmo is enabled
     */
    public set boundingBoxGizmoEnabled(value: boolean) {
        if (value) {
            this.gizmos.boundingBoxGizmo = this.gizmos.boundingBoxGizmo || new BoundingBoxGizmo(this._boundingBoxColor, this._defaultKeepDepthUtilityLayer);
            this.gizmos.boundingBoxGizmo.attachedMesh = this._attachedMesh;
            if (this._attachedMesh) {
                this._attachedMesh.removeBehavior(this.boundingBoxDragBehavior);
                this._attachedMesh.addBehavior(this.boundingBoxDragBehavior);
            }
        } else if (this.gizmos.boundingBoxGizmo) {
            if (this._attachedMesh) {
                this._attachedMesh.removeBehavior(this.boundingBoxDragBehavior);
            }
            this.gizmos.boundingBoxGizmo.attachedMesh = null;
        }
        this._gizmosEnabled.boundingBoxGizmo = value;
    }
    public get boundingBoxGizmoEnabled(): boolean {
        return this._gizmosEnabled.boundingBoxGizmo;
    }

    /**
     * Disposes of the gizmo manager
     */
    public dispose() {
        this.scene.onPointerObservable.remove(this._pointerObserver);
        for (var key in this.gizmos) {
            var gizmo = <Nullable<Gizmo>>((<any>this.gizmos)[key]);
            if (gizmo) {
                gizmo.dispose();
            }
        }
        this._defaultKeepDepthUtilityLayer.dispose();
        this.boundingBoxDragBehavior.detach();
        this.onAttachedToMeshObservable.clear();
    }
}