import { Point } from "@devexpress/utils/lib/geometry/point";
import { History } from "../../History/History";
import { Connector } from "../../Model/Connectors/Connector";
import { ConnectorRenderPointsContext } from "../../Model/Connectors/Routing/ConnectorRenderPointsContext";
import { ItemKey } from "../../Model/DiagramItem";
import { DiagramModel } from "../../Model/Model";
import { ModelUtils } from "../../Model/ModelUtils";
import { Shape } from "../../Model/Shapes/Shape";
import { DiagramModelOperation } from "../../ModelOperationSettings";
import { Selection } from "../../Selection/Selection";
import { DiagramMouseEvent, MouseButton, MouseEventElementType } from "../Event";
import { MouseHandler } from "../MouseHandler";
import { IVisualizerManager } from "../Visualizers/VisualizersManager";
import { MouseHandlerDraggingState } from "./MouseHandlerDraggingState";
import { SelectionDragHelper } from "../../Model/Helpers/DragHelper";

export class DraggingConnector {
    readonly startPoints: Point[];
    readonly startRenderContext: ConnectorRenderPointsContext | undefined;
    constructor(readonly connector: Connector) {
        this.startPoints = connector.points.map(x => x.clone());
        this.startRenderContext = connector.tryCreateRenderPointsContext();
    }
}

export abstract class MouseHandlerDragDiagramItemStateBase extends MouseHandlerDraggingState {
    private fixedX: boolean;
    private fixedY: boolean;
    private lockInitDrag: boolean;
    dragHelper: SelectionDragHelper;

    startPoint: Point;
    startScrollLeft = 0;
    startScrollTop = 0;
    shouldClone: boolean;

    protected constructor(handler: MouseHandler, history: History,
        protected model: DiagramModel,
        protected selection: Selection,
        protected visualizerManager: IVisualizerManager) {
        super(handler, history);
    }

    protected abstract get areValidDraggingShapes(): boolean;
    protected abstract get areValidDraggingConnectors(): boolean;

    finish(): void {
        this.dragHelper?.finish();
        this.visualizerManager.resetExtensionLines();
        this.visualizerManager.resetContainerTarget();
        this.visualizerManager.resetConnectionTarget();
        this.visualizerManager.resetConnectionPoints();
        super.finish();
    }
    onMouseDown(evt: DiagramMouseEvent): void {
        this.handler.addDiagramItemToSelection(evt);
        this.shouldClone = this.handler.canCopySelectedItems(evt);
        this.startPoint = evt.modelPoint;
        this.initDrag();
        this.lockInitDrag = false;
        super.onMouseDown(evt);
    }

    onMouseMove(evt: DiagramMouseEvent): void {
        this.mouseMoveEvent = evt;
        if(evt.button !== MouseButton.Left) {
            this.cancelChanges();
            this.handler.switchToDefaultState();
            return;
        }
        if(!this.canApplyChangesOnMouseMove(this.startPoint, evt.modelPoint))
            return;
        if(this.handler.canCopySelectedItems(evt))
            if(!this.lockInitDrag) {
                this.cancelChanges();
                this.shouldClone = true;
                this.copySelection();
                this.initDrag();
                this.lockInitDrag = true;
            }

        this.onApplyChanges(evt);
        this.onAfterApplyChanges();
        this.updateContainers(evt);
    }
    private updateContainers(evt: DiagramMouseEvent) : void {
        this.visualizerManager.setExtensionLines(this.selection.getSelectedShapes(false, true));
        const container = ModelUtils.findContainerByEventKey(this.model, this.selection, evt.source.key);
        if(container && this.allowInsertToContainer(evt, container))
            this.visualizerManager.setContainerTarget(container, evt.source.type);
        else
            this.visualizerManager.resetContainerTarget();
    }
    onMouseUp(evt: DiagramMouseEvent) : void {
        super.onMouseUp(evt);
        if(this.handler.canRemoveDiagramItemToSelection(evt) && this.handler.canMultipleSelection(evt))
            this.handler.removeDiagramItemFromSelection(evt.button, evt.source.key);
    }
    onApplyChanges(evt: DiagramMouseEvent): void {
        this.calculateFixedPosition(evt);
        this.dragHelper.move(this.shouldClone, (pt) => this.getSnappedPoint(evt, pt), () => {
            this.visualizerManager.resetConnectionTarget();
            this.visualizerManager.resetConnectionPoints();
        },
        (shape, connectionPointIndex) => {
            this.visualizerManager.setConnectionTarget(shape, MouseEventElementType.Shape);
            this.visualizerManager.setConnectionPoints(shape, MouseEventElementType.Shape, connectionPointIndex, true);
        });
        const container = ModelUtils.findContainerByEventKey(this.model, this.selection, evt.source.key);
        if(container && this.allowInsertToContainer(evt, container))
            ModelUtils.insertSelectionToContainer(this.history, this.model, this.selection, container);
        else
            ModelUtils.removeSelectionFromContainer(this.history, this.model, this.selection);
        this.handler.tryUpdateModelSize((offsetLeft, offsetTop) => this.dragHelper.onTryUpdateModelSize(offsetLeft, offsetTop));
    }
    getDraggingElementKeys(): ItemKey[] {
        return this.dragHelper.draggingShapes.map(x => x.shape.key).concat(this.dragHelper.draggingConnectors.map(x => x.connector.key));
    }
    getSnappedPoint(evt: DiagramMouseEvent, point: Point): Point {
        return this.handler.getSnappedPointOnDragDiagramItem(evt, point, this.fixedX, this.fixedY, this.startPoint);
    }

    private initDrag() : void {
        this.dragHelper = new SelectionDragHelper(this.history, this.model, this.handler.permissionsProvider, this.startPoint, this.selection.getSelectedItems(true));
        this.initDraggingShapes();

        if(!this.areValidDraggingShapes) {
            this.handler.switchToDefaultState();
            return;
        }
        this.initDraggingConnectors();
        if(!this.areValidDraggingConnectors) {
            this.handler.switchToDefaultState();
            return;
        }
    }
    private initDraggingShapes() {
        this.dragHelper.initDraggingShapes(this.selection.getSelectedShapes(false, true), this.shouldClone);
    }
    private initDraggingConnectors(): void {
        this.dragHelper.initDraggingConnectors(this.selection.getSelectedConnectors(false, true), this.shouldClone);
    }
    private copySelection() : void {
        ModelUtils.cloneSelectionToOffset(this.history, this.model, (key: ItemKey) => {
            const item = this.model.findItem(key);
            if(item)
                this.handler.addInteractingItem(item, DiagramModelOperation.AddShape);
        }, this.selection, 0, 0);
    }
    private calculateFixedPosition(evt: DiagramMouseEvent) {
        this.fixedX = false;
        this.fixedY = false;
        if(this.handler.canCalculateFixedPosition(evt)) {
            const dx = Math.abs(this.startPoint.x - evt.modelPoint.x);
            const dy = Math.abs(this.startPoint.y - evt.modelPoint.y);
            if(dx < dy)
                this.fixedX = true;
            else
                this.fixedY = true;
        }
    }
    private allowInsertToContainer(evt: DiagramMouseEvent, container: Shape): boolean {
        if(this.handler.canMultipleSelection(evt))
            return false;
        return container && container.expanded && ModelUtils.canInsertSelectionToContainer(this.model, this.selection, container);
    }
}