import { SMouseEvent, SNetUtil } from "@saga-web/base";
import {
    SCanvasPaintEngine,
    SCanvasView,
    SPainter,
    SPoint,
    SRect,
    SSvgPaintEngine
} from "@saga-web/draw";
import { SGraphScene } from "./SGraphScene";
import { SGraphItem } from "./SGraphItem";
import { v1 as uuidv1 } from "uuid";
import { SColor } from "@saga-web/draw";

/**
 * Graph 图形引擎视图类
 *
 * @author 庞利祥 <sybotan@126.com>
 */
export class SGraphView extends SCanvasView {
    /** 场景对象 */
    private _scene: SGraphScene | null = null;
    get scene(): SGraphScene | null {
        return this._scene;
    }
    set scene(v: SGraphScene | null) {
        if (this._scene != null) {
            this._scene.view = null;
        }
        this._scene = v;
        if (this._scene != null) {
            this._scene.view = this;
        }
        this.update();
    }
    /** 背景色 */
    backgroundColor: SColor = SColor.Transparent;
    /** 旋转角度 */
    rotate: number = 0;

    /**
     * 构造函数
     *
     * @param id      画布对象 ID
     */
    constructor(id: string) {
        super(id);
    }

    /**
     * 保存场景 SVG 文件
     *
     * @param name    文件名
     * @param width   svg 宽度
     * @param height  svg 高度
     */
    saveSceneSvg(name: string, width: number, height: number): void {
        let url = URL.createObjectURL(
            new Blob([this.sceneSvgData(width, height)], {
                type: "text/xml,charset=UTF-8"
            })
        );
        SNetUtil.downLoad(name, url);
    }

    /**
     * 场景 SVG 图形的数据
     *
     * @param width   svg 宽度
     * @param height  svg 高度
     * @return URL 地址
     */
    sceneSvgData(width: number, height: number): string {
        if (null == this.scene) {
            return "";
        }
        let engine = new SSvgPaintEngine(width, height);
        let painter = new SPainter(engine);

        // 保存视图缩放比例与原点位置
        let s0 = this.scale;
        let x0 = this.origin.x;
        let y0 = this.origin.y;

        // 场景中无对象
        let rect = this.scene.allItemRect();
        this.fitRectToSize(width, height, rect);
        this.onDraw(painter);

        // 恢复视图缩放比例与原点位置
        this.scale = s0;
        this.origin.x = x0;
        this.origin.y = y0;

        return engine.toSvg();
    }

    /**
     * 适配视图到视图
     */
    fitSceneToView(): void {
        if (null == this.scene) {
            return;
        }

        // 场景中无对象
        let rect = this.scene.allItemRect();
        this.fitRectToSize(this.width, this.height, rect);
    }

    /**
     * 适配选中的对象在视图中可见
     */
    fitSelectedToView(): void {
        if (null == this.scene) {
            return;
        }

        // 场景中无对象
        let rect = this.scene.selectedItemRect();
        this.fitRectToSize(this.width, this.height, rect);
    }

    /**
     * 适配任意对象在视图中可见
     */
    fitItemToView(itemList: SGraphItem[]): void {
        if (null == this.scene) {
            return;
        }
        let rect: SRect | null = null;

        // 依次取 item 列中的所有 item。将所有 item 的边界做并焦处理。
        for (let item of itemList) {
            if (rect == null) {
                rect = item.boundingRect().translated(item.pos.x, item.pos.y);
            } else {
                rect.union(
                    item.boundingRect().translated(item.pos.x, item.pos.y)
                );
            }
        }
        // 场景中无对象
        this.fitRectToSize(this.width, this.height, rect);
    }

    /**
     * 将场景中的 x, y 坐标转换成视图坐标。
     *
     * @param x     场景中的横坐标
     * @param y     场景中的纵坐标
     * @return 视图坐标
     */
    mapFromScene(x: number, y: number): SPoint;

    /**
     * 将场景中的 x, y 坐标转换成视图坐标。
     *
     * @param pos   场景中的坐标
     * @return 视图坐标
     */
    mapFromScene(pos: SPoint): SPoint;

    /**
     * 将场景中的 x, y 坐标转换成视图坐标(重载实现)。
     *
     * @param x     场景中的横坐标
     * @param y     场景中的纵坐标
     * @return 视图坐标
     */
    mapFromScene(x: number | SPoint, y?: number): SPoint {
        if (x instanceof SPoint) {
            // 如果传入的是 SPoint 对象
            return new SPoint(
                x.x * this.scale + this.origin.x,
                x.y * this.scale + this.origin.y
            );
        }

        // @ts-ignore
        return new SPoint(
            x * this.scale + this.origin.x,
            (y == undefined ? 0 : y) * this.scale + this.origin.y
        );
    }

    /**
     * 将视图的 x, y 坐标转换成场景坐标。
     *
     * @param x     视图横坐标
     * @param y     视图纵坐标
     * @return 场景坐标
     */
    mapToScene(x: number, y: number): SPoint;

    /**
     * 将视图的 x, y 坐标转换成场景坐标。
     *
     * @param pos     视图坐标
     * @return 场景坐标
     */
    mapToScene(pos: SPoint): SPoint;

    /**
     * 将视图的 x, y 坐标转换成场景坐标。（不推荐在外部调用）
     *
     * @param x       视图的横坐标或 SPoint 对象
     * @param y       视图的纵坐标
     * @return 场景坐标
     */
    mapToScene(x: number | SPoint, y?: number): SPoint {
        if (x instanceof SPoint) {
            // 如果传入的是 SPoint 对象
            return new SPoint(
                (x.x - this.origin.x) / this.scale,
                (x.y - this.origin.y) / this.scale
            );
        }

        return new SPoint(
            (x - this.origin.x) / this.scale,
            ((y == undefined ? 0 : y) - this.origin.y) / this.scale
        );
    }

    /**
     * 保存指定大小图像,并且适配到中央而不影响原图
     *
     * @param name    名称
     * @param type    图像类型
     * @param width   要保存图形的宽
     * @param height  要保存图形的高
     * @param bg      生成图的背景色
     */
    saveImageSize(
        name: string,
        type: string,
        width: number,
        height: number,
        bg: string = "#ffffff"
    ): void {
        const can = document.createElement("CANVAS") as HTMLCanvasElement;
        let vi: any = this.generateView(can, width, height, bg);
        vi.saveImage(name, type);
        // @ts-ignore
        this.scene.view = this;
        can.remove();
        vi = null;
    }

    /**
     * 保存指定大小图像,并且适配到中央而不影响原图所使用的图像的 URL
     *
     * @param type    图像类型
     * @param width   要保存图形的宽
     * @param height  要保存图形的高
     * @param bg      生成图的背景色
     * @return 图像的 URL
     */
    imageSizeUrl(
        type: string,
        width: number,
        height: number,
        bg: string = "#FFFFFF"
    ): string {
        const can = document.createElement("CANVAS") as HTMLCanvasElement;
        let vi: any = this.generateView(can, width, height, bg);
        const str = vi.canvasView.toDataURL(`image/${type}`);
        can.remove();
        vi = null;
        return str;
    }

    /**
     * 生成新的view
     *
     * @param can       canvas dom
     * @param width     要保存图形的宽
     * @param height    要保存图形的高
     * @param bg        生成图的背景色
     * @return 图像的 URL
     */
    private generateView(
        can: HTMLCanvasElement,
        width: number,
        height: number,
        bg: string = "#FFFFFF"
    ): SGraphView {
        can.width = width;
        can.height = height;
        can.id = uuidv1();
        const body = document.getElementsByTagName("body")[0];
        body.appendChild(can);
        let engine = new SCanvasPaintEngine(
            can.getContext("2d") as CanvasRenderingContext2D
        );
        let painter = new SPainter(engine);
        let vi = new SGraphView(can.id);
        vi.scene = this.scene;
        vi.fitSceneToView();
        vi.backgroundColor = new SColor(bg);
        vi.onDraw(painter);
        return vi;
    }

    /**
     * 绘制视图
     *
     * @param painter       绘制对象
     */
    protected onDraw(painter: SPainter): void {
        painter.save();
        painter.clearRect(0, 0, this.width, this.height);
        painter.restore();

        // 如果未设备场景
        if (this.scene == null) {
            return;
        }
        // 绘制背景
        painter.save();
        this.drawBackground(painter);
        painter.restore();

        // 绘制场景
        painter.save();
        painter.translate(this.origin.x, this.origin.y);
        painter.scale(this.scale, this.scale);
        painter.rotate(this.rotate);
        this.scene.drawScene(painter, new SRect());
        painter.restore();

        // 绘制前景
        painter.save();
        this.drawForeground(painter);
        painter.restore();
    }

    /**
     * 绘制场景背景
     *
     * @param painter     绘制对象
     */
    protected drawBackground(painter: SPainter): void {
        painter.brush.color = this.backgroundColor;
        painter.pen.color = SColor.Transparent;
        painter.drawRect(0, 0, this.width, this.height);
        // DO NOTHING
    }

    /**
     * 绘制场景前景
     *
     * @param painter     绘制对象
     */
    protected drawForeground(painter: SPainter): void {
        // DO NOTHING
    }

    /**
     * 鼠标双击事件
     *
     * @param event       事件参数
     */
    protected onDoubleClick(event: MouseEvent): void {
        if (this.scene != null) {
            let ce = this.toSceneMotionEvent(event);
            this.scene.onDoubleClick(ce);
        }
    }

    /**
     * 鼠标按下事件
     *
     * @param event       事件参数
     */
    protected onMouseDown(event: MouseEvent): void {
        super.onMouseDown(event);
        if (this.scene != null) {
            let ce = this.toSceneMotionEvent(event);
            this.scene.onMouseDown(ce);
        }
    }

    /**
     * 鼠标移动事件
     *
     * @param event       事件参数
     */
    protected onMouseMove(event: MouseEvent): void {
        super.onMouseMove(event);
        if (this.scene != null) {
            let ce = this.toSceneMotionEvent(event);
            this.scene.onMouseMove(ce);
        }
    }

    /**
     * 鼠标松开事件
     *
     * @param event       事件参数
     */
    protected onMouseUp(event: MouseEvent): void {
        super.onMouseUp(event);
        if (this.scene != null) {
            let ce = this.toSceneMotionEvent(event);
            this.scene.onMouseUp(ce);
        }
    }

    /**
     * 上下文菜单事件
     *
     * @param event       事件参数
     */
    protected onContextMenu(event: MouseEvent): void {
        if (this.scene != null) {
            let ce = this.toSceneMotionEvent(event);
            this.scene.onContextMenu(ce);
        }
    }

    /**
     * 按键按下事件
     *
     * @param event       事件参数
     */
    protected onKeyDown(event: KeyboardEvent): void {
        if (this.scene != null) {
            this.scene.onKeyDown(event);
        }
    }

    /**
     * 按键松开事件
     *
     * @param event       事件参数
     */
    protected onKeyUp(event: KeyboardEvent): void {
        if (this.scene != null) {
            this.scene.onKeyUp(event);
        }
    }

    /**
     * 适配场景在视图中可见
     *
     * @param width       宽度
     * @param height      高度
     * @param rect        对象的矩阵大小
     */
    private fitRectToSize(
        width: number,
        height: number,
        rect: SRect | null
    ): void {
        // 未设置场景
        if (null == rect || !rect.isValid()) {
            return;
        }

        this.scale = Math.min(width / rect.width, height / rect.height) * 0.8;

        // 计算场景中心点
        let center = rect.center();
        this.origin.x = width / 2.0 - center.x * this.scale;
        this.origin.y = height / 2.0 - center.y * this.scale;
    }

    /**
     * MouseEvent 事件转换成场景 SMouseEvent 事件
     *
     * @param event       事件参数
     * @return MouseEvent 事件转换成场景 SMouseEvent 事件
     */
    private toSceneMotionEvent(event: MouseEvent): SMouseEvent {
        let se = new SMouseEvent(event);
        se.matrix.translate(this.origin.x, this.origin.y);
        se.matrix.scale(this.scale, this.scale);
        se.matrix.rotate(this.rotate);

        const mp = new SPoint(event.offsetX, event.offsetY).matrixTransform(
            se.matrix.inversed()
        );

        se.x = mp.x;
        se.y = mp.y;
        return se;
    }
}