import { Command } from "./Command";
import { findLayerRecursively } from "../utils/layerHelper";
import { fabric } from "fabric-with-all";
import {
  findObjectById,
  generateId,
  insertObjectAtZIndex,
  removeCanvasObjectByObject,
} from "../utils/helper";

/**
 * 填充组图层背景命令
 */
export class FillLayerBackgroundCommand extends Command {
  constructor(options) {
    super({ name: "填充组图层背景", saveState: true });
    this.canvas = options.canvas;
    this.layers = options.layers;
    this.canvasManager = options.canvasManager;
    this.layerId = options.layerId;
    this.fillColor = options.fillColor;
    this.oldFill = null;
    this.oldFillColor = null;
    this.newFill = null;

    const { layer } = findLayerRecursively(this.layers.value, this.layerId);

    this.layer = layer;

    this.group = null;

    this.originalfabricObjects = this._collectOriginalObjects(); // 记录所有的原始对象
  }

  async execute() {
    const layer = this.layer;
    // 只允许填充背景层或普通图层
    if (!layer.isBackground && !layer.isFixed && !layer.fabricObjects?.length) return false;

    // 记录原填充色
    this.oldFill = layer.fill ?? null;
    this.oldFillColor = layer.oldFillColor ?? null;

    // 更新fabric对象填充
    // 判断是否有遮罩层  有遮罩使用遮罩层大小 否则使用第一个大小
    const originalInfo =
      findObjectById(this.canvas.value, layer.fabricObjects?.[0]?.id)?.object?.getBoundingRect?.(
        true,
        true
      ) ||
      layer?.clippingMask ||
      layer.fabricObjects?.[0];

    this.newFill = new fabric.Rect({
      width: originalInfo.width,
      height: originalInfo.height,
      left: originalInfo.left || 0,
      top: originalInfo.top || 0,
      fill: this.fillColor,
      layerId: this.layerId,
      id: generateId("fill-"),
      selectable: false,
      evented: false,
      originX: originalInfo.originX || "center",
      originY: originalInfo.originY || "center",
      scaleX: originalInfo.scaleX || 1,
      scaleY: originalInfo.scaleY || 1,
    });

    // 判断fabricObjects是否是组，是组则添加填充到最前面，否则创建组
    if (layer.fabricObjects && layer.fabricObjects.length > 0) {
      // 如果是组，直接添加到组中
      // 否则创建一个新的组 插入到原本的图层对象前面
      const layerObjects = this.canvas
        .getObjects()
        .reverse()
        .filter((obj) => obj.layerId === this.layerId);
      let insertIndex =
        this.canvas.getObjects()?.findIndex((obj) => obj.id === layer.fabricObjects?.[0]?.id) || 0;
      insertIndex = insertIndex == -1 ? 0 : insertIndex;

      this.group = new fabric.Group([this.newFill, ...layerObjects]);
      this.group.set({
        id: layerObjects[0]?.id || generateId("group-"),
        layerId: layerObjects[0]?.layerId,
      });
      this.group.setCoords();
      layer.fabricObjects = [this.group?.toObject?.(["id", "layerId"]) || this.group];
      removeCanvasObjectByObject(this.canvas, layer.fabricObjects[0]);

      insertObjectAtZIndex(this.canvas, this.group, insertIndex, false); // 插入到画布的指定位置
      // 将新填充对象添加到画布
    }

    this.canvas.renderAll();

    layer.fill = this.newFill.toObject(["id", "layerId"]);
    layer.fillColor = this.fillColor;

    this.canvasManager.thumbnailManager?.generateLayerThumbnail(this.layer.id);
    return true;
  }

  async undo() {
    this.layer.fillColor = this.oldFillColor;
    this.layer.fill = this.oldFill;

    this.group.removeWithUpdate(this.newFill);
    this.canvas.remove(this.newFill);
    this.canvas.renderAll();

    this.canvasManager.thumbnailManager?.generateLayerThumbnail(this.layer.id);
    return true;
  }

  _collectOriginalObjects() {
    if (this.layer.children && this.layer.children.length > 0) {
      // 如果是组图层，收集所有子图层的fabric对象
      return this.layer.children
        .flatMap((child) => child.fabricObjects || [])
        .map((obj) => {
          return findObjectById(this.canvas.value, obj.id)?.object || obj;
        });
    } else if (this.layer.fabricObjects && this.layer.fabricObjects.length > 0) {
      // 如果是普通图层，直接返回其fabric对象
      return this.layer.fabricObjects.map((obj) => {
        return findObjectById(this.canvas.value, obj.id)?.object || obj;
      });
    } else {
      // 如果没有fabric对象，返回空数组
      return [];
    }
  }
}