import UI_ListItem  from "./UI_ListItem";
import VirtualList from "./VirtualList";

const { ccclass, property } = cc._decorator;
@ccclass
export default class PM_UI_List<T> extends cc.Component {

    @property(cc.Node)
    itemContainer: cc.Node = null;
    @property(cc.Node)
    copyeeItem: cc.Node = null;
    @property(cc.ScrollView)
    scroll: cc.ScrollView = null;
    mItems: cc.Node[] = [];

    ////// 虚拟列表 begin ///////
    @property
    isVirtual: boolean = false;
    @property({ type: cc.Integer, tooltip: "视口显示数量(用于虚拟列表)" })
    viewPortItemCount: number = 1;
    ////// 虚拟列表 end ///////

    private addItems(data: T[]) {
        let _len = data.length;
        for (let i = 0; i < _len; i++) {
            let _item = cc.instantiate(this.copyeeItem);
            let _dataItem = data[i];
            this.mItems.push(_item);
            let _itemCls = _item.getComponent(UI_ListItem);
            _itemCls.showInfo(_dataItem);
            _itemCls.itemData = _dataItem;

            this.itemContainer.addChild(_item);
        }
    }
    
    private mVirtualListMrg:VirtualList;
    private mListData: T[];
    showList(data: T[]) {
        this.mListData = data;
        this.initDataIdx();
        this.itemContainer.removeAllChildren();
        if (!this.isVirtual) {
            this.addItems(data);
        }
        else {
            if(!this.mVirtualListMrg){
                this.mVirtualListMrg = new VirtualList();
            }
            this.mVirtualListMrg.initVirtualList(this.viewPortItemCount,this.mListData,this.itemContainer,this.scroll,this.copyeeItem)
        }
    }

    private initDataIdx() {
        this.mListData.forEach((item, idx) => {
            item["_list_idx_"] = idx;
        })
    }
}