import * as Tools from "../tool";


class TracerEvent {
    //拦截window.history.pusgState原生方法
    private _pushState: any;
    private _replaceState: any;
    //时间监听处理方法集
    private handlePageChangeEventList: any[];
    private isPageChangeHandle : boolean;


    constructor() {
        this.handlePageChangeEventList = [];
        this.isPageChangeHandle = false;
        this.resgisterPageChangeEventListener();
    }


    private resgisterPageChangeEventListener = () => {
        //监听相关内容
        var self = this;
        //hashchange
        (<any>window).addEventListener("hashchange",this.onHandleEvent);
        //pushStateModel  replaceStateModel
        self._pushState = window.history.pushState;
        window.history.pushState = function(state, title, url) {
            let oldURL = window.location.href;
            let newURL = url ? url : oldURL;
            // hook 
            self.onHandleEvent({
                eventName:'pushState',
                oldURL,
                newURL,
                state,
                title,
            })
            //run 
            return self._pushState.apply(window.history, arguments);
        };
        self._replaceState = window.history.replaceState
        window.history.replaceState = function(state, title, url) {
            let oldURL = window.location.href;
            let newURL = url ? url : oldURL;// hook 
            self.onHandleEvent({
                eventName:'replaceState',
                oldURL,
                newURL,
                state,
                title,
            })
            return self._replaceState.apply(window.history, arguments);
        };
    };

    
    private checkPageUrlChange = (oldUrl,newUrL) => {
        //其中某一次不存在
        if(!oldUrl || !newUrL || !Tools.isString(oldUrl) || !Tools.isString(newUrL) ){
            return false;
        }
        //has path没有变化
        if(newUrL.indexOf('?') > -1 && oldUrl.indexOf('?') > -1){
            let newPath = newUrL.split('?')[0]
            let oldPath = newUrL.split('?')[0]
            if( newPath === oldPath){
                return false;
            }
        }
        return true
    }


    private onHandleEvent = (event) => {
        if(this.isPageChangeHandle){
            return false;
        }
        const{ newURL , oldURL } = event
        if(!this.checkPageUrlChange(oldURL,newURL)){return false}
        //on Hook
        this.isPageChangeHandle = true
        Tools.asynGenerator(
            (next) => {
                this.handlePageChangeEventList.forEach( (onHook) =>{
                    try{
                        onHook(event)
                    }catch(e){
                        console.error(e)
                    }
                })
                next()
            },
            (next) =>{
                this.isPageChangeHandle = false
            }
        )
    }


    //注册页面跳转事件处理钩子
    public addPageChangeEventLister = (onHandleHook) => {
        if(Tools.isFunction(onHandleHook)){
            this.handlePageChangeEventList.push(onHandleHook)
        }
    }


    public stopPageChangeEventCatch = () => {
        window.history.pushState  = this._pushState
        window.history.replaceState = this._replaceState
        this._pushState = false
        this._replaceState = false;
        (<any>window).removeEventListener("hashchange",this.onHandleEvent);
    }

    public resumePageChangeEventCatch = () => {
        this.resgisterPageChangeEventListener()
    }

    
}

export default TracerEvent;