/**
 * Http请求
 * @author Egret、袁浩
 */
 export class HttpRequest {
    private onIOError: (url: String) => void
    private onComplete: (httpRequest: HttpRequest) => void
    private onProgress: (loaded: number, total: number) => void
    /**
     * @private
     */
    public constructor(onIOError: (url: String) => void, onComplete: (data: HttpRequest) => void, onProgress: (loaded: number, total: number) => void) {
        this.onIOError = onIOError;
        this.onComplete = onComplete;
        this.onProgress = onProgress;
    }

    /**
     * @private
     */
    private _xhr: XMLHttpRequest;

    /**
     * 
     */
    public timeout: number = 0;

    /**
     * @private
     * 本次请求返回的数据，数据类型根据responseType设置的值确定。
     */

    public get response(): any {
        if (!this._xhr) {
            return null;
        }

        if (this._xhr.response != undefined) {
            return this._xhr.response;
        }

        if (this._responseType == "text") {
            return this._xhr.responseText;
        }

        if (this._responseType == "arraybuffer" && /msie 9.0/i.test(navigator.userAgent)) {
            let w: any = window;
            return w.convertResponseBodyToText(this._xhr["responseBody"]);
        }

        if (this._responseType == "document") {
            return this._xhr.responseXML;
        }

        /*if (this._xhr.responseXML) {
            return this._xhr.responseXML;
        }
        if (this._xhr.responseText != undefined) {
            return this._xhr.responseText;
        }*/
        return null;
    }

    /**
     * @private
     */
    private _responseType: "" | "arraybuffer" | "blob" | "document" | "json" | "text";

    /**
     * @private
     * 设置返回的数据格式，请使用 HttpResponseType 里定义的枚举值。设置非法的值或不设置，都将使用HttpResponseType.TEXT。
     */
    public get responseType(): "" | "arraybuffer" | "blob" | "document" | "json" | "text" {
        return this._responseType;
    }

    public set responseType(value: "" | "arraybuffer" | "blob" | "document" | "json" | "text") {
        this._responseType = value;
    }

    /**
     * @private
     */
    private _withCredentials: boolean;

    /**
     * @private
     * 表明在进行跨站(cross-site)的访问控制(Access-Control)请求时，是否使用认证信息(例如cookie或授权的header)。 默认为 false。(这个标志不会影响同站的请求)
     */
    public get withCredentials(): boolean {
        return this._withCredentials;
    }

    public set withCredentials(value: boolean) {
        this._withCredentials = value;
    }

    /**
     * @private
     */
    private _url: string = "";
    public get url(): string {
        return this._url;
    }
    private _method: string = "";

    /**
     * @private
     *
     * @returns
     */
    private getXHR(): XMLHttpRequest {
        if (window["XMLHttpRequest"]) {
            return new window["XMLHttpRequest"]();
        } else {
            return new ActiveXObject("MSXML2.XMLHTTP");
        }
    }

    /**
     * @private
     * 初始化一个请求.注意，若在已经发出请求的对象上调用此方法，相当于立即调用abort().
     * @param url 该请求所要访问的URL该请求所要访问的URL
     * @param method 请求所使用的HTTP方法， 请使用 HttpMethod 定义的枚举值.
     */
    public open(url: string, method: string = "GET"): void {
        this._url = url;
        this._method = method;
        if (this._xhr) {
            this._xhr.abort();
            this._xhr = null;
        }
        let xhr = this.getXHR();//new XMLHttpRequest();
        if (window["XMLHttpRequest"]) {
            xhr.addEventListener("load", this.onload.bind(this));
            xhr.addEventListener("error", this.onerror.bind(this));
        } else {
            xhr.onreadystatechange = this.onReadyStateChange.bind(this);
        }
        xhr.onprogress = this.updateProgress.bind(this);
        xhr.ontimeout = this.onTimeout.bind(this)
        xhr.open(this._method, this._url, true);
        this._xhr = xhr;
    }

    /**
     * @private
     * 发送请求.
     * @param data 需要发送的数据
     */
    public send(data?: any): void {
        if (this._responseType != null) {
            this._xhr.responseType = this._responseType;
        }
        if (this._withCredentials != null) {
            this._xhr.withCredentials = this._withCredentials;
        }
        if (this.headerObj) {
            for (let key in this.headerObj) {
                this._xhr.setRequestHeader(key, this.headerObj[key]);
            }
        }
        this._xhr.timeout = this.timeout;
        this._xhr.send(data);
    }

    /**
     * @private
     * 如果请求已经被发送,则立刻中止请求.
     */
    public abort(): void {
        if (this._xhr) {
            this._xhr.abort();
        }
    }

    /**
     * @private
     * 返回所有响应头信息(响应头名和值), 如果响应头还没接受,则返回"".
     */
    public getAllResponseHeaders(): string {
        if (!this._xhr) {
            return null;
        }
        let result = this._xhr.getAllResponseHeaders();
        return result ? result : "";
    }

    private headerObj: any;
    /**
     * @private
     * 给指定的HTTP请求头赋值.在这之前,您必须确认已经调用 open() 方法打开了一个url.
     * @param header 将要被赋值的请求头名称.
     * @param value 给指定的请求头赋的值.
     */
    public setRequestHeader(header: string, value: string): void {
        if (!this.headerObj) {
            this.headerObj = {};
        }
        this.headerObj[header] = value;
    }

    /**
     * @private
     * 返回指定的响应头的值, 如果响应头还没被接受,或该响应头不存在,则返回"".
     * @param header 要返回的响应头名称
     */
    public getResponseHeader(header: string): string {
        if (!this._xhr) {
            return null;
        }
        let result = this._xhr.getResponseHeader(header);
        return result ? result : "";
    }
    /**
     * @private
     */
    private onTimeout(): void {
        this.onIOError && this.onIOError(this.url);
    }

    /**
     * @private
     */
    private onReadyStateChange(): void {
        let xhr = this._xhr;
        if (xhr.readyState == 4) {// 4 = "loaded"
            let ioError = (xhr.status >= 400 || xhr.status == 0);
            let url = this._url;
            let self = this;
            window.setTimeout(function (): void {
                if (ioError) {//请求错误
                    self.onIOError && self.onIOError(self.url);
                }
                else {
                    self.onComplete && self.onComplete(self);
                }
            }, 0)

        }
    }

    /**
     * @private
     */
    private updateProgress(event): void {
        if (event.lengthComputable) {
            this.onProgress && this.onProgress(event.loaded, event.total);
        }
    }


    /**
     * @private
     */
    private onload(): void {
        let self = this;
        let xhr = this._xhr;
        let url = this._url;
        let ioError = (xhr.status >= 400);
        window.setTimeout(function (): void {
            if (ioError) {//请求错误
                self.onIOError && self.onIOError(self.url);
            }
            else {
                self.onComplete && self.onComplete(self);
            }
        }, 0);
    }

    /**
     * @private
     */
    private onerror(): void {
        let url = this._url;
        let self = this;
        window.setTimeout(function (): void {
            self.onIOError && self.onIOError(self.url);
        }, 0);
    }
}