import { Transport } from "../transport.js";
import debugModule from "debug"; // debug()
import { yeast } from "../contrib/yeast.js";
import { encode } from "../contrib/parseqs.js";
import { encodePayload, decodePayload } from "engine.io-parser";
import { XHR as XMLHttpRequest } from "./xmlhttprequest.js";
import { Emitter } from "@socket.io/component-emitter";
import { installTimerFunctions, pick } from "../util.js";
import { globalThisShim as globalThis } from "../globalThis.js";
const debug = debugModule("engine.io-client:polling"); // debug()
function empty() { }
const hasXHR2 = (function () {
    const xhr = new XMLHttpRequest({
        xdomain: false
    });
    return null != xhr.responseType;
})();
export class Polling extends Transport {
    /**
     * XHR Polling constructor.
     *
     * @param {Object} opts
     * @api public
     */
    constructor(opts) {
        super(opts);
        this.polling = false;
        if (typeof location !== "undefined") {
            const isSSL = "https:" === location.protocol;
            let port = location.port;
            // some user agents have empty `location.port`
            if (!port) {
                port = isSSL ? "443" : "80";
            }
            this.xd =
                (typeof location !== "undefined" &&
                    opts.hostname !== location.hostname) ||
                    port !== opts.port;
            this.xs = opts.secure !== isSSL;
        }
        /**
         * XHR supports binary
         */
        const forceBase64 = opts && opts.forceBase64;
        this.supportsBinary = hasXHR2 && !forceBase64;
    }
    /**
     * Transport name.
     */
    get name() {
        return "polling";
    }
    /**
     * Opens the socket (triggers polling). We write a PING message to determine
     * when the transport is open.
     *
     * @api private
     */
    doOpen() {
        this.poll();
    }
    /**
     * Pauses polling.
     *
     * @param {Function} callback upon buffers are flushed and transport is paused
     * @api private
     */
    pause(onPause) {
        this.readyState = "pausing";
        const pause = () => {
            debug("paused");
            this.readyState = "paused";
            onPause();
        };
        if (this.polling || !this.writable) {
            let total = 0;
            if (this.polling) {
                debug("we are currently polling - waiting to pause");
                total++;
                this.once("pollComplete", function () {
                    debug("pre-pause polling complete");
                    --total || pause();
                });
            }
            if (!this.writable) {
                debug("we are currently writing - waiting to pause");
                total++;
                this.once("drain", function () {
                    debug("pre-pause writing complete");
                    --total || pause();
                });
            }
        }
        else {
            pause();
        }
    }
    /**
     * Starts polling cycle.
     *
     * @api public
     */
    poll() {
        debug("polling");
        this.polling = true;
        this.doPoll();
        this.emitReserved("poll");
    }
    /**
     * Overloads onData to detect payloads.
     *
     * @api private
     */
    onData(data) {
        debug("polling got data %s", data);
        const callback = packet => {
            // if its the first message we consider the transport open
            if ("opening" === this.readyState && packet.type === "open") {
                this.onOpen();
            }
            // if its a close packet, we close the ongoing requests
            if ("close" === packet.type) {
                this.onClose({ description: "transport closed by the server" });
                return false;
            }
            // otherwise bypass onData and handle the message
            this.onPacket(packet);
        };
        // decode payload
        decodePayload(data, this.socket.binaryType).forEach(callback);
        // if an event did not trigger closing
        if ("closed" !== this.readyState) {
            // if we got data we're not polling
            this.polling = false;
            this.emitReserved("pollComplete");
            if ("open" === this.readyState) {
                this.poll();
            }
            else {
                debug('ignoring poll - transport state "%s"', this.readyState);
            }
        }
    }
    /**
     * For polling, send a close packet.
     *
     * @api private
     */
    doClose() {
        const close = () => {
            debug("writing close packet");
            this.write([{ type: "close" }]);
        };
        if ("open" === this.readyState) {
            debug("transport open - closing");
            close();
        }
        else {
            // in case we're trying to close while
            // handshaking is in progress (GH-164)
            debug("transport not open - deferring close");
            this.once("open", close);
        }
    }
    /**
     * Writes a packets payload.
     *
     * @param {Array} data packets
     * @param {Function} drain callback
     * @api private
     */
    write(packets) {
        this.writable = false;
        encodePayload(packets, data => {
            this.doWrite(data, () => {
                this.writable = true;
                this.emitReserved("drain");
            });
        });
    }
    /**
     * Generates uri for connection.
     *
     * @api private
     */
    uri() {
        let query = this.query || {};
        const schema = this.opts.secure ? "https" : "http";
        let port = "";
        // cache busting is forced
        if (false !== this.opts.timestampRequests) {
            query[this.opts.timestampParam] = yeast();
        }
        if (!this.supportsBinary && !query.sid) {
            query.b64 = 1;
        }
        // avoid port if default for schema
        if (this.opts.port &&
            (("https" === schema && Number(this.opts.port) !== 443) ||
                ("http" === schema && Number(this.opts.port) !== 80))) {
            port = ":" + this.opts.port;
        }
        const encodedQuery = encode(query);
        const ipv6 = this.opts.hostname.indexOf(":") !== -1;
        return (schema +
            "://" +
            (ipv6 ? "[" + this.opts.hostname + "]" : this.opts.hostname) +
            port +
            this.opts.path +
            (encodedQuery.length ? "?" + encodedQuery : ""));
    }
    /**
     * Creates a request.
     *
     * @param {String} method
     * @api private
     */
    request(opts = {}) {
        Object.assign(opts, { xd: this.xd, xs: this.xs }, this.opts);
        return new Request(this.uri(), opts);
    }
    /**
     * Sends data.
     *
     * @param {String} data to send.
     * @param {Function} called upon flush.
     * @api private
     */
    doWrite(data, fn) {
        const req = this.request({
            method: "POST",
            data: data
        });
        req.on("success", fn);
        req.on("error", (xhrStatus, context) => {
            this.onError("xhr post error", xhrStatus, context);
        });
    }
    /**
     * Starts a poll cycle.
     *
     * @api private
     */
    doPoll() {
        debug("xhr poll");
        const req = this.request();
        req.on("data", this.onData.bind(this));
        req.on("error", (xhrStatus, context) => {
            this.onError("xhr poll error", xhrStatus, context);
        });
        this.pollXhr = req;
    }
}
export class Request extends Emitter {
    /**
     * Request constructor
     *
     * @param {Object} options
     * @api public
     */
    constructor(uri, opts) {
        super();
        installTimerFunctions(this, opts);
        this.opts = opts;
        this.method = opts.method || "GET";
        this.uri = uri;
        this.async = false !== opts.async;
        this.data = undefined !== opts.data ? opts.data : null;
        this.create();
    }
    /**
     * Creates the XHR object and sends the request.
     *
     * @api private
     */
    create() {
        const opts = pick(this.opts, "agent", "pfx", "key", "passphrase", "cert", "ca", "ciphers", "rejectUnauthorized", "autoUnref");
        opts.xdomain = !!this.opts.xd;
        opts.xscheme = !!this.opts.xs;
        const xhr = (this.xhr = new XMLHttpRequest(opts));
        try {
            debug("xhr open %s: %s", this.method, this.uri);
            xhr.open(this.method, this.uri, this.async);
            try {
                if (this.opts.extraHeaders) {
                    xhr.setDisableHeaderCheck && xhr.setDisableHeaderCheck(true);
                    for (let i in this.opts.extraHeaders) {
                        if (this.opts.extraHeaders.hasOwnProperty(i)) {
                            xhr.setRequestHeader(i, this.opts.extraHeaders[i]);
                        }
                    }
                }
            }
            catch (e) { }
            if ("POST" === this.method) {
                try {
                    xhr.setRequestHeader("Content-type", "text/plain;charset=UTF-8");
                }
                catch (e) { }
            }
            try {
                xhr.setRequestHeader("Accept", "*/*");
            }
            catch (e) { }
            // ie6 check
            if ("withCredentials" in xhr) {
                xhr.withCredentials = this.opts.withCredentials;
            }
            if (this.opts.requestTimeout) {
                xhr.timeout = this.opts.requestTimeout;
            }
            xhr.onreadystatechange = () => {
                if (4 !== xhr.readyState)
                    return;
                if (200 === xhr.status || 1223 === xhr.status) {
                    this.onLoad();
                }
                else {
                    // make sure the `error` event handler that's user-set
                    // does not throw in the same tick and gets caught here
                    this.setTimeoutFn(() => {
                        this.onError(typeof xhr.status === "number" ? xhr.status : 0);
                    }, 0);
                }
            };
            debug("xhr data %s", this.data);
            xhr.send(this.data);
        }
        catch (e) {
            // Need to defer since .create() is called directly from the constructor
            // and thus the 'error' event can only be only bound *after* this exception
            // occurs.  Therefore, also, we cannot throw here at all.
            this.setTimeoutFn(() => {
                this.onError(e);
            }, 0);
            return;
        }
        if (typeof document !== "undefined") {
            this.index = Request.requestsCount++;
            Request.requests[this.index] = this;
        }
    }
    /**
     * Called upon error.
     *
     * @api private
     */
    onError(err) {
        this.emitReserved("error", err, this.xhr);
        this.cleanup(true);
    }
    /**
     * Cleans up house.
     *
     * @api private
     */
    cleanup(fromError) {
        if ("undefined" === typeof this.xhr || null === this.xhr) {
            return;
        }
        this.xhr.onreadystatechange = empty;
        if (fromError) {
            try {
                this.xhr.abort();
            }
            catch (e) { }
        }
        if (typeof document !== "undefined") {
            delete Request.requests[this.index];
        }
        this.xhr = null;
    }
    /**
     * Called upon load.
     *
     * @api private
     */
    onLoad() {
        const data = this.xhr.responseText;
        if (data !== null) {
            this.emitReserved("data", data);
            this.emitReserved("success");
            this.cleanup();
        }
    }
    /**
     * Aborts the request.
     *
     * @api public
     */
    abort() {
        this.cleanup();
    }
}
Request.requestsCount = 0;
Request.requests = {};
/**
 * Aborts pending requests when unloading the window. This is needed to prevent
 * memory leaks (e.g. when using IE) and to ensure that no spurious error is
 * emitted.
 */
if (typeof document !== "undefined") {
    // @ts-ignore
    if (typeof attachEvent === "function") {
        // @ts-ignore
        attachEvent("onunload", unloadHandler);
    }
    else if (typeof addEventListener === "function") {
        const terminationEvent = "onpagehide" in globalThis ? "pagehide" : "unload";
        addEventListener(terminationEvent, unloadHandler, false);
    }
}
function unloadHandler() {
    for (let i in Request.requests) {
        if (Request.requests.hasOwnProperty(i)) {
            Request.requests[i].abort();
        }
    }
}