import {extend, warnOnce, isWorker} from './util';
import {config} from './config';

import type {Callback} from '../types/callback';
import type {Cancelable} from '../types/cancelable';

/**
 * A `RequestParameters` object to be returned from Map.options.transformRequest callbacks.
 * @example
 * ```ts
 * // use transformRequest to modify requests that begin with `http://myHost`
 * transformRequest: function(url, resourceType) {
 *  if (resourceType === 'Source' && url.indexOf('http://myHost') > -1) {
 *    return {
 *      url: url.replace('http', 'https'),
 *      headers: { 'my-custom-header': true },
 *      credentials: 'include'  // Include cookies for cross-origin requests
 *    }
 *   }
 * }
 * ```
 */
export type RequestParameters = {
    /**
     * The URL to be requested.
     */
    url: string;
    /**
     * The headers to be sent with the request.
     */
    headers?: any;
    /**
     * Request method `'GET' | 'POST' | 'PUT'`.
     */
    method?: 'GET' | 'POST' | 'PUT';
    /**
     * Request body.
     */
    body?: string;
    /**
     * Response body type to be returned `'string' | 'json' | 'arrayBuffer'`.
     */
    type?: 'string' | 'json' | 'arrayBuffer' | 'image';
    /**
     * `'same-origin'|'include'` Use 'include' to send cookies with cross-origin requests.
     */
    credentials?: 'same-origin' | 'include';
    /**
     * If `true`, Resource Timing API information will be collected for these transformed requests and returned in a resourceTiming property of relevant data events.
     */
    collectResourceTiming?: boolean;
};

/**
 * The response callback used in various places
 */
export type ResponseCallback<T> = (
    error?: Error | null,
    data?: T | null,
    cacheControl?: string | null,
    expires?: string | null
) => void;

/**
 * An error thrown when a HTTP request results in an error response.
 */
export class AJAXError extends Error {
    /**
     * The response's HTTP status code.
     */
    status: number;

    /**
     * The response's HTTP status text.
     */
    statusText: string;

    /**
     * The request's URL.
     */
    url: string;

    /**
     * The response's body.
     */
    body: Blob;

    /**
     * @param status - The response's HTTP status code.
     * @param statusText - The response's HTTP status text.
     * @param url - The request's URL.
     * @param body - The response's body.
     */
    constructor(status: number, statusText: string, url: string, body: Blob) {
        super(`AJAXError: ${statusText} (${status}): ${url}`);
        this.status = status;
        this.statusText = statusText;
        this.url = url;
        this.body = body;
    }
}

// Ensure that we're sending the correct referrer from blob URL worker bundles.
// For files loaded from the local file system, `location.origin` will be set
// to the string(!) "null" (Firefox), or "file://" (Chrome, Safari, Edge, IE),
// and we will set an empty referrer. Otherwise, we're using the document's URL.
/* global self */
export const getReferrer = isWorker() ?
    () => (self as any).worker && (self as any).worker.referrer :
    () => (window.location.protocol === 'blob:' ? window.parent : window).location.href;

export const getProtocolAction = url => config.REGISTERED_PROTOCOLS[url.substring(0, url.indexOf('://'))];

// Determines whether a URL is a file:// URL. This is obviously the case if it begins
// with file://. Relative URLs are also file:// URLs iff the original document was loaded
// via a file:// URL.
const isFileURL = url => /^file:/.test(url) || (/^file:/.test(getReferrer()) && !/^\w+:/.test(url));

function makeFetchRequest(requestParameters: RequestParameters, callback: ResponseCallback<any>): Cancelable {
    const controller = new AbortController();
    const request = new Request(requestParameters.url, {
        method: requestParameters.method || 'GET',
        body: requestParameters.body,
        credentials: requestParameters.credentials,
        headers: requestParameters.headers,
        referrer: getReferrer(),
        signal: controller.signal
    });
    let complete = false;
    let aborted = false;

    if (requestParameters.type === 'json') {
        request.headers.set('Accept', 'application/json');
    }

    const validateOrFetch = (err, cachedResponse?, responseIsFresh?) => {
        if (aborted) return;

        if (err) {
            // Do fetch in case of cache error.
            // HTTP pages in Edge trigger a security error that can be ignored.
            if (err.message !== 'SecurityError') {
                warnOnce(err);
            }
        }

        if (cachedResponse && responseIsFresh) {
            return finishRequest(cachedResponse);
        }

        if (cachedResponse) {
            // We can't do revalidation with 'If-None-Match' because then the
            // request doesn't have simple cors headers.
        }

        fetch(request).then(response => {
            if (response.ok) {
                return finishRequest(response);

            } else {
                return response.blob().then(body => callback(new AJAXError(response.status, response.statusText, requestParameters.url, body)));
            }
        }).catch(error => {
            if (error.code === 20) {
                // silence expected AbortError
                return;
            }
            callback(new Error(error.message));
        });
    };

    const finishRequest = (response) => {
        (
            (requestParameters.type === 'arrayBuffer' || requestParameters.type === 'image') ? response.arrayBuffer() :
                requestParameters.type === 'json' ? response.json() :
                    response.text()
        ).then(result => {
            if (aborted) return;
            complete = true;
            callback(null, result, response.headers.get('Cache-Control'), response.headers.get('Expires'));
        }).catch(err => {
            if (!aborted) callback(new Error(err.message));
        });
    };

    validateOrFetch(null, null);

    return {cancel: () => {
        aborted = true;
        if (!complete) controller.abort();
    }};
}

function makeXMLHttpRequest(requestParameters: RequestParameters, callback: ResponseCallback<any>): Cancelable {
    const xhr: XMLHttpRequest = new XMLHttpRequest();

    xhr.open(requestParameters.method || 'GET', requestParameters.url, true);
    if (requestParameters.type === 'arrayBuffer' || requestParameters.type === 'image') {
        xhr.responseType = 'arraybuffer';
    }
    for (const k in requestParameters.headers) {
        xhr.setRequestHeader(k, requestParameters.headers[k]);
    }
    if (requestParameters.type === 'json') {
        xhr.responseType = 'text';
        xhr.setRequestHeader('Accept', 'application/json');
    }
    xhr.withCredentials = requestParameters.credentials === 'include';
    xhr.onerror = () => {
        callback(new Error(xhr.statusText));
    };
    xhr.onload = () => {
        if (((xhr.status >= 200 && xhr.status < 300) || xhr.status === 0) && xhr.response !== null) {
            let data: unknown = xhr.response;
            if (requestParameters.type === 'json') {
                // We're manually parsing JSON here to get better error messages.
                try {
                    data = JSON.parse(xhr.response);
                } catch (err) {
                    return callback(err);
                }
            }
            callback(null, data, xhr.getResponseHeader('Cache-Control'), xhr.getResponseHeader('Expires'));
        } else {
            const body = new Blob([xhr.response], {type: xhr.getResponseHeader('Content-Type')});
            callback(new AJAXError(xhr.status, xhr.statusText, requestParameters.url, body));
        }
    };
    xhr.send(requestParameters.body);
    return {cancel: () => xhr.abort()};
}

export const makeRequest = function(requestParameters: RequestParameters, callback: ResponseCallback<any>): Cancelable {
    // We're trying to use the Fetch API if possible. However, in some situations we can't use it:
    // - IE11 doesn't support it at all. In this case, we dispatch the request to the main thread so
    //   that we can get an accruate referrer header.
    // - Safari exposes window.AbortController, but it doesn't work actually abort any requests in
    //   some versions (see https://bugs.webkit.org/show_bug.cgi?id=174980#c2)
    // - Requests for resources with the file:// URI scheme don't work with the Fetch API either. In
    //   this case we unconditionally use XHR on the current thread since referrers don't matter.
    if (/:\/\//.test(requestParameters.url) && !(/^https?:|^file:/.test(requestParameters.url))) {
        if (isWorker() && (self as any).worker && (self as any).worker.actor) {
            return (self as any).worker.actor.send('getResource', requestParameters, callback);
        }
        if (!isWorker()) {
            const action = getProtocolAction(requestParameters.url) || makeFetchRequest;
            return action(requestParameters, callback);
        }
    }
    if (!isFileURL(requestParameters.url)) {
        if (fetch && Request && AbortController && Object.prototype.hasOwnProperty.call(Request.prototype, 'signal')) {
            return makeFetchRequest(requestParameters, callback);
        }
        if (isWorker() && (self as any).worker && (self as any).worker.actor) {
            const queueOnMainThread = true;
            return (self as any).worker.actor.send('getResource', requestParameters, callback, undefined, queueOnMainThread);
        }
    }
    return makeXMLHttpRequest(requestParameters, callback);
};

export const getJSON = function(requestParameters: RequestParameters, callback: ResponseCallback<any>): Cancelable {
    return makeRequest(extend(requestParameters, {type: 'json'}), callback);
};

export const getArrayBuffer = function(
    requestParameters: RequestParameters,
    callback: ResponseCallback<ArrayBuffer>
): Cancelable {
    return makeRequest(extend(requestParameters, {type: 'arrayBuffer'}), callback);
};

export const postData = function(requestParameters: RequestParameters, callback: ResponseCallback<string>): Cancelable {
    return makeRequest(extend(requestParameters, {method: 'POST'}), callback);
};

export function sameOrigin(inComingUrl: string) {
    // URL class should be available everywhere
    // https://developer.mozilla.org/en-US/docs/Web/API/URL
    // In addtion, a relative URL "/foo" or "./foo" will throw exception in its ctor,
    // try-catch is expansive so just use a heuristic check to avoid it
    // also check data URL
    if (!inComingUrl ||
        inComingUrl.indexOf('://') <= 0 || // relative URL
        inComingUrl.indexOf('data:image/') === 0 || // data image URL
        inComingUrl.indexOf('blob:') === 0) { // blob
        return true;
    }
    const urlObj = new URL(inComingUrl);
    const locationObj = window.location;
    return urlObj.protocol === locationObj.protocol && urlObj.host === locationObj.host;
}
/**
 * A type used to store the tile's expiration date and cache control definition
 */
export type ExpiryData = {cacheControl?: string | null; expires?: Date | string | null};
export const getVideo = function(urls: Array<string>, callback: Callback<HTMLVideoElement>): Cancelable {
    const video: HTMLVideoElement = window.document.createElement('video');
    video.muted = true;
    video.onloadstart = function() {
        callback(null, video);
    };
    for (let i = 0; i < urls.length; i++) {
        const s: HTMLSourceElement = window.document.createElement('source');
        if (!sameOrigin(urls[i])) {
            video.crossOrigin = 'Anonymous';
        }
        s.src = urls[i];
        video.appendChild(s);
    }
    return {cancel: () => {}};
};