/*******************************************************************************

    ηMatrix - a browser extension to black/white list requests.
    Copyright (C) 2014-2019 Raymond Hill
    Copyright (C) 2019-2020 Alessio Vanni

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://libregit.org/heckyel/ematrix
    uMatrix Home: https://github.com/gorhill/uMatrix
*/

'use strict';

/******************************************************************************/

ηMatrix.webRequest = (function() {

    Cu.import('chrome://ematrix/content/lib/UriTools.jsm');

    // Intercept and filter web requests according to white and black lists.
    var onBeforeRootFrameRequestHandler = function (details) {
        let ηm = ηMatrix;
        let requestURL = details.url;
        let requestHostname = UriTools.hostnameFromURI(requestURL);
        let tabId = details.tabId;

        ηm.tabContextManager.push(tabId, requestURL);

        let tabContext = ηm.tabContextManager.mustLookup(tabId);
        let rootHostname = tabContext.rootHostname;

        // Disallow request as per matrix?
        let block = ηm.mustBlock(rootHostname, requestHostname, 'doc');

        let pageStore = ηm.pageStoreFromTabId(tabId);
        pageStore.recordRequest('doc', requestURL, block);
        ηm.logger.writeOne(tabId, 'net', rootHostname, requestURL, 'doc', block);

        // Not blocked
        if (!block) {
            // rhill 2013-11-07: Senseless to do this for
            // behind-the-scene requests.
            ηm.cookieHunter.recordPageCookies(pageStore);
            return;
        }

        // Blocked
        var query = btoa(JSON.stringify({
            url: requestURL,
            hn: requestHostname,
            why: '?'
        }));

        vAPI.tabs.replace(tabId,
                          vAPI.getURL('main-blocked.html?details=') + query);

        return {
            cancel: true
        };
    };

    // Intercept and filter web requests according to white and black lists.
    var onBeforeRequestHandler = function (details) {
        let ηm = ηMatrix;
        let requestURL = details.url;
        let requestScheme = UriTools.schemeFromURI(requestURL);

        if (UriTools.isNetworkScheme(requestScheme) === false) {
            return;
        }

        var requestType = requestTypeNormalizer[details.type] || 'other';

        // https://github.com/gorhill/httpswitchboard/issues/303
        // Wherever the main doc comes from, create a receiver page
        // URL: synthetize one if needed.
        if (requestType === 'doc' && details.parentFrameId === -1) {
            return onBeforeRootFrameRequestHandler(details);
        }

        // Re-classify orphan HTTP requests as behind-the-scene
        // requests. There is not much else which can be done, because
        // there are URLs which cannot be handled by ηMatrix,
        // i.e. `opera://startpage`, as this would lead to
        // complications with no obvious solution, like how to scope
        // on unknown scheme? Etc.
        // https://github.com/gorhill/httpswitchboard/issues/191
        // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
        let tabContext = ηm.tabContextManager.mustLookup(details.tabId);
        let tabId = tabContext.tabId;
        let rootHostname = tabContext.rootHostname;
        let specificity = 0;

        // Filter through matrix
        let block = ηm.tMatrix.mustBlock(rootHostname,
                                         UriTools.hostnameFromURI(requestURL),
                                         requestType);
        if (block) {
            specificity = ηm.tMatrix.specificityRegister;
        }

        // Record request.
        // https://github.com/gorhill/httpswitchboard/issues/342
        // The way requests are handled now, it may happen at this
        // point some processing has already been performed, and that
        // a synthetic URL has been constructed for logging
        // purpose. Use this synthetic URL if it is available.
        let pageStore = ηm.mustPageStoreFromTabId(tabId);

        // Enforce strict secure connection?
        if (tabContext.secure
            && UriTools.isSecureScheme(requestScheme) === false) {
            pageStore.hasMixedContent = true;
            if (block === false) {
                block = ηm.tMatrix.evaluateSwitchZ('https-strict', rootHostname);
            }
        }

        pageStore.recordRequest(requestType, requestURL, block);
        ηm.logger.writeOne(tabId, 'net', rootHostname,
                           requestURL, details.type, block);

        if (block) {
            pageStore.cacheBlockedCollapsible(requestType,
                                              requestURL, specificity);
            return {
                'cancel': true
            };
        }
    };

    // Sanitize outgoing headers as per user settings.
    var onBeforeSendHeadersHandler = function (details) {
        let ηm = ηMatrix;
        let requestURL = details.url;
        let requestScheme = UriTools.schemeFromURI(requestURL);

        // Ignore non-network schemes
        if (UriTools.isNetworkScheme(requestScheme) === false) {
            return;
        }

        // Re-classify orphan HTTP requests as behind-the-scene
        // requests. There is not much else which can be done, because
        // there are URLs which cannot be handled by HTTP Switchboard,
        // i.e. `opera://startpage`, as this would lead to
        // complications with no obvious solution, like how to scope
        // on unknown scheme? Etc.
        // https://github.com/gorhill/httpswitchboard/issues/191
        // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
        let tabId = details.tabId;
        let pageStore = ηm.mustPageStoreFromTabId(tabId);
        let requestType = requestTypeNormalizer[details.type] || 'other';
        let requestHeaders = details.requestHeaders;
        let headerIndex, headerValue;

        // https://github.com/gorhill/httpswitchboard/issues/342
        // Is this hyperlink auditing?  If yes, create a synthetic URL
        // for reporting hyperlink auditing in request log. This way
        // the user is better informed of what went on.

        // https://html.spec.whatwg.org/multipage/links.html#hyperlink-auditing
        //
        // Target URL = the href of the link
        // Doc URL = URL of the document containing the target URL
        // Ping URLs = servers which will be told that user clicked target URL
        //
        // `Content-Type` = `text/ping` (always present)
        // `Ping-To` = target URL (always present)
        // `Ping-From` = doc URL
        // `Referer` = doc URL
        // request URL = URL which will receive the information
        //
        // With hyperlink-auditing, removing header(s) is pointless, the whole
        // request must be cancelled.
        headerIndex = headerIndexFromName('ping-to', requestHeaders);
        if (headerIndex !== -1) {
            headerValue = requestHeaders[headerIndex].value;
            if (headerValue !== '') {
                let block = ηm.userSettings.processHyperlinkAuditing;
                pageStore.recordRequest('other',
                                        requestURL
                                        + '{Ping-To:'
                                        + headerValue
                                        + '}', block);
                ηm.logger.writeOne(tabId, 'net', '', requestURL, 'ping', block);
                if (block) {
                    ηm.hyperlinkAuditingFoiledCounter += 1;
                    return {
                        'cancel': true
                    };
                }
            }
        }

        // If we reach this point, request is not blocked, so what is
        // left to do is to sanitize headers.
        let rootHostname = pageStore.pageHostname;
        let requestHostname = UriTools.hostnameFromURI(requestURL);
        let modified = false;

        // Process `Cookie` header.
        headerIndex = headerIndexFromName('cookie', requestHeaders);
        if (headerIndex !== -1
            && ηm.mustBlock(rootHostname, requestHostname, 'cookie')) {
            modified = true;
            headerValue = requestHeaders[headerIndex].value;
            requestHeaders.splice(headerIndex, 1);
            ηm.cookieHeaderFoiledCounter++;
            if (requestType === 'doc') {
                ηm.logger.writeOne(tabId, 'net', '', headerValue, 'COOKIE', true);
            }
        }

        // Process `Referer` header.
        // https://github.com/gorhill/httpswitchboard/issues/222#issuecomment-44828402

        // https://github.com/gorhill/uMatrix/issues/320
        // http://tools.ietf.org/html/rfc6454#section-7.3
        //   "The user agent MAY include an Origin header field in any HTTP
        //   "request.
        //   "The user agent MUST NOT include more than one Origin header field in
        //   "any HTTP request.
        //   "Whenever a user agent issues an HTTP request from a "privacy-
        //   "sensitive" context, the user agent MUST send the value "null" in the
        //   "Origin header field."

        // https://github.com/gorhill/uMatrix/issues/358
        // Do not spoof `Origin` header for the time being.

        // https://github.com/gorhill/uMatrix/issues/773
        // For non-GET requests, remove `Referer` header instead of spoofing it.

        headerIndex = headerIndexFromName('referer', requestHeaders);
        if (headerIndex !== -1) {
            headerValue = requestHeaders[headerIndex].value;
            if (headerValue !== '') {
                let toDomain = UriTools.domainFromHostname(requestHostname);
                if (toDomain !== ''
                    && toDomain !== UriTools.domainFromURI(headerValue)) {
                    pageStore.has3pReferrer = true;
                    if (ηm.tMatrix.evaluateSwitchZ('referrer-spoof',
                                                   rootHostname)) {
                        modified = true;
                        let newValue;
                        if (details.method === 'GET') {
                            newValue = requestHeaders[headerIndex].value =
                                requestScheme + '://' + requestHostname + '/';
                        } else {
                            requestHeaders.splice(headerIndex, 1);
                        }
                        ηm.refererHeaderFoiledCounter++;
                        if (requestType === 'doc') {
                            ηm.logger.writeOne(tabId, 'net', '',
                                               headerValue, 'REFERER', true);
                            if (newValue !== undefined) {
                                ηm.logger.writeOne(tabId, 'net', '',
                                                   newValue, 'REFERER', false);
                            }
                        }
                    }
                }
            }
        }

        if (modified) {
            return {
                requestHeaders: requestHeaders
            };
        }
    };

    // To prevent inline javascript from being executed.

    // Prevent inline scripting using `Content-Security-Policy`:
    // https://dvcs.w3.org/hg/content-security-policy/raw-file/tip/csp-specification.dev.html

    // This fixes:
    // https://github.com/gorhill/httpswitchboard/issues/35
    var onHeadersReceived = function (details) {
        // Ignore schemes other than 'http...'
        let ηm = ηMatrix;
        let tabId = details.tabId;
        let requestURL = details.url;
        let requestType = requestTypeNormalizer[details.type] || 'other';

        // https://github.com/gorhill/uMatrix/issues/145
        // Check if the main_frame is a download
        if (requestType === 'doc') {
            ηm.tabContextManager.push(tabId, requestURL);
        }

        let tabContext = ηm.tabContextManager.lookup(tabId);
        if (tabContext === null) {
            return;
        }

        let csp = [];
        let cspReport = [];
        let rootHostname = tabContext.rootHostname;
        let requestHostname = UriTools.hostnameFromURI(requestURL);

        // Inline script tags.
        if (ηm.mustAllow(rootHostname, requestHostname, 'script') !== true) {
            csp.push(ηm.cspNoInlineScript);
        }

        // Inline style tags.
        if (ηm.mustAllow(rootHostname, requestHostname, 'css') !== true) {
            csp.push(ηm.cspNoInlineStyle);
        }

        // https://bugzilla.mozilla.org/show_bug.cgi?id=1302667
        let cspNoWorker = ηm.cspNoWorker;
        if (cspNoWorker === undefined) {
            cspNoWorker = cspNoWorkerInit();
        }

        if (ηm.tMatrix.evaluateSwitchZ('no-workers', rootHostname)) {
            csp.push(cspNoWorker);
        } else if (ηm.rawSettings.disableCSPReportInjection === false) {
            cspReport.push(cspNoWorker);
        }

        let headers = details.responseHeaders;
        let cspDirectives, i;

        if (csp.length !== 0) {
            cspDirectives = csp.join(',');
            i = headerIndexFromName('content-security-policy', headers);
            if (i !== -1) {
                headers[i].value += ',' + cspDirectives;
            } else {
                headers.push({
                    name: 'Content-Security-Policy',
                    value: cspDirectives
                });
            }
            if (requestType === 'doc') {
                ηm.logger.writeOne(tabId, 'net', '', cspDirectives, 'CSP', false);
            }
        }

        if (cspReport.length !== 0) {
            cspDirectives = cspReport.join(',');
            i = headerIndexFromName('content-security-policy-report-only',
                                    headers);
            if (i !== -1) {
                headers[i].value += ',' + cspDirectives;
            } else {
                headers.push({
                    name: 'Content-Security-Policy-Report-Only',
                    value: cspDirectives
                });
            }
        }

        return {
            responseHeaders: headers
        };
    };

    let cspNoWorkerInit = function () {
        if (ηMatrix.cspNoWorker === undefined) {
            ηMatrix.cspNoWorker = "worker-src 'none'; "
                +"frame-src data: blob: *; "
                +"report-uri about:blank";
        }

        return ηMatrix.cspNoWorker;
    };

    // Caller must ensure headerName is normalized to lower case.
    let headerIndexFromName = function (headerName, headers) {
        for (let i=0; i<headers.length; ++i) {
            if ( headers[i].name.toLowerCase() === headerName ) {
                return i;
            }
        }

        return -1;
    };

    let requestTypeNormalizer = {
        'font'          : 'css',
        'image'         : 'image',
        'imageset'      : 'image',
        'main_frame'    : 'doc',
        'media'         : 'media',
        'object'        : 'media',
        'other'         : 'other',
        'script'        : 'script',
        'stylesheet'    : 'css',
        'sub_frame'     : 'frame',
        'websocket'     : 'xhr',
        'xmlhttprequest': 'xhr'
    };

    vAPI.net.onBeforeRequest = {
        extra: [ 'blocking' ],
        callback: onBeforeRequestHandler
    };

    vAPI.net.onBeforeSendHeaders = {
        extra: [ 'blocking', 'requestHeaders' ],
        callback: onBeforeSendHeadersHandler
    };

    vAPI.net.onHeadersReceived = {
        urls: [ 'http://*/*', 'https://*/*' ],
        types: [ 'main_frame', 'sub_frame' ],
        extra: [ 'blocking', 'responseHeaders' ],
        callback: onHeadersReceived
    };

    return {
        start: function () {
            vAPI.net.registerListeners();
        },
    };
})();