import * as bodyParser from 'body-parser';
import { blue, yellow } from 'colors';
import * as cookieParser from 'cookie-parser';
import * as cors from "cors";
import * as express from 'express';
import * as session from 'express-session';
import * as expressValidator from 'express-validator';
import * as fs from 'fs';
import { Server as HttpServer } from "http";
import { createServer, Server as HttpsServer } from "https";
import * as passport from 'passport';
import * as request from 'request';
import * as webpack from 'webpack';
import * as wdm from 'webpack-dev-middleware';
import * as whm from 'webpack-hot-middleware';
import * as zlib from 'zlib';
import { publicDirectory } from '.';
import { logPort } from './ActionUtilities';
import { SSL } from './apis/google/CredentialsLoader';
import { getForgot, getLogin, getLogout, getReset, getSignup, postForgot, postLogin, postReset, postSignup } from './authentication/AuthenticationManager';
import { Database } from './database';
import RouteManager from './RouteManager';
import RouteSubscriber from './RouteSubscriber';
import { WebSocket } from './websocket';
import expressFlash = require('express-flash');
import flash = require('connect-flash');
const MongoStore = require('connect-mongo')(session);
const config = require('../../webpack.config');
const compiler = webpack(config);

/* RouteSetter is a wrapper around the server that prevents the server
   from being exposed. */
export type RouteSetter = (server: RouteManager) => void;
//export let disconnect: Function;

export let resolvedPorts: { server: number, socket: number } = { server: 1050, socket: 4321 };
export let resolvedServerUrl: string;

export default async function InitializeServer(routeSetter: RouteSetter) {
    const isRelease = determineEnvironment();
    const app = buildWithMiddleware(express());

    const compiler = webpack(config);

    app.use(require("webpack-dev-middleware")(compiler, {
        publicPath: config.output.publicPath
    }));

    app.use(require("webpack-hot-middleware")(compiler));

    // route table managed by express.  routes are tested sequentially against each of these map rules.  when a match is found, the handler is called to process the request
    app.get(new RegExp(/^\/+$/), (req, res) => res.redirect(req.user ? "/home" : "/login")); // target urls that consist of one or more '/'s with nothing in between
    app.use(express.static(publicDirectory, { setHeaders: res => res.setHeader("Access-Control-Allow-Origin", "*") }));  //all urls that start with dash's public directory: /files/  (e.g., /files/images, /files/audio, etc)
    app.use(cors({ origin: (_origin: any, callback: any) => callback(null, true) }));
    app.use(wdm(compiler, { publicPath: config.output.publicPath }));
    app.use(whm(compiler));
    registerAuthenticationRoutes(app);  // this adds routes to authenticate a user (login, etc)
    registerCorsProxy(app);  // this adds a /corsProxy/ route to allow clients to get to urls that would otherwise be blocked by cors policies
    isRelease && !SSL.Loaded && SSL.exit();
    routeSetter(new RouteManager(app, isRelease)); // this sets up all the regular supervised routes (things like /home, download/upload api's, pdf, search, session, etc)
    registerEmbeddedBrowseRelativePathHandler(app); // this allows renered web pages which internally have relative paths to find their content

    let server: HttpServer | HttpsServer;
    isRelease && process.env.serverPort && (resolvedPorts.server = Number(process.env.serverPort));
    await new Promise<void>(resolve => server = isRelease ?
        createServer(SSL.Credentials, app).listen(resolvedPorts.server, resolve) :
        app.listen(resolvedPorts.server, resolve)
    );
    logPort("server", resolvedPorts.server);

    resolvedServerUrl = `${isRelease && process.env.serverName ? `https://${process.env.serverName}.com` : "http://localhost"}:${resolvedPorts.server}`;

    // initialize the web socket (bidirectional communication: if a user changes
    // a field on one client, that change must be broadcast to all other clients)
    await WebSocket.initialize(isRelease, app);

    //disconnect = async () => new Promise<Error>(resolve => server.close(resolve));
    return isRelease;
}

const week = 7 * 24 * 60 * 60 * 1000;
const secret = "64d6866242d3b5a5503c675b32c9605e4e90478e9b77bcf2bc";

function buildWithMiddleware(server: express.Express) {
    [
        cookieParser(),
        session({
            secret,
            resave: true,
            cookie: { maxAge: week },
            saveUninitialized: true,
            store: process.env.DB === "MEM" ? new session.MemoryStore() : new MongoStore({ url: Database.url })
        }),
        flash(),
        expressFlash(),
        bodyParser.json({ limit: "10mb" }),
        bodyParser.urlencoded({ extended: true }),
        expressValidator(),
        passport.initialize(),
        passport.session(),
        (req: express.Request, res: express.Response, next: express.NextFunction) => {
            res.locals.user = req.user;
            if ((req.originalUrl.endsWith(".png") /*|| req.originalUrl.endsWith(".js")*/) && req.method === 'GET' && (res as any)._contentLength) {
                const period = 30000;
                res.set('Cache-control', `public, max-age=${period}`);
            } else {
                // for the other requests set strict no caching parameters
                res.set('Cache-control', `no-store`);
            }
            next();
        }
    ].forEach(next => server.use(next));
    return server;
}

/* Determine if the enviroment is dev mode or release mode. */
function determineEnvironment() {
    const isRelease = process.env.RELEASE === "true";

    const color = isRelease ? blue : yellow;
    const label = isRelease ? "release" : "development";
    console.log(`\nrunning server in ${color(label)} mode`);

    // swilkins: I don't think we need to read from ClientUtils.RELEASE anymore. Should be able to invoke process.env.RELEASE
    // on the client side, thanks to dotenv in webpack.config.js
    let clientUtils = fs.readFileSync("./src/client/util/ClientUtils.ts.temp", "utf8");
    clientUtils = `//AUTO-GENERATED FILE: DO NOT EDIT\n${clientUtils.replace('"mode"', String(isRelease))}`;
    fs.writeFileSync("./src/client/util/ClientUtils.ts", clientUtils, "utf8");

    return isRelease;
}

function registerAuthenticationRoutes(server: express.Express) {
    server.get("/signup", getSignup);
    server.post("/signup", postSignup);

    server.get("/login", getLogin);
    server.post("/login", postLogin);

    server.get("/logout", getLogout);

    server.get("/forgotPassword", getForgot);
    server.post("/forgotPassword", postForgot);

    const reset = new RouteSubscriber("resetPassword").add("token").build;
    server.get(reset, getReset);
    server.post(reset, postReset);
}

function registerCorsProxy(server: express.Express) {
    server.use("/corsProxy", async (req, res) => {
        const referer = req.headers.referer ? decodeURIComponent(req.headers.referer) : "";
        let requrlraw = decodeURIComponent(req.url.substring(1));
        const qsplit = requrlraw.split("?q=");
        const newqsplit = requrlraw.split("&q=");
        if (qsplit.length > 1 && newqsplit.length > 1) {
            const lastq = newqsplit[newqsplit.length - 1];
            requrlraw = qsplit[0] + "?q=" + lastq.split("&")[0] + "&" + qsplit[1].split("&")[1];
        }
        const requrl = requrlraw.startsWith("/") ? referer + requrlraw : requrlraw;
        // cors weirdness here...
        // if the referer is a cors page and the cors() route (I think) redirected to /corsProxy/<path> and the requested url path was relative,
        // then we redirect again to the cors referer and just add the relative path.
        if (!requrl.startsWith("http") && req.originalUrl.startsWith("/corsProxy") && referer?.includes("corsProxy")) {
            res.redirect(referer + (referer.endsWith("/") ? "" : "/") + requrl);
        } else {
            proxyServe(req, requrl, res);
        }
    });
}

function proxyServe(req: any, requrl: string, response: any) {
    const htmlBodyMemoryStream = new (require('memorystream'))();
    var retrieveHTTPBody: any;
    const sendModifiedBody = () => {
        const header = response.headers["content-encoding"];
        if (header && header.includes("gzip")) {
            try {
                const replacer = (match: any, href: string, offset: any, string: any) => {
                    return `href="${resolvedServerUrl + "/corsProxy/http" + href}"`;
                };
                const zipToStringDecoder = new (require('string_decoder').StringDecoder)('utf8');
                const bodyStream = htmlBodyMemoryStream.read();
                if (bodyStream) {
                    const htmlText = zipToStringDecoder.write(zlib.gunzipSync(bodyStream).toString('utf8')
                        .replace('<head>', '<head> <style>[id ^= "google"] { display: none; } </style>')
                        .replace(/href="https?([^"]*)"/g, replacer)
                        .replace(/target="_blank"/g, ""));
                    response.send(zlib.gzipSync(htmlText));
                } else {
                    req.pipe(request(requrl)).pipe(response);
                    console.log("EMPTY body:" + req.url);
                }
            } catch (e) {
                console.log("EROR?: ", e);
            }
        } else req.pipe(request(requrl)).pipe(response);
    }
    retrieveHTTPBody = () => {
        req.headers.cookie = "";
        req.pipe(request(requrl))
            .on("error", (e: any) => console.log(`Malformed CORS url: ${requrl}`, e))
            .on("response", (res: any) => {
                res.headers;
                const headers = Object.keys(res.headers);
                const headerCharRegex = /[^\t\x20-\x7e\x80-\xff]/;
                headers.forEach(headerName => {
                    const header = res.headers[headerName];
                    if (Array.isArray(header)) {
                        res.headers[headerName] = header.filter(h => !headerCharRegex.test(h));
                    } else if (headerCharRegex.test(header || "")) {
                        delete res.headers[headerName];
                    } else res.headers[headerName] = header;
                });
                response.headers = response._headers = res.headers;
            })
            .on("end", sendModifiedBody)
            .pipe(htmlBodyMemoryStream);
    };
    retrieveHTTPBody();
}

function registerEmbeddedBrowseRelativePathHandler(server: express.Express) {
    server.use("*", (req, res) => {
        const relativeUrl = req.originalUrl;
        if (!req.user) res.redirect("/home");  // When no user is logged in, we interpret a relative URL as being a reference to something they don't have access to and redirect to /home 
        else if (!res.headersSent && req.headers.referer?.includes("corsProxy")) { // a request for something by a proxied referrer means it must be a relative reference.  So construct a proxied absolute reference here.
            try {
                const proxiedRefererUrl = decodeURIComponent(req.headers.referer); // (e.g., http://localhost:<port>/corsProxy/https://en.wikipedia.org/wiki/Engelbart)
                const dashServerUrl = proxiedRefererUrl.match(/.*corsProxy\//)![0]; // the dash server url (e.g.: http://localhost:<port>/corsProxy/ )
                const actualReferUrl = proxiedRefererUrl.replace(dashServerUrl, ""); // the url of the referer without the proxy (e.g., : https://en.wikipedia.org/wiki/Engelbart)
                const absoluteTargetBaseUrl = actualReferUrl.match(/https?:\/\/[^\/]*/)![0]; // the base of the original url (e.g.,  https://en.wikipedia.org)
                const redirectedProxiedUrl = dashServerUrl + encodeURIComponent(absoluteTargetBaseUrl + relativeUrl); // the new proxied full url (e.g., http://localhost:<port>/corsProxy/https://en.wikipedia.org/<somethingelse>)
                if (relativeUrl.startsWith("//")) res.redirect("http:" + relativeUrl);
                else res.redirect(redirectedProxiedUrl);
            } catch (e) {
                console.log("Error embed: ", e);
            }
        } else if (relativeUrl.startsWith("/search") && !req.headers.referer?.includes("corsProxy")) { // detect search query and use default search engine
            res.redirect(req.headers.referer + "corsProxy/" + encodeURIComponent("http://www.google.com" + relativeUrl));
        } else {
            res.end();
        }
    });
}