"use strict";

// Core modules
const fs = require("fs");

// Modules from file
const shared = require("../app/scripts/shared.js");
const urlK = require("../app/scripts/constants/url.js");
const selectorK = require("../app/scripts/constants/css-selector.js");
const urlHelper = require("../app/scripts/url-helper.js");
const scraper = require("../app/scripts/game-scraper.js");
const {
    prepareBrowser,
    preparePage,
} = require("../app/scripts/puppeteer-helper.js");
const searcher = require("../app/scripts/game-searcher.js");

// Classes from file
const GameInfo = require("../app/scripts/classes/game-info.js");
const LoginResult = require("../app/scripts/classes/login-result.js");
const UserData = require("../app/scripts/classes/user-data.js");

//#region Export classes
module.exports.GameInfo = GameInfo;
module.exports.LoginResult = LoginResult;
module.exports.UserData = UserData;
//#endregion Export classes

//#region Export properties
/**
 * Shows log messages and other useful functions for module debugging.
 * @param {Boolean} value
 */
module.exports.debug = function (value) {
    shared.debug = value;

    // Configure logger
    shared.logger.level = value ? "debug" : "warn";
};
/**
 * @public
 * Indicates whether a user is logged in to the F95Zone platform or not.
 * @returns {String}
 */
module.exports.isLogged = function () {
    return shared.isLogged;
};
/**
 * @public
 * If true, it opens a new browser for each request
 * to the F95Zone platform, otherwise it reuses the same.
 * @returns {String}
 */
module.exports.setIsolation = function (value) {
    shared.isolation = value;
};
/**
 * @public
 * Path to the cache directory
 * @returns {String}
 */
module.exports.getCacheDir = function () {
    return shared.cacheDir;
};
/**
 * @public
 * Set path to the cache directory
 * @returns {String}
 */
module.exports.setCacheDir = function (value) {
    shared.cacheDir = value;

    // Create directory if it doesn't exist
    if (!fs.existsSync(shared.cacheDir)) fs.mkdirSync(shared.cacheDir);
};
/**
 * @public
 * Set local chromium path.
 * @returns {String}
 */
module.exports.setChromiumPath = function (value) {
    shared.chromiumLocalPath = value;
};
//#endregion Export properties

//#region Global variables
var _browser = null;
const USER_NOT_LOGGED = "User not authenticated, unable to continue";
//#endregion

//#region Export methods
/**
 * @public
 * Log in to the F95Zone platform.
 * This **must** be the first operation performed before accessing any other script functions.
 * @param {String} username Username used for login
 * @param {String} password Password used for login
 * @returns {Promise<LoginResult>} Result of the operation
 */
module.exports.login = async function (username, password) {
    if (shared.isLogged) {
        shared.logger.info("Already logged in");
        const result = new LoginResult(true, "Already logged in");
        return result;
    }

    // If cookies are loaded, use them to authenticate
    shared.cookies = loadCookies();
    if (shared.cookies !== null) {
        shared.logger.info("Valid session, no need to re-authenticate");
        shared.isLogged = true;
        const result = new LoginResult(true, "Logged with cookies");
        return result;
    }

    // Else, log in throught browser
    shared.logger.info(
        "No saved sessions or expired session, login on the platform"
    );

    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;

    const result = await loginF95(browser, username, password);
    shared.isLogged = result.success;

    if (result.success) {
    // Reload cookies
        shared.cookies = loadCookies();
        shared.logger.info("User logged in through the platform");
    } else {
        shared.logger.warn("Error during authentication: " + result.message);
    }
    if (shared.isolation) await browser.close();
    return result;
};
/**
 * @public
 * This method loads the main data from the F95 portal
 * used to provide game information. You **must** be logged
 * in to the portal before calling this method.
 * @returns {Promise<Boolean>} Result of the operation
 */
module.exports.loadF95BaseData = async function () {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return false;
    }

    shared.logger.info("Loading base data...");

    // Prepare a new web page
    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;

    const page = await preparePage(browser); // Set new isolated page
    await page.setCookie(...shared.cookies); // Set cookies to avoid login

    // Go to latest update page and wait for it to load
    await page.goto(urlK.F95_LATEST_UPDATES, {
        waitUntil: shared.WAIT_STATEMENT,
    });

    // Obtain engines (disk/online)
    await page.waitForSelector(selectorK.ENGINE_ID_SELECTOR);
    shared.engines = await loadValuesFromLatestPage(
        page,
        shared.enginesCachePath,
        selectorK.ENGINE_ID_SELECTOR,
        "engines"
    );

    // Obtain statuses (disk/online)
    await page.waitForSelector(selectorK.STATUS_ID_SELECTOR);
    shared.statuses = await loadValuesFromLatestPage(
        page,
        shared.statusesCachePath,
        selectorK.STATUS_ID_SELECTOR,
        "statuses"
    );

    await page.close();
    if (shared.isolation) await browser.close();
    shared.logger.info("Base data loaded");
    return true;
};
/**
 * @public
 * Chek if exists a new version of the game.
 * You **must** be logged in to the portal before calling this method.
 * @param {GameInfo} info Information about the game to get the version for
 * @returns {Promise<Boolean>} true if an update is available, false otherwise
 */
module.exports.chekIfGameHasUpdate = async function (info) {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return false;
    }

    // F95 change URL at every game update,
    // so if the URL is different an update is available
    const exists = await urlHelper.urlExists(info.f95url, true);
    if (!exists) return true;

    // Parse version from title
    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;

    const onlineVersion = await scraper.getGameVersionFromTitle(browser, info);

    if (shared.isolation) await browser.close();

    return onlineVersion.toUpperCase() !== info.version.toUpperCase();
};
/**
 * @public
 * Starting from the name, it gets all the information about the game you are looking for.
 * You **must** be logged in to the portal before calling this method.
 * @param {String} name Name of the game searched
 * @param {Boolean} includeMods Indicates whether to also take mods into account when searching
 * @returns {Promise<GameInfo[]>} List of information obtained where each item corresponds to
 * an identified game (in the case of homonymy of titles)
 */
module.exports.getGameData = async function (name, includeMods) {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return null;
    }

    // Gets the search results of the game being searched for
    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;
    const urlList = await searcher.getSearchGameResults(browser, name);

    // Process previous partial results
    const promiseList = [];
    for (const url of urlList) {
    // Start looking for information
        promiseList.push(scraper.getGameInfo(browser, url));
    }

    // Filter for mods
    const result = [];
    for (const info of await Promise.all(promiseList)) {
    // Ignore empty results
        if (!info) continue;
        // Skip mods if not required
        if (info.isMod && !includeMods) continue;
        // Else save data
        result.push(info);
    }

    if (shared.isolation) await browser.close();
    return result;
};
/**
 * @public
 * Starting from the url, it gets all the information about the game you are looking for.
 * You **must** be logged in to the portal before calling this method.
 * @param {String} url URL of the game to obtain information of
 * @returns {Promise<GameInfo>} Information about the game. If no game was found, null is returned
 */
module.exports.getGameDataFromURL = async function (url) {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return null;
    }

    // Check URL
    const exists = await urlHelper.urlExists(url);
    if (!exists) throw new URIError(url + " is not a valid URL");
    if (!urlHelper.isF95URL(url))
        throw new Error(url + " is not a valid F95Zone URL");

    // Gets the search results of the game being searched for
    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;

    // Get game data
    const result = await scraper.getGameInfo(browser, url);

    if (shared.isolation) await browser.close();
    return result;
};
/**
 * @public
 * Gets the data of the currently logged in user.
 * You **must** be logged in to the portal before calling this method.
 * @returns {Promise<UserData>} Data of the user currently logged in
 */
module.exports.getUserData = async function () {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return null;
    }

    // Prepare a new web page
    if (_browser === null && !shared.isolation) _browser = await prepareBrowser();
    const browser = shared.isolation ? await prepareBrowser() : _browser;
    const page = await preparePage(browser); // Set new isolated page
    await page.setCookie(...shared.cookies); // Set cookies to avoid login
    await page.goto(urlK.F95_BASE_URL); // Go to base page

    // Explicitly wait for the required items to load
    await Promise.all([
        page.waitForSelector(selectorK.USERNAME_ELEMENT),
        page.waitForSelector(selectorK.AVATAR_PIC),
    ]);

    const threads = getUserWatchedGameThreads(browser);

    const username = await page.evaluate(
    /* istanbul ignore next */ (selector) =>
            document.querySelector(selector).innerText,
        selectorK.USERNAME_ELEMENT
    );

    const avatarSrc = await page.evaluate(
    /* istanbul ignore next */ (selector) =>
            document.querySelector(selector).getAttribute("src"),
        selectorK.AVATAR_PIC
    );

    const ud = new UserData();
    ud.username = username;
    ud.avatarSrc = urlHelper.isStringAValidURL(avatarSrc) ? avatarSrc : null;
    ud.watchedThreads = await threads;

    await page.close();
    if (shared.isolation) await browser.close();

    return ud;
};
/**
 * @public
 * Logout from the current user and gracefully close shared browser.
 * You **must** be logged in to the portal before calling this method.
 */
module.exports.logout = async function () {
    if (!shared.isLogged || !shared.cookies) {
        shared.logger.warn(USER_NOT_LOGGED);
        return;
    }

    // Logout
    shared.isLogged = false;

    // Gracefully close shared browser
    if (!shared.isolation && _browser !== null) {
        await _browser.close();
        _browser = null;
    }
};
//#endregion

//#region Private methods

//#region Cookies functions
/**
 * @private
 * Loads and verifies the expiration of previously stored cookies from disk
 * if they exist, otherwise it returns null.
 * @return {object[]} List of dictionaries or null if cookies don't exist
 */
function loadCookies() {
    // Check the existence of the cookie file
    if (fs.existsSync(shared.cookiesCachePath)) {
    // Read cookies
        const cookiesJSON = fs.readFileSync(shared.cookiesCachePath);
        const cookies = JSON.parse(cookiesJSON);

        // Check if the cookies have expired
        for (const cookie of cookies) {
            if (isCookieExpired(cookie)) return null;
        }

        // Cookies loaded and verified
        return cookies;
    } else return null;
}
/**
 * @private
 * Check the validity of a cookie.
 * @param {object} cookie Cookies to verify the validity. It's a dictionary
 * @returns {Boolean} true if the cookie has expired, false otherwise
 */
function isCookieExpired(cookie) {
    // Local variables
    let expiredCookies = false;

    // Ignore cookies that never expire
    const expirationUnixTimestamp = cookie.expire;

    if (expirationUnixTimestamp !== "-1") {
    // Convert UNIX epoch timestamp to normal Date
        const expirationDate = new Date(expirationUnixTimestamp * 1000);

        if (expirationDate < Date.now()) {
            shared.logger.warn(
                "Cookie " + cookie.name + " expired, you need to re-authenticate"
            );
            expiredCookies = true;
        }
    }

    return expiredCookies;
}
//#endregion Cookies functions

//#region Latest Updates page parserer
/**
 * @private
 * If present, it reads the file containing the searched values (engines or states)
 * from the disk, otherwise it connects to the F95 portal (at the page
 * https://f95zone.to/latest) and downloads them.
 * @param {puppeteer.Page} page Page used to locate the required elements
 * @param {String} path Path to disk of the JSON file containing the data to read / write
 * @param {String} selector CSS selector of the required elements
 * @param {String} elementRequested Required element (engines or states) used to detail log messages
 * @returns {Promise<String[]>} List of required values in uppercase
 */
async function loadValuesFromLatestPage(
    page,
    path,
    selector,
    elementRequested
) {
    // If the values already exist they are loaded from disk without having to connect to F95
    shared.logger.info("Load " + elementRequested + " from disk...");
    if (fs.existsSync(path)) {
        const valueJSON = fs.readFileSync(path);
        return JSON.parse(valueJSON);
    }

    // Otherwise, connect and download the data from the portal
    shared.logger.info("No " + elementRequested + " cached, downloading...");
    const values = await getValuesFromLatestPage(
        page,
        selector,
        "Getting " + elementRequested + " from page"
    );
    fs.writeFileSync(path, JSON.stringify(values));
    return values;
}
/**
 * @private
 * Gets all the textual values of the elements present
 * in the F95 portal page and identified by the selector
 * passed by parameter
 * @param {puppeteer.Page} page Page used to locate items specified by the selector
 * @param {String} selector CSS selector
 * @param {String} logMessage Log message indicating which items the selector is requesting
 * @return {Promise<String[]>} List of uppercase strings indicating the textual values of the elements identified by the selector
 */
async function getValuesFromLatestPage(page, selector, logMessage) {
    shared.logger.info(logMessage);

    const result = [];
    const elements = await page.$$(selector);

    for (const element of elements) {
        const text = await element.evaluate(
            /* istanbul ignore next */ (e) => e.innerText
        );

        // Save as upper text for better match if used in query
        result.push(text.toUpperCase());
    }
    return result;
}
//#endregion

//#region User
/**
 * @private
 * Log in to the F95Zone portal and, if successful, save the cookies.
 * @param {puppeteer.Browser} browser Browser object used for navigation
 * @param {String} username Username to use during login
 * @param {String} password Password to use during login
 * @returns {Promise<LoginResult>} Result of the operation
 */
async function loginF95(browser, username, password) {
    const page = await preparePage(browser); // Set new isolated page
    await page.goto(urlK.F95_LOGIN_URL); // Go to login page

    // Explicitly wait for the required items to load
    await Promise.all([
        page.waitForSelector(selectorK.USERNAME_INPUT),
        page.waitForSelector(selectorK.PASSWORD_INPUT),
        page.waitForSelector(selectorK.LOGIN_BUTTON),
    ]);

    await page.type(selectorK.USERNAME_INPUT, username); // Insert username
    await page.type(selectorK.PASSWORD_INPUT, password); // Insert password
    await Promise.all([
        page.click(selectorK.LOGIN_BUTTON), // Click on the login button
        page.waitForNavigation({
            waitUntil: shared.WAIT_STATEMENT,
        }), // Wait for page to load
    ]);

    // Prepare result
    let message = "";

    // Check if the user is logged in
    const success = await page.evaluate(
    /* istanbul ignore next */ (selector) =>
            document.querySelector(selector) !== null,
        selectorK.AVATAR_INFO
    );

    const errorMessageExists = await page.evaluate(
    /* istanbul ignore next */
        (selector) => document.querySelector(selector) !== null,
        selectorK.LOGIN_MESSAGE_ERROR
    );

    // Save cookies to avoid re-auth
    if (success) {
        const c = await page.cookies();
        fs.writeFileSync(shared.cookiesCachePath, JSON.stringify(c));
        message = "Authentication successful";
    } else if (errorMessageExists) {
        const errorMessage = await page.evaluate(
            /* istanbul ignore next */ (selector) =>
                document.querySelector(selector).innerText,
            selectorK.LOGIN_MESSAGE_ERROR
        );

        if (errorMessage === "Incorrect password. Please try again.") {
            message = "Incorrect password";
        } else if (
            errorMessage ===
      "The requested user '" + username + "' could not be found."
        ) {
            // The escaped quotes are important!
            message = "Incorrect username";
        } else message = errorMessage;
    } else message = "Unknown error";

    await page.close(); // Close the page
    return new LoginResult(success, message);
}
/**
 * @private
 * Gets the list of URLs of threads the user follows.
 * @param {puppeteer.Browser} browser Browser object used for navigation
 * @returns {Promise<String[]>} URL list
 */
async function getUserWatchedGameThreads(browser) {
    const page = await preparePage(browser); // Set new isolated page
    await page.goto(urlK.F95_WATCHED_THREADS); // Go to the thread page

    // Explicitly wait for the required items to load
    await page.waitForSelector(selectorK.WATCHED_THREAD_FILTER_POPUP_BUTTON);

    // Show the popup
    await Promise.all([
        page.click(selectorK.WATCHED_THREAD_FILTER_POPUP_BUTTON),
        page.waitForSelector(selectorK.UNREAD_THREAD_CHECKBOX),
        page.waitForSelector(selectorK.ONLY_GAMES_THREAD_OPTION),
        page.waitForSelector(selectorK.FILTER_THREADS_BUTTON),
    ]);

    // Set the filters
    await page.evaluate(
    /* istanbul ignore next */ (selector) =>
            document.querySelector(selector).removeAttribute("checked"),
        selectorK.UNREAD_THREAD_CHECKBOX
    ); // Also read the threads already read

    // Filter the threads
    await page.click(selectorK.ONLY_GAMES_THREAD_OPTION);
    await page.click(selectorK.FILTER_THREADS_BUTTON);
    await page.waitForSelector(selectorK.WATCHED_THREAD_URLS);

    // Get the threads urls
    const urls = [];
    let nextPageExists = false;
    do {
    // Get all the URLs
        for (const handle of await page.$$(selectorK.WATCHED_THREAD_URLS)) {
            const src = await page.evaluate(
                /* istanbul ignore next */ (element) => element.href,
                handle
            );
            // If 'unread' is left, it will redirect to the last unread post
            const url = src.replace("/unread", "");
            urls.push(url);
        }

        nextPageExists = await page.evaluate(
            /* istanbul ignore next */ (selector) => document.querySelector(selector),
            selectorK.WATCHED_THREAD_NEXT_PAGE
        );

        // Click to next page
        if (nextPageExists) {
            await page.click(selectorK.WATCHED_THREAD_NEXT_PAGE);
            await page.waitForSelector(selectorK.WATCHED_THREAD_URLS);
        }
    } while (nextPageExists);

    await page.close();
    return urls;
}
//#endregion User

//#endregion Private methods