const MongoDB = require("../mongoDB.js");
const { client_logger } = require('../utils/analyticsLogger');
const bcrypt = require('bcrypt');
const crypto = require('crypto');
const { getSessionId, getUserId, getProfileId } = require('../utils/sessionUtils.js');
const { getCookiesOptions } = require('../config/cookiesOptions');
const Notifications = require("../notifications");

// Object Definitions
const Post = require("../def/post.js")
const Profile = require("../def/profile.js");
const DUMMY_BCRYPT_HASH = '$2b$10$2zQfAaxK0cN13N7V2Q5hAOL3wxY5E9OQj1YxDCEV4VpWw2X2gYd6C';
const PASSWORD_TOKEN_TTL_MINUTES = parseInt(process.env.PASSWORD_TOKEN_TTL_MINUTES || '20', 10);
const PASSWORD_TOKEN_PATH = process.env.PASSWORD_TOKEN_PATH || '/token-login';
const FRONTEND_URL = (process.env.FRONTEND_URL || 'https://social.emmint.com').replace(/\/+$/, '');

const createPasswordTokenHash = (rawToken) =>
    crypto.createHash('sha256').update(rawToken).digest('hex');

const createSessionFromUser = async ({ DB, user, req, res }) => {
    const sessionObj = await DB.newSession(user._id);
    const cookiesOptions = getCookiesOptions(req);
    res.cookie('user_sid', user._id, cookiesOptions);
    res.cookie('session_id', sessionObj.insertedId, cookiesOptions);
    const latestUpdatedProfile = await DB.latestProfile(user._id);
    if (latestUpdatedProfile && latestUpdatedProfile._id) {
        res.cookie('profile_id', latestUpdatedProfile._id, cookiesOptions);
    }
    client_logger.identify({
        distinctId: user._id,
        properties: {
            name: latestUpdatedProfile?.profile?.firstName || '',
        }
    });
    client_logger.capture({
        distinctId: user._id,
        event: 'server@' + req.method + '@' + req.originalUrl,
    });
    return {
        status: "ok",
        user_sid: user._id,
        session_id: sessionObj.insertedId,
        profile_id: latestUpdatedProfile?._id
    };
};

// Function to Singup new users. An user is a combination of a user obj and a profile.
// When new users are subscribed, they have a single profile, which is the personal one.
// Other profiles can be link to that user, like groups or courses.
const signup = async function (req, res) {
    const username = (req.body.username || "").trim().toLowerCase();
    const password = req.body.password;
    const email = (req.body.email || "").trim().toLowerCase();
    const profile = req.body.profile;
    if (!username || !password || !email) return res.json({ status: "Incomplete information!" });
    // Check if the new user has an invitation.
    const DB = await MongoDB.getDB;
    if (!await DB.getInvitation(email)) {
        client_logger.capture({
            distinctId: 'app_level',
            event: 'server@' + req.method + '@' + req.originalUrl + '@NotInvited',
            properties: {
                username: username,
                email: email,
            }
        });
        return res.json({ status: "Not invitation found!" });
    }
    let isUserAlreadyRegistered = await DB.getUser(email);
    if (isUserAlreadyRegistered && isUserAlreadyRegistered._id) return res.json({ status: "This user is already registered" });
    const hashedPassword = await bcrypt.hash(password, 10);
    const newUserObject = await DB.newUser({
        username,
        email,
        password: hashedPassword
    });
    // If newUserObject it's an error message, we check by looking toLowerCase function 
    if (!newUserObject.toLowerCase) {
        let user = {
            userid: newUserObject.insertedId,
            profile: profile,
        }
        // Filter the provided information by the template, and adding to the DB, and login.
        const userObj = new Profile(user);
        await DB.newProfile(userObj);
        client_logger.capture({
            distinctId: newUserObject.insertedId,
            event: 'server@' + req.method + '@' + req.originalUrl,
        });
        // TODO: this might fail, add catch scenarios
        return await login(req, res);
    }
    // Error return
    client_logger.capture({
        distinctId: 'app_level',
        event: 'server@' + req.method + '@' + req.originalUrl + '@error',
        properties: {
            ustatus: newUserObject,
        }
    });
    return res.json({ status: newUserObject })
}

// Function for user Login, it returns the coockies/json for user_id session_id and profile_id
const login = async function (req, res) {
    // Check if user is already logged in and redirect to root if so.
    const session_id = getSessionId(req);
    const user_sid = getUserId(req);
    const DB = await MongoDB.getDB;
    if (session_id && user_sid) {
        const userInfo = await DB.checkSessionOnDB(session_id, user_sid);
        if (userInfo) return res.redirect('/');
    }
    const invalidCredentials = () => res.status(401).json({ status: "Invalid credentials" });
    const username = (req.body.username || req.body.email || "").trim().toLowerCase();
    const password = req.body.password || "";
    if (!username || !password) return invalidCredentials();
    const user = await DB.getUser(username);

    if (!user) {
        client_logger.capture({
            distinctId: 'app_level',
            event: 'server@' + req.method + '@' + req.originalUrl + '@invalidCredentials',
            properties: { username },
        });
    }
    const isSamePassword = await bcrypt.compare(password, user?.password || DUMMY_BCRYPT_HASH);
    if (!user || !isSamePassword) return invalidCredentials();
    try {
        return res.json(await createSessionFromUser({ DB, user, req, res }));
    } catch (error) {
        console.error(error);
        client_logger.capture({
            distinctId: 'app_level',
            event: 'server@' + req.method + '@' + req.originalUrl + '@error',
        });
        return res.json({ status: "Error on this User Profile, please contact admin." });
    }

}

// route for user logout
const logout = async function (req, res) {
    const session_id = getSessionId(req);
    const user_sid = getUserId(req);
    if (session_id && user_sid) {
        const cookiesOptions = getCookiesOptions(req);
        res.clearCookie('session_id', cookiesOptions);
        res.clearCookie('user_sid', cookiesOptions);
        //remove from DB
        const DB = await MongoDB.getDB;
        DB.removeSession(session_id);
        client_logger.capture({
            distinctId: user_sid,
            event: 'server@' + req.method + '@' + req.originalUrl,
        });
        res.redirect('/');
    } else {
        res.redirect('/login');
    }
}

const resetPassword = async function (req, res) {
    const DB = await MongoDB.getDB;

    const genericResetResponse = {
        status: "ok",
        details: "If the account exists, check your email for next steps"
    };
    // Logic for non-logged in users.
    const username = (req.body.username || req.body.email || "").trim().toLowerCase();
    if (!username) return res.json(genericResetResponse);
    const user = await DB.getUser(username);
    if (!user) {
        client_logger.capture({
            distinctId: 'app_level',
            event: 'server@' + req.method + '@' + req.originalUrl + '@resetRequestedUnknownUser',
            properties: { username }
        });
        return res.json(genericResetResponse);
    }
    const rawToken = crypto.randomBytes(32).toString('hex');
    const tokenHash = createPasswordTokenHash(rawToken);
    const expiresAt = new Date(Date.now() + PASSWORD_TOKEN_TTL_MINUTES * 60 * 1000);
    const tokenStored = await DB.createPasswordLoginToken(user._id, tokenHash, expiresAt);
    if (!tokenStored) {
        return res.json(genericResetResponse);
    }
    const loginUrl = `${FRONTEND_URL}${PASSWORD_TOKEN_PATH}?token=${rawToken}`;
    Notifications.sendEmail(username, "Your secure sign-in link",
        `
<p>Hello,</p>
<p>Use this one-time sign-in link to access your account:</p>
<p><a href="${loginUrl}">${loginUrl}</a></p>
<p>This link expires in ${PASSWORD_TOKEN_TTL_MINUTES} minutes and can only be used once.</p>
<p>If you did not request this, you can ignore this email.</p>
<p>Blessings</p>
<p>Emmanuel International Ministries</p>
`);
    client_logger.capture({
        distinctId: user._id,
        event: 'server@' + req.method + '@' + req.originalUrl,
        properties: {
            username: username,
        }
    });
    return res.json(genericResetResponse);
}

const loginWithPasswordToken = async function (req, res) {
    const DB = await MongoDB.getDB;
    const token = (req.body.token || "").trim();
    if (!token || token.length < 32) {
        return res.status(401).json({ status: "Invalid or expired token" });
    }
    const tokenHash = createPasswordTokenHash(token);
    const tokenDoc = await DB.consumePasswordLoginToken(tokenHash);
    if (!tokenDoc || !tokenDoc.userId) {
        return res.status(401).json({ status: "Invalid or expired token" });
    }
    const user = await DB.getUserById(tokenDoc.userId);
    if (!user || !user._id) {
        return res.status(401).json({ status: "Invalid or expired token" });
    }
    try {
        return res.json(await createSessionFromUser({ DB, user, req, res }));
    } catch (error) {
        console.error("Token login error", error);
        return res.status(500).json({ status: "Internal server error" });
    }
}


module.exports = {
    signup,
    login,
    logout,
    resetPassword,
    loginWithPasswordToken,
}