var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var bcrypt = require('bcrypt');
var jwt = require('jsonwebtoken');

var auth = require('../lib/auth.js');
const { generateUUID } = require('../lib/utils.js');
var _ = require('lodash');

var QRCode = require('qrcode');
var OTPAuth = require('otpauth');

var UserSchema = new Schema(
  {
    username: { type: String, unique: true, required: true },
    password: { type: String, required: true },
    firstname: { type: String, required: true },
    lastname: { type: String, required: true },
    email: { type: String, required: false },
    phone: { type: String, required: false },
    role: { type: String, default: 'user' },
    totpEnabled: { type: Boolean, default: false },
    totpSecret: { type: String, default: '' },
    enabled: { type: Boolean, default: true },
    refreshTokens: [
      { _id: false, sessionId: String, userAgent: String, token: String },
    ],
  },
  { timestamps: true },
);

var totpConfig = {
  issuer: 'AuditForge',
  label: '',
  algorithm: 'SHA1',
  digits: 6,
  period: 30,
  secret: '',
};

//check TOTP token
var checkTotpToken = function (token, secret) {
  if (!token) throw { fn: 'BadParameters', message: 'TOTP token required' };
  if (token.length !== 6)
    throw { fn: 'BadParameters', message: 'Invalid TOTP token length' };
  if (!secret) throw { fn: 'BadParameters', message: 'TOTP secret required' };

  let newConfig = totpConfig;
  newConfig.secret = secret;
  let totp = new OTPAuth.TOTP(newConfig);
  let delta = totp.validate({
    token: token,
    window: 5,
  });
  //The token is valid in 2 windows in the past and the future, current window is 0.
  if (delta === null) {
    throw { fn: 'Unauthorized', message: 'Wrong TOTP token.' };
  } else if (delta < -2 || delta > 2) {
    throw { fn: 'Unauthorized', message: 'TOTP token out of window.' };
  }
  return true;
};

/*
 *** Statics ***
 */

// Create user
UserSchema.statics.create = function (user) {
  return new Promise((resolve, reject) => {
    var hash = bcrypt.hashSync(user.password, 10);
    user.password = hash;
    new User(user)
      .save()
      .then(function () {
        resolve();
      })
      .catch(function (err) {
        if (err.code === 11000)
          reject({ fn: 'BadParameters', message: 'Username already exists' });
        else reject(err);
      });
  });
};

// Get all users
UserSchema.statics.getAll = function () {
  return new Promise((resolve, reject) => {
    var query = this.find();
    query.select(
      'username firstname lastname email phone role totpEnabled enabled',
    );
    query
      .exec()
      .then(function (rows) {
        resolve(rows);
      })
      .catch(function (err) {
        reject(err);
      });
  });
};

// Get one user by its username
UserSchema.statics.getByUsername = function (username) {
  return new Promise((resolve, reject) => {
    var query = this.findOne({ username: username });
    query.select(
      'username firstname lastname email phone role totpEnabled enabled',
    );
    query
      .exec()
      .then(function (row) {
        if (row) resolve(row);
        else throw { fn: 'NotFound', message: 'User not found' };
      })
      .catch(function (err) {
        reject(err);
      });
  });
};

// Update user with password verification (for updating my profile)
UserSchema.statics.updateProfile = function (username, user) {
  return new Promise((resolve, reject) => {
    var query = this.findOne({ username: username });
    var payload = {};
    query
      .exec()
      .then(function (row) {
        if (!row) throw { fn: 'NotFound', message: 'User not found' };
        else if (bcrypt.compareSync(user.password, row.password)) {
          if (user.username) row.username = user.username;
          if (user.firstname) row.firstname = user.firstname;
          if (user.lastname) row.lastname = user.lastname;
          if (!_.isNil(user.email)) row.email = user.email;
          if (!_.isNil(user.phone)) row.phone = user.phone;
          if (user.newPassword)
            row.password = bcrypt.hashSync(user.newPassword, 10);
          if (typeof user.totpEnabled == 'boolean')
            row.totpEnabled = user.totpEnabled;

          payload.id = row._id;
          payload.username = row.username;
          payload.role = row.role;
          payload.firstname = row.firstname;
          payload.lastname = row.lastname;
          payload.email = row.email;
          payload.phone = row.phone;
          payload.roles = auth.acl.getRoles(payload.role);

          return row.save();
        } else
          throw { fn: 'Unauthorized', message: 'Current password is invalid' };
      })
      .then(function () {
        var token = jwt.sign(payload, auth.jwtSecret, {
          expiresIn: '15 minutes',
        });
        resolve({ token: `JWT ${token}` });
      })
      .catch(function (err) {
        if (err.code === 11000)
          reject({ fn: 'BadParameters', message: 'Username already exists' });
        else reject(err);
      });
  });
};

// Update user (for admin usage)
UserSchema.statics.updateUser = function (userId, user) {
  return new Promise((resolve, reject) => {
    if (user.password) user.password = bcrypt.hashSync(user.password, 10);
    var query = this.findOneAndUpdate({ _id: userId }, user);
    query
      .exec()
      .then(function (row) {
        if (row) resolve('User updated successfully');
        else reject({ fn: 'NotFound', message: 'User not found' });
      })
      .catch(function (err) {
        if (err.code === 11000)
          reject({ fn: 'BadParameters', message: 'Username already exists' });
        else reject(err);
      });
  });
};

// Update refreshtoken
UserSchema.statics.updateRefreshToken = function (refreshToken, userAgent) {
  return new Promise((resolve, reject) => {
    var token = '';
    var newRefreshToken = '';
    try {
      var decoded = jwt.verify(refreshToken, auth.jwtRefreshSecret);
      var userId = decoded.userId;
      var sessionId = decoded.sessionId;
      var expiration = decoded.exp;
    } catch (err) {
      if (err.name === 'TokenExpiredError')
        throw { fn: 'Unauthorized', message: 'Expired refreshToken' };
      else throw { fn: 'Unauthorized', message: 'Invalid refreshToken' };
    }
    var query = this.findById(userId);
    query
      .exec()
      .then(row => {
        if (row && row.enabled !== false) {
          // Check session exist and sessionId not null (if null then it is a login)
          if (sessionId !== null) {
            var sessionExist = row.refreshTokens.findIndex(
              e => e.sessionId === sessionId && e.token === refreshToken,
            );
            if (sessionExist === -1)
              // Not found
              throw { fn: 'Unauthorized', message: 'Session not found' };
          }

          // Generate new token
          var payload = {};
          payload.id = row._id;
          payload.username = row.username;
          payload.role = row.role;
          payload.firstname = row.firstname;
          payload.lastname = row.lastname;
          payload.email = row.email;
          payload.phone = row.phone;
          payload.roles = auth.acl.getRoles(payload.role);

          token = jwt.sign(payload, auth.jwtSecret, {
            expiresIn: '15 minutes',
          });

          // Remove expired sessions
          row.refreshTokens = row.refreshTokens.filter(e => {
            try {
              var decoded = jwt.verify(e.token, auth.jwtRefreshSecret);
            } catch (err) {
              var decoded = null;
            }
            return decoded !== null;
          });
          // Update or add new refresh token
          var foundIndex = row.refreshTokens.findIndex(
            e => e.sessionId === sessionId,
          );
          if (foundIndex === -1) {
            // Not found
            sessionId = generateUUID();
            newRefreshToken = jwt.sign(
              { sessionId: sessionId, userId: userId },
              auth.jwtRefreshSecret,
              { expiresIn: '7 days' },
            );
            row.refreshTokens.push({
              sessionId: sessionId,
              userAgent: userAgent,
              token: newRefreshToken,
            });
          } else {
            newRefreshToken = jwt.sign(
              { sessionId: sessionId, userId: userId, exp: expiration },
              auth.jwtRefreshSecret,
            );
            row.refreshTokens[foundIndex].token = newRefreshToken;
          }
          return row.save();
        } else if (row) {
          reject({ fn: 'Unauthorized', message: 'Account disabled' });
        } else reject({ fn: 'NotFound', message: 'Session not found' });
      })
      .then(() => {
        resolve({ token: token, refreshToken: newRefreshToken });
      })
      .catch(err => {
        if (err.code === 11000)
          reject({ fn: 'BadParameters', message: 'Username already exists' });
        else reject(err);
      });
  });
};

// Remove session
UserSchema.statics.removeSession = function (userId, sessionId) {
  return new Promise((resolve, reject) => {
    var query = this.findById(userId);
    query
      .exec()
      .then(row => {
        if (row) {
          row.refreshTokens = row.refreshTokens.filter(
            e => e.sessionId !== sessionId,
          );
          return row.save();
        } else reject({ fn: 'NotFound', message: 'User not found' });
      })
      .then(() => {
        resolve('Session removed successfully');
      })
      .catch(err => {
        if (err.code === 11000)
          reject({ fn: 'BadParameters', message: 'Username already exists' });
        else reject(err);
      });
  });
};

// gen totp QRCode url
UserSchema.statics.getTotpQrcode = function (username) {
  return new Promise((resolve, reject) => {
    let newConfig = totpConfig;
    newConfig.label = username;
    const secret = new OTPAuth.Secret({
      size: 10,
    }).base32;
    newConfig.secret = secret;

    let totp = new OTPAuth.TOTP(newConfig);
    let totpUrl = totp.toString();

    QRCode.toDataURL(totpUrl, function (err, url) {
      resolve({
        totpQrCode: url,
        totpSecret: secret,
      });
    });
  });
};

// verify TOTP and Setup enabled status and secret code
UserSchema.statics.setupTotp = function (token, secret, username) {
  return new Promise((resolve, reject) => {
    checkTotpToken(token, secret);

    var query = this.findOne({ username: username });
    query
      .exec()
      .then(function (row) {
        if (!row) throw { errmsg: 'User not found' };
        else if (row.totpEnabled === true)
          throw { errmsg: 'TOTP already enabled by this user' };
        else {
          row.totpEnabled = true;
          row.totpSecret = secret;
          return row.save();
        }
      })
      .then(function () {
        resolve({ msg: true });
      })
      .catch(function (err) {
        reject(err);
      });
  });
};

// verify TOTP and Cancel enabled status and secret code
UserSchema.statics.cancelTotp = function (token, username) {
  return new Promise((resolve, reject) => {
    var query = this.findOne({ username: username });
    query
      .exec()
      .then(function (row) {
        if (!row) throw { errmsg: 'User not found' };
        else if (row.totpEnabled !== true)
          throw { errmsg: 'TOTP is not enabled yet' };
        else {
          checkTotpToken(token, row.totpSecret);
          row.totpEnabled = false;
          row.totpSecret = '';
          return row.save();
        }
      })
      .then(function () {
        resolve({ msg: 'TOTP is canceled.' });
      })
      .catch(function (err) {
        reject(err);
      });
  });
};

/*
 *** Methods ***
 */

// Authenticate user with username and password, return JWT token
UserSchema.methods.getToken = function (userAgent) {
  return new Promise((resolve, reject) => {
    var user = this;
    var query = User.findOne({ username: user.username });
    query
      .exec()
      .then(function (row) {
        if (row && row.enabled === false)
          throw { fn: 'Unauthorized', message: 'Authentication Failed.' };

        if (row && bcrypt.compareSync(user.password, row.password)) {
          if (row.totpEnabled && user.totpToken)
            checkTotpToken(user.totpToken, row.totpSecret);
          else if (row.totpEnabled)
            throw { fn: 'BadParameters', message: 'Missing TOTP token' };
          var refreshToken = jwt.sign(
            { sessionId: null, userId: row._id },
            auth.jwtRefreshSecret,
          );
          return User.updateRefreshToken(refreshToken, userAgent);
        } else {
          if (!row) {
            // We compare two random strings to generate delay
            var randomHash =
              '$2b$10$' +
              [...Array(53)].map(() => Math.random().toString(36)[2]).join('');
            bcrypt.compareSync(user.password, randomHash);
          }

          throw { fn: 'Unauthorized', message: 'Authentication Failed.' };
        }
      })
      .then(row => {
        resolve({ token: row.token, refreshToken: row.refreshToken });
      })
      .catch(function (err) {
        reject(err);
      });
  });
};

var User = mongoose.model('User', UserSchema);
module.exports = User;