const { v4: uuidv4 } = require('uuid');
const bcrypt = require('bcryptjs');

class UserController {

  constructor(database) {
    this.database = database;
  };

  createUser(data, scb, ecb) {
    console.log('UserController: create user: ' + data.username);
    let collection = this.database.collection('users');
    collection.findOne({ username: data.username }, {}, function (dbErr, dbRes) {
      if (dbErr === null) {
        if (dbRes === null) {
          bcrypt.hash(data.password, 10, (err, hash) => {
            if (err) {
              ecb({
                code: 'app error',
                message: 'could not hash password'
              });
            }
            let user = {
              id: uuidv4(),
              username: data.username,
              passwordHash: hash,
              role: 'user'
            };
            collection.insertOne(user, function (insertErr, insertRes) {
              if (insertErr === null) {
                let res = {
                  id: user.id,
                  username: user.username,
                  role: user.role
                };
                scb(res);
              } else {
                ecb({
                  code: 'database error. could not create user',
                  message: insertErr.message
                });
              }
            });
          });
        } else {
          ecb({
            code: 'app error',
            message: 'user already exists'
          })
        }
      } else {
        ecb({
          code: 'database error',
          message: dbErr.message
        });
      }
    });
  };

  login(data, scb, ecb) {
    console.log('UserController: login: ' + data.username);
    let collection = this.database.collection('users');
    collection.findOne({ username: data.username }, {}, function (dbErr, user) {
      if (dbErr === null) {
        if (user === null) {
          ecb({
            code: 'app error',
            message: 'user already exists'
          });
        } else {
          bcrypt.compare(data.password, user.passwordHash, (cryptErr, cryptRes) => {
            if (cryptErr) {
              ecb({
                code: 'app error',
                message: 'could not hash password'
              });
            } else {
              if (cryptRes === true) {
                let res = {
                  id: user.id,
                  username: user.username,
                  role: user.role
                };
                scb(res);
              } else {
                ecb({ code: 'user error', message: 'authentication failed' });
              }
            }
          });
        }
      } else {
        ecb({
          code: 'database error',
          message: dbErr.message
        });
      }
    });
  };

  getUserData(user, scb, ecb) {
    scb({});
  };

};

module.exports = UserController;