const mongoose = require('../mongoose');
const uuid = require('uuid');
const bcrypt = require('bcrypt');

const SALT_ROUNDS = 10;

const UserSchema = new mongoose.Schema({
  id: {
    type: String,
    default: uuid.v4,
    unique: true,
    required: true
  },
  displayName: String,
  disabled: Boolean,
  password: String,
  profiles: [{
    id: {
      type: String,
      required: true
    },
    provider: {
      type: String,
      required: true
    }
  }],
  roles: [String]
});

// Add the indixies on the user profile data.
UserSchema.index({
  'profiles.id': 1,
  'profiles.provider': 1
}, {
  unique: true,
  background: false
});

/**
 * toJSON overrides to remove the password field from the json
 * output.
 */
UserSchema.options.toJSON = {};
UserSchema.options.toJSON.hide = 'password profiles roles disabled';
UserSchema.options.toJSON.transform = (doc, ret, options) => {
  if (options.hide) {
    options.hide.split(' ').forEach((prop) => {
      delete ret[prop];
    });
  }

  return ret;
};

/**
 * Finds a user given their email address that we have for them in the system
 * and ensures that the retuned user matches the password passed in as well.
 * @param  {string}   email     - email to look up the user by
 * @param  {string}   password  - password to match against the found user
 * @param  {Function} done     [description]
 */
UserSchema.statics.findLocalUser = function(email, password) {
  return User.findOne({
    profiles: {
      $elemMatch: {
        id: email,
        provider: 'local'
      }
    }
  })
  .then((user) => {
    if (!user) {
      return false;
    }

    return new Promise((resolve, reject) => {
      bcrypt.compare(password, user.password, (err, res) => {
        if (err) {
          return reject(err);
        }

        if (!res) {
          return resolve(false);
        }

        return resolve(user);
      });
    });
  });
};

/**
 * Merges two users together by taking all the profiles on a given user and
 * pushing them into the source user followed by deleting the destination user's
 * user account. This will not merge the roles associated with the source user.
 * @param  {String} dstUserID id of the user to which is the target of the merge
 * @param  {String} srcUserID id of the user to which is the source of the merge
 * @return {Promise}          resolves when the users are merged
 */
UserSchema.statics.mergeUsers = function(dstUserID, srcUserID) {
  let srcUser, dstUser;

  return Promise.all([
    User.findOne({id: dstUserID}).exec(),
    User.findOne({id: srcUserID}).exec()
  ]).then((users) => {
    dstUser = users[0];
    srcUser = users[1];

    srcUser.profiles.forEach((profile) => {
      dstUser.profiles.push(profile);
    });

    return srcUser.remove();
  }).then(() => dstUser.save());
};

/**
 * Finds a user given a social profile and if the user does not exist, creates
 * them.
 * @param  {Object}   profile - User social/external profile
 * @param  {Function} done    [description]
 */
UserSchema.statics.findOrCreateExternalUser = function(profile) {
  return User.findOne({
    profiles: {
      $elemMatch: {
        id: profile.id,
        provider: profile.provider
      }
    }
  })
  .then((user) => {
    if (user) {
      return user;
    }

    // The user was not found, lets create them!
    user = new User({
      displayName: profile.displayName,
      roles: [],
      profiles: [
        {
          id: profile.id,
          provider: profile.provider
        }
      ]
    });

    return user.save();
  });
};

UserSchema.statics.changePassword = function(id, password) {
  return new Promise((resolve, reject) => {
    bcrypt.hash(password, SALT_ROUNDS, (err, hashedPassword) => {
      if (err) {
        return reject(err);
      }

      resolve(hashedPassword);
    });
  })
  .then((hashedPassword) => {
    return User.update({id}, {
      $set: {
        password: hashedPassword
      }
    });
  });
};

/**
 * Creates local users.
 * @param  {Array} users Users to create
 * @return {Promise}     Resolves with the users that were created
 */
UserSchema.statics.createLocalUsers = function(users) {
  return Promise.all(users.map((user) => {
    return User
      .createLocalUser(user.email, user.password, user.displayName);
  }));
};

/**
 * Creates the local user with a given email, password, and name.
 * @param  {String}   email       email of the new user
 * @param  {String}   password    plaintext password of the new user
 * @param  {String}   displayName name of the display user
 * @param  {Function} done        callback
 */
UserSchema.statics.createLocalUser = function(email, password, displayName) {
  if (!email) {
    return Promise.reject('email is required');
  }

  if (!password) {
    return Promise.reject('password is required');
  }

  if (!displayName) {
    return Promise.reject('displayName is required');
  }

  return new Promise((resolve, reject) => {
    bcrypt.hash(password, SALT_ROUNDS, (err, hashedPassword) => {
      if (err) {
        return reject(err);
      }

      let user = new User({
        displayName: displayName,
        password: hashedPassword,
        roles: [],
        profiles: [
          {
            id: email,
            provider: 'local'
          }
        ]
      });

      user.save((err) => {
        if (err) {
          return reject(err);
        }

        return resolve(user);
      });
    });
  });
};

/**
 * Disables a given user account.
 * @param  {String}   id   id of a user
 * @param  {Function} done callback after the operation is complete
 */
UserSchema.statics.disableUser = function(id) {
  return User.update({
    id: id
  }, {
    $set: {
      disabled: true
    }
  });
};

/**
 * Enables a given user account.
 * @param  {String}   id   id of a user
 * @param  {Function} done callback after the operation is complete
 */
UserSchema.statics.enableUser = function(id) {
  return User.update({
    id: id
  }, {
    $set: {
      disabled: false
    }
  });
};

/**
 * Adds a role to a user.
 * @param  {String}   id   id of a user
 * @param  {String}   role role to add
 * @param  {Function} done callback after the operation is complete
 */
UserSchema.statics.addRoleToUser = function(id, role) {
  return User.update({
    id: id
  }, {
    $addToSet: {
      roles: role
    }
  });
};

/**
 * Removes a role from a user.
 * @param  {String}   id   id of a user
 * @param  {String}   role role to remove
 * @param  {Function} done callback after the operation is complete
 */
UserSchema.statics.removeRoleFromUser = function(id, role) {
  return User.update({
    id: id
  }, {
    $pull: {
      roles: role
    }
  });
};

/**
 * Finds a user with the id.
 * @param {String} id  user id (uuid)
*/
UserSchema.statics.findById = function(id) {
  return User.findOne({id});
};

/**
 * Finds users in an array of idd.
 * @param {Array} ids  array of user identifiers (uuid)
*/
UserSchema.statics.findByIdArray = function(ids) {
  return User.find({
    'id': {$in: ids}
  });
};

const User = mongoose.model('User', UserSchema);

module.exports = User;
module.exports.Schema = UserSchema;