'use strict';

var mongoose = require('mongoose-bird')();
var Schema = mongoose.Schema;
var crypto = require('crypto');

var UserSchema = new Schema({
  name: String,
  email: {
    type: String,
    lowercase: true
  },
  role: {
    type: String,
    default: 'user'
  },
  password: String,
  provider: String,
  salt: String
});

/**
 * Virtuals
 */

// Public profile information
UserSchema
  .virtual('profile')
  .get(function() {
    return {
      'name': this.name,
      'role': this.role
    };
  });

// Non-sensitive info we'll be putting in the token
UserSchema
  .virtual('token')
  .get(function() {
    return {
      '_id': this._id,
      'role': this.role
    };
  });

/**
 * Validations
 */

// Validate empty email
UserSchema
  .path('email')
  .validate(function(email) {
    return email.length;
  }, 'Email cannot be blank');

// Validate empty password
UserSchema
  .path('password')
  .validate(function(password) {
    return password.length;
  }, 'Password cannot be blank');

// Validate email is not taken
UserSchema
  .path('email')
  .validate(function(value, respond) {
    var self = this;
    return this.constructor.findOneAsync({ email: value })
      .then(function(user) {
        if (user) {
          if (self.id === user.id) {
            return respond(true);
          }
          return respond(false);
        }
        return respond(true);
      })
      .catch(function(err) {
        throw err;
      });
  }, 'The specified email address is already in use.');

var validatePresenceOf = function(value) {
  return value && value.length;
};

/**
 * Pre-save hook
 */
UserSchema
  .pre('save', function(next) {
    // Handle new/update passwords
    if (this.password) {
      if (!validatePresenceOf(this.password)) {
        next(new Error('Invalid password'));
      }

      // Make salt with a callback
      var _this = this;
      this.makeSalt(function(saltErr, salt) {
        if (saltErr) {
          next(saltErr);
        }
        _this.salt = salt;
        _this.encryptPassword(_this.password, function(encryptErr, hashedPassword) {
          if (encryptErr) {
            next(encryptErr);
          }
          _this.password = hashedPassword;
          next();
        });
      });
    } else {
      next();
    }
  });

/**
 * Methods
 */
UserSchema.methods = {
  /**
   * Authenticate - check if the passwords are the same
   *
   * @param {String} password
   * @param {Function} callback
   * @return {Boolean}
   * @api public
   */
  authenticate: function(password, callback) {
    if (!callback) {
      return this.password === this.encryptPassword(password);
    }

    var _this = this;
    this.encryptPassword(password, function(err, pwdGen) {
      if (err) {
        callback(err);
      }

      if (_this.password === pwdGen) {
        callback(null, true);
      }
      else {
        callback(null, false);
      }
    });
  },

  /**
   * Make salt
   *
   * @param {Number} byteSize Optional salt byte size, default to 16
   * @param {Function} callback
   * @return {String}
   * @api public
   */
  makeSalt: function(byteSize, callback) {
    var defaultByteSize = 16;

    if (typeof arguments[0] === 'function') {
      callback = arguments[0];
      byteSize = defaultByteSize;
    }
    else if (typeof arguments[1] === 'function') {
      callback = arguments[1];
    }

    if (!byteSize) {
      byteSize = defaultByteSize;
    }

    if (!callback) {
      return crypto.randomBytes(byteSize).toString('base64');
    }

    return crypto.randomBytes(byteSize, function(err, salt) {
      if (err) {
        callback(err);
      }
      return callback(null, salt.toString('base64'));
    });
  },

  /**
   * Encrypt password
   *
   * @param {String} password
   * @param {Function} callback
   * @return {String}
   * @api public
   */
  encryptPassword: function(password, callback) {
    if (!password || !this.salt) {
      return null;
    }

    var defaultIterations = 10000;
    var defaultKeyLength = 64;
    var salt = new Buffer(this.salt, 'base64');

    if (!callback) {
      return crypto.pbkdf2Sync(password, salt, defaultIterations, defaultKeyLength)
                   .toString('base64');
    }

    return crypto.pbkdf2(password, salt, defaultIterations, defaultKeyLength, function(err, key) {
      if (err) {
        callback(err);
      }
      return callback(null, key.toString('base64'));
    });
  }
};

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