#-- encoding: UTF-8
#-- copyright
# OpenProject is a project management system.
#
# Copyright (C) 2012-2013 the OpenProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# See doc/COPYRIGHT.rdoc for more details.
#++

require 'net/ldap'

class LdapAuthSource < AuthSource
  validates_presence_of :host, :port, :attr_login
  validates_length_of :name, :host, :maximum => 60, :allow_nil => true
  validates_length_of :account, :account_password, :base_dn, :maximum => 255, :allow_nil => true
  validates_length_of :attr_login, :attr_firstname, :attr_lastname, :attr_mail, :maximum => 30, :allow_nil => true
  validates_numericality_of :port, :only_integer => true

  before_validation :strip_ldap_attributes
  after_initialize :set_default_port

  def authenticate(login, password)
    return nil if login.blank? || password.blank?
    attrs = get_user_dn(login)

    if attrs && attrs[:dn] && authenticate_dn(attrs[:dn], password)
      logger.debug "Authentication successful for '#{login}'" if logger && logger.debug?
      return attrs.except(:dn)
    end
  rescue  Net::LDAP::LdapError => error
    raise "LdapError: " + error.message
  end

  # test the connection to the LDAP
  def test_connection
    ldap_con = initialize_ldap_con(self.account, self.account_password)
    ldap_con.open { }
  rescue  Net::LDAP::LdapError => text
    raise "LdapError: " + text.to_s
  end

  def auth_method_name
    "LDAP"
  end

  private

  def strip_ldap_attributes
    [:attr_login, :attr_firstname, :attr_lastname, :attr_mail].each do |attr|
      write_attribute(attr, read_attribute(attr).strip) unless read_attribute(attr).nil?
    end
  end

  def initialize_ldap_con(ldap_user, ldap_password)
    options = { :host => self.host,
                :port => self.port,
                :encryption => (self.tls ? :simple_tls : nil)
              }
    options.merge!(:auth => { :method => :simple, :username => ldap_user, :password => ldap_password }) unless ldap_user.blank? && ldap_password.blank?
    Net::LDAP.new options
  end

  def get_user_attributes_from_ldap_entry(entry)
    {
     :dn => entry.dn,
     :firstname => LdapAuthSource.get_attr(entry, self.attr_firstname),
     :lastname => LdapAuthSource.get_attr(entry, self.attr_lastname),
     :mail => LdapAuthSource.get_attr(entry, self.attr_mail),
     :auth_source_id => self.id
    }
  end

  # Return the attributes needed for the LDAP search.  It will only
  # include the user attributes if on-the-fly registration is enabled
  def search_attributes
    if onthefly_register?
      ['dn', self.attr_firstname, self.attr_lastname, self.attr_mail]
    else
      ['dn']
    end
  end

  # Check if a DN (user record) authenticates with the password
  def authenticate_dn(dn, password)
    if dn.present? && password.present?
      initialize_ldap_con(dn, password).bind
    end
  end

  # Get the user's dn and any attributes for them, given their login
  def get_user_dn(login)
    ldap_con = initialize_ldap_con(self.account, self.account_password)
    login_filter = Net::LDAP::Filter.eq( self.attr_login, login )
    object_filter = Net::LDAP::Filter.eq( "objectClass", "*" )
    attrs = {}

    ldap_con.search( :base => self.base_dn,
                     :filter => object_filter & login_filter,
                     :attributes=> search_attributes) do |entry|

      if onthefly_register?
        attrs = get_user_attributes_from_ldap_entry(entry)
      else
        attrs = {:dn => entry.dn}
      end

      logger.debug "DN found for #{login}: #{attrs[:dn]}" if logger && logger.debug?
    end

    attrs
  end

  def self.get_attr(entry, attr_name)
    if !attr_name.blank?
      entry[attr_name].is_a?(Array) ? entry[attr_name].first : entry[attr_name]
    end
  end

  def set_default_port
    self.port = 389 if self.port.to_i == 0
  end
end