class Course < ActiveRecord::Base
  include Redmine::SafeAttributes

  STATUS_ACTIVE     = 1
  STATUS_CLOSED     = 5
  STATUS_ARCHIVED   = 9
  
  attr_accessible :code, :extra, :name, :state, :tea_id, :time , :location, :state, :term, :password,:is_public,:description,:class_period, :open_student
  #belongs_to :project, :class_name => 'Course', :foreign_key => :extra, primary_key: :identifier
  belongs_to :teacher, :class_name => 'User', :foreign_key => :tea_id  # 定义一个方法teacher，该方法通过tea_id来调用User表
  belongs_to :school, :class_name => 'School', :foreign_key => :school_id #定义一个方法school，该方法通过school_id来调用School表
  has_many :bid
  has_many :members, :include => [:principal, :roles], :conditions => "#{Principal.table_name}.type='User' AND #{Principal.table_name}.status=#{Principal::STATUS_ACTIVE}"
  has_many :memberships, :class_name => 'Member'
  has_many :member_principals, :class_name => 'Member',
           :include => :principal,
           :conditions => "#{Principal.table_name}.type='Group' OR (#{Principal.table_name}.type='User' AND #{Principal.table_name}.status=#{Principal::STATUS_ACTIVE})"
  has_many :principals, :through => :member_principals, :source => :principal
  has_many :users, :through => :members
  has_many :homeworks, :through => :homework_for_courses, :source => :bid, :dependent => :destroy
  has_many :journals_for_messages, :as => :jour, :dependent => :destroy
  has_many :homework_for_courses, :dependent => :destroy
  has_many :student, :class_name => 'StudentsForCourse', :source => :user
  has_many :course_infos, :class_name => 'CourseInfos',:dependent => :destroy
  has_many :enabled_modules, :dependent => :delete_all
  has_many :boards, :dependent => :destroy, :order => "position ASC"
  #has_many :course_journals_for_messages, :class_name => 'CourseJournalsForMessage', :as => :jour, :dependent => :destroy
  has_many :news, :dependent => :destroy, :include => :author
  has_one :course_status, :class_name => "CourseStatus", :dependent => :destroy

  has_many :course_groups, :dependent => :destroy

  acts_as_taggable
  acts_as_nested_set :order => 'name', :dependent => :destroy
  acts_as_attachable :view_permission => :view_course_files,
                     :delete_permission => :manage_files

  validates_presence_of :password, :term,:name
  validates_format_of  :class_period, :with =>/^[1-9]\d*$/
  validates_format_of  :name,:with =>/^[a-zA-Z0-9_\u4e00-\u9fa5]+$/
  validates_length_of :description, :maximum => 10000
  before_save :self_validate
  after_create :create_board_sync
  before_destroy :delete_all_members

  safe_attributes 'extra',
  'time',
  'name',
  'extra',
  'code',
  'location',
  'tea_id',
  'password',
  'term',
  'is_public',
  'description',
  'class_period',
  'open_student'

  acts_as_customizable

  scope :all_course
  scope :active, lambda { where(:status => STATUS_ACTIVE) }
  scope :status, lambda {|arg| where(arg.blank? ? nil : {:status => arg.to_i}) }
  scope :all_public, lambda { where(:is_public => true) }
  scope :visible, lambda {|*args| where(Course.visible_condition(args.shift || User.current, *args)) }
  scope :allowed_to, lambda {|*args|
    user = User.current
    permission = nil
    if args.first.is_a?(Symbol)
      permission = args.shift
    else
      user = args.shift
      permission = args.shift
    end
    where(Course.allowed_to_condition(user, permission, *args))
  }
  scope :like, lambda {|arg|
    if arg.blank?
      where(nil)
    else
      pattern = "%#{arg.to_s.strip.downcase}%"
      where(" LOWER(name) LIKE :p ", :p => pattern)
    end
  }

  def visible?(user=User.current)
    user.allowed_to?(:view_course, self)
  end

  def parent_id_changed?
    false
  end

  # Returns the mail adresses of users that should be always notified on project events
  def recipients
    notified_users.collect {|user| user.mail}
  end

  # Returns the users that should be notified on project events
  def notified_users
    # TODO: User part should be extracted to User#notify_about?
    members.select {|m| m.principal.present? && (m.mail_notification? || m.principal.mail_notification == 'all')}.collect {|m| m.principal}
  end


  # 课程的短描述信息
  def short_description(length = 255)
    description.gsub(/<\/?.*?>/,"").html_safe if description
    #description.gsub(/^(.{#{length}}[^\n\r]*).*$/m, '\1...').strip if description
  end

  # 课程的短名称信息
  def short_name(length = 8)
    name.gsub(/<\/?.*?>/,"").html_safe if name
  end

  def strip_html(html)
    return html if html.empty? || !html.include?('<')
    output = ""
    tokenizer = HTML::Tokenizer.new(html)
    while token = tokenizer.next
      node = HTML::Node.parse(nil, 0, 0, token, false)
      output += token unless (node.kind_of? HTML::Tag) or (token =~ /^<!/)
    end
    return output
  end

  def extra_frozen?
    errors[:extra].blank? && !(new_record? || extra.blank?)
  end

  def archived?
    self.status == STATUS_ARCHIVED
  end

  def self.visible_condition(user, options={})
    allowed_to_condition(user, :view_course, options)
  end

   # 获取课程的资源类型列表
  def attachmenttypes
    @attachmenttypes = Attachmentstype.find(:all, :conditions => ["#{Attachmentstype.table_name}.typeId= ?",self.attachmenttype ])
  end


  # 获取资源后缀名列表
  def contenttypes
    attachmenttypes
    if  @attachmenttypes.length >0
      @attachmenttypes.last().suffixArr
    end
  end

  def active?
    self.status == STATUS_ACTIVE
  end

  #课程权限判断
  def allows_to?(action)
    if archived?
      # No action allowed on archived projects
      return false
    end
    unless active? || Redmine::AccessControl.read_action?(action)
      # No write action allowed on closed projects
      return false
    end
    # No action allowed on disabled modules
    if action.is_a? Hash
      allowed_actions.include? "#{action[:controller]}/#{action[:action]}"
    else
      allowed_permissions.include? action
    end
  end

  # 课程允许的权限集合
  def allowed_permissions
    @allowed_permissions ||= begin
      module_names = enabled_modules.all(:select => :name).collect {|m| m.name}
      Redmine::AccessControl.modules_permissions(module_names).collect {|p| p.name}
    end
  end

  # 课程允许的动作集合
  def allowed_actions
    @actions_allowed ||= allowed_permissions.inject([]) { |actions, permission| actions += Redmine::AccessControl.allowed_actions(permission) }.flatten
  end

  # 返回用户组可以访问的课程
  def users_by_role
    members.includes(:user, :roles).all.inject({}) do |h, m|
      m.roles.each do |r|
        h[r] ||= []
        h[r] << m.user
      end
      h
    end
  end

  #自定义验证
  def self_validate

  end

  # 创建课程讨论区
  def create_board_sync
    @board = self.boards.build
    self.name=" #{l(:label_borad_course) }"
    @board.name = self.name
    @board.description = self.name.to_s
    @board.project_id = -1
    if @board.save
      logger.debug "[Course Model] ===> #{@board.to_json}"
    else
      logger.error "[Course Model] ===> Auto create board when course saved, because #{@board.full_messages}"
    end
  end

  # 新增课程留言
  # add by nwb
  def self.add_new_jour(user, notes, id, options={})
    course = Course.find(id)
    if options.count == 0
      pjfm = course.journals_for_messages.build(:user_id => user.id, :notes => notes, :reply_id => 0)
    else
      pjfm = course.journals_for_messages.build(options)
    end
    pjfm.save
    pjfm
  end

  # 删除课程所有成员
  def delete_all_members
    if self.members && self.members.count > 0
      me, mr = Member.table_name, MemberRole.table_name
      connection.delete("DELETE FROM #{mr} WHERE #{mr}.member_id IN (SELECT #{me}.id FROM #{me} WHERE #{me}.course_id = #{id})")
      Member.delete_all(['course_id = ?', id])
    end
  end

  def get_endup_time
    begin
      end_time = Time.parse(self.endup_time)
    rescue Exception => e
      end_time = Time.parse("3000-01-01")
      Rails.logger.error "[Error] course endup_time error. ===> #{e}"
    ensure 
      return end_time
    end
  end

  def get_time
    begin
      time = Date.new(self.time).to_time
    rescue Exception => e
      time = Time.parse("3000-01-01")
      Rails.logger.error "[Error] course time error. ===> #{e}"
    ensure
      return time
    end
  end

  def self.allowed_to_condition(user, permission, options={})
     perm = Redmine::AccessControl.permission(permission)
    base_statement = (perm && perm.read? ? "#{Course.table_name}.status <> #{Course::STATUS_ARCHIVED}" : "#{Course.table_name}.status = #{Course::STATUS_ACTIVE}")
    if perm && perm.course_module
      base_statement << " AND #{Course.table_name}.id IN (SELECT em.course_id FROM #{EnabledModule.table_name} em WHERE em.name='#{perm.course_module}')"
    end

     if options[:course]
       course_statement = "#{Course.table_name}.id = #{options[:course].id}"
       course_statement << " OR (#{Course.table_name}.lft > #{options[:course].lft} AND #{Course.table_name}.rgt < #{options[:course].rgt})" if options[:with_subcourses]
       base_statement = "(#{course_statement}) AND (#{base_statement})"
     end

    if user.admin?
      base_statement
    else
      statement_by_role = {}
      unless options[:member]
        role = user.logged? ? Role.non_member : Role.anonymous
        if role.allowed_to?(permission)
          statement_by_role[role] = "#{Course.table_name}.is_public = #{connection.quoted_true}"
        end
      end
      if user.logged?
        user.courses_by_role.each do |role, courses|
          if role.allowed_to?(permission) && courses.any?
            statement_by_role[role] = "#{Course.table_name}.id IN (#{courses.collect(&:id).join(',')})"
          end
        end
      end
      if statement_by_role.empty?
        "1=0"
      else
        if block_given?
          statement_by_role.each do |role, statement|
            if s = yield(role, user)
              statement_by_role[role] = "(#{statement} AND (#{s}))"
            end
          end
        end
        "((#{base_statement}) AND (#{statement_by_role.values.join(' OR ')}))"
      end
    end
  end

  #项目与课程分离后，很多课程的名称等信息为空，这些数据信息存储在项目表中！！就是数据兼容的问题
  #def name
  #  read_attribute('name') || Project.find_by_identifier(self.extra).try(:name)
  #end
end