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
  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 :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, :through => :students_for_courses, :source => :user
  has_many :course_infos, :dependent => :destroy

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

  validates_presence_of :password, :term
  validates_format_of  :class_period, :message => "class period can only digital!", :with =>/^[1-9]\d*$/
  safe_attributes 'extra',
  'time',
  'name',
  'extra',
  'code',
  'location',
  'tea_id',
  'password',
  'term',
  'password',
  'description'

  acts_as_customizable

  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))
  }

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

   # 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 validate
    if  !class_period.match([0-9])
      errors.add_to_base("class period can only digital")
    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

end