class Page < ActiveRecord::Base

  class MissingRootPageError < StandardError
    def initialize(message = 'Database missing root page'); super end
  end

  # Callbacks
  before_save :update_virtual, :update_status

  # Associations
  acts_as_tree :order => 'virtual DESC, title ASC'
  has_many :parts, :class_name => 'PagePart', :order => 'id', :dependent => :destroy
  accepts_nested_attributes_for :parts, :allow_destroy => true
  belongs_to :layout
  belongs_to :created_by, :class_name => 'User'
  belongs_to :updated_by, :class_name => 'User'

  # Validations
  validates_presence_of :title, :slug, :breadcrumb, :status_id

  validates_length_of :title, :maximum => 255
  validates_length_of :slug, :maximum => 100
  validates_length_of :breadcrumb, :maximum => 160

  validates_format_of :slug, :with => %r{^([-_.A-Za-z0-9]*|/)$}
  validates_uniqueness_of :slug, :scope => :parent_id
  validates_numericality_of :id, :status_id, :parent_id, :allow_nil => true, :only_integer => true

  validate :valid_class_name

  include Radiant::Taggable
  include StandardTags
  include Annotatable

  annotate :description
  attr_accessor :request, :response, :pagination_parameters

  set_inheritance_column :class_name

  def layout_with_inheritance
    unless layout_without_inheritance
      parent.layout if parent?
    else
      layout_without_inheritance
    end
  end
  alias_method_chain :layout, :inheritance

  def description
    self["description"]
  end

  def description=(value)
    self["description"] = value
  end

  def cache?
    true
  end

  def child_url(child)
    clean_url(url + '/' + child.slug)
  end

  def headers
    # Return a blank hash that child classes can override or merge
    { }
  end

  def part(name)
    if new_record? or parts.to_a.any?(&:new_record?)
      parts.to_a.find {|p| p.name == name.to_s }
    else
      parts.find_by_name name.to_s
    end
  end

  def has_part?(name)
    !part(name).nil?
  end

  def has_or_inherits_part?(name)
    has_part?(name) || inherits_part?(name)
  end

  def inherits_part?(name)
    !has_part?(name) && self.ancestors.any? { |page| page.has_part?(name) }
  end

  def published?
    status == Status[:published]
  end
  
  def status
   Status.find(self.status_id)
  end
  
  def status=(value)
    self.status_id = value.id
  end

  def url
    if parent?
      parent.child_url(self)
    else
      clean_url(slug)
    end
  end

  def process(request, response)
    @request, @response = request, response
    if layout
      content_type = layout.content_type.to_s.strip
      @response.headers['Content-Type'] = content_type unless content_type.empty?
    end
    headers.each { |k,v| @response.headers[k] = v }
    @response.body = render
    @response.status = response_code
  end

  def response_code
    200
  end

  def render
    if layout
      parse_object(layout)
    else
      render_part(:body)
    end
  end

  def render_part(part_name)
    part = part(part_name)
    if part
      parse_object(part)
    else
      ''
    end
  end

  def render_snippet(snippet)
    parse_object(snippet)
  end

  def find_by_url(url, live = true, clean = true)
    return nil if virtual?
    url = clean_url(url) if clean
    my_url = self.url
    if (my_url == url) && (not live or published?)
      self
    elsif (url =~ /^#{Regexp.quote(my_url)}([^\/]*)/)
      slug_child = children.find_by_slug($1)
      if slug_child
        found = slug_child.find_by_url(url, live, clean)
        return found if found
      end
      children.each do |child|
        found = child.find_by_url(url, live, clean)
        return found if found
      end
      file_not_found_types = ([FileNotFoundPage] + FileNotFoundPage.descendants)
      file_not_found_names = file_not_found_types.collect { |x| x.name }
      condition = (['class_name = ?'] * file_not_found_names.length).join(' or ')
      condition = "status_id = #{Status[:published].id} and (#{condition})" if live
      children.find(:first, :conditions => [condition] + file_not_found_names)
    end
  end

  def update_status
    self[:published_at] = Time.now if self[:status_id] == Status[:published].id && self[:published_at] == nil
    
    if self[:published_at] != nil && (self[:status_id] == Status[:published].id || self[:status_id] == Status[:scheduled].id)
      self[:status_id] = Status[:scheduled].id if self[:published_at]  > Time.now
      self[:status_id] = Status[:published].id if self[:published_at] <= Time.now
    end

    true    
  end


  def to_xml(options={}, &block)
    super(options.reverse_merge(:include => :parts), &block)
  end

  class << self
    def find_by_url(url, live = true)
      root = find_by_parent_id(nil)
      raise MissingRootPageError unless root
      root.find_by_url(url, live)
    end

    def display_name(string = nil)
      if string
        @display_name = string
      else
        @display_name ||= begin
          n = name.to_s
          n.sub!(/^(.+?)Page$/, '\1')
          n.gsub!(/([A-Z])/, ' \1')
          n.strip
        end
      end
      @display_name = @display_name + " - not installed" if missing? && @display_name !~ /not installed/
      @display_name
    end
    def display_name=(string)
      display_name(string)
    end

    def load_subclasses
      ([RADIANT_ROOT] + Radiant::Extension.descendants.map(&:root)).each do |path|
        Dir["#{path}/app/models/*_page.rb"].each do |page|
          $1.camelize.constantize if page =~ %r{/([^/]+)\.rb}
        end
      end
      if ActiveRecord::Base.connection.tables.include?('pages') && Page.column_names.include?('class_name') # Assume that we have bootstrapped
        Page.connection.select_values("SELECT DISTINCT class_name FROM pages WHERE class_name <> '' AND class_name IS NOT NULL").each do |p|
          begin
            p.constantize
          rescue NameError, LoadError
            eval(%Q{class #{p} < Page; def self.missing?; true end end}, TOPLEVEL_BINDING)
          end
        end
      end
    end

    def new_with_defaults(config = Radiant::Config)
      page = new
      page.parts.concat default_page_parts(config)
      default_status = config['defaults.page.status']
      page.status = Status[default_status] if default_status
      page
    end

    def is_descendant_class_name?(class_name)
      (Page.descendants.map(&:to_s) + [nil, "", "Page"]).include?(class_name)
    end

    def descendant_class(class_name)
      raise ArgumentError.new("argument must be a valid descendant of Page") unless is_descendant_class_name?(class_name)
      if ["", nil, "Page"].include?(class_name)
        Page
      else
        class_name.constantize
      end
    end

    def missing?
      false
    end

    private

      def default_page_parts(config = Radiant::Config)
        default_parts = config['defaults.page.parts'].to_s.strip.split(/\s*,\s*/)
        default_parts.map do |name|
          PagePart.new(:name => name, :filter_id => config['defaults.page.filter'])
        end
      end
  end

  private

    def valid_class_name
      unless Page.is_descendant_class_name?(class_name)
        errors.add :class_name, "must be set to a valid descendant of Page"
      end
    end

    def attributes_protected_by_default
      super - [self.class.inheritance_column]
    end
    

    def update_virtual
      unless self.class == Page.descendant_class(class_name)
        self.virtual = Page.descendant_class(class_name).new.virtual?
      else
        self.virtual = virtual?
      end
      true
    end

    def clean_url(url)
      "/#{ url.strip }/".gsub(%r{//+}, '/')
    end

    def parent?
      !parent.nil?
    end

    def lazy_initialize_parser_and_context
      unless @parser and @context
        @context = PageContext.new(self)
        @parser = Radius::Parser.new(@context, :tag_prefix => 'r')
      end
      @parser
    end

    def parse(text)
      lazy_initialize_parser_and_context.parse(text)
    end

    def parse_object(object)
      text = object.content
      text = parse(text)
      text = object.filter.filter(text) if object.respond_to? :filter_id
      text
    end

end