module Documentation
  class Page < ActiveRecord::Base
    
    validates :title, :presence => true
    validates :position, :presence => true
    validates :permalink, :presence => true, :uniqueness => {:scope => :parent_id}
    
    default_scope -> { order(:position) }
    scope :roots, -> { where(:parent_id => nil) }
    
    belongs_to :parent, :class_name => 'Documentation::Page', :foreign_key => 'parent_id'
    
    before_validation do
      if self.position.blank?
        last_position = self.class.unscoped.where(:parent_id => self.parent_id).order(:position => :desc).first
        self.position = last_position ? last_position.position + 1 : 1
      end
    end
    
    before_validation :set_permalink
    before_save :compile_content
    
    #
    # Ensure the page is updated in the index after saving/destruction
    #
    after_commit :index, :on => [:create, :update]
    after_commit :delete_from_index, :on => :destroy

    #
    # Store all the parents of this object. THis is automatically populated when it is loaded
    # from a path
    #
    attr_accessor :parents
    
    #
    # Set the permalink for this page
    #
    def set_permalink
      proposed_permalink = self.title.parameterize
      index = 1
      while self.permalink.blank?
        if self.class.where(:permalink => proposed_permalink, :parent_id => self.parent_id).exists?
          index += 1
          proposed_permalink = self.title.parameterize + "-#{index}"
        else
          self.permalink = proposed_permalink
        end
      end
    end
    
    #
    # Return a default empty array for parents
    #
    def parents
      @parents ||= self.parent ? [self.parent.parents, self.parent].flatten : []
    end

    #
    # Return a full breadcrumb to this page (as it has been loaded)
    #
    def breadcrumb
      @breadcrumb ||= [parents, new_record? ? nil : self].flatten.compact
    end
    
    #
    # Return the path where this page can be viewed in the site
    #
    def preview_path
      if path = Documentation.config.preview_path_prefix
        "#{path}#{full_permalink}"
      else
        nil
      end
    end
    
    #
    # Return a full permalink tot his page
    #
    def full_permalink
      @full_permalink ||= begin
        if parents.empty?
          self.permalink
        else
          previous = breadcrumb.compact.map(&:permalink).compact
          previous.empty? ? self.permalink : previous.join('/')
        end
      end
    end

    #
    # Return all child pages
    #
    def children
      @children ||= begin
        if self.new_record?
          []
        else
          children = self.class.where(:parent_id => self.id)
          children.each { |c| c.parents = [parents, self].flatten }
          children
        end
      end
    end

    #
    # Does this page have children?
    #
    def has_children?
      !children.empty?
    end

    #
    # Return pages which should be included in the navigation
    #
    def navigation
      if has_children?
        root_parent = parents[-1]
        if root_parent.nil?
          pages = self.class.roots
        else
          pages = (root_parent || self).children
        end
      else
        root_parent = parents[-2] || parents[-1]
        if root_parent.nil? || (root_parent.parent.nil? && parents.size <= 1)
          pages = self.class.roots
        else
          pages = (root_parent || self).children
        end
      end
      
      
      pages.map do |c|
        child_pages = []
        child_pages = c.children if breadcrumb.include?(c)
        [c, child_pages]
      end
    end

    #
    # Create the compiled content
    #
    def compile_content
      mr = Documentation::MarkdownRenderer.new
      mr.page = self
      rc = Redcarpet::Markdown.new(mr, :space_after_headers => true, :fenced_code_blocks => true, :no_intra_emphasis => true, :highlight => true)
      self.compiled_content = rc.render(self.content.to_s).html_safe
    end
    
    #
    # Index this page
    #
    def index
      if searcher = Documentation.config.searcher
        searcher.index(self)
      end
    end
    
    #
    # Delete this page from the index
    #
    def delete_from_index
      if searcher = Documentation.config.searcher
        searcher.delete(self)
      end
    end
    
    #
    # Find a page using the searcher if one exists otherwise just fall back to AR
    # searching. Returns a Documentation::SearchResult object.
    #
    def self.search(query, options = {})
      if searcher = Documentation.config.searcher
        searcher.search(query, options)
      end
    end

    #
    # Find a page by passing a path to the page from the root of the 
    # site
    #
    def self.find_from_path(path_string)
      raise ActiveRecord::RecordNotFound, "Couldn't find page without a path" if path_string.blank?
      path_parts = path_string.split('/')
      path = []
      path_parts.each_with_index do |p, i|
        page = self.where(:parent_id => (path.last ? path.last.id : nil)).find_by_permalink(p)
        if page
          page.parents = path.dup
          page.parent = path.last
          path << page
        else
          raise ActiveRecord::RecordNotFound, "Couldn't find page at #{path_string}"
        end
      end
      path.last
    end

    #
    # Reorder pgaes
    #
    def self.reorder(parent, order = [])
      order = order.map(&:to_i)
      order = self.where(:parent_id => parent.id).map(&:id) if order.empty?
      order.each_with_index do |id, index|
        command = self.find_by_id!(id)
        command.position = index + 1
        command.save
      end
    end
    
  end
end