require 'json'
require 'ostruct'
require 'active_model/naming'

module Scrivito
  # The CMS file class
  # @api public
  class BasicObj
    extend ActiveModel::Naming

    include AttributeContent
    include ModelIdentity

    def self.type_computer
      @_type_computer ||= TypeComputer.new(Scrivito::BasicObj, ::Obj)
    end

    def self.reset_type_computer!
      @_type_computer = nil
    end

    # Create a new {BasicObj Obj} in the cms
    #
    # This allows you to set the different attributes types of an obj by
    # providing a hash with the attributes names as key and the values you want
    # to set as values
    #
    # @example Reference lists have to be provided as an Array of {BasicObj Objs}
    #   Obj.create(:reference_list => [other_obj])
    #
    # @example Passing an {BasicObj Obj} allows you to set a reference
    #   Obj.create(:reference => other_obj)
    #
    # @example you can upload files by passing a ruby File object
    #   Obj.create(:blob => File.new("image.png"))
    #
    # @example Link list can be set as an Array of {Link Links}
    #   Obj.create(:link_list => [
    #     # external link
    #     Link.new(:url => "http://www.example.com", :title => "Example"),
    #     # internal link
    #     Link.new(:obj => other_obj, :title => "Other Obj")
    #   ])
    #
    # @example Dates attributes accept Time, Date and their subclasses (DateTime for example)
    #   Obj.create(:date => Time.new)
    #   Obj.create(:date => Date.now)
    #
    # @example String, text, html and enum can be set by passing a {String} value
    #   Obj.create(:title => "My Title")
    #
    # @example Arrays of {String Strings} allow you to set multi enum fields
    #   Obj.create(:tags => ["ruby", "rails"])
    #
    # @example Simply pass an Array of {BasicWidget Widgets} to change a widget field. See {BasicWidget#clone Widget#clone} on how to clone a widget.
    #   # Add new widgets
    #   Obj.create(:widgets => [Widget.new(_obj_class: 'TitleWidget', title: 'My Title')])
    #
    #   # Add a widget clone
    #   Obj.create(:widgets => [another_obj.widgets.first.clone])
    #
    #   # Changing a widget field
    #   obj.update(:widgets => [obj.widgets.first])
    #
    #   # Clear a widget field
    #   obj.update(:widgets => [])
    #
    # @api public
    # @param [Hash] attributes
    # @return [Obj] the newly created {BasicObj Obj}
    def self.create(attributes)
      attributes = with_default_obj_class(attributes)
      api_attributes, widget_properties = prepare_attributes_for_rest_api(attributes, nil)
      json = CmsRestApi.post(cms_rest_api_path, obj: api_attributes)
      obj = find(json['id'] || json['_id'])
      CmsRestApi::WidgetExtractor.notify_persisted_widgets(obj, widget_properties)
      obj
    end

    # Create a new {BasicObj Obj} instance with the given values and attributes.
    # Normally this method should not be used.
    # Instead Objs should be loaded from the cms database.
    def initialize(attributes = {})
      update_data(ObjDataFromHash.new(attributes))
    end

    # @api public
    def id
      read_attribute('_id')
    end

    def revision=(revision)
      raise "cannot change revision once set!" if @revision
      @revision = revision
    end

    def revision
      @revision or raise "revision not set!"
    end

    ### FINDERS ####################

    # Find a {BasicObj Obj} by its id.
    # If the parameter is an Array containing ids, return a list of corresponding Objs.
    # @param [String, Integer, Array<String, Integer>]id_or_list
    # @return [Obj, Array<Obj>]
    # @api public
    def self.find(id_or_list)
      Workspace.current.find_obj(id_or_list)
    end

    def self.find_by_id(id)
      Workspace.current.find_obj_by_id(id)
    end

    # Find a {BasicObj Obj} by its id.
    # If the parameter is an Array containing ids, return a list of corresponding Objs.
    # The results include deleted objects as well.
    # @param [String, Integer, Array<String, Integer>]id_or_list
    # @return [Obj, Array<Obj>]
    # @api public
    def self.find_including_deleted(id_or_list)
      Workspace.current.find_obj_including_deleted(id_or_list)
    end

    # Returns a {ObjSearchEnumerator} with the given initial subquery consisting of the four arguments.
    #
    # Note that +field+ and +value+ can also be arrays for searching several fields or searching for several values.
    #
    # {ObjSearchEnumerator}s can be chained using one of the chainable methods (e.g. {ObjSearchEnumerator#and} and {ObjSearchEnumerator#and_not}).
    #
    # @example Look for the first 10 Objs whose ObjClass is "Pressrelease" and whose title contains "quarterly":
    #   Obj.where(:_obj_class, :equals, 'Pressrelease').and(:title, :contains, 'quarterly').take(10)
    # @param [Symbol, String, Array<Symbol, String>] field See {ObjSearchEnumerator#and} for details
    # @param [Symbol, String] operator See {ObjSearchEnumerator#and} for details
    # @param [String, Array<String>] value See {ObjSearchEnumerator#and} for details
    # @param [Hash] boost See {ObjSearchEnumerator#and} for details
    # @return [ObjSearchEnumerator]
    # @api public
    def self.where(field, operator, value, boost = nil)
      ObjSearchEnumerator.new.and(field, operator, value, boost)
    end

    # Returns a {ObjSearchEnumerator} of all {BasicObj Obj}s.
    # If invoked on a subclass of Obj, the result will be restricted to instances of that subclass.
    # @return [ObjSearchEnumerator]
    # @api public
    def self.all
      if superclass == Scrivito::BasicObj
        search_for_all
      else
        find_all_by_obj_class(name)
      end
    end

    # Returns a {ObjSearchEnumerator} of all Objs with the given +obj_class+.
    # @param [String] obj_class Name of the ObjClass.
    # @return [ObjSearchEnumerator]
    # @api public
    def self.find_all_by_obj_class(obj_class)
      search_for_all.and(:_obj_class, :equals, obj_class)
    end

    # Find the {BasicObj Obj} with the given path.
    # Returns +nil+ if no matching Obj exists.
    # @param [String] path Path of the {BasicObj Obj}.
    # @return [Obj]
    # @api public
    def self.find_by_path(path)
      Workspace.current.find_obj_by_path(path)
    end

    # Find an {BasicObj Obj} with the given name.
    # If several Objs with the given name exist, an arbitrary one of these Objs is chosen and returned.
    # If no Obj with the name exits, +nil+ is returned.
    # @param [String] name Name of the {BasicObj Obj}.
    # @return [Obj]
    # @api public
    def self.find_by_name(name)
      where(:_name, :equals, name).batch_size(1).first
    end

    # Returns a {ObjSearchEnumerator} of all Objs with the given name.
    # @param [String] name Name of the {BasicObj Obj}.
    # @return [ObjSearchEnumerator]
    # @api public
    def self.find_all_by_name(name)
      where(:_name, :equals, name)
    end

    # Returns the {BasicObj Obj} with the given permalink, or +nil+ if no matching Obj exists.
    # @param [String] permalink The permalink of the {BasicObj Obj}.
    # @return [Obj]
    # @api public
    def self.find_by_permalink(permalink)
      Workspace.current.find_obj_by_permalink(permalink)
    end

    # Returns the {BasicObj Obj} with the given permalink, or raise ResourceNotFound if no matching Obj exists.
    # @param [String] permalink The permalink of the {BasicObj Obj}.
    # @return [Obj]
    # @api public
    def self.find_by_permalink!(permalink)
      find_by_permalink(permalink) or
        raise ResourceNotFound, "Could not find Obj with permalink '#{permalink}'"
    end

    # Hook method to control which page classes should be available for a page with given path.
    # Override it to allow only certain classes or none.
    # Must return either +NilClass+, or +Array+.
    #
    # Be aware that the given argument is a parent path.
    # E.g. when creating a page with path +/products/shoes+ then the argument will be +/products+.
    #
    # If +NilClass+ is returned, then all possible classes will be available.
    # By default +NilClass+ is returned.
    #
    # If +Array+ is returned, then it should include desired class names.
    # Each class name must be either a +String+ or a +Symbol+.
    # Only this class names will be available. Order of the class names will be preserved.
    #
    # @param [String] parent_path Path of the parent obj
    # @return [NilClass, Array<Symbol, String>]
    # @api public
    def self.valid_page_classes_beneath(parent_path)
    end

    # Update the {BasicObj Obj} with the attributes provided.
    #
    # For an overview of which values you can set via this method see the
    # documentation of {BasicObj.create Obj.create}.
    #
    # Additionally, +update+ accepts a +_widget_pool+ hash in +attributes+ to modify widgets.
    # The keys of +_widget_pool+ are widget instances, the values are the modified attributes of
    # these particular widgets.
    #
    # @api public
    # @param [Hash] attributes
    # @example Move the +widget_to_move+ widget from the +left+ widget field of the +two_column_widget1+ widget to +left+ of +two_column_widget2+:
    #   obj.update(
    #     _widget_pool: {
    #       two_column_widget1 => {left: two_column_widget1.left - [widget_to_move]},
    #       two_column_widget2 => {left: two_column_widget2.left + [widget_to_move]}
    #     },
    #     headline: "Some widgets were moved!"
    #   )
    #
    # @example Move the +widget_to_move+ widget from the +right+ widget field of the +two_column_widget1+ widget to the top-level widget field +main_content+:
    #   obj.update(
    #     main_content: @obj.main_content + [widget_to_move],
    #     _widget_pool: {
    #       two_column_widget1 => {
    #         right: two_column_widget1.right - [widget_to_move]
    #       }
    #     }
    #   )
    def update(attributes)
      api_attributes, widget_properties = prepare_attributes_for_rest_api(attributes)
      CmsRestApi.put(cms_rest_api_path, obj: api_attributes)
      Workspace.reload
      reload
      CmsRestApi::WidgetExtractor.notify_persisted_widgets(self, widget_properties)
      self
    end

    # Destroys the {BasicObj Obj} in the current {Workspace}
    # @api public
    def destroy
      if children.any?
        raise ClientError.new(I18n.t('scrivito.errors.models.basic_obj.has_children'), 412)
      end

      CmsRestApi.delete(cms_rest_api_path)

      Workspace.reload
    end

    def to_param
      id
    end

    # return the {BasicObj Obj} that is the parent of this Obj.
    # returns +nil+ for the root Obj.
    # @api public
    def parent
      if child_path?
        BasicObj.find_by_path(parent_path)
      end
    end

    # Returns an Array of all the ancestor objects, starting at the root and ending at this object's parent.
    # @return [Array<Obj>]
    # @api public
    def ancestors
      return [] unless child_path?

      ancestor_paths = parent_path.scan(/\/[^\/]+/).inject([""]) do |list, component|
        list << list.last + component
      end
      ancestor_paths[0] = "/"
      Workspace.current.find_objs_by_paths(ancestor_paths)
    end

    # return a list of all child {BasicObj Obj}s.
    # @return [Array<Obj>]
    # @api public
    def children
      return [] unless path

      Workspace.current.find_objs_by_parent_path(path)
    end

    ### ATTRIBUTES #################

    # returns the {BasicObj Obj}'s path as a String.
    # @api public
    def path
      read_attribute('_path')
    end

    # returns the {BasicObj Obj}'s name, i.e. the last component of the path.
    # @api public
    def name
      if child_path?
        path.match(/[^\/]+$/)[0]
      else
        ""
      end
    end

    # Returns the root {BasicObj Obj}, i.e. the Obj with the path "/"
    # @return [Obj]
    # @api public
    def self.root
      BasicObj.find_by_path("/") or raise ResourceNotFound,
          "Obj.root not found: There is no Obj with path '/'."
    end

    # Returns the homepage obj. This can be overwritten in your application's +Obj+.
    # Use {#homepage?} to check if an obj is the homepage.
    # @return [Obj]
    # @api public
    def self.homepage
      root
    end

    # @api private
    def self.generate_widget_pool_id
      SecureRandom.hex(4)
    end

    # returns the obj's permalink.
    # @api public
    def permalink
      read_attribute('_permalink')
    end

    # This method determines the controller that should be invoked when the +Obj+ is requested.
    # By default a controller matching the Obj's obj_class will be used.
    # If the controller does not exist, the CmsController will be used as a fallback.
    # Overwrite this method to force a different controller to be used.
    # @return [String]
    # @api public
    def controller_name
      obj_class_name
    end

    # This method determines the action that should be invoked when the +Obj+ is requested.
    # The default action is 'index'.
    # Overwrite this method to force a different action to be used.
    # @return [String]
    # @api public
    def controller_action_name
      "index"
    end

    # Returns true if the current obj is the {.homepage} obj.
    # @api public
    def homepage?
      self == self.class.homepage
    end

    # This method is used to calculate a part of a URL of this Obj.
    #
    # The routing schema: <code><em><obj.id></em>/<em><obj.slug></em></code>
    #
    # The default is {http://apidock.com/rails/ActiveSupport/Inflector/parameterize parameterize}
    # on +obj.title+.
    #
    # You can customize this part by overwriting {#slug}.
    # @return [String]
    # @api public
    def slug
      (title || '').parameterize
    end

    # This method determines the description that is shown in the changes list.
    # It can be overriden by a custom value.
    # @api public
    def description_for_editor
      slug.presence || path
    end

    # Returns the title of the content or the name.
    # @return [String]
    # @api public
    def display_title
      self.title || name
    end

    # @api public
    def title
      read_attribute('title')
    end

    # Returns true if image? or generic?
    def binary?
      [:image, :generic].include?(read_attribute('_obj_type').to_sym)
    end

    # Returns true if this object is the root object.
    # @api public
    def root?
      path == "/"
    end

    # Returns a list of children excluding the binary? ones unless :all is specfied.
    # This is mainly used for navigations.
    # @return [Array<Obj>]
    # @api public
    def toclist(*args)
      return [] if binary?
      toclist = children
      toclist = toclist.reject { |toc| toc.binary? } unless args.include?(:all)
      toclist
    end

    # @param objs_to_be_sorted [Array<BasicObj>] unsorted list of Objs
    # @param list [Array<BasicObj>] list of Objs that defines the order
    # @return [Array<BasicObj>] a sorted list of Objs. Any objs present in +objs_to_be_sorted+ but not in +list+ are appended at the end, sorted by +Obj#id+
    def self.sort_by_list(objs_to_be_sorted, list)
      (list & objs_to_be_sorted) + (objs_to_be_sorted - list).sort_by(&:id)
    end

    # This should be a SET, because it's faster in this particular case.
    INTERNAL_KEYS = Set.new(%w[
      body
      _id
      _last_changed
      _path
      _permalink
      title
    ])

    # Returns the value of an internal or external attribute specified by its name.
    # Passing an invalid key will not raise an error, but return +nil+.
    # @api public
    def [](key)
      key = key.to_s
      if INTERNAL_KEYS.include?(key)
        read_attribute(key)
      else
        super
      end
    end

    # Reloads the attributes of this object from the database.
    # Notice that the ruby class of this Obj instance will NOT change,
    # even if the obj_class in the database has changed.
    # @api public
    def reload
      id = self.id.to_s

      reload_data = Proc.new do
        CmsBackend.instance.find_obj_data_by(Workspace.current.revision, :id, [id]).first.first
      end

      update_data(reload_data)
    end

    # @return [String]
    # @api public
    def obj_class_name
      read_attribute('_obj_class')
    end

    def obj_class
      raise ScrivitoError, "BasicObj#obj_class is no longer available"+
        ", please use BasicObj#obj_class_name instead."
    end

    # @api public
    def last_changed
      read_attribute('_last_changed')
    end

    def new?(revision=Workspace.current.base_revision)
      return false unless revision

      if read_attribute('_modification') != 'deleted'
        cms_data_for_revision(revision).nil?
      else
        false
      end
    end

    def deleted?(revision=Workspace.current.base_revision)
      return false unless revision

      if read_attribute('_modification') == 'deleted'
        cms_data_for_revision(revision).present?
      end
    end

    def modification(revision=Workspace.current.base_revision)
      return Modification::UNMODIFIED unless revision

      obj_data_from_revision = cms_data_for_revision(revision)

      if deleted?(revision)
        Modification::DELETED
      elsif new?(revision)
        Modification::NEW
      else # Edited
        if obj_data_from_revision.present?
          if data_from_cms == obj_data_from_revision
            Modification::UNMODIFIED
          else
            Modification::EDITED
          end
        else
          Modification::UNMODIFIED
        end
      end
    end

    def widget_data_for_revision(id, revision)
      if revision_obj_data = cms_data_for_revision(revision)
        revision_obj_data.value_of('_widget_pool')[id]
      end
    end

    def in_revision(revision)
      if obj_data = cms_data_for_revision(revision)
        obj = Obj.instantiate(obj_data)
        obj.revision = revision

        obj
      end
    end

    # For a binary Obj, the content_type is equal to the content_type of its body (i.e. its data).
    # For non-binary Objs, a the default content_type is "text/html".
    # Override this method in subclasses to define a different content_type.
    # Note that only Objs with content_type "text/html"
    # will be rendered with layout and templates by the DefaultCmsController.
    # @return [String]
    # @api public
    def content_type
      if binary?
        body_content_type
      else
        "text/html"
      end
    end
    alias mime_type content_type

    # returns the extension (the part after the last dot) from the Obj's name.
    # returns an empty string if no extension is present in the Obj's name.
    # @return [String]
    # @api public
    def file_extension
      File.extname(name)[1..-1] || ""
    end

    # Returns the body (main content) of the Obj for non-binary Objs.
    # Returns +nil+ for binary Objs.
    # @return [String]
    # @api public
    def body
      if binary?
        nil
      else
        read_attribute('body')
      end
    end

    # for binary Objs body_length equals the file size
    # for non-binary Objs body_length equals the number of characters in the body (main content)
    # @api public
    def body_length
      if binary?
        blob = find_blob
        blob ? blob.length : 0
      else
        (body || "").length
      end
    end

    # returns an URL to retrieve the Obj's body for binary Objs.
    # returns +nil+ for non-binary Objs.
    # @return [String]
    # @api public
    def body_data_url
      if binary?
        blob = find_blob
        blob.url if blob
      end
    end

    # returns the content type of the Obj's body for binary Objs.
    # returns +nil+ for non-binary Objs.
    # @return [String]
    # @api public
    def body_content_type
      if binary?
        blob = find_blob
        if blob
          blob.content_type
        else
          "application/octet-stream"
        end
      end
    end

    def inspect
      "<#{self.class} id=\"#{id}\" path=\"#{path}\">"
    end

    def details_view_path
      "#{obj_class_name.underscore}/details"
    end

    def widget_from_pool(widget_id)
      widget_data = widget_data_from_pool(widget_id)
      instantiate_widget(widget_id, widget_data) if widget_data
    end

    # for internal testing purposes only
    def blob_id
      find_blob.try(:id)
    end

    # Reverts changes of this object.
    # After calling this method it's as if this object has been never modified in the current working copy.
    # This method does not work with +new+ or +deleted+ objects.
    # This method also does also not work for the +published+ workspace or the +rtc+ working copy.
    def revert
      Workspace.current.assert_revertable

      if binary?
        raise "revert not supported for binary objs"
      else
        case modification
        when Modification::UNMODIFIED
          # don't do anything
        when Modification::EDITED
          previous_content = CmsRestApi.get(
              "revisions/#{Workspace.current.base_revision_id}/objs/#{id}")
          updated_content = previous_content.except('id', '_id')

          added_widget_ids = read_widget_pool.keys - previous_content['_widget_pool'].keys
          added_widget_ids.each do |added_widget_id|
            updated_content['_widget_pool'][added_widget_id] = nil
          end

          CmsRestApi.put(cms_rest_api_path, obj: updated_content)

          reload
        else
          raise ScrivitoError, "cannot revert changes, since obj is #{modification}."
        end
      end
    end

    def mark_resolved
      CmsRestApi.put(cms_rest_api_path, obj: {_conflicts: nil})
      reload
    end

    def container_and_field_name_for_widget(widget_id)
      if field_name = field_name_in_data_for_widget(data_from_cms, widget_id)
        return [self, field_name]
      else
        read_widget_pool.each do |parent_widget_id, widget_data|
          if field_name = field_name_in_data_for_widget(widget_data, widget_id)
            return [widget_from_pool(parent_widget_id), field_name]
          end
        end
      end
      [nil, nil]
    end

    def widget_data_from_pool(widget_id)
      read_widget_pool[widget_id]
    end

    def has_conflict?
      read_attribute('_conflicts') != nil
    end

    def all_widgets_from_pool
      read_widget_pool.keys.map do |widget_id|
        widget_from_pool(widget_id)
      end
    end

    def generate_widget_pool_id
      10.times do
        id = self.class.generate_widget_pool_id

        return id if widget_data_from_pool(id).nil?
      end

      raise ScrivitoError.new('Could not generate a new unused widget id')
    end

    private

    def cms_data_for_revision(revision)
      if revision
        CmsBackend.instance.find_obj_data_by(revision, "id", [id]).first.first
      end
    end

    def field_name_in_data_for_widget(data, widget_id)
      data.all_custom_attributes.find do |attribute_name|
        (value, type) = data.value_and_type_of(attribute_name)
        type == "widget" && value.include?(widget_id)
      end
    end

    def read_widget_pool
      read_attribute('_widget_pool')
    end

    def instantiate_widget(widget_id, widget_data)
      BasicWidget.instantiate(widget_data).tap do |widget|
        widget.id = widget_id
        widget.obj = self
      end
    end

    def parent_path
      raise "parent_path called for root" if root?
      path.gsub(/\/[^\/]+$/, "").presence || "/"
    end

    def as_date(value)
      DateAttribute.parse(value) unless value.nil?
    end

    def find_blob
      blob_spec = read_attribute('blob')
      Blob.find(blob_spec["id"]) if blob_spec
    end

    def cms_rest_api_path(obj_id = id)
      "#{self.class.cms_rest_api_path}/#{obj_id}"
    end

    def child_path?
      !path.nil? && !root?
    end

    def prepare_attributes_for_rest_api(attributes)
      self.class.prepare_attributes_for_rest_api(attributes, self)
    end

    class << self
      def restore(obj_id)
        Workspace.current.assert_revertable

        base_revision_path = "revisions/#{Workspace.current.base_revision_id}/objs/#{obj_id}"
        obj_attributes = CmsRestApi.get(base_revision_path).except('id').merge('_id' => obj_id)
        CmsRestApi.post(cms_rest_api_path, obj: obj_attributes)
      end

      def cms_rest_api_path
        "workspaces/#{Workspace.current.id}/objs"
      end

      def prepare_attributes_for_rest_api(attributes, obj)
        widget_properties = CmsRestApi::WidgetExtractor.call(attributes, obj)
        api_attributes = CmsRestApi::AttributeSerializer.convert(attributes)
        api_attributes['_widget_pool'] =
            CmsRestApi::AttributeSerializer.generate_widget_pool_changes(widget_properties)

        if obj
          widget_pool = api_attributes['_widget_pool']
          widget_gc = WidgetGarbageCollection.new(obj, {obj => attributes}.merge(widget_properties))
          widget_gc.widgets_to_delete.each { |widget| widget_pool[widget.id] = nil }
        end

        [api_attributes, widget_properties]
      end

      private

      def search_for_all
        ObjSearchEnumerator.new.batch_size(1000)
      end
    end
  end

end