require 'active_model/naming'

module Scrivito

# This class represents a CMS workspace
# @api public
class Workspace
  PUBLISHED_ID = 'published'

  extend ActiveModel::Naming

  include ModelIdentity

  PublishPreventedDueToContentChange = Class.new(ScrivitoError)

  # Set the currently used workspace
  # @api public
  # @param [Scrivito::Workspace] workspace
  def self.current=(workspace)
    @current = workspace
  end

  def self.current_using_proc=(workspace_proc)
    @current = workspace_proc
  end

  # Returns the currently used workspace
  # @api public
  # @return [Scrivito::Workspace]
  def self.current
    if @current.respond_to? :call
      @current = @current.call
    else
      @current ||= default
    end
  end

  # Returns all the workspaces
  # @api public
  # @return [Array<Scrivito::Workspace>]
  def self.all
    result_json = CmsRestApi.get('/workspaces')

    result_json['results'].map do |workspace_json|
      Workspace.find(workspace_json['id'])
    end
  end

  def self.default
    published
  end

  def self.published
    cache.fetch(PUBLISHED_ID) do
      cache[PUBLISHED_ID] = find(PUBLISHED_ID)
    end
  end

  # Find a workspace by its id
  # @api public
  # @param [String] id
  # @return [Scrivito::Workspace]
  # @raise [Scrivito::ResourceNotFound]
  def self.find(id)
    if workspace_data = CmsBackend.instance.find_workspace_data_by_id(id)
      Workspace.new workspace_data
    else
      raise ResourceNotFound, "Could not find #{self} with id #{id}"
    end
  end

  # Find a workspace by its title.
  # If multiple workspaces share the same title, one of them is returned.
  # If no workspace with the given title can be found, nil is returned.
  # @api public
  # @param [String] title
  # @return [Scrivito::Workspace]
  def self.find_by_title(title)
    all.detect { |workspace| workspace.title == title }
  end

  delegate :content_state, :base_revision_id, :base_content_state, :uses_obj_classes, to: :data

  # Create a new workspace
  # @api public
  # @param [Hash] attributes
  # @return [Scrivito::Workspace]
  def self.create(attributes)
    workspace_json = CmsRestApi.post("/workspaces", workspace: attributes)

    self.find(workspace_json["id"])
  end

  # reloads the current workspace to reflect any changes to it that may have happened concurrently
  # since it was loaded
  # @api public
  def self.reload
    id = current.id
    self.current_using_proc = proc { find(id) }
  end

  def self.cache
    @cache ||= {}
  end

  def initialize(workspace_data)
    @workspace_data = workspace_data
  end

  # Reloads this workspace to reflect any changes to it that may have happened concurrently since
  # it was loaded
  # @api public
  def reload
    @workspace_data = CmsBackend.instance.find_workspace_data_by_id(self.id)

    # Clear all cached instance variables.
    @base_revision = nil
    @memberships   = nil
    @revision      = nil
  end

  def api_request(verb, path, payload = nil)
    response = CmsRestApi.public_send(verb, "#{backend_url}#{path}", payload)
    reload if [:post, :put, :delete].include?(verb)
    response
  end

  def task_unaware_api_request(verb, path, payload = nil)
    CmsRestApi.task_unaware_request(verb, "#{backend_url}#{path}", payload)
  end

  # Updates this workspace's attributes
  # @api public
  # @param [Hash] attributes
  # @return [Scrivito::Workspace]
  def update(attributes)
    CmsRestApi.put(backend_url, workspace: attributes)
    reload
  end

  # Destroy this workspace
  # @api public
  def destroy
    reset_workspace_if_current
    CmsRestApi.delete(backend_url)
  end

  # Publish the changes of this workspace
  # @api public
  def publish
    CmsRestApi.put("#{backend_url}/publish", {})

    reset_workspace_if_current
  end

  # Rebases the current workspace on the published content
  # @api public
  def rebase
    CmsRestApi.put("#{backend_url}/rebase", {})
    reload
  end

  # Returns the id of the workspace
  # @api public
  # @return [String]
  def id
    @workspace_data.id
  end

  def revision_id
    @workspace_data.revision_id
  end

  # Returns the title of the workspace
  # @api public
  # @return [String]
  def title
    @workspace_data.title
  end

  # @api public
  # Returns the members of this workspace and their roles
  #
  # @return [MembershipCollection]
  def memberships
    @memberships ||= MembershipCollection.new(self)
  end

  def data
    @workspace_data
  end

  def published?
    self.id == 'published'
  end

  def rtc?
    self.id == 'rtc'
  end

  def outdated?
    !published? && Workspace.published.revision.id != base_revision_id
  end

  def revision
    @revision ||= Revision.new(id: revision_id, content_state: content_state, workspace: self)
  end

  def base_revision
    if base_revision_id
      @base_revision ||= Revision.new(
        id: base_revision_id,
        content_state: base_content_state,
        workspace: self,
        base: true
      )
    end
  end

  def as_current(&block)
    old_workspace = Workspace.current

    begin
      Workspace.current = self

      yield
    ensure
      Workspace.current = old_workspace
    end
  end

  def assert_revertable
    raise ScrivitoError, 'published workspace is not modifiable' if published?
    raise ScrivitoError, 'rtc workspace may contain attribute and class changes' if rtc?
  end

  # {ObjCollection} for this working copy
  # @api public
  # @return {ObjCollection}
  def objs
    @objs ||= ObjCollection.new(self)
  end

  # Returns all obj classes of this working copy.
  #
  # @api public
  # @deprecated
  #
  # @example Find the obj class named "Homepage" in the "rtc" {Workspace}.
  #   Workspace.find('rtc').obj_classes['Homepage']
  #
  # @return {ObjClassCollection}
  def obj_classes
    @obj_classes ||= ObjClassCollection.new(self)
  end

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

  private

  def backend_url
    "/workspaces/#{id}"
  end

  def reset_workspace_if_current
    if Workspace.current == self
      Workspace.current = Workspace.default
    end
  end

end

end