module Saasable::Mongoid::SaasDocument
  @saas_document = nil

  def self.included klass
    if @saas_document and @saas_document.name != klass.name
      raise Saasable::Errors::MultipleSaasDocuments, "you can only have one Saasable::SaasDocument"
    else
      @saas_document = klass
    end

    klass.extend ClassMethods
    klass.send(:include, InstanceMethods)
    klass.class_eval do
      # Fields
      field :hosts, :type => Array

      # Validations
      validates_uniqueness_of :hosts

      # Indexes
      index({hosts: 1})
    end

    klass.instance_variable_set("@_active_saas", nil)
    klass.instance_variable_set("@_after_activate_chain", [])
    klass.instance_variable_set("@_after_deactivate_chain", [])
  end

  def self.saas_document
    @saas_document
  end

  module InstanceMethods
    def activate!
      Saasable::Mongoid::ScopedDocument.scoped_documents.each do |klass|
        saasble_criteria = Mongoid::Criteria.new(klass).where(saas_id: self._id)
        klass.default_scoping = klass.default_scoping? ? saasble_criteria.merge(klass.default_scoping.call).to_proc : saasble_criteria.to_proc

        klass.fields["saas_id"].default_val = self._id
        klass.fields["saas_id"].options[:default] = self._id
      end

      self.class.instance_variable_set("@_active_saas", self)
      self.class.instance_variable_get("@_after_activate_chain").each { |method_name| send(method_name) }
    end

    def deactivate!
      self.class.deactivate_all!
    end
  end

  module ClassMethods
    def deactivate_all!
      Saasable::Mongoid::ScopedDocument.scoped_documents.each do |klass|
        saasble_criteria = Mongoid::Criteria.new(klass).where(saas_id: @_active_saas._id)
        klass.default_scoping = klass.default_scoping.call.remove_scoping(saasble_criteria).to_proc

        klass.fields["saas_id"].default_val = nil
        klass.fields["saas_id"].options.delete(:default)
      end

      last_active_saas, @_active_saas = active_saas, nil
      @_after_deactivate_chain.each { |method_name| last_active_saas.send(method_name) }
    end

    def find_by_host! a_host
      raise Saasable::Errors::NoSaasDocuments, "you need to set one Saasable::SaasDocument" if Saasable::Mongoid::SaasDocument.saas_document.nil?

      a_saas = Saasable::Mongoid::SaasDocument.saas_document.where(:hosts => a_host).first
      if a_saas.nil?
        raise Saasable::Errors::SaasNotFound, "no #{Saasable::Mongoid::SaasDocument.saas_document.name} found for the host: \"#{a_host}\""
      else
        return a_saas
      end
    end

    def active_saas
      @_active_saas
    end

    def after_activate *method_names
      @_after_activate_chain += method_names
    end

    def after_deactivate *method_names
      @_after_deactivate_chain += method_names
    end

    def remove_after_activate *method_names
      @_after_activate_chain -= method_names
    end

    def remove_after_deactivate *method_names
      @_after_deactivate_chain -= method_names
    end
  end
end