module Composable
  module Tenant
    def self.without_tenant(*tenants)
      old_excluded_tenants = Composable::Tenant::DataSet.excluded_tenants
      Composable::Tenant::DataSet.excluded_tenants = Set.new(tenants.map(&:to_sym))
      yield
    ensure
      Composable::Tenant::DataSet.excluded_tenants = old_excluded_tenants
    end

    def self.set_tenant(tenant, record)
      Composable::Tenant::DataSet.tenant = [tenant, record]
      record
    end

    module ModelExtensions
      extend ActiveSupport::Concern

      module ClassMethods
        def tenant(tenant, scope = nil, **options)
          # Create the association
          foreign_key = options.fetch(:foreign_key, "#{tenant}_id").to_sym
          primary_key = options.fetch(:primary_key, :id).to_sym

          belongs_to tenant, scope, **options

          default_scope lambda {
            return if Composable::Tenant::DataSet.excluded_tenants.include?(tenant.to_sym)
            raise Composable::Tenant::NoTenantSet.new(tenant: tenant) unless Composable::Tenant::DataSet.tenant(tenant)

            where(foreign_key => Composable::Tenant::DataSet.tenant(tenant).send(primary_key))
          }, all_queries: true

          # Makes sure new instances have tenant set
          before_validation lambda { |record|
            return if Composable::Tenant::DataSet.excluded_tenants.include?(tenant.to_sym)

            record.send("#{foreign_key}=", Composable::Tenant::DataSet.tenant(tenant).send(primary_key))
          }, on: :create

          # Rewrite the accessors to make tenant immutable
          to_include = Module.new do
            define_method "#{foreign_key}=" do |integer|
              write_attribute(foreign_key, integer)
              raise Composable::Tenant::TenantIsImmutable.new(method_name: "#{foreign_key}=") if send("#{foreign_key}_changed?") &&
                persisted? &&
                !send("#{foreign_key}_was").nil?

              integer
            end

            define_method "#{tenant}=" do |model|
              super(model)
              raise Composable::Tenant::TenantIsImmutable.new(method_name: "#{tenant}=") if send("#{foreign_key}_changed?") &&
                persisted? &&
                !send("#{foreign_key}_was").nil?

              model
            end
          end

          include to_include
        end
      end
    end
  end
end

ActiveSupport.on_load(:active_record) do |base|
  base.include Composable::Tenant::ModelExtensions
end