require 'active_graph/core/instrumentable'
require 'active_graph/transaction'
require 'active_graph/core/query_builder'
require 'active_graph/core/responses'

module ActiveGraph
  module Core
    module Querable
      extend ActiveSupport::Concern
      include Instrumentable
      include Responses

      class_methods do
        def query(*args)
          options = case args.size
                    when 3
                      args.pop
                    when 2
                      args.pop if args[0].is_a?(::ActiveGraph::Core::Query)
                    end || {}

          queries(options) { append(*args) }[0]
        end

        def queries(options = {}, &block)
          query_builder = QueryBuilder.new

          query_builder.instance_eval(&block)

          new_or_current_transaction(options[:transaction]) do |tx|
            query_set(tx, query_builder.queries, { commit: !options[:transaction] }.merge(options))
          end
        end

# If called without a block, returns a Transaction object
# which can be used to call query/queries/mark_failed/commit
# If called with a block, the Transaction object is yielded
# to the block and `commit` is ensured.  Any uncaught exceptions
# will mark the transaction as failed first
        def transaction
          return Transaction.new unless block_given?

          begin
            tx = transaction

            yield tx
          rescue => e
            tx.mark_failed if tx

            raise e
          ensure
            tx.close if tx
          end
        end

        def setup_queries!(queries, options = {})
          return if options[:skip_instrumentation]
          queries.each do |query|
            ActiveSupport::Notifications.instrument('neo4j.core.cypher_query', query: query)
          end
        end

        def query_set(transaction, queries, options = {})
          setup_queries!(queries, skip_instrumentation: options[:skip_instrumentation])

          ActiveSupport::Notifications.instrument('neo4j.core.bolt.request') do
            self.wrap_level = options[:wrap_level]
            queries.map do |query|
              result_from_data(transaction.root_tx.run(query.cypher, query.parameters))
            end
          rescue Neo4j::Driver::Exceptions::Neo4jException => e
            raise ActiveGraph::Core::CypherError.new_from(e.code, e.message) # , e.stack_track.to_a
          end
        end

        private

        def new_or_current_transaction(tx, &block)
          if tx
            yield(tx)
          else
            transaction(&block)
          end
        end
      end
    end
  end
end