module Prick
  module Build
    class BuildBatch
      include Timer

      attr_reader :builder
      forward_to :builder, :conn

      def kind() @nodes.first&.kind end
      attr_reader :nodes

      def initialize(builder) 
        @builder = builder
        @nodes = [] 
      end

      def execute(&block)
        name = self.class.to_s.sub(/.*::/, "").split(/(?=[A-Z])/).map(&:downcase).join(" ")
        time "Execute #{name} (nodes: #{nodes.size})" do
          yield
        end
      end

      def dump
        puts kind.upcase
        indent { nodes.each(&:dump) }
      end
    end

    class SqlBatch < BuildBatch
      def execute
        super {
          begin
            sql = []
            if nodes.first.is_a?(ExeNode)
              time "Execute script" do
                sql = [nodes.first.source]
              end
            end
            conn.execute sql + nodes[sql.size..-1].map(&:source)

          rescue PG::SyntaxError, PG::Error => ex 
            error, line, pos = parse_pg_message(ex.message)
            if line
              if line < nodes.first.lines
                node = nodes.first;
              else
                line -= nodes.first.lines
                node = nodes[1..-1].find { |node|
                  line -= 1
                  if line < node.lines
                    line -= 2
                    true
                  else
                    line -= node.lines
                    false
                  end
                }
              end

              if node.is_a?(SqlNode)
                message = ["prick: #{error} in #{node.path}", line, pos].compact.join(":")
              else
                message = "prick: #{error} from #{node.path}"
              end
            else
              raise
            end
            raise PostgresError.new(message)
          end
        }
      end

    private
      # Returns [error, line, pos] tuple
      def parse_pg_message(message)
        message =~ /ERROR:\s*(.*?)\n(LINE (\d+): ).*?\n(\s*\^)/m or return nil
        [$1, $3.to_i, $4.size - $2.size]
      end
    end

    class ModuleBatch < BuildBatch
      def execute
        super { 
          nodes.each { |node| 
            sql = node&.call
            conn.execute sql if sql 
          }
        }
      end
    end

    class FoxBatch < BuildBatch
      # Inlining Fox instead of using command line program as it saves some deciseconds
      def execute
        t_type = t_fox = t_exe = nil

        super {
          timer = Timer.new "Execute fox batch (nodes: #{nodes.size}, clean: #{builder.clean})"
          t_type = Timer.new "  Load data model"

          files = nodes.map(&:path)

          # Load meta object
          meta = PgMeta.new(conn, exclude_schemas: builder.pg_graph_ignore_schemas)

          # Create type object
          type = PgGraph::Type.new(meta, builder.reflections_file)

          # Timer
          t_type.stop
          t_fox = Timer.new "  Parse files"

          # Create fox object
          fox = FixtureFox::Fox.new(type)

          # Parse files
          for file in files
            source, lines = fox.tokenize(file)
            fox.parse(source, lines)
          end

          # Analyze
          fox.assign_types
          fox.generate

          # Dump state file
          fox.write_state(FOX_STATE_PATH)

          # Timer
          t_fox.stop
          t_exe = Timer.new "  Execute SQL"

          delete = builder.clean ? :none : :touched
          begin
            conn.execute fox.to_sql(format: :exec, delete: delete)

            # FIXME: Why only in FoxBatch - should be set higher up in the system
            conn.execute "update prick.versions set built_at = now() at time zone 'UTC'"
          rescue PG::SyntaxError, PG::Error => ex 
            raise PostgresError, "prick: #{ex.message}"
          end
        }
        t_type.emit
        t_fox.emit
        t_exe.emit
      end
    end
  end
end