require 'bel_parser/language'
require 'bel_parser/quoting'
require 'bel_parser/parsers/ast/node'
require 'concurrent/hash'
require_relative '../keywords'
require_relative '../state_function'

module BELParser
  module Script
    module State
      class Set
        extend StateFunction
        extend BELParser::Script::Keyword
        extend BELParser::Quoting

        TARGET_NODE = BELParser::Parsers::AST::Set
        LIST_NODE   = BELParser::Parsers::AST::List
        FIELDS      = %w(type name id date authors comment)

        def self.consume(ast_node, script_context)
          return nil unless ast_node.is_a?(TARGET_NODE)
          name_node, value_node = ast_node.children
          name_string           = name_node.identifier.string_literal
          case
          when is_citation?(name_string)
            handle_citation(value_node, script_context)
          when is_support?(name_string)
            handle_support(value_node, script_context)
          when value_node.children[0].is_a?(LIST_NODE)
            value_node
              .children[0]
              .list_items
              .each do |list_item|
                handle_annotation(name_string, list_item, script_context)
              end
          else
            case name_string
            when /\ASTATEMENT_GROUP\Z/
              handle_statement_group(value_node, script_context)
            else
              handle_annotation(name_string, value_node, script_context)
            end
          end
        end

        def self.handle_citation(value_node, script_context)
          if value_node.is_a?(LIST_NODE)
            script_context[:citation] =
              Hash[
                FIELDS.zip(
                  value_node
                    .list_items
                    .map { |li| li.children[0].string_literal })
              ]
          end
        end

        def self.handle_support(value_node, script_context)
          script_context[:support] = value_node.children[0].string_literal
        end

        def self.handle_annotation(name_string, value_node, script_context)
          # add to annotation state
          script_context[:annotations]              ||= Concurrent::Hash.new
          script_context[:annotations][name_string]   = value_node.children[0].string_literal
        end
        private_class_method :handle_annotation

        def self.handle_statement_group(value_node, script_context)
          script_context[:statement_group] = value_node.children[0].string_literal

          # clear annotation state
          script_context[:annotations]     ||= Concurrent::Hash.new
          script_context[:annotations].clear
          script_context[:citation] = nil
        end
        private_class_method :handle_statement_group
      end
    end
  end
end