# MIT License
#
# Copyright (c) 2018, Dane Avilla
#
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# in the Software without restriction, including without limitation the rights
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# furnished to do so, subject to the following conditions:
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# SOFTWARE.

require 'google/protobuf/empty_pb'

module GraphqlGrpc
  # :nodoc:
  module Schema
    # TODO: Find better way to detect queries
    # Currently look for methods named 'get' or with no args
    def query?(name_sym, rpc_desc)
      name_sym.to_s.start_with?('get') ||
        rpc_desc.rpc_desc.input == Google::Protobuf::Empty
    end

    def streaming_response?(rpc_desc)
      rpc_desc&.rpc_desc&.output.class == GRPC::RpcDesc::Stream
    end

    def gql_mutations
      @function_map.reject do |name_sym, rpc_desc|
        query?(name_sym, rpc_desc) || streaming_response?(rpc_desc)
      end
    end

    def gql_queries
      @function_map.select do |name_sym, rpc_desc|
        query?(name_sym, rpc_desc) && !streaming_response?(rpc_desc)
      end
    end

    def to_schema_types
      function_output_types = @function_map.values.map do |function|
        function.rpc_desc.output
      end.flatten.uniq
      output_types = TypeLibrary.new(function_output_types)
      function_input_types = @function_map.values.map do |function|
        function.rpc_desc.input
      end.flatten.uniq
      input_types = InputTypeLibrary.new(function_input_types)
      input_types.to_schema_types + "\nscalar Url\n" + output_types.to_schema_types
    end

    def to_function_types(ggg_function_hash)
      ggg_function_hash.values.sort_by(&:name).map(&:to_query_type).join("\n  ")
    end

    def to_schema_query
      if gql_queries.empty?
        'type Query {'\
             '  # """This gRPC stub does not contain any methods that are mapped to '\
             'GraphQL queries; this placeholder query field keeps the Query type from '\
             'being empty which can break tools (GraphiQL) which expect Query to contain '\
             'at least one field."""'\
             '
'\
             '  grpcPlacholder: Url'\
             '}'
      else
        "type Query { #{to_function_types(gql_queries)} }"
      end
    end

    def to_schema_mutations
      return '' if gql_mutations.empty?

      "type Mutation { #{to_function_types(gql_mutations)} }"
    end

    def to_gql_schema
      <<GRAPHQL_SCHEMA
  #{to_schema_types}
  #{to_schema_query}
  #{to_schema_mutations}
  schema {
  query: Query
  #{gql_mutations.empty? ? '' : 'mutation: Mutation'}
  }
GRAPHQL_SCHEMA
    end
  end
end