class GraphQL::Tracing::PlatformTracing

def self.use(schema_defn, options = {})
  tracer = self.new(**options)
  schema_defn.tracer(tracer)
end

def cached_platform_key(ctx, key)
  cache = ctx.namespace(self.class)[:platform_key_cache] ||= {}
  cache.fetch(key) { cache[key] = yield }
end

def fallback_transaction_name(context)
  context[:tracing_fallback_transaction_name]
end

def initialize(options = {})
  @options = options
  @platform_keys = self.class.platform_keys
  @trace_scalars = options.fetch(:trace_scalars, false)
end

def trace(key, data)
  case key
  when "lex", "parse", "validate", "analyze_query", "analyze_multiplex", "execute_query", "execute_query_lazy", "execute_multiplex"
    platform_key = @platform_keys.fetch(key)
    platform_trace(platform_key, key, data) do
      yield
    end
  when "execute_field", "execute_field_lazy"
    if data[:context]
      field = data[:context].field
      platform_key = field.metadata[:platform_key]
      trace_field = true # implemented with instrumenter
    else
      field = data[:field]
      return_type = field.type.unwrap
      trace_field = if return_type.kind.scalar? || return_type.kind.enum?
        (field.trace.nil? && @trace_scalars) || field.trace
      else
        true
      end
      platform_key = if trace_field
        context = data.fetch(:query).context
        cached_platform_key(context, field) { platform_field_key(data[:owner], field) }
      else
        nil
      end
    end
    if platform_key && trace_field
      platform_trace(platform_key, key, data) do
        yield
      end
    else
      yield
    end
  when "authorized", "authorized_lazy"
    type = data.fetch(:type)
    context = data.fetch(:context)
    platform_key = cached_platform_key(context, type) { platform_authorized_key(type) }
    platform_trace(platform_key, key, data) do
      yield
    end
  when "resolve_type", "resolve_type_lazy"
    type = data.fetch(:type)
    context = data.fetch(:context)
    platform_key = cached_platform_key(context, type) { platform_resolve_type_key(type) }
    platform_trace(platform_key, key, data) do
      yield
    end
  else
    # it's a custom key
    yield
  end
end

def transaction_name(query)
  selected_op = query.selected_operation
  txn_name = if selected_op
    op_type = selected_op.operation_type
    op_name = selected_op.name || fallback_transaction_name(query.context) || "anonymous"
    "#{op_type}.#{op_name}"
  else
    "query.anonymous"
  end
  "GraphQL/#{txn_name}"
end