# Licensed to Elasticsearch B.V. under one or more contributor
# license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright
# ownership. Elasticsearch B.V. licenses this file to you under
# the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#
# This code was automatically generated from the Elasticsearch Specification
# See https://github.com/elastic/elasticsearch-specification
# See Elasticsearch::ES_SPECIFICATION_COMMIT for commit hash.
module Elasticsearch
  module API
    module Indices
      module Actions
        # Get field usage stats.
        # Get field usage information for each shard and field of an index.
        # Field usage statistics are automatically captured when queries are running on a cluster.
        # A shard-level search request that accesses a given field, even if multiple times during that request, is counted as a single use.
        # The response body reports the per-shard usage count of the data structures that back the fields in the index.
        # A given request will increment each count by a maximum value of 1, even if the request accesses the same field multiple times.
        # This functionality is experimental and is not ready for production usage. Experimental
        # features may change or be removed at any time. Elastic will work to fix any issues, but
        # experimental features are not subject to the support SLA of official GA features. Specific
        # Support terms apply.
        #
        # @option arguments [String, Array] :index Comma-separated list or wildcard expression of index names used to limit the request. (*Required*)
        # @option arguments [Boolean] :allow_no_indices A setting that does two separate checks on the index expression.
        #  If `false`, the request returns an error (1) if any wildcard expression
        #  (including `_all` and `*`) resolves to zero matching indices or (2) if the
        #  complete set of resolved indices, aliases or data streams is empty after all
        #  expressions are evaluated. If `true`, index expressions that resolve to no
        #  indices are allowed and the request returns an empty result.
        # @option arguments [String, Array<String>] :expand_wildcards Type of index that wildcard patterns can match.
        #  If the request can target data streams, this argument determines whether wildcard expressions match hidden data streams.
        #  Supports comma-separated values, such as `open,hidden`. Server default: open.
        # @option arguments [Boolean] :ignore_unavailable If `false`, the request returns an error if it targets a concrete (non-wildcarded)
        #  index, alias, or data stream that is missing, closed, or otherwise unavailable.
        #  If `true`, unavailable concrete targets are silently ignored.
        # @option arguments [String, Array<String>] :fields Comma-separated list or wildcard expressions of fields to include in the statistics.
        # @option arguments [Boolean] :error_trace When set to `true` Elasticsearch will include the full stack trace of errors
        #  when they occur.
        # @option arguments [String, Array<String>] :filter_path Comma-separated list of filters in dot notation which reduce the response
        #  returned by Elasticsearch.
        # @option arguments [Boolean] :human When set to `true` will return statistics in a format suitable for humans.
        #  For example `"exists_time": "1h"` for humans and
        #  `"exists_time_in_millis": 3600000` for computers. When disabled the human
        #  readable values will be omitted. This makes sense for responses being consumed
        #  only by machines.
        # @option arguments [Boolean] :pretty If set to `true` the returned JSON will be "pretty-formatted". Only use
        #  this option for debugging only.
        # @option arguments [Hash] :headers Custom HTTP headers
        #
        # @see https://www.elastic.co/docs/api/doc/elasticsearch/v9/operation-indices-field-usage-stats
        #
        def field_usage_stats(arguments = {})
          request_opts = { endpoint: arguments[:endpoint] || 'indices.field_usage_stats' }

          defined_params = [:index].each_with_object({}) do |variable, set_variables|
            set_variables[variable] = arguments[variable] if arguments.key?(variable)
          end
          request_opts[:defined_params] = defined_params unless defined_params.empty?

          raise ArgumentError, "Required argument 'index' missing" unless arguments[:index]

          arguments = arguments.clone
          headers = arguments.delete(:headers) || {}

          body = nil

          _index = arguments.delete(:index)

          method = Elasticsearch::API::HTTP_GET
          path   = "#{Utils.listify(_index)}/_field_usage_stats"
          params = Utils.process_params(arguments)

          Elasticsearch::API::Response.new(
            perform_request(method, path, params, body, headers, request_opts)
          )
        end
      end
    end
  end
end
