/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */

import type * as estypes from '@elastic/elasticsearch/lib/api/typesWithBodyKey';
import { Query } from '@kbn/es-query';

/*
 * Contains utility functions for building and processing queries.
 */

// Builds the base filter criteria used in queries,
// adding criteria for the time range and an optional query.
export function buildBaseFilterCriteria(
  timeFieldName?: string,
  earliestMs?: number,
  latestMs?: number,
  query?: Query['query']
): estypes.QueryDslQueryContainer[] {
  const filterCriteria = [];
  if (timeFieldName && earliestMs && latestMs) {
    filterCriteria.push({
      range: {
        [timeFieldName]: {
          gte: earliestMs,
          lte: latestMs,
          format: 'epoch_millis',
        },
      },
    });
  }

  if (query && typeof query === 'object') {
    filterCriteria.push(query);
  }

  return filterCriteria;
}

// Wraps the supplied aggregations in a sampler aggregation.
// A supplied samplerShardSize (the shard_size parameter of the sampler aggregation)
// of less than 1 indicates no sampling, and the aggs are returned as-is.
export function buildSamplerAggregation(
  aggs: any,
  samplerShardSize: number
): Record<string, estypes.AggregationsAggregationContainer> {
  if (samplerShardSize < 1) {
    return aggs;
  }

  return {
    sample: {
      sampler: {
        shard_size: samplerShardSize,
      },
      aggs,
    },
  };
}

// Returns the path of aggregations in the elasticsearch response, as an array,
// depending on whether sampling is being used.
// A supplied samplerShardSize (the shard_size parameter of the sampler aggregation)
// of less than 1 indicates no sampling, and an empty array is returned.
export function getSamplerAggregationsResponsePath(samplerShardSize: number): string[] {
  return samplerShardSize > 0 ? ['sample'] : [];
}

// Returns a name which is safe to use in elasticsearch aggregations for the supplied
// field name. Aggregation names must be alpha-numeric and can only contain '_' and '-' characters,
// so if the supplied field names contains disallowed characters, the provided index
// identifier is used to return a safe 'dummy' name in the format 'field_index' e.g. field_0, field_1
export function getSafeAggregationName(fieldName: string, index: number): string {
  return fieldName.match(/^[a-zA-Z0-9-_.]+$/) ? fieldName : `field_${index}`;
}