override fun doReduce()

in alerting/src/main/kotlin/org/opensearch/alerting/aggregation/bucketselectorext/BucketSelectorExtAggregator.kt [88:141]
51 lines of code
13 McCabe index (conditional complexity)

    override fun doReduce(aggregations: Aggregations, reduceContext: ReduceContext): InternalAggregation {
        val parentBucketPathList = AggregationPath.parse(parentBucketPath).pathElementsAsStringList
        var subAggregations: Aggregations = aggregations
        for (i in 0 until parentBucketPathList.size - 1) {
            subAggregations = subAggregations.get<SingleBucketAggregation>(parentBucketPathList[0]).aggregations
        }
        val originalAgg = subAggregations.get(parentBucketPathList.last()) as InternalMultiBucketAggregation<*, *>
        val buckets = originalAgg.buckets
        val factory = reduceContext.scriptService().compile(script, BucketAggregationSelectorScript.CONTEXT)
        val selectedBucketsIndex: MutableList<Int> = ArrayList()
        for (i in buckets.indices) {
            val bucket = buckets[i]
            if (bucketSelectorExtFilter != null) {
                var accepted = true
                if (bucketSelectorExtFilter!!.isCompositeAggregation) {
                    val compBucketKeyObj = (bucket as InternalComposite.InternalBucket).key
                    val filtersMap: HashMap<String, IncludeExclude>? = bucketSelectorExtFilter!!.filtersMap
                    for (sourceKey in compBucketKeyObj.keys) {
                        if (filtersMap != null) {
                            if (filtersMap.containsKey(sourceKey)) {
                                val obj = compBucketKeyObj[sourceKey]
                                accepted = isAccepted(obj!!, filtersMap[sourceKey])
                                if (!accepted) break
                            } else {
                                accepted = false
                                break
                            }
                        }
                    }
                } else {
                    accepted = isAccepted(bucket.key, bucketSelectorExtFilter!!.filters)
                }
                if (!accepted) continue
            }

            val vars: MutableMap<String, Any> = HashMap()
            if (script.params != null) {
                vars.putAll(script.params)
            }
            for ((varName, bucketsPath) in bucketsPathsMap) {
                val value = BucketHelpers.resolveBucketValue(originalAgg, bucket, bucketsPath, gapPolicy)
                vars[varName] = value
            }
            val executableScript = factory.newInstance(vars)
            // TODO: can we use one instance of the script for all buckets? it should be stateless?
            if (executableScript.execute()) {
                selectedBucketsIndex.add(i)
            }
        }

        return BucketSelectorIndices(
            name(), parentBucketPath, selectedBucketsIndex, originalAgg.metadata
        )
    }