cw_ts_overlap_buckets.sqlx

config { hasOutput: true }
/*
 * Copyright 2022 Google LLC
 *
 * Licensed 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.
 */

/*
 Merges two periods together if they overlap and returns unique id for each merged bucket.
 Coalesces meeting periods as well (not just overlapping periods) if includeMeets is true.
*/
CREATE OR REPLACE FUNCTION ${self()}(includeMeets BOOLEAN, inputs ARRAY<STRUCT<st TIMESTAMP, et TIMESTAMP>>)
RETURNS array<struct<bucketNo int64, st TIMESTAMP, et TIMESTAMP>>
LANGUAGE js 
OPTIONS (
    description="Merges two periods together if they overlap and returns unique id for each merged bucket. Coalesces meeting periods as well (not just overlapping periods) if includeMeets is true."
)
AS """
    var ret = [ ]
    var bucketNo = 1;
    var st = null;
    var et = null;
    for ( var j = 0 ; j < inputs.length ; j ++ ) {
        var t = inputs[j];
        if (j == 0) {
            st = t.st;
            et = t.et;
        } else if (t.st < et ||
                (t.st != null && et != null &&
                    t.st.getTime() == et.getTime() && includeMeets)) {
            if (et < t.et) {
                et = t.et;
            }
        } else {
            ret.push({ bucketNo, st, et });
            st = t.st;
            et = t.et;
            bucketNo++;
        }
    }
    if (inputs.length > 0) {
        ret.push({ bucketNo, st, et });
    }
    return ret;
""";