Name        : FIRSTDAYOFTHEWEEK
Author      : Mohammad Reza Hassanzadeh (github.com/MohammadRhz)
Version     : 1.0.1
Overview    : Get the date of the first day of the week when the date you want is in the range of that week
Type        : SCALAR
Jar         : /opt/confluent-ksqldb/ext/DateTimeUtils-1.0.0.jar
Variations  :

      Variation   : FIRSTDAYOFTHEWEEK(timestamp BIGINT, shift INT, truncateTime BOOLEAN)
      Returns     : BIGINT
      Description : Returns timestamp of the first day of the week
      timestamp   : Unix timestamp in milliseconds
      timezone    : Timezone (set GMT as default)
      shift       : Useful when the first day of the week is other than Monday. Use -2 for Saturday and -1 for Sunday.
      truncateTime: Makes Hour, Minute, Second, and Millisecond 0


      Variation   : FIRSTDAYOFTHEWEEK(dateTimeStr VARCHAR, inFormatPattern VARCHAR, outFormatPattern VARCHAR, shift INT, truncateTime BOOLEAN)
      Returns     : VARCHAR
      Description : Returns a formatted string of the date(time) of the first day of the week
      inFormatPattern: Format of the input dateTimeStr. e.g.: yyyy-MM-dd HH:mm:ss.fff
      outFormatPattern: Format of the output dateTimeStr. e.g.: yyyy-MM-dd
      timezone    : Timezone (set GMT as default)
      shift       : Useful when the first day of the week is other than Monday. Use -2 for Saturday and -1 for Sunday.
      truncateTime: Makes Hour, Minute, Second, and Millisecond 0


      Variation   : FIRSTDAYOFTHEWEEK(dateTimeStr VARCHAR, formatPattern VARCHAR, shift INT, truncateTime BOOLEAN)
      Returns     : VARCHAR
      Description : Returns a formatted string of the date(time) of the first day of the week
      dateTimeStr : A formatted date and time string. e.g.: 2022-10-27 22:19:01.000
      formatPattern: Format of the input dateTimeStr (Returned format will be the same as the input format). e.g.: yyyy-MM-dd HH:mm:ss.fff
      timezone    : Timezone (set GMT as default)
      shift       : Useful when the first day of the week is other than Monday. Use -2 for Saturday and -1 for Sunday.
      truncateTime: Makes Hour, Minute, Second, and Millisecond 0

-- 1666523533000 is Sunday, October 23, 2022 2:42:13 PM GMT+03:30

select FIRSTDAYOFTHEWEEK(1666523533000,'GMT',0,false) from test emit changes;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|1666005133000  -- Monday, October 17, 2022 2:42:13 PM GMT+03:30



-- In case the week in your area starts on Saturday
select FIRSTDAYOFTHEWEEK(1666523533000,'GMT',-2,false) from test emit changes;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|1666437133000  -- Saturday, October 22, 2022 2:42:13 PM GMT+03:30


    
select FIRSTDAYOFTHEWEEK(1666523533000,'GMT',0,true) from test emit changes;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|1665952200000  -- Monday, October 17, 2022 12:00:00 AM GMT+03:30

select FIRSTDAYOFTHEWEEK('2022-10-23 12:13:14','yyyy-MM-dd HH:mm:ss','GMT',0,false) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-17 12:13:14



select FIRSTDAYOFTHEWEEK('2022-10-24 12:13:14','yyyy-MM-dd HH:mm:ss', 'yyyy-MM-dd HH:00:00','GMT',0,false) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-24 12:00:00



select FIRSTDAYOFTHEWEEK('2022-10-25','yyyy-MM-dd', 'yyyy-MM-dd HH:00:00','GMT',0,false) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-24 00:00:00



select FIRSTDAYOFTHEWEEK('2022-10-26 22','yyyy-MM-dd HH','GMT',0,false) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-24 22



select FIRSTDAYOFTHEWEEK('2022-10-27 18:19:20','yyyy-MM-dd HH:mm:ss','GMT',0,true) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-24 00:00:00


-- In case the week in your area starts on Saturday
select FIRSTDAYOFTHEWEEK('2022-10-28 18:19:20','yyyy-MM-dd HH:mm:ss','GMT',-2,true) from test;

+-----------------------------------------------------------------------------+
|KSQL_COL_0                                                                   |
+-----------------------------------------------------------------------------+
|2022-10-22 00:00:00