How to do a for loop in xslt 1.0 to output a 52 week calendar irrespective of the data - xslt-1.0

Question

I understand some of the limitations of XSLT1.0 with the for-each loop. I need a way of processing a file 52 times so I can allocate an output to each of the 52 weeks of the year. The file is a simple Time Away From Work XML (each node has date / time / code etc...) and I need each week to contain the records of any TAFWs booked for that week, but I must always output 52 sections even if there is no data in the week.
The data will be sorted by date, but I need a way of cycling it round 52 times. It must always be 52 weeks from last week, so it always need to be relative otherwise I would have created a temp xml within the XSLT.
For-each only works if there is more than 52 nodes, so I can't use that as there may not be more than 52 nodes.
RAW Data
<Record>
<emp_number>73001486</emp_number>
<paycode>HOLIDAY</paycode>
<allday_flag>True</allday_flag>
<halfday_flag>False</halfday_flag>
<nethours>96.000</nethours>
<startdate_time>2021-12-14 00:00:00</startdate_time>
<enddate_time>2021-12-16 00:00:00</enddate_time>
</Record>
Output:
2021-12-06
2021-12-13
73001486,HOLIDAY,96
Any ideas gratefully received!
Update: Week start is previous week, which I can derive from passed information. Always full weeks. I don't care about holidays which span weeks, I just care about TAFW start dates within the 52 week periods (which I am comfortable with deducing).

Answer 1

I think your question should be broken into several separate steps - and neither of these is exactly trivial.
The first step would be to generate 52 weeks from a given start date. Well, actually the first step would be to calculate the start date, but at this point I don't know what to use as the input for this, so let's assume it's a given:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/>
<xsl:template match="/">
<output>
<xsl:call-template name="generate-weeks">
<xsl:with-param name="start-date" select="'2020-11-30'" />
<xsl:with-param name="n" select="52" />
</xsl:call-template>
</output>
</xsl:template>
<xsl:template name="generate-weeks">
<xsl:param name="start-date"/>
<xsl:param name="n" select="52"/>
<xsl:if test="$n > 0">
<week start-date="{$start-date}"/>
<xsl:call-template name="generate-weeks">
<xsl:with-param name="start-date">
<xsl:variable name="JDN">
<xsl:call-template name="JDN">
<xsl:with-param name="date" select="$start-date" />
</xsl:call-template>
</xsl:variable>
<xsl:call-template name="GD">
<xsl:with-param name="JDN" select="$JDN + 7" />
</xsl:call-template>
</xsl:with-param>
<xsl:with-param name="n" select="$n - 1" />
</xsl:call-template>
</xsl:if>
</xsl:template>
<xsl:template name="JDN">
<xsl:param name="date"/>
<xsl:variable name="year" select="substring($date, 1, 4)"/>
<xsl:variable name="month" select="substring($date, 6, 2)"/>
<xsl:variable name="day" select="substring($date, 9, 2)"/>
<xsl:variable name="a" select="floor((14 - $month) div 12)"/>
<xsl:variable name="y" select="$year + 4800 - $a"/>
<xsl:variable name="m" select="$month + 12*$a - 3"/>
<xsl:value-of select="$day + floor((153*$m + 2) div 5) + 365*$y + floor($y div 4) - floor($y div 100) + floor($y div 400) - 32045" />
</xsl:template>
<xsl:template name="GD">
<xsl:param name="JDN"/>
<xsl:variable name="f" select="$JDN + 1401 + floor((floor((4 * $JDN + 274277) div 146097) * 3) div 4) - 38"/>
<xsl:variable name="e" select="4*$f + 3"/>
<xsl:variable name="g" select="floor(($e mod 1461) div 4)"/>
<xsl:variable name="h" select="5*$g + 2"/>
<xsl:variable name="D" select="floor(($h mod 153) div 5 ) + 1"/>
<xsl:variable name="M" select="(floor($h div 153) + 2) mod 12 + 1"/>
<xsl:variable name="Y" select="floor($e div 1461) - 4716 + floor((14 - $M) div 12)"/>
<xsl:value-of select="$Y" />
<xsl:value-of select="format-number($M, '-00')"/>
<xsl:value-of select="format-number($D, '-00')"/>
</xsl:template>
</xsl:stylesheet>
This will produce:
Result
<?xml version="1.0" encoding="utf-8"?>
<output>
<week start-date="2020-11-30"/>
<week start-date="2020-12-07"/>
<week start-date="2020-12-14"/>
<week start-date="2020-12-21"/>
<week start-date="2020-12-28"/>
<week start-date="2021-01-04"/>
<week start-date="2021-01-11"/>
<week start-date="2021-01-18"/>
<week start-date="2021-01-25"/>
<week start-date="2021-02-01"/>
<week start-date="2021-02-08"/>
<week start-date="2021-02-15"/>
<week start-date="2021-02-22"/>
<week start-date="2021-03-01"/>
<week start-date="2021-03-08"/>
<week start-date="2021-03-15"/>
<week start-date="2021-03-22"/>
<week start-date="2021-03-29"/>
<week start-date="2021-04-05"/>
<week start-date="2021-04-12"/>
<week start-date="2021-04-19"/>
<week start-date="2021-04-26"/>
<week start-date="2021-05-03"/>
<week start-date="2021-05-10"/>
<week start-date="2021-05-17"/>
<week start-date="2021-05-24"/>
<week start-date="2021-05-31"/>
<week start-date="2021-06-07"/>
<week start-date="2021-06-14"/>
<week start-date="2021-06-21"/>
<week start-date="2021-06-28"/>
<week start-date="2021-07-05"/>
<week start-date="2021-07-12"/>
<week start-date="2021-07-19"/>
<week start-date="2021-07-26"/>
<week start-date="2021-08-02"/>
<week start-date="2021-08-09"/>
<week start-date="2021-08-16"/>
<week start-date="2021-08-23"/>
<week start-date="2021-08-30"/>
<week start-date="2021-09-06"/>
<week start-date="2021-09-13"/>
<week start-date="2021-09-20"/>
<week start-date="2021-09-27"/>
<week start-date="2021-10-04"/>
<week start-date="2021-10-11"/>
<week start-date="2021-10-18"/>
<week start-date="2021-10-25"/>
<week start-date="2021-11-01"/>
<week start-date="2021-11-08"/>
<week start-date="2021-11-15"/>
<week start-date="2021-11-22"/>
</output>
The next step would be pre-process the input records and assign each one the value of the starting day of its week. This can be then used to assign each record to the corresponding week by matching the two start-dates. I suggest you ask a separate question (or questions) about that.