Control Detail Row Count by Main Field

<script>
(function () {
  'use strict';

  var CONTROL_FIELD = 'field54450'; // Main-form control field
  var DETAIL_MARK = 'detail_2';     // Detail table 2
  var LOG_PREFIX = '[Detail 2 Row Count Control]';

  var syncing = false;

  function isEmpty(value) {
    return value === undefined || value === null || String(value).trim() === '';
  }

  function parseTargetCount(value) {
    if (isEmpty(value)) {
      return null; // Empty values do not control the detail table
    }

    var count = parseInt(String(value).trim(), 10);

    if (isNaN(count)) {
      console.warn(LOG_PREFIX, 'Control field is not a valid number, skipped:', value);
      return null;
    }

    // Control from 0; negative values are treated as 0
    return Math.max(0, count);
  }

  function getDetailRowIndexes() {
    var rowIndexStr = WfForm.getDetailAllRowIndexStr(DETAIL_MARK) || '';

    if (rowIndexStr === '') {
      return [];
    }

    return rowIndexStr.split(',').filter(function (rowIndex) {
      return rowIndex !== '';
    });
  }

  function syncDetailRows(triggerSource) {
    if (syncing) {
      return;
    }

    var controlValue = WfForm.getFieldValue(CONTROL_FIELD);
    var targetCount = parseTargetCount(controlValue);

    if (targetCount === null) {
      console.log(LOG_PREFIX, triggerSource + ', empty or invalid value, row count not controlled', controlValue);
      return;
    }

    syncing = true;

    try {
      var rowIndexes = getDetailRowIndexes();
      var currentCount = rowIndexes.length;

      console.log(LOG_PREFIX, triggerSource + ', start syncing', {
        controlValue: controlValue,
        targetCount: targetCount,
        currentCount: currentCount,
        rowIndexes: rowIndexes
      });

      if (currentCount < targetCount) {
        for (var i = 0; i < targetCount - currentCount; i += 1) {
          WfForm.addDetailRow(DETAIL_MARK, {});
        }
      }

      if (currentCount > targetCount) {
        var deleteCount = currentCount - targetCount;
        var deleteRows = rowIndexes.slice(targetCount).reverse();

        for (var j = 0; j < deleteCount; j += 1) {
          WfForm.delDetailRow(DETAIL_MARK, deleteRows[j]);
        }
      }

      console.log(LOG_PREFIX, 'Sync finished, target row count: ' + targetCount);
    } catch (error) {
      console.error(LOG_PREFIX, 'Failed to sync detail 2 row count', error);
    } finally {
      window.setTimeout(function () {
        syncing = false;
      }, 300);
    }
  }

  jQuery(document).ready(function () {
    // Run once 1 second after page load
    window.setTimeout(function () {
      syncDetailRows('1 second after page load');
    }, 1000);

    // Sync when the main-form field changes
    WfForm.bindFieldChangeEvent(CONTROL_FIELD, function () {
      syncDetailRows('field54450 changed');
    });

    // Resync after manual row changes so the detail table stays aligned with the control field
    if (WfForm.ACTION_ADDROW && WfForm.registerAction) {
      WfForm.registerAction(WfForm.ACTION_ADDROW + '2', function () {
        window.setTimeout(function () {
          syncDetailRows('detail 2 manually added row');
        }, 300);
      });
    }

    if (WfForm.ACTION_DELROW && WfForm.registerAction) {
      WfForm.registerAction(WfForm.ACTION_DELROW + '2', function () {
        window.setTimeout(function () {
          syncDetailRows('detail 2 manually deleted row');
        }, 300);
      });
    }
  });
})();
</script>