add refund logic and fix books inventory logic

app/Views/inventory/teacher_distribute.php

@@ -47,8 +47,13 @@
           <strong>School Year:</strong> <?= esc($schoolYear) ?>,
           <strong>Semester:</strong> <?= esc($semester) ?>
         </div>
-        <div><strong>On Hand:</strong> <?= (int)$onHand ?></div>
+        <div>
+          <strong>On Hand:</strong> <?= (int)$onHand ?>
+        </div>
       </div>
+      <?php if ((int)($priceConfirmed ?? 0) !== 1 || (int)($unitChargeCents ?? 0) <= 0): ?>
+        <div class="mt-2 text-danger">This book cannot be distributed until its active-year charge price is confirmed.</div>
+      <?php endif; ?>
     </div>
 
     <!-- Submission form (POST) -->
@@ -57,6 +62,7 @@
       <!-- Keep class section hidden -->
       <input type="hidden" name="class_section_id" value="<?= esc($class_section_id) ?>">
       <input type="hidden" name="item_id" value="<?= esc($item_id) ?>">
+      <input type="hidden" name="idempotency_key" value="<?= esc(hash('sha256', (string) microtime(true) . ':' . (string) random_int(1, PHP_INT_MAX))) ?>">
 
       <div class="card">
         <div class="card-header d-flex justify-content-between align-items-center">
@@ -96,7 +102,7 @@
                       class="form-check-input student-box"
                       name="student_ids[]"
                       value="<?= esc($sid) ?>"
-                      <?= $given ? 'checked' : '' ?><?= $disabledAttr ?>>
+                      <?= $given ? 'checked disabled' : $disabledAttr ?>>
                   </td>
                   <td><?= esc($student['school_id'] ?? '-') ?></td>
                   <td><?= esc($student['firstname'] ?? '') ?></td>
@@ -123,7 +129,7 @@
             <textarea class="form-control" rows="2" name="note" placeholder="e.g., Distributed in class today"<?= $disabledAttr ?>></textarea>
           </div>
           <div class="d-flex gap-2">
-            <button type="button" class="btn btn-success"<?= $disabledAttr ?>>Deduct & Save</button>
+            <button type="submit" class="btn btn-success"<?= $disabledAttr ?><?= ((int)($priceConfirmed ?? 0) !== 1 || (int)($unitChargeCents ?? 0) <= 0) ? ' disabled' : '' ?>>Deduct & Save</button>
             <button type="button" class="btn btn-secondary" id="clearSelectionBtn"<?= $disabledAttr ?>>Cancel</button>
           </div>
         </div>
@@ -148,34 +154,18 @@
 
   document.getElementById('checkAllBtn')?.addEventListener('click', () => {
     if (distributeReadonly) return;
-    document.querySelectorAll('.student-box').forEach(cb => cb.checked = true);
-  });
-  document.getElementById('uncheckAllBtn')?.addEventListener('click', () => {
-    if (distributeReadonly) return;
-    document.querySelectorAll('.student-box').forEach(cb => cb.checked = false);
-  });
-</script>
-
-<script>
-  // Auto-submit filter when book changes
-  document.getElementById('bookSelect')?.addEventListener('change', () => {
-    document.getElementById('filterForm').submit();
-  });
-
-  document.getElementById('checkAllBtn')?.addEventListener('click', () => {
-    if (distributeReadonly) return;
-    document.querySelectorAll('.student-box').forEach(cb => cb.checked = true);
+    document.querySelectorAll('.student-box:not(:disabled)').forEach(cb => cb.checked = true);
   });
 
   document.getElementById('uncheckAllBtn')?.addEventListener('click', () => {
     if (distributeReadonly) return;
-    document.querySelectorAll('.student-box').forEach(cb => cb.checked = false);
+    document.querySelectorAll('.student-box:not(:disabled)').forEach(cb => cb.checked = false);
   });
 
   // Cancel button clears all checkboxes
   document.getElementById('clearSelectionBtn')?.addEventListener('click', () => {
     if (distributeReadonly) return;
-    document.querySelectorAll('.student-box').forEach(cb => cb.checked = false);
+    document.querySelectorAll('.student-box:not(:disabled)').forEach(cb => cb.checked = false);
   });
 </script>