Refactor card badge and multiselect template tags to properly implement and/or improve caching and context handling

- Updated `card_badge` and `card_multiselect` template tags to utilize `reverse_lazy` for URL resolution.
- Enhanced caching mechanisms in `card_badge.html` and `card_multiselect.html` to improve performance.
- Introduced a new template `_card_multiselect_options.html` for rendering multiselect options.
- Improved context management in `card_multiselect` to handle selected cards and dynamic placeholders.
- Added error handling for query hashing in `card_multiselect` to ensure robustness.
- Updated `trade_offer_tags` to optimize database queries using `select_related` for related objects.

cards/templatetags/card_badge.py

@@ -1,41 +1,46 @@
 from django import template
+from django.conf import settings
 from django.template.loader import render_to_string
 from django.utils.safestring import mark_safe
-from django.urls import reverse
+from django.urls import reverse_lazy
 
 register = template.Library()
 
-@register.inclusion_tag("templatetags/card_badge.html")
-def card_badge(card, quantity=None, expanded=False):
-    url = reverse('cards:card_detail', args=[card.pk])
-    return {
+@register.inclusion_tag("templatetags/card_badge.html", takes_context=True)
+def card_badge(context, card, quantity=None, expanded=False):
+    """
+    Renders a card badge.
+    """
+    url = reverse_lazy('cards:card_detail', args=[card.pk])
+    tag_context = {
         'quantity': quantity,
         'style': card.style,
         'name': card.name,
         'rarity': card.rarity_icon,
         'cardset': card.cardset,
         'expanded': expanded,
+        'cache_key': f'card_badge_{card.pk}_{quantity}_{expanded}',
         'url': url,
     }
+    context.update(tag_context)
+    return context
 
 @register.filter
 def card_badge_inline(card, quantity=None):
     """
-    Renders an inline card badge.
+    Renders an inline card badge by directly rendering the template.
     """
-    url = reverse('cards:card_detail', args=[card.pk])
-    html = render_to_string("templatetags/card_badge.html", {
+    url = reverse_lazy('cards:card_detail', args=[card.pk])
+    tag_context = {
         'quantity': quantity,
         'style': card.style,
         'name': card.name,
         'rarity': card.rarity_icon,
         'cardset': card.cardset,
         'expanded': True,
+        'cache_key': f'card_badge_{card.pk}_{quantity}_{True}',
+        'CACHE_TIMEOUT': settings.CACHE_TIMEOUT,
         'url': url,
-    })
-    return mark_safe(html)
-
-@register.filter
-def addstr(arg1, arg2):
-    """concatenate arg1 & arg2"""
-    return str(arg1) + str(arg2)
+    }
+    html = render_to_string("templatetags/card_badge.html", tag_context)
+    return mark_safe(html)

cards/templatetags/card_multiselect.py

@@ -1,54 +1,72 @@
+import uuid
 from django import template
 from cards.models import Card
-
+from django.db.models.query import QuerySet
+import json
+import hashlib
+import logging
 register = template.Library()
 
-@register.inclusion_tag('templatetags/card_multiselect.html')
-def card_multiselect(field_name, label, placeholder, cards=None, selected_values=None, cache_timeout=86400):
+@register.filter
+def get_item(dictionary, key):
+    """Allows accessing dictionary items using a variable key in templates."""
+    return dictionary.get(key)
+
+@register.simple_tag
+def fetch_all_cards():
+    """Simple tag to fetch all Card objects."""
+    return Card.objects.order_by('pk').all()
+
+@register.inclusion_tag('templatetags/card_multiselect.html', takes_context=True)
+def card_multiselect(context, field_name, label, placeholder, cards=None, selected_values=None):
     """
-    Renders a multiselect field for choosing cards while supporting quantity data.
-    
-    Updated to allow `card_filter` to be either a dictionary (of lookup parameters) or a QuerySet.
-    This is useful when you want to limit available cards based on your new trades models (e.g. showing only
-    cards that appear in active trade offers).
-    
-    Parameters:
-      - field_name: The name attribute for the select tag.
-      - label: Label text to show above the selector.
-      - placeholder: Placeholder text to show in the select.
-      - selected_values: (Optional) A list of selected values; if a value includes a quantity it should be in the format "card_id:quantity".
-      - cache_timeout: (Optional) Cache timeout (in seconds) for the options block.
-      - cache_key: (Optional) Cache key.
+    Prepares context for rendering a card multiselect input.
+    Database querying and rendering are handled within the template's cache block.
     """
     if selected_values is None:
         selected_values = []
-    # Create a mapping {card_id: quantity}
+
     selected_cards = {}
     for val in selected_values:
         parts = str(val).split(':')
-        card_id = parts[0]
-        quantity = parts[1] if len(parts) > 1 else 1
-        selected_cards[card_id] = quantity
+        if len(parts) >= 1 and parts[0]:
+            card_id = parts[0]
+            quantity = parts[1] if len(parts) > 1 else 1
+            selected_cards[str(card_id)] = quantity
 
-    if cards is None:
-       cards = Card.objects.all()
+    effective_field_name = field_name if field_name is not None else 'card_multiselect'
+    effective_label = label if label is not None else 'Card'
+    effective_placeholder = placeholder if placeholder is not None else 'Select Cards'
 
-    # Loop through available cards and attach pre‑selected quantity
-    for card in cards:
-        pk_str = str(card.pk)
-        if pk_str in selected_cards:
-            card.selected_quantity = selected_cards[pk_str]
-            card.selected = True
-        else:
-            card.selected_quantity = 1
-            card.selected = False
+    selected_cards_key_part = json.dumps(selected_cards, sort_keys=True)
 
-    return {
-        'field_name': field_name,
-        'field_id': field_name,  # using the name as id for simplicity
-        'label': label,
-        'cards': cards,
-        'placeholder': placeholder,
-        'selected_values': list(selected_cards.keys()),
-        'cache_timeout': cache_timeout
-    }
+    has_passed_cards = isinstance(cards, QuerySet)
+
+    if has_passed_cards:
+        try:
+            query_string = str(cards.query)
+            passed_cards_identifier = hashlib.sha256(query_string.encode('utf-8')).hexdigest()
+        except Exception as e:
+            logging.warning(f"Could not generate query hash for card_multiselect. Error: {e}")
+            passed_cards_identifier = 'specific_qs_fallback_' + str(uuid.uuid4())
+    else:
+        passed_cards_identifier = 'all_cards'
+
+    # Define the variables specific to this tag
+    tag_specific_context = {
+        'field_name': effective_field_name,
+        'field_id': effective_field_name,
+        'label': effective_label,
+        'placeholder': effective_placeholder,
+        'passed_cards': cards if has_passed_cards else None,
+        'has_passed_cards': has_passed_cards,
+        'selected_cards': selected_cards,
+        'selected_cards_key_part': selected_cards_key_part,
+        'passed_cards_identifier': passed_cards_identifier,
+    }
+
+    # Update the original context with the tag-specific variables
+    # This preserves CACHE_TIMEOUT and other parent context variables
+    context.update(tag_specific_context)
+
+    return context # Return the MODIFIED original context