Initial implementation of custom price triggers

- likely to have some bugs, but this is good enough for a preview release.

token_bot/history_manager/update_trigger.py

@@ -29,6 +29,10 @@ class UpdateTrigger:
     def squelched(self):
         return self._squelched
 
+    @squelched.setter
+    def squelched(self, value):
+        self._squelched = value
+
     def _find_next_trigger(
         self,
         comparison_operator: Callable,
@@ -93,12 +97,47 @@ class UpdateTrigger:
             case AlertType.ALL_TIME_HIGH:
                 time_range = now - start_time
                 comparison_operator = operator.gt
+            case AlertType.SPECIFIC_PRICE:
+                # For custom price alerts, check if the price crosses the threshold
+                # We alert when price moves from below to above (or vice versa)
+                target_price = self._alert.price
+                if self._last_trigger is None:
+                    # First time - check if current price crossed the threshold
+                    if new_datum[1] >= target_price:
+                        self._last_trigger = new_datum
+                        self._last_alerting = new_datum
+                        return True
+                    return False
+                else:
+                    # Check if we crossed the threshold
+                    old_price = self._last_trigger[1]
+                    new_price = new_datum[1]
+
+                    # Alert if we cross the threshold in either direction
+                    crossed_up = old_price < target_price <= new_price
+                    crossed_down = old_price >= target_price > new_price
+
+                    if crossed_up or crossed_down:
+                        self._last_trigger = new_datum
+                        self._last_alerting = new_datum
+                        was_squelched = self._squelched
+                        self._squelched = True
+                        return not was_squelched
+                    elif self._squelched:
+                        # Update last_trigger but don't alert (we're tracking current price)
+                        self._last_trigger = new_datum
+                        # If we moved away from threshold, allow next crossing to alert
+                        if (crossed_up and new_price < target_price) or (crossed_down and new_price >= target_price):
+                            self._squelched = False
+                    else:
+                        # Just update the last trigger for tracking
+                        self._last_trigger = new_datum
+                    return False
             case _:
-                # TODO: The logic here is certainly wrong for Custom
                 time_range = datetime.timedelta(days=int(365.25 * 6))
                 comparison_operator = operator.eq
 
-        if new_datum[0] > now - time_range:
+        if new_datum[0] > now - time_range and self._alert.alert_type != AlertType.SPECIFIC_PRICE:
             if self._last_trigger is None:
                 self._last_trigger = new_datum
                 self._last_alerting = new_datum