fix: Change the not condition to exactly match the HA not condition (#2387)

BREAKING CHANGE: Changes the behavior of the `not` condition when there
is more than one condition present. Users who desire the previous
behavior should wrap their conditions in an `and` first.

 - Closes: #2383

docs/configuration/conditions.md

@@ -202,7 +202,10 @@ match.
 
 ## `not`
 
-Evaluates to `true` if _all_ embedded conditions evaluate to `false`.
+Evaluates to `true` if every embedded condition is `false`. At least one
+condition is required.
+
+> [!IMPORTANT] > `not` is a **NOR** operation, not a **NAND**. If _any_ sub-condition is `true`, the `not` condition evaluates to `false` — even if other sub-conditions are `false`. To pass, _all_ sub-conditions must be `false`. This behavior matches the [Home Assistant equivalent](https://www.home-assistant.io/docs/scripts/conditions/#not-condition).
 
 ```yaml
 conditions:
@@ -213,7 +216,7 @@ conditions:
 | Parameter    | Description                                                                                                     |
 | ------------ | --------------------------------------------------------------------------------------------------------------- |
 | `condition`  | Must be `not`.                                                                                                  |
-| `conditions` | A list of other conditions _all_ of which must evaluate `false` in order for this condition to evaluate `true`. |
+| `conditions` | A list of other conditions _none_ of which must evaluate `true` in order for this condition to evaluate `true`. |
 
 ## `numeric_state`
 
@@ -244,7 +247,7 @@ conditions:
 
 ## `screen`
 
-Matches based on [media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries).
+Matches based on [media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Media_queries/Using).
 
 ```yaml
 conditions:
@@ -253,9 +256,9 @@ conditions:
 ```
 
 | Parameter     | Description                                                                                                                                                                                                                                                                                                                                                             |
-| ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| ------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `condition`   | Must be `screen`.                                                                                                                                                                                                                                                                                                                                                       |
-| `media_query` | Any valid [media query](https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries) string. Media queries must start and end with parentheses. This may be used to alter card configuration based on device/media properties (e.g. viewport width, orientation). Please note that `width` and `height` refer to the entire viewport not just the card. |
+| `media_query` | Any valid [media query](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Media_queries/Using) string. Media queries must start and end with parentheses. This may be used to alter card configuration based on device/media properties (e.g. viewport width, orientation). Please note that `width` and `height` refer to the entire viewport not just the card. |
 
 See the [screen conditions examples](../examples.md?id=screen-conditions).
 
@@ -334,7 +337,7 @@ conditions:
 
 ## `user_agent`
 
-Matches based on the [User-Agent](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent).
+Matches based on the [User-Agent](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/User-Agent).
 
 ```yaml
 conditions:

src/conditions/conditions-manager.ts

@@ -331,13 +331,13 @@ export class ConditionsManager implements ConditionsManagerReadonlyInterface {
         return { result: true, triggerData };
       }
       case 'not': {
-        // "Not" is just an inversed `and`. There is no trigger data for "not
+        // "Not" is an inverted `or` (NOR). There is no trigger data for "not
         // triggering".
         return {
           result: !this._evaluateCondition(
             {
               ...condition,
-              condition: 'and',
+              condition: 'or',
             },
             newState,
             oldState,

tests/conditions/conditions-manager.test.ts

@@ -1317,17 +1317,21 @@ describe('ConditionsManager', () => {
         stateManager,
       );
 
+      // Neither sub-condition is true initially, so `not` passes.
       expect(manager.getEvaluation().result).toBeTruthy();
 
+      // fullscreen becomes true — any sub-condition being true means `not` fails.
       stateManager.setState({ fullscreen: true });
-      expect(manager.getEvaluation().result).toBeTruthy();
+      expect(manager.getEvaluation().result).toBeFalsy();
 
       stateManager.setState({ expand: true });
       expect(manager.getEvaluation().result).toBeFalsy();
 
+      // fullscreen reverts, but expand is still true, so `not` still fails.
       stateManager.setState({ fullscreen: false });
-      expect(manager.getEvaluation().result).toBeTruthy();
+      expect(manager.getEvaluation().result).toBeFalsy();
 
+      // Both sub-conditions are false again, so `not` passes.
       stateManager.setState({ expand: false });
       expect(manager.getEvaluation().result).toBeTruthy();