add per-room notif overrides

Fixes #163

lib/models/push_rules.dart

@@ -15,18 +15,20 @@ class const PushRules({final PushRuleset global = const .new()})
       _$PushRulesFromJson(json);
 }
 
-/// Push rules by kind, apart from room and sender rules, which Nexus doesn't
-/// use. The first rule that matches decides what happens.
+/// Push rules by kind, apart from sender rules, which Nexus doesn't use. The
+/// first rule that matches decides what happens.
 @Freezed(toJson: false, fromJson: false)
 @JsonSerializable()
 class const PushRuleset({
   final IList<PushRule> override = const .empty(),
   final IList<PushRule> content = const .empty(),
+  final IList<PushRule> room = const .empty(),
   final IList<PushRule> underride = const .empty(),
 }) with _$PushRuleset {
   IList<PushRule> ofKind(PushRuleKind kind) => switch (kind) {
     .override => override,
     .content => content,
+    .room => room,
     .underride => underride,
   };
 
@@ -46,7 +48,7 @@ class const PushRuleset({
       _$PushRulesetFromJson(json);
 }
 
-enum PushRuleKind { override, content, underride }
+enum PushRuleKind { override, content, room, underride }
 
 @Freezed(toJson: false, fromJson: false)
 @JsonSerializable()
@@ -60,6 +62,9 @@ class const PushRule({
 
   /// What content rules match in messages' bodies.
   final String? pattern,
+
+  /// What override and underride rules match.
+  final IList<PushCondition> conditions = const .empty(),
 }) with _$PushRule {
   Map<String, Object?> toJson() => _$PushRuleToJson(this);
 
@@ -67,6 +72,24 @@ class const PushRule({
       _$PushRuleFromJson(json);
 }
 
+/// Only the fields of event_match conditions are kept.
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const PushCondition({
+  required final String kind,
+  final String? key,
+  final String? pattern,
+}) with _$PushCondition {
+  /// Matches events in the room with [roomId].
+  factory PushCondition.inRoom(String roomId) =>
+      .new(kind: "event_match", key: "room_id", pattern: roomId);
+
+  Map<String, Object?> toJson() => _$PushConditionToJson(this);
+
+  factory PushCondition.fromJson(Map<String, Object?> json) =>
+      _$PushConditionFromJson(json);
+}
+
 /// What happens when a push rule matches. Actions Nexus doesn't support are
 /// dropped, so they're replaced when these are changed.
 @Freezed(toJson: false, fromJson: false)

lib/models/room_notification_level.dart

@@ -0,0 +1,49 @@
+import "package:material_ui/material_ui.dart";
+import "package:nexus/models/push_rules.dart";
+
+enum RoomNotificationLevel(
+  final String title,
+  final String description,
+  final IconData icon,
+) {
+  global(
+    "Default",
+    "Follows your global notification rules.",
+    Icons.notifications,
+  ),
+  allMessages(
+    "All Messages",
+    "Every message notifies you.",
+    Icons.notifications_active,
+  ),
+  mentionsAndKeywords(
+    "Mentions & Keywords",
+    "Only messages that mention you or contain your keywords notify you.",
+    Icons.alternate_email,
+  ),
+  mute("Mute", "Nothing in this room notifies you.", Icons.notifications_off);
+
+  static RoomNotificationLevel of(PushRuleset ruleset, String roomId) =>
+      switch ((ruleset.find(.override, roomId), ruleset.find(.room, roomId))) {
+        (PushRule(enabled: true, actions: PushActions(notify: false)), _) =>
+          .mute,
+        (_, PushRule(enabled: true, actions: PushActions(notify: true))) =>
+          .allMessages,
+        (_, PushRule(enabled: true)) => .mentionsAndKeywords,
+        _ => .global,
+      };
+
+  ({PushRuleKind kind, PushRule rule})? ruleFor(String roomId) =>
+      switch (this) {
+        .global => null,
+        .allMessages => (
+          kind: .room,
+          rule: .new(ruleId: roomId, actions: .notifyWithSound),
+        ),
+        .mentionsAndKeywords => (kind: .room, rule: .new(ruleId: roomId)),
+        .mute => (
+          kind: .override,
+          rule: .new(ruleId: roomId, conditions: .new([.inRoom(roomId)])),
+        ),
+      };
+}