feat(uddf): persist MacDive waypoint gas switches via existing gasSwitches pipe

MacDive marks gas changes using <switchmix ref="gas-UUID"/> inside
individual waypoint samples. The parser previously recorded this on
the sample map (point['gasMixRef']) but it went nowhere; the importer
resolves gas switches via tankRef, but MacDive's switchmix ref is a
gas-mix UUID, not a tank UUID.

Parser now emits gas switches into diveData['gasSwitches'] with
gasMixRef (alongside the existing tankRef-from-top-level-<gasswitches>
path), deduping timestamp|gasMixRef|tankRef so both sources feed one
consumer. Tanks also record uddfGasMixRef so the downstream importer
can resolve gas-mix UUID -> tank id.

Importer now resolves both tankRef and gasMixRef to tankId, so
single-pipe persistence works for both source-level and waypoint-level
switch markers.

Adds unit test for parser emission, integration test verifying
gas_switches rows land on the correct dive_tanks rows, and updates
the MacDive real-sample regression to assert gasSwitches entries
rather than the now-removed sample-level gasMixRef. Closes the
parser-to-DB gap noted as a known limitation in M1.

Author: ericgriffin

lib/core/services/export/uddf/uddf_full_import_service.dart

@@ -1373,8 +1373,16 @@ class UddfFullImportService {
       final mixLink = tankDataElement.findElements('link').firstOrNull;
       if (mixLink != null) {
         final mixRef = mixLink.getAttribute('ref');
-        if (mixRef != null && gasMixes.containsKey(mixRef)) {
-          tankInfo['gasMix'] = gasMixes[mixRef];
+        if (mixRef != null) {
+          // Record the UDDF gas-mix UUID on the tank so the importer can
+          // resolve waypoint-level <switchmix ref> markers (which reference
+          // gas mixes, not tanks) back to a tank for the gas_switches row.
+          if (mixRef.isNotEmpty) {
+            tankInfo['uddfGasMixRef'] = mixRef;
+          }
+          if (gasMixes.containsKey(mixRef)) {
+            tankInfo['gasMix'] = gasMixes[mixRef];
+          }
         }
       }
 
@@ -1528,6 +1536,11 @@ class UddfFullImportService {
     final samplesElement = diveElement.findElements('samples').firstOrNull;
     if (samplesElement != null) {
       final profile = <Map<String, dynamic>>[];
+      // Gas switches emitted from waypoint-level <switchmix ref="..."/>.
+      // MacDive marks deco gas changes on individual samples this way; we feed
+      // them into the same `diveData['gasSwitches']` pipe as the top-level
+      // <gasswitches> section so the importer has one consumer.
+      final waypointGasSwitches = <Map<String, dynamic>>[];
       GasMix? currentMix;
       GasMix? pendingSwitchMix;
       double? lastWaypointCns;
@@ -1565,8 +1578,22 @@ class UddfFullImportService {
         if (switchMix != null) {
           final mixRef = switchMix.getAttribute('ref');
           if (mixRef != null) {
-            // Record the gas mix reference on the sample for downstream consumers
-            point['gasMixRef'] = mixRef;
+            // Emit a gas switch entry for the importer to persist. Shape
+            // matches the top-level <gasswitches> parser (timestamp/depth/
+            // tankRef), plus `gasMixRef` so the importer can resolve the
+            // MacDive-style gas-UUID reference to a tank.
+            final timestamp = point['timestamp'] as int?;
+            if (timestamp != null) {
+              final entry = <String, dynamic>{
+                'timestamp': timestamp,
+                'gasMixRef': mixRef,
+              };
+              final depth = point['depth'];
+              if (depth != null) {
+                entry['depth'] = depth;
+              }
+              waypointGasSwitches.add(entry);
+            }
 
             if (gasMixes.containsKey(mixRef)) {
               currentMix = gasMixes[mixRef];
@@ -1733,6 +1760,24 @@ class UddfFullImportService {
       if (currentMix != null && !diveData.containsKey('tanks')) {
         diveData['gasMix'] = currentMix;
       }
+
+      // Merge waypoint-level gas switches with any entries emitted earlier
+      // from the top-level <gasswitches> section, deduping on
+      // timestamp+gasMixRef+tankRef so both paths feed one consumer.
+      if (waypointGasSwitches.isNotEmpty) {
+        final existing =
+            (diveData['gasSwitches'] as List<Map<String, dynamic>>?) ??
+            const <Map<String, dynamic>>[];
+        final seen = <String>{};
+        final merged = <Map<String, dynamic>>[];
+        for (final gs in [...existing, ...waypointGasSwitches]) {
+          final key = '${gs['timestamp']}|${gs['gasMixRef']}|${gs['tankRef']}';
+          if (seen.add(key)) {
+            merged.add(gs);
+          }
+        }
+        diveData['gasSwitches'] = merged;
+      }
     }
 
     // Parse information after dive

lib/features/dive_import/data/services/uddf_entity_importer.dart

@@ -1236,7 +1236,12 @@ class UddfEntityImporter {
       final gasSwitchesData =
           diveData['gasSwitches'] as List<Map<String, dynamic>>?;
       if (gasSwitchesData != null && gasSwitchesData.isNotEmpty) {
+        // Build lookups from both UDDF tank ID and UDDF gas mix UUID to the
+        // persisted tank row id. MacDive-style switches reference a gas mix
+        // UUID (via <switchmix ref>), while top-level <gasswitches>
+        // entries reference a tank UUID (via <tankref>); we accept either.
         final tankIdByRef = <String, String>{};
+        final tankIdByGasMixRef = <String, String>{};
         final tanksData = diveData['tanks'] as List<Map<String, dynamic>>?;
         if (tanksData != null) {
           for (var i = 0; i < tanks.length && i < tanksData.length; i++) {
@@ -1246,6 +1251,15 @@ class UddfEntityImporter {
             if (ref != null && ref.isNotEmpty) {
               tankIdByRef[ref] = tank.id;
             }
+            final gasMixRef = (tankData['uddfGasMixRef'] as String?)?.trim();
+            // First tank linked to a given gas wins; later tanks sharing the
+            // same gas don't overwrite. This is a pragmatic resolution for
+            // dives where multiple tanks carry the same mix.
+            if (gasMixRef != null &&
+                gasMixRef.isNotEmpty &&
+                !tankIdByGasMixRef.containsKey(gasMixRef)) {
+              tankIdByGasMixRef[gasMixRef] = tank.id;
+            }
           }
         }
 
@@ -1254,9 +1268,16 @@ class UddfEntityImporter {
               final timestamp = gs['timestamp'] as int?;
               if (timestamp == null) return null;
               final tankRef = (gs['tankRef'] as String?)?.trim();
-              final tankId = tankRef != null && tankRef.isNotEmpty
-                  ? tankIdByRef[tankRef]
-                  : null;
+              final gasMixRef = (gs['gasMixRef'] as String?)?.trim();
+              String? tankId;
+              if (tankRef != null && tankRef.isNotEmpty) {
+                tankId = tankIdByRef[tankRef];
+              }
+              if ((tankId == null || tankId.isEmpty) &&
+                  gasMixRef != null &&
+                  gasMixRef.isNotEmpty) {
+                tankId = tankIdByGasMixRef[gasMixRef];
+              }
               if (tankId == null || tankId.isEmpty) return null;
               return GasSwitch(
                 id: _uuid.v4(),

test/core/services/export/uddf/uddf_macdive_import_test.dart

@@ -763,18 +763,31 @@ void main() {
     });
 
     test(
-      'samples with <switchmix ref> record gasMixRef on the right sample',
+      'emits gasSwitches from waypoint <switchmix ref> for multi-tank dives',
       () async {
+        // MacDive deco-dive style: two tanks, each linked to a gas definition;
+        // profile samples mark the switch via <switchmix ref="mix-deco"/>.
         const uddf = '''<?xml version="1.0" encoding="UTF-8" ?>
 <uddf xmlns="http://www.streit.cc/uddf/3.2/" version="3.2.1">
   <gasdefinitions>
-    <mix id="mix-bottom"><o2>0.32</o2></mix>
-    <mix id="mix-deco"><o2>0.80</o2></mix>
+    <mix id="mix-bottom"><o2>0.32</o2><he>0.0</he></mix>
+    <mix id="mix-deco"><o2>0.80</o2><he>0.0</he></mix>
   </gasdefinitions>
   <profiledata><repetitiongroup id="rg-1">
     <dive id="d-1">
       <informationbeforedive><datetime>2024-06-01T09:00:00</datetime></informationbeforedive>
-      <informationafterdive><greatestdepth>40</greatestdepth><diveduration>3600</diveduration></informationafterdive>
+      <informationafterdive>
+        <greatestdepth>40</greatestdepth>
+        <diveduration>3600</diveduration>
+      </informationafterdive>
+      <tankdata>
+        <link ref="mix-bottom" />
+        <tankvolume>0.012</tankvolume>
+      </tankdata>
+      <tankdata>
+        <link ref="mix-deco" />
+        <tankvolume>0.007</tankvolume>
+      </tankdata>
       <samples>
         <waypoint><divetime>0</divetime><depth>0</depth><switchmix ref="mix-bottom"/></waypoint>
         <waypoint><divetime>120</divetime><depth>30</depth></waypoint>
@@ -784,17 +797,20 @@ void main() {
   </repetitiongroup></profiledata>
 </uddf>''';
         final r = await service.importAllDataFromUddf(uddf);
-        final profile = r.dives.first['profile'] as List<Map<String, dynamic>>;
-        expect(profile.length, 3);
-        final switches = profile
-            .where((p) => p['gasMixRef'] != null)
-            .map((p) => p['gasMixRef'])
-            .toList();
+        final dive = r.dives.first;
+        final switches =
+            (dive['gasSwitches'] as List?)?.cast<Map<String, dynamic>>() ??
+            const [];
         expect(
-          switches,
-          ['mix-bottom', 'mix-deco'],
-          reason: 'only samples with <switchmix ref> should have gasMixRef',
+          switches.length,
+          2,
+          reason: 'two waypoints carry <switchmix ref>',
         );
+        expect(switches[0]['timestamp'], 0);
+        expect(switches[0]['gasMixRef'], 'mix-bottom');
+        expect(switches[1]['timestamp'], 2400);
+        expect(switches[1]['gasMixRef'], 'mix-deco');
+        expect(switches[1]['depth'], 6);
       },
     );
   });

test/core/services/export/uddf/uddf_macdive_real_sample_test.dart

@@ -72,19 +72,23 @@ void main() {
       );
     });
 
-    test('at least one dive has gas-switch markers', () async {
-      final result = await service.importAllDataFromUddf(content);
-      final withSwitch = result.dives.where((d) {
-        final profile = d['profile'] as List?;
-        if (profile == null) return false;
-        return profile.any((p) => (p as Map)['gasMixRef'] != null);
-      });
-      expect(
-        withSwitch,
-        isNotEmpty,
-        reason: 'sample contains multi-gas dives with <switchmix ref>',
-      );
-    });
+    test(
+      'at least one dive has gasSwitches entries from waypoint switchmix',
+      () async {
+        final result = await service.importAllDataFromUddf(content);
+        final withSwitches = result.dives.where((d) {
+          final switches = d['gasSwitches'] as List?;
+          return switches != null && switches.isNotEmpty;
+        });
+        expect(
+          withSwitches,
+          isNotEmpty,
+          reason:
+              'sample contains multi-gas deco dives marked via <switchmix ref> '
+              'on waypoints; parser should emit those to diveData["gasSwitches"]',
+        );
+      },
+    );
 
     test('at least one site has country populated', () async {
       final result = await service.importAllDataFromUddf(content);