feat: skip QSOs with unchanged confirmation data

When syncing from LoTW/DCL, only update QSOs if confirmation data
has changed. This avoids unnecessary database updates and makes it
clear which QSOs actually changed.

- LoTW: Checks if lotwQslRstatus or lotwQslRdate changed
- DCL: Checks if dclQslRstatus, dclQslRdate, DOK, or grid changed
- Frontend: Shows skipped count in sync summary

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/backend/services/dcl.service.js

@@ -192,6 +192,7 @@ export async function syncQSOs(userId, dclApiKey, sinceDate = null, jobId = null
 
     let addedCount = 0;
     let updatedCount = 0;
+    let skippedCount = 0;
     const errors = [];
     const addedQSOs = [];
     const updatedQSOs = [];
@@ -219,18 +220,29 @@ export async function syncQSOs(userId, dclApiKey, sinceDate = null, jobId = null
           .limit(1);
 
         if (existing.length > 0) {
-          // Update existing QSO with DCL confirmation and DOK data
+          const existingQSO = existing[0];
+
+          // Check if DCL confirmation or DOK data has changed
+          const dataChanged =
+            existingQSO.dclQslRstatus !== dbQSO.dclQslRstatus ||
+            existingQSO.dclQslRdate !== dbQSO.dclQslRdate ||
+            existingQSO.darcDok !== (dbQSO.darcDok || existingQSO.darcDok) ||
+            existingQSO.myDarcDok !== (dbQSO.myDarcDok || existingQSO.myDarcDok) ||
+            existingQSO.grid !== (dbQSO.grid || existingQSO.grid);
+
+          if (dataChanged) {
+            // Update existing QSO with changed DCL confirmation and DOK data
             await db
               .update(qsos)
               .set({
                 dclQslRdate: dbQSO.dclQslRdate,
                 dclQslRstatus: dbQSO.dclQslRstatus,
-              darcDok: dbQSO.darcDok || existing[0].darcDok,
+                darcDok: dbQSO.darcDok || existingQSO.darcDok,
-              myDarcDok: dbQSO.myDarcDok || existing[0].myDarcDok,
+                myDarcDok: dbQSO.myDarcDok || existingQSO.myDarcDok,
-              grid: dbQSO.grid || existing[0].grid,
+                grid: dbQSO.grid || existingQSO.grid,
-              gridSource: dbQSO.gridSource || existing[0].gridSource,
+                gridSource: dbQSO.gridSource || existingQSO.gridSource,
               })
-            .where(eq(qsos.id, existing[0].id));
+              .where(eq(qsos.id, existingQSO.id));
             updatedCount++;
             // Track updated QSO (CALL and DATE)
             updatedQSOs.push({
@@ -239,6 +251,10 @@ export async function syncQSOs(userId, dclApiKey, sinceDate = null, jobId = null
               band: dbQSO.band,
               mode: dbQSO.mode,
             });
+          } else {
+            // Skip - same data
+            skippedCount++;
+          }
         } else {
           // Insert new QSO
           await db.insert(qsos).values(dbQSO);
@@ -274,6 +290,7 @@ export async function syncQSOs(userId, dclApiKey, sinceDate = null, jobId = null
       total: adifQSOs.length,
       added: addedCount,
       updated: updatedCount,
+      skipped: skippedCount,
       addedQSOs,
       updatedQSOs,
       confirmed: adifQSOs.filter(q => q.dcl_qsl_rcvd === 'Y').length,

src/backend/services/lotw.service.js

@@ -222,6 +222,7 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
 
   let addedCount = 0;
   let updatedCount = 0;
+  let skippedCount = 0;
   const errors = [];
   const addedQSOs = [];
   const updatedQSOs = [];
@@ -247,6 +248,14 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
         .limit(1);
 
       if (existing.length > 0) {
+        const existingQSO = existing[0];
+
+        // Check if LoTW confirmation data has changed
+        const confirmationChanged =
+          existingQSO.lotwQslRstatus !== dbQSO.lotwQslRstatus ||
+          existingQSO.lotwQslRdate !== dbQSO.lotwQslRdate;
+
+        if (confirmationChanged) {
           await db
             .update(qsos)
             .set({
@@ -254,7 +263,7 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
               lotwQslRstatus: dbQSO.lotwQslRstatus,
               lotwSyncedAt: dbQSO.lotwSyncedAt,
             })
-          .where(eq(qsos.id, existing[0].id));
+            .where(eq(qsos.id, existingQSO.id));
           updatedCount++;
           // Track updated QSO (CALL and DATE)
           updatedQSOs.push({
@@ -263,6 +272,10 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
             band: dbQSO.band,
             mode: dbQSO.mode,
           });
+        } else {
+          // Skip - same data
+          skippedCount++;
+        }
       } else {
         await db.insert(qsos).values(dbQSO);
         addedCount++;
@@ -288,13 +301,14 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
     }
   }
 
-  logger.info('LoTW sync completed', { total: adifQSOs.length, added: addedCount, updated: updatedCount, jobId });
+  logger.info('LoTW sync completed', { total: adifQSOs.length, added: addedCount, updated: updatedCount, skipped: skippedCount, jobId });
 
   return {
     success: true,
     total: adifQSOs.length,
     added: addedCount,
     updated: updatedCount,
+    skipped: skippedCount,
     addedQSOs,
     updatedQSOs,
     errors: errors.length > 0 ? errors : undefined,

src/frontend/src/routes/qsos/+page.svelte

@@ -296,7 +296,12 @@
     <div class="alert {syncResult.success ? 'alert-success' : 'alert-error'}">
       {#if syncResult.success}
         <h3>Sync Complete!</h3>
-        <p>Total: {syncResult.total}, Added: {syncResult.added}, Updated: {syncResult.updated}</p>
+        <p>
+          Total: {syncResult.total},
+          Added: {syncResult.added},
+          Updated: {syncResult.updated || 0},
+          Skipped: {syncResult.skipped || 0}
+        </p>
         {#if syncResult.errors && syncResult.errors.length > 0}
           <p class="text-small">Some QSOs had errors</p>
         {/if}