Add cancellation reason tracking with user/system codes and UI

internal/syncengine/engine.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/syncserver/internal/config"
@@ -61,7 +62,12 @@ func (e *Engine) Run(ctx context.Context, jobID int64, pairID int64) error {
 	}
 
 	jobCtx, cancel := context.WithCancel(ctx)
-	enqueueErr := e.queue.Enqueue(pairID, jobID, cancel)
+	cancelledByUser := atomic.Bool{}
+	wrappedCancel := func() {
+		cancelledByUser.Store(true)
+		cancel()
+	}
+	enqueueErr := e.queue.Enqueue(pairID, jobID, wrappedCancel)
 	if enqueueErr != nil {
 		return enqueueErr
 	}
@@ -199,8 +205,15 @@ func (e *Engine) Run(ctx context.Context, jobID int64, pairID int64) error {
 
 	if err != nil {
 		if jobCtx.Err() != nil {
+			code := "cancelled_shutdown"
+			msg := "Job was cancelled due to server shutdown"
+			if cancelledByUser.Load() {
+				code = "cancelled_user"
+				msg = "Job was cancelled by user"
+			}
+			e.setJobError(jobID, code, msg)
 			e.setJobStatus(jobID, "cancelled")
-			e.emit(Event{Type: "status", JobID: jobID, Key: "status", Value: "cancelled"})
+			e.emit(Event{Type: "status", JobID: jobID, Key: "status", Value: "cancelled", Line: msg})
 			return jobCtx.Err()
 		}
 		e.setJobStatus(jobID, "failed")
@@ -239,9 +252,9 @@ func (e *Engine) resolveSSHKey(machine *models.Machine) (string, error) {
 	return sshKey.PrivateKeyPath, nil
 }
 
-func (e *Engine) Cancel(jobID int64, syncPairID int64) bool {
+func (e *Engine) Cancel(jobID int64, syncPairID int64, byUser bool) bool {
 	if e.queue.IsRunning(syncPairID) {
-		e.queue.Cancel(syncPairID)
+		e.queue.Cancel(syncPairID, byUser)
 		return true
 	}
 	return false