Add structured logging and better error handling

internal/jobs/manager.go

@@ -6,6 +6,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"log/slog"
 	"os"
 	"path"
 	"path/filepath"
@@ -76,6 +77,12 @@ func (manager *Manager) UpdatePreferences(next preferences.Preferences) error {
 		return err
 	}
 	manager.policy.SetAllowedPorts(next.AllowedPorts)
+	slog.Debug("preferences saved",
+		"parallel_downloads", next.MaxConcurrentDownloads,
+		"connections_per_download", next.ConnectionsPerDownload,
+		"min_free_gb", next.MinFreeGB,
+		"download_paths", len(next.DownloadPaths),
+	)
 	return nil
 }
 
@@ -137,6 +144,11 @@ func (manager *Manager) Create(request CreateRequest) (Snapshot, error) {
 
 	manager.store(job)
 	job.saveRecord()
+	job.logger().Info("download added",
+		"url", job.displayURL,
+		"file_name", requestedName,
+		"target", job.snapshot().MoveTarget,
+	)
 	manager.launchDownload(job)
 	return job.snapshot(), nil
 }
@@ -186,7 +198,12 @@ func (manager *Manager) Delete(id string) error {
 	delete(manager.jobs, id)
 	manager.mutex.Unlock()
 
-	return os.RemoveAll(job.directory)
+	if err := os.RemoveAll(job.directory); err != nil {
+		job.logger().Error("could not remove download files", "directory", job.directory, "error", err)
+		return err
+	}
+	job.logger().Info("download removed")
+	return nil
 }
 
 func (manager *Manager) Shutdown(ctx context.Context) {
@@ -208,6 +225,7 @@ func (manager *Manager) Shutdown(ctx context.Context) {
 	select {
 	case <-finished:
 	case <-ctx.Done():
+		slog.Warn("stopped waiting for downloads to save progress", "error", ctx.Err())
 	}
 }