.clean up the code

backend/download_validation.go

@@ -1,44 +0,0 @@
-package backend
-
-import (
-	"fmt"
-	"math"
-)
-
-const (
-	previewMaxSeconds         = 35
-	previewExpectedMinSeconds = 60
-	largeMismatchMinExpected  = 90
-	minAllowedDurationDiff    = 15
-	durationDiffRatio         = 0.25
-)
-
-func ValidateDownloadedTrackDuration(filePath string, expectedSeconds int) (bool, error) {
-	if filePath == "" || expectedSeconds <= 0 {
-		return false, nil
-	}
-
-	actualDuration, err := GetAudioDuration(filePath)
-	if err != nil || actualDuration <= 0 {
-		return false, nil
-	}
-
-	actualSeconds := int(math.Round(actualDuration))
-	if actualSeconds <= 0 {
-		return false, nil
-	}
-
-	if expectedSeconds >= previewExpectedMinSeconds && actualSeconds <= previewMaxSeconds {
-		return true, fmt.Errorf("detected preview/sample download: file is %ds, expected about %ds. file was removed", actualSeconds, expectedSeconds)
-	}
-
-	if expectedSeconds >= largeMismatchMinExpected {
-		allowedDiff := int(math.Max(minAllowedDurationDiff, math.Round(float64(expectedSeconds)*durationDiffRatio)))
-		diff := int(math.Abs(float64(actualSeconds - expectedSeconds)))
-		if diff > allowedDiff {
-			return true, fmt.Errorf("downloaded file duration mismatch: file is %ds, expected about %ds. file was removed", actualSeconds, expectedSeconds)
-		}
-	}
-
-	return true, nil
-}