fix(downloads): support Transmission and aria2 end to end

Fixes #65

internal/service/download_torrent_normalize.go

@@ -0,0 +1,80 @@
+package service
+
+import "strings"
+
+func normalizedTorrentProgress(progress float64) float64 {
+	if progress < 0 {
+		return 0
+	}
+	if progress > 1 {
+		return 1
+	}
+	return progress
+}
+
+func canonicalTorrentState(state string, progress float64) string {
+	state = strings.ToLower(strings.TrimSpace(state))
+	complete := normalizedTorrentProgress(progress) >= 1
+	switch state {
+	case "completed", "complete", "seeding", "uploading", "stalledup", "pausedup", "queuedup", "forcedup":
+		if complete || state == "completed" || state == "complete" || state == "seeding" {
+			return "completed"
+		}
+		return "downloading"
+	case "downloading", "forceddl", "metadl", "stalleddl", "active":
+		if complete {
+			return "completed"
+		}
+		return "downloading"
+	case "queued", "queueddl", "download_pending", "seed_pending", "waiting":
+		if complete {
+			return "completed"
+		}
+		return "queued"
+	case "paused", "pauseddl", "stoppeddl", "stopped":
+		if complete {
+			return "completed"
+		}
+		return "paused"
+	case "checking", "checkingdl", "checkingup", "checkingresumedata", "check_pending", "moving":
+		return "checking"
+	case "error", "missingfiles":
+		return "error"
+	case "removed":
+		return "removed"
+	case "":
+		if complete {
+			return "completed"
+		}
+		return ""
+	default:
+		if complete {
+			return "completed"
+		}
+		return state
+	}
+}
+
+func downloaderPayloadPath(dir, name string) string {
+	dir = strings.TrimSpace(dir)
+	name = strings.TrimSpace(name)
+	if name == "" {
+		return dir
+	}
+	if dir == "" {
+		return name
+	}
+	separator := "/"
+	if strings.Contains(dir, `\`) && !strings.Contains(dir, "/") {
+		separator = `\`
+	}
+	return strings.TrimRight(dir, `/\`) + separator + strings.TrimLeft(name, `/\`)
+}
+
+func downloaderPathBase(value string) string {
+	value = strings.TrimRight(strings.TrimSpace(value), `/\`)
+	if i := strings.LastIndexAny(value, `/\`); i >= 0 {
+		return value[i+1:]
+	}
+	return value
+}