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

Fixes #65

internal/service/download_controls.go

@@ -0,0 +1,105 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"strings"
+
+	"github.com/ShukeBta/MediaStationGo/internal/model"
+)
+
+func (d *DownloadService) PauseDownloadTask(ctx context.Context, taskID string) error {
+	return d.controlDownloadTask(ctx, taskID, "paused", func(target downloadTarget, externalID string) error {
+		if target.legacyQB {
+			return d.qb.Pause(ctx, externalID)
+		}
+		return target.adapter.Pause(ctx, externalID)
+	})
+}
+
+func (d *DownloadService) ResumeDownloadTask(ctx context.Context, taskID string) error {
+	return d.controlDownloadTask(ctx, taskID, "queued", func(target downloadTarget, externalID string) error {
+		if target.legacyQB {
+			return d.qb.Resume(ctx, externalID)
+		}
+		return target.adapter.Resume(ctx, externalID)
+	})
+}
+
+func (d *DownloadService) controlDownloadTask(ctx context.Context, taskID, status string, operation func(downloadTarget, string) error) error {
+	taskID = strings.TrimSpace(taskID)
+	if taskID == "" {
+		return errors.New("task id is required")
+	}
+	var task model.DownloadTask
+	if d == nil || d.repo == nil || d.repo.DB == nil {
+		return errors.New("download repository is unavailable")
+	}
+	if err := d.repo.DB.WithContext(ctx).Where("id = ?", taskID).First(&task).Error; err != nil {
+		return err
+	}
+	clientID, externalID := d.resolveTaskDownloaderIdentity(ctx, &task)
+	if externalID == "" {
+		return errors.New("download task has no client task id")
+	}
+	target, err := d.downloadTargetByID(ctx, clientID)
+	if err != nil {
+		return err
+	}
+	if err := operation(target, externalID); err != nil {
+		return err
+	}
+	return d.repo.DB.WithContext(ctx).Model(&model.DownloadTask{}).
+		Where("id = ?", task.ID).
+		Updates(map[string]any{
+			"status":             status,
+			"download_client_id": clientID,
+			"external_id":        externalID,
+			"source":             firstNonEmpty(target.typ, task.Source),
+		}).Error
+}
+
+func (d *DownloadService) resolveTaskDownloaderIdentity(ctx context.Context, task *model.DownloadTask) (string, string) {
+	if task == nil {
+		return "", ""
+	}
+	clientID := strings.TrimSpace(task.DownloadClientID)
+	persistedExternalID := strings.TrimSpace(task.ExternalID)
+	externalID := persistedExternalID
+	if externalID == "" {
+		externalID = torrentURLInfoHash(task.URL)
+	}
+	if clientID != "" && persistedExternalID != "" {
+		return clientID, externalID
+	}
+	live, _ := d.listLiveTorrents(ctx, "")
+	for _, torrent := range live {
+		if clientID != "" && torrent.ClientID != clientID {
+			continue
+		}
+		if externalID != "" && strings.EqualFold(torrent.Hash, externalID) {
+			clientID = firstNonEmpty(clientID, torrent.ClientID)
+			return clientID, torrent.Hash
+		}
+		if downloadTaskMatchesLiveTorrent(*task, torrent) {
+			clientID = firstNonEmpty(clientID, torrent.ClientID)
+			externalID = firstNonEmpty(externalID, torrent.Hash)
+			return clientID, externalID
+		}
+	}
+	if clientID == "" && d.manager != nil {
+		var matched []managedDownloadTarget
+		for _, target := range d.manager.targets() {
+			if strings.TrimSpace(task.Source) == "" || target.client.Type == task.Source {
+				matched = append(matched, target)
+			}
+		}
+		if len(matched) == 1 {
+			clientID = matched[0].client.ID
+		}
+	}
+	if clientID == "" && d.qb != nil && d.qb.IsConfigured() && (task.Source == "" || task.Source == "qbittorrent") {
+		clientID = legacyQBitDownloadClientID
+	}
+	return clientID, externalID
+}