package backup

import "fmt"

// RestoreApp restores an app's HDD data from a restic snapshot.
func (m *Manager) RestoreApp(stackName, snapshotID string) error {
	// Validate app has backup enabled
	if !m.settings.IsAppBackupEnabled(stackName) {
		return fmt.Errorf("backup not enabled for %s", stackName)
	}

	// Resolve HDD paths for this app
	if m.stackProvider == nil {
		return fmt.Errorf("stack provider not configured")
	}
	hddMounts := m.stackProvider.GetStackHDDMounts(stackName)
	if len(hddMounts) == 0 {
		return fmt.Errorf("no HDD data paths found for %s", stackName)
	}

	// Validate snapshot exists
	snapshots, err := m.restic.ListSnapshots(100)
	if err != nil {
		return fmt.Errorf("listing snapshots: %w", err)
	}
	found := false
	for _, s := range snapshots {
		if s.ID == snapshotID {
			found = true
			break
		}
	}
	if !found {
		return fmt.Errorf("snapshot %s not found", snapshotID)
	}

	// Use the running flag to prevent concurrent backup/restore
	m.mu.Lock()
	if m.running {
		m.mu.Unlock()
		return fmt.Errorf("backup or restore already in progress")
	}
	m.running = true
	m.mu.Unlock()

	defer func() {
		m.mu.Lock()
		m.running = false
		m.mu.Unlock()
	}()

	m.logger.Printf("[WARN] RESTORE starting: stack=%s, snapshot=%s, paths=%v", stackName, snapshotID, hddMounts)

	// Execute restore
	if err := m.restic.RestoreAppData(snapshotID, hddMounts); err != nil {
		m.logger.Printf("[ERROR] RESTORE failed for %s: %v", stackName, err)
		return err
	}

	m.logger.Printf("[INFO] RESTORE completed: stack=%s, snapshot=%s", stackName, snapshotID)
	return nil
}