package backup

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"sync"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
	"gitea.dooplex.hu/admin/felhom-controller/internal/monitor"
	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
)

// Manager orchestrates database dumps and restic backups.
type Manager struct {
	cfg            *config.Config
	restic         *ResticManager
	logger         *log.Logger
	pinger         *monitor.Pinger
	settings       *settings.Settings
	stackProvider  StackDataProvider
	systemDataPath string // fallback drive for SSD-only apps

	mu                  sync.Mutex
	lastDBDump          *DBDumpStatus
	lastBackup          *BackupStatus
	running             bool
	snapshotHistory     []SnapshotRecord // ring buffer, last 20 entries
	snapshotHistoryFile string           // path to persist snapshot history JSON
	lastCheckTime       time.Time
	lastCheckOK         bool

	// Cached status for page rendering (refreshed periodically)
	cachedStatus *FullBackupStatus
	cacheTime    time.Time

	// AfterBackup is called after a backup completes to refresh the cache.
	// Set by main.go to avoid circular import with scheduler.
	AfterBackup func()

	// MigrationActiveCheck returns true if a full drive migration is in progress.
	// Set by main.go to coordinate with DriveMigrator.
	MigrationActiveCheck func() bool
}

// SnapshotRecord combines restic snapshot metadata with our run stats.
type SnapshotRecord struct {
	SnapshotID   string        `json:"snapshot_id"`
	Time         time.Time     `json:"time"`
	FilesNew     int           `json:"files_new"`
	FilesChanged int           `json:"files_changed"`
	DataAdded    string        `json:"data_added"`
	Duration     time.Duration `json:"duration"`
	Success      bool          `json:"success"`
	HasStats     bool          `json:"has_stats"` // false for historical entries loaded from restic
}

// DriveRepoInfo holds per-drive restic repository statistics for the Részletek section.
type DriveRepoInfo struct {
	DrivePath      string
	DriveLabel     string // filled by handler from settings
	TotalSize      string
	TotalSizeBytes int64
	SnapshotCount  int
}

// CrossDriveSummaryItem holds display data for one app's cross-drive backup.
type CrossDriveSummaryItem struct {
	StackName     string
	DisplayName   string
	Method        string // "rsync" or "restic"
	MethodLabel   string // "Egyszerű másolat" or "Restic"
	DestPath      string
	DestLabel     string // storage path label
	Schedule      string
	ScheduleLabel string // "Naponta" or "Hetente" or "Kézi"
	LastStatus    string // "ok", "error", "running", ""
	LastRunShort  string // formatted short time e.g. "03:15"
	SizeHuman     string
}

// FullBackupStatus contains everything the backup page needs.
type FullBackupStatus struct {
	Enabled bool
	Running bool

	// DB Dumps
	LastDBDump    *DBDumpStatus
	DumpFiles     []DumpFileInfo
	DiscoveredDBs []DiscoveredDB

	// Restic
	LastBackup        *BackupStatus
	SnapshotHistory   []SnapshotRecord
	RepoStats         *RepoStats
	PerDriveRepoStats []DriveRepoInfo // per-drive Tier 1 restic stats

	// Schedule
	DBDumpSchedule string
	ResticSchedule string
	PruneSchedule  string
	NextDBDump     time.Time
	NextBackup     time.Time
	Retention      config.RetentionConfig

	// Repository health
	LastCheckTime time.Time
	LastCheckOK   bool

	// Remote (placeholder)
	RemoteEnabled bool

	// App data backup
	AppDataInfo []AppBackupInfo

	// Cross-drive backup summary
	CrossDriveSummary  []CrossDriveSummaryItem
	UnconfiguredApps   []CrossDriveSummaryItem // apps with HDD data but no cross-drive config
	CrossDriveWarnings []string                // destination health warnings

	// Flash messages (set by handlers, passed through redirect)
	FlashSuccess string
	FlashError   string
}

// DBDumpStatus holds the last DB dump result.
type DBDumpStatus struct {
	LastRun  time.Time
	Results  []DumpResult
	Success  bool
	Duration time.Duration
}

// BackupStatus holds the last backup result.
type BackupStatus struct {
	LastRun   time.Time
	Snapshot  *SnapshotResult
	Success   bool
	Duration  time.Duration
	RepoStats *RepoStats
}

// NewManager creates a new backup manager.
func NewManager(cfg *config.Config, pinger *monitor.Pinger, sett *settings.Settings, logger *log.Logger) *Manager {
	if cfg.Paths.SystemDataPath == "" {
		logger.Printf("[WARN] SystemDataPath is empty in config — SSD-only apps will not have correct backup paths")
	}
	dataDir := cfg.Paths.DataDir
	if dataDir == "" {
		dataDir = "/opt/docker/felhom-controller/data"
	}
	return &Manager{
		cfg:                 cfg,
		restic:              NewResticManager(cfg, logger),
		logger:              logger,
		pinger:              pinger,
		settings:            sett,
		systemDataPath:      cfg.Paths.SystemDataPath,
		snapshotHistoryFile: filepath.Join(dataDir, "snapshot-history.json"),
	}
}

// GetAppDrivePath returns the drive path for an app.
// Uses HDD_PATH from app.yaml if set, otherwise falls back to system data path.
func (m *Manager) GetAppDrivePath(stackName string) string {
	if m.stackProvider != nil {
		if hddPath := m.stackProvider.GetStackHDDPath(stackName); hddPath != "" {
			return hddPath
		}
	}
	if m.systemDataPath == "" {
		m.logger.Printf("[ERROR] systemDataPath is empty — cannot determine drive for %s", stackName)
	}
	return m.systemDataPath
}

// groupStacksByDrive groups deployed stacks by their home drive path.
func (m *Manager) groupStacksByDrive() map[string][]StackSummary {
	if m.stackProvider == nil {
		return nil
	}
	result := make(map[string][]StackSummary)
	for _, stack := range m.stackProvider.ListDeployedStacks() {
		drive := m.GetAppDrivePath(stack.Name)
		result[drive] = append(result[drive], stack)
	}
	if m.isDebug() {
		for drive, stacks := range result {
			names := make([]string, len(stacks))
			for i, s := range stacks {
				names[i] = s.Name
			}
			m.logger.Printf("[DEBUG] groupStacksByDrive: %s → [%s]", drive, strings.Join(names, ", "))
		}
	}
	return result
}

// activeDrives returns sorted list of drives that have deployed apps.
func (m *Manager) activeDrives() []string {
	groups := m.groupStacksByDrive()
	var drives []string
	var disconnected []string
	for d := range groups {
		if m.settings != nil && (m.settings.IsDisconnected(d) || m.settings.IsDecommissioned(d)) {
			disconnected = append(disconnected, d)
		}
		drives = append(drives, d)
	}
	sort.Strings(drives)
	if m.isDebug() {
		m.logger.Printf("[DEBUG] activeDrives: %d total (%s), %d disconnected/decommissioned",
			len(drives), strings.Join(drives, ", "), len(disconnected))
	}
	return drives
}

// RunDBDumps discovers and dumps all databases to per-drive, per-app paths.
func (m *Manager) RunDBDumps(ctx context.Context) error {
	if err := m.acquireRunning(); err != nil {
		return err
	}
	defer m.releaseRunning()
	return m.runDBDumpsInternal(ctx)
}

// runDBDumpsInternal is the implementation of RunDBDumps. Caller must hold the running flag.
func (m *Manager) runDBDumpsInternal(ctx context.Context) error {
	start := time.Now()
	m.logger.Printf("[INFO] Starting database dump run")

	dbs, err := DiscoverDatabases(ctx, m.logger, m.isDebug())
	if err != nil {
		m.logger.Printf("[ERROR] Database discovery failed: %v", err)
		return err
	}

	if len(dbs) == 0 {
		m.logger.Printf("[INFO] No database containers found")
		m.mu.Lock()
		m.lastDBDump = &DBDumpStatus{
			LastRun:  time.Now(),
			Success:  true,
			Duration: time.Since(start),
		}
		m.mu.Unlock()
		return nil
	}

	m.logger.Printf("[INFO] Discovered %d database(s): %s", len(dbs), dbNames(dbs))

	// Dump each DB to its app's drive path
	var results []DumpResult
	allOK := true
	var summary []string
	var totalSize int64

	for _, db := range dbs {
		drivePath := m.GetAppDrivePath(db.StackName)

		// Skip if drive is disconnected or decommissioned
		if m.settings != nil && m.settings.IsDisconnected(drivePath) {
			m.logger.Printf("[WARN] Skipping DB dump for %s — drive disconnected: %s", db.StackName, drivePath)
			summary = append(summary, fmt.Sprintf("SKIP %s (drive disconnected)", db.ContainerName))
			continue
		}
		if m.settings != nil && m.settings.IsDecommissioned(drivePath) {
			m.logger.Printf("[WARN] Skipping DB dump for %s — drive decommissioned: %s", db.StackName, drivePath)
			summary = append(summary, fmt.Sprintf("SKIP %s (drive decommissioned)", db.ContainerName))
			continue
		}

		dumpDir := AppDBDumpPath(drivePath, db.StackName)

		result := DumpOne(ctx, db, dumpDir, m.logger, m.isDebug())
		results = append(results, result)

		if result.Error != nil {
			allOK = false
			summary = append(summary, fmt.Sprintf("FAIL %s: %v", result.DB.ContainerName, result.Error))
			m.logger.Printf("[ERROR] DB dump failed for %s: %v", result.DB.ContainerName, result.Error)
		} else {
			totalSize += result.Size
			summary = append(summary, fmt.Sprintf("OK %s (%s)", result.DB.ContainerName, humanizeBytes(result.Size)))

			// Persist validation result to settings.json
			if m.settings != nil && result.FilePath != "" {
				filename := filepath.Base(result.FilePath)
				cache := settings.DBValidationCache{
					ValidatedAt: time.Now().Format(time.RFC3339),
					TableCount:  result.Validation.TableCount,
					HasHeader:   result.Validation.Valid,
				}
				if !result.Validation.Valid {
					cache.Error = result.Validation.Error
				}
				if err := m.settings.SetDBValidation(filename, cache); err != nil {
					m.logger.Printf("[WARN] Failed to cache validation for %s: %v", filename, err)
				}
			}
		}
	}

	duration := time.Since(start)
	m.mu.Lock()
	m.lastDBDump = &DBDumpStatus{
		LastRun:  time.Now(),
		Results:  results,
		Success:  allOK,
		Duration: duration,
	}
	m.mu.Unlock()

	// Ping healthcheck
	uuid := m.cfg.Monitoring.PingUUIDs.DBDump
	body := fmt.Sprintf("DB dump: %d databases, %s total\n%s",
		len(results), humanizeBytes(totalSize), strings.Join(summary, "\n"))

	if allOK {
		m.pinger.Ping(uuid, body)
		m.logger.Printf("[INFO] DB dump completed: %d databases, %s total (%s)",
			len(results), humanizeBytes(totalSize), duration.Round(time.Millisecond))
	} else {
		m.pinger.Fail(uuid, body)
		return fmt.Errorf("some database dumps failed")
	}

	return nil
}

// RunBackup runs per-drive restic backup snapshots.
func (m *Manager) RunBackup(ctx context.Context) error {
	if err := m.acquireRunning(); err != nil {
		return err
	}
	defer m.releaseRunning()
	return m.runBackupInternal(ctx)
}

// runBackupInternal is the implementation of RunBackup. Caller must hold the running flag.
func (m *Manager) runBackupInternal(ctx context.Context) error {
	// Skip if a full drive migration is in progress
	if m.MigrationActiveCheck != nil && m.MigrationActiveCheck() {
		m.logger.Printf("[WARN] Skipping nightly backup — drive migration in progress")
		return nil
	}

	start := time.Now()
	m.logger.Printf("[INFO] Starting restic backup (per-drive)")

	driveStacks := m.groupStacksByDrive()
	if len(driveStacks) == 0 {
		m.logger.Printf("[INFO] No deployed stacks — skipping backup")
		return nil
	}

	// Infrastructure paths included in every drive's primary repo
	infraPaths := []string{
		m.cfg.Paths.StacksDir,
		"/opt/docker/felhom-controller/controller.yaml",
	}

	var lastResult *SnapshotResult
	var anyErr error
	driveCount := 0

	for drivePath, stacks := range driveStacks {
		if m.isDebug() {
			m.logger.Printf("[DEBUG] runBackupInternal: processing drive %s (%d stacks)", drivePath, len(stacks))
		}
		result, err := m.backupDrive(ctx, drivePath, stacks, infraPaths)
		if err != nil {
			anyErr = err
			continue
		}
		if result != nil {
			lastResult = result
			driveCount++
		}
	}

	duration := time.Since(start)

	if anyErr != nil && driveCount == 0 {
		// All drives failed
		m.pinger.Fail(m.cfg.Monitoring.PingUUIDs.Backup, fmt.Sprintf("Backup failed: %v", anyErr))
		m.mu.Lock()
		m.lastBackup = &BackupStatus{
			LastRun:  time.Now(),
			Success:  false,
			Duration: duration,
		}
		m.mu.Unlock()
		return anyErr
	}

	// Get aggregated stats
	stats := m.aggregateRepoStats()

	m.mu.Lock()
	m.lastBackup = &BackupStatus{
		LastRun:   time.Now(),
		Snapshot:  lastResult,
		Success:   anyErr == nil,
		Duration:  duration,
		RepoStats: stats,
	}
	if lastResult != nil {
		m.appendSnapshotRecord(SnapshotRecord{
			SnapshotID:   lastResult.SnapshotID,
			Time:         time.Now(),
			FilesNew:     lastResult.FilesNew,
			FilesChanged: lastResult.FilesChanged,
			DataAdded:    lastResult.DataAdded,
			Duration:     duration,
			Success:      true,
			HasStats:     true,
		})
	}
	m.mu.Unlock()

	if lastResult != nil {
		body := fmt.Sprintf("Backup OK (%d drives)\nSnapshot: %s\nNew files: %d, Changed: %d\nData added: %s\nDuration: %s",
			driveCount, lastResult.SnapshotID, lastResult.FilesNew, lastResult.FilesChanged, lastResult.DataAdded,
			duration.Round(time.Second))
		m.pinger.Ping(m.cfg.Monitoring.PingUUIDs.Backup, body)

		m.logger.Printf("[INFO] Restic backup completed: %d drives, snapshot %s, %d new, %d changed, %s added (%s)",
			driveCount, lastResult.SnapshotID, lastResult.FilesNew, lastResult.FilesChanged, lastResult.DataAdded,
			duration.Round(time.Millisecond))
	}

	// Refresh cache so the page shows updated data immediately
	if m.AfterBackup != nil {
		m.AfterBackup()
	}

	return anyErr
}

// backupDrive runs restic backup for a single drive. Returns nil result if skipped.
// Caller must hold the running flag.
func (m *Manager) backupDrive(ctx context.Context, drivePath string, stacks []StackSummary, infraPaths []string) (*SnapshotResult, error) {
	// Skip disconnected or decommissioned drives
	if m.settings != nil && m.settings.IsDisconnected(drivePath) {
		m.logger.Printf("[WARN] Skipping backup for drive %s — disconnected", drivePath)
		return nil, nil
	}
	if m.settings != nil && m.settings.IsDecommissioned(drivePath) {
		m.logger.Printf("[WARN] Skipping backup for drive %s — decommissioned", drivePath)
		return nil, nil
	}

	repoPath := PrimaryResticRepoPath(drivePath)

	// Ensure repo is initialized
	if err := m.restic.EnsureInitialized(repoPath); err != nil {
		m.logger.Printf("[ERROR] Restic init failed for %s: %v", repoPath, err)
		return nil, err
	}

	// Build paths for this drive
	var paths []string
	paths = append(paths, infraPaths...)

	for _, stack := range stacks {
		// App data (appdata/<stack>/)
		appData := AppDataDir(drivePath, stack.Name)
		if _, err := os.Stat(appData); err == nil {
			paths = append(paths, appData)
		}
		// HDD mounts (for apps with custom mount points)
		if m.stackProvider != nil {
			for _, mount := range m.stackProvider.GetStackHDDMounts(stack.Name) {
				if _, err := os.Stat(mount); err == nil {
					paths = append(paths, mount)
				}
			}
		}
		// DB dumps for this stack
		dumpDir := AppDBDumpPath(drivePath, stack.Name)
		if _, err := os.Stat(dumpDir); err == nil {
			paths = append(paths, dumpDir)
		}
	}

	// Deduplicate paths
	paths = dedup(paths)

	if m.isDebug() {
		m.logger.Printf("[DEBUG] backupDrive %s: repo=%s, %d include paths:", drivePath, repoPath, len(paths))
		for _, p := range paths {
			m.logger.Printf("[DEBUG]   %s", p)
		}
	}

	tags := []string{"felhom", m.cfg.Customer.ID, filepath.Base(drivePath)}
	m.logger.Printf("[INFO] Backing up drive %s (%d apps, %d paths)", drivePath, len(stacks), len(paths))

	result, err := m.restic.Snapshot(repoPath, paths, tags)
	if err != nil {
		m.logger.Printf("[ERROR] Restic backup failed for drive %s: %v", drivePath, err)
		return nil, err
	}

	// Prune check (weekly — Sunday)
	if shouldPrune(m.cfg.Backup.PruneSchedule) {
		m.logger.Printf("[INFO] Running weekly prune for %s", repoPath)
		if err := m.restic.Prune(repoPath, m.cfg.Backup.Retention); err != nil {
			m.logger.Printf("[WARN] Restic prune failed for %s: %v", repoPath, err)
		}
	}

	return result, nil
}

// tryAcquireRunning attempts to set the running flag without blocking.
// Returns true if acquired, false if already running.
func (m *Manager) tryAcquireRunning() bool {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.running {
		return false
	}
	m.running = true
	return true
}

// TryRunDriveBackup runs a backup for a single drive if no other backup is in progress.
// Returns error if the backup lock cannot be acquired or if backup fails.
func (m *Manager) TryRunDriveBackup(ctx context.Context, drivePath string) error {
	if !m.tryAcquireRunning() {
		return fmt.Errorf("backup already in progress")
	}
	defer m.releaseRunning()

	driveStacks := m.groupStacksByDrive()
	stacks, ok := driveStacks[drivePath]
	if !ok || len(stacks) == 0 {
		m.logger.Printf("[INFO] No deployed stacks on drive %s — skipping backup", drivePath)
		return nil
	}

	infraPaths := []string{
		m.cfg.Paths.StacksDir,
		"/opt/docker/felhom-controller/controller.yaml",
	}

	result, err := m.backupDrive(ctx, drivePath, stacks, infraPaths)
	if err != nil {
		return err
	}

	if result != nil {
		m.logger.Printf("[INFO] Single-drive backup for %s: snapshot %s, %d new, %d changed, %s added",
			drivePath, result.SnapshotID, result.FilesNew, result.FilesChanged, result.DataAdded)
	}

	return nil
}

// RunIntegrityCheck runs restic check on all primary repos and pings healthchecks.
func (m *Manager) RunIntegrityCheck(ctx context.Context) error {
	m.logger.Printf("[INFO] Starting restic integrity check")
	start := time.Now()

	drives := m.activeDrives()
	if len(drives) == 0 {
		m.logger.Printf("[INFO] No active drives — skipping integrity check")
		return nil
	}

	if m.isDebug() {
		m.logger.Printf("[DEBUG] RunIntegrityCheck: checking %d drives", len(drives))
	}

	var checkErr error
	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			if m.isDebug() {
				m.logger.Printf("[DEBUG] RunIntegrityCheck: skipping %s (repo does not exist)", repoPath)
			}
			continue
		}
		if m.isDebug() {
			m.logger.Printf("[DEBUG] RunIntegrityCheck: checking repo %s", repoPath)
		}
		if err := m.restic.Check(repoPath); err != nil {
			m.logger.Printf("[ERROR] Restic check failed for %s: %v", repoPath, err)
			checkErr = err
		} else if m.isDebug() {
			m.logger.Printf("[DEBUG] RunIntegrityCheck: repo %s OK", repoPath)
		}
	}

	duration := time.Since(start)
	uuid := m.cfg.Monitoring.PingUUIDs.BackupIntegrity

	m.mu.Lock()
	m.lastCheckTime = time.Now()
	m.lastCheckOK = checkErr == nil
	m.mu.Unlock()

	if checkErr != nil {
		m.logger.Printf("[ERROR] Restic integrity check failed (%s): %v", duration.Round(time.Second), checkErr)
		m.pinger.Fail(uuid, fmt.Sprintf("restic check failed: %v", checkErr))
		return checkErr
	}

	m.logger.Printf("[INFO] Restic integrity check passed (%d repos, %s)", len(drives), duration.Round(time.Second))
	m.pinger.Ping(uuid, fmt.Sprintf("restic check passed (%d repos, %s)", len(drives), duration.Round(time.Second)))
	return nil
}

// RunFullBackup runs DB dumps followed by restic backup.
func (m *Manager) RunFullBackup(ctx context.Context) error {
	if err := m.acquireRunning(); err != nil {
		return err
	}
	defer m.releaseRunning()

	if m.isDebug() {
		drives := m.activeDrives()
		driveStacks := m.groupStacksByDrive()
		totalStacks := 0
		for _, s := range driveStacks {
			totalStacks += len(s)
		}
		m.logger.Printf("[DEBUG] RunFullBackup: starting full backup — %d active drives, %d stacks", len(drives), totalStacks)
	}

	// Step 1: DB dumps
	if m.isDebug() {
		m.logger.Printf("[DEBUG] RunFullBackup: phase 1 — database dumps")
	}
	if err := m.runDBDumpsInternal(ctx); err != nil {
		m.logger.Printf("[WARN] DB dump had errors, continuing with backup anyway")
	}

	// Step 2: Restic backup
	if m.isDebug() {
		m.logger.Printf("[DEBUG] RunFullBackup: phase 2 — restic snapshots")
	}
	return m.runBackupInternal(ctx)
}

// GetStatus returns the current backup status.
func (m *Manager) GetStatus() (*DBDumpStatus, *BackupStatus) {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.lastDBDump, m.lastBackup
}

// GetRepoStats returns aggregated repository statistics across all primary repos.
func (m *Manager) GetRepoStats() (*RepoStats, error) {
	stats := m.aggregateRepoStats()
	if stats.SnapshotCount == 0 && stats.TotalSize == "" {
		return stats, fmt.Errorf("no repos available")
	}
	return stats, nil
}

// IsRunning returns whether a backup or restore is currently in progress.
func (m *Manager) IsRunning() bool {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.running
}

// acquireRunning atomically sets the running flag. Returns error if already running.
func (m *Manager) acquireRunning() error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.running {
		return fmt.Errorf("backup already in progress")
	}
	m.running = true
	return nil
}

// releaseRunning clears the running flag.
func (m *Manager) releaseRunning() {
	m.mu.Lock()
	m.running = false
	m.mu.Unlock()
}

// GetResticPassword returns the restic repository encryption password.
func (m *Manager) GetResticPassword() (string, error) {
	return m.restic.GetPassword()
}

// ListSnapshots returns snapshots from all primary restic repositories, merged and sorted.
func (m *Manager) ListSnapshots(limit int) ([]SnapshotInfo, error) {
	drives := m.activeDrives()
	var allSnapshots []SnapshotInfo
	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			continue
		}
		snapshots, err := m.restic.ListSnapshots(repoPath, 0)
		if err != nil {
			m.logger.Printf("[WARN] Could not list snapshots from %s: %v", repoPath, err)
			continue
		}
		for i := range snapshots {
			snapshots[i].RepoPath = repoPath
		}
		allSnapshots = append(allSnapshots, snapshots...)
	}
	// Sort newest first
	sort.Slice(allSnapshots, func(i, j int) bool {
		return allSnapshots[i].Time.After(allSnapshots[j].Time)
	})
	if limit > 0 && len(allSnapshots) > limit {
		allSnapshots = allSnapshots[:limit]
	}
	return allSnapshots, nil
}

// ListAllSnapshots returns snapshots from primary restic repos across all active drives.
// All snapshots get Tier=1.
func (m *Manager) ListAllSnapshots(limit int) ([]SnapshotInfo, error) {
	drives := m.activeDrives()
	var allSnapshots []SnapshotInfo

	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			continue
		}
		snapshots, err := m.restic.ListSnapshots(repoPath, 0)
		if err != nil {
			m.logger.Printf("[WARN] Could not list snapshots from %s: %v", repoPath, err)
			continue
		}
		for i := range snapshots {
			snapshots[i].RepoPath = repoPath
			snapshots[i].Tier = 1
		}
		allSnapshots = append(allSnapshots, snapshots...)
	}

	// Sort newest first
	sort.Slice(allSnapshots, func(i, j int) bool {
		return allSnapshots[i].Time.After(allSnapshots[j].Time)
	})
	if limit > 0 && len(allSnapshots) > limit {
		allSnapshots = allSnapshots[:limit]
	}
	return allSnapshots, nil
}

// SetStackProvider sets the stack data provider for app data discovery.
// C3: Write is protected by mutex since stackProvider is read by concurrent goroutines.
func (m *Manager) SetStackProvider(provider StackDataProvider) {
	m.mu.Lock()
	m.stackProvider = provider
	m.mu.Unlock()
}

// UnlockRepo runs restic unlock on the given repo path.
func (m *Manager) UnlockRepo(ctx context.Context, repoPath string) error {
	if !m.restic.RepoExists(repoPath) {
		return nil // no repo to unlock
	}
	cmd := m.restic.UnlockCommand(ctx, repoPath)
	out, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("restic unlock: %v (%s)", err, strings.TrimSpace(string(out)))
	}
	m.logger.Printf("[INFO] Restic repo unlocked: %s", repoPath)
	return nil
}

// GetStackHDDMounts returns HDD mount paths for the named stack via the stack provider.
func (m *Manager) GetStackHDDMounts(name string) []string {
	if m.stackProvider == nil {
		return nil
	}
	return m.stackProvider.GetStackHDDMounts(name)
}

// DumpStackDB runs a database dump for containers belonging to a specific stack.
// Dumps to the stack's home drive: <drive>/backups/primary/<stack>/db-dumps/.
func (m *Manager) DumpStackDB(ctx context.Context, stackName string) error {
	dbs, err := DiscoverDatabases(ctx, m.logger, m.isDebug())
	if err != nil {
		return fmt.Errorf("database discovery failed: %w", err)
	}

	var stackDBs []DiscoveredDB
	for _, db := range dbs {
		if db.StackName == stackName {
			stackDBs = append(stackDBs, db)
		}
	}
	if len(stackDBs) == 0 {
		m.logger.Printf("[DEBUG] No databases found for stack %s — skipping pre-backup dump", stackName)
		return nil
	}

	drivePath := m.GetAppDrivePath(stackName)
	if drivePath == "" || !filepath.IsAbs(drivePath) {
		return fmt.Errorf("cannot determine absolute drive path for %s (systemDataPath not configured?)", stackName)
	}
	dumpDir := AppDBDumpPath(drivePath, stackName)

	m.logger.Printf("[INFO] Running pre-backup DB dump for %s (%d database(s)) → %s", stackName, len(stackDBs), dumpDir)

	for _, db := range stackDBs {
		result := DumpOne(ctx, db, dumpDir, m.logger, m.isDebug())
		if result.Error != nil {
			return fmt.Errorf("DB dump failed for %s: %w", result.DB.ContainerName, result.Error)
		}
		m.logger.Printf("[INFO] Pre-backup DB dump OK: %s (%s)", result.DB.ContainerName, humanizeBytes(result.Size))

		// Persist validation to settings
		if m.settings != nil && result.FilePath != "" {
			filename := filepath.Base(result.FilePath)
			cache := settings.DBValidationCache{
				ValidatedAt: time.Now().Format(time.RFC3339),
				TableCount:  result.Validation.TableCount,
				HasHeader:   result.Validation.Valid,
			}
			if !result.Validation.Valid {
				cache.Error = result.Validation.Error
			}
			_ = m.settings.SetDBValidation(filename, cache)
		}
	}
	return nil
}

// perDriveRepoStats returns per-drive restic repository statistics for the Részletek section.
func (m *Manager) perDriveRepoStats() []DriveRepoInfo {
	drives := m.activeDrives()
	var infos []DriveRepoInfo
	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			continue
		}
		stats, err := m.restic.Stats(repoPath)
		if err != nil {
			continue
		}
		infos = append(infos, DriveRepoInfo{
			DrivePath:      drive,
			TotalSize:      stats.TotalSize,
			TotalSizeBytes: stats.TotalSizeBytes,
			SnapshotCount:  stats.SnapshotCount,
		})
	}
	return infos
}

// aggregateRepoStats combines stats from all primary restic repos.
func (m *Manager) aggregateRepoStats() *RepoStats {
	drives := m.activeDrives()
	agg := &RepoStats{}
	var totalBytes int64

	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			continue
		}
		stats, err := m.restic.Stats(repoPath)
		if err != nil {
			continue
		}
		agg.SnapshotCount += stats.SnapshotCount
		totalBytes += stats.TotalSizeBytes
		if stats.LatestSnapshot != nil {
			if agg.LatestSnapshot == nil || stats.LatestSnapshot.Time.After(agg.LatestSnapshot.Time) {
				agg.LatestSnapshot = stats.LatestSnapshot
			}
		}
	}

	agg.TotalSizeBytes = totalBytes
	if totalBytes > 0 {
		agg.TotalSize = humanizeBytes(totalBytes)
	}
	return agg
}

// listAllDumpFiles scans per-drive per-stack DB dump directories.
func (m *Manager) listAllDumpFiles() []DumpFileInfo {
	var allFiles []DumpFileInfo
	for drive, stacks := range m.groupStacksByDrive() {
		for _, stack := range stacks {
			dumpDir := AppDBDumpPath(drive, stack.Name)
			if files, err := ListDumpFiles(dumpDir); err == nil {
				allFiles = append(allFiles, files...)
			}
		}
	}
	return allFiles
}

func shouldPrune(schedule string) bool {
	loc, err := time.LoadLocation("Europe/Budapest")
	if err != nil {
		loc = time.UTC
	}
	now := time.Now().In(loc)

	switch strings.ToLower(schedule) {
	case "weekly":
		return now.Weekday() == time.Sunday
	case "daily":
		return true
	default:
		return now.Weekday() == time.Sunday
	}
}

// appendSnapshotRecord adds a record to the ring buffer (max 20). Caller must hold m.mu.
func (m *Manager) appendSnapshotRecord(rec SnapshotRecord) {
	m.snapshotHistory = append(m.snapshotHistory, rec)
	if len(m.snapshotHistory) > 20 {
		m.snapshotHistory = m.snapshotHistory[len(m.snapshotHistory)-20:]
	}
	m.saveSnapshotHistory()
}

// saveSnapshotHistory persists the current snapshotHistory to disk as JSON.
// Caller must hold m.mu. Writes atomically (tmp file + rename).
func (m *Manager) saveSnapshotHistory() {
	if m.snapshotHistoryFile == "" {
		return
	}
	data, err := json.Marshal(m.snapshotHistory)
	if err != nil {
		m.logger.Printf("[WARN] Could not marshal snapshot history: %v", err)
		return
	}
	tmp := m.snapshotHistoryFile + ".tmp"
	if err := os.WriteFile(tmp, data, 0644); err != nil {
		m.logger.Printf("[WARN] Could not write snapshot history tmp file: %v", err)
		return
	}
	if err := os.Rename(tmp, m.snapshotHistoryFile); err != nil {
		m.logger.Printf("[WARN] Could not rename snapshot history file: %v", err)
	}
}

// loadSnapshotHistoryFromFile reads the persisted snapshot history from disk.
// Returns nil if the file does not exist or cannot be read.
func (m *Manager) loadSnapshotHistoryFromFile() []SnapshotRecord {
	if m.snapshotHistoryFile == "" {
		return nil
	}
	data, err := os.ReadFile(m.snapshotHistoryFile)
	if err != nil {
		if !os.IsNotExist(err) {
			m.logger.Printf("[WARN] Could not read snapshot history file: %v", err)
		}
		return nil
	}
	var records []SnapshotRecord
	if err := json.Unmarshal(data, &records); err != nil {
		m.logger.Printf("[WARN] Could not parse snapshot history file: %v", err)
		return nil
	}
	return records
}

// LoadSnapshotHistory populates the snapshot history on startup.
// First tries to load persisted history (with delta stats) from disk.
// Merges with restic repo snapshots to pick up any entries not in the persisted file.
func (m *Manager) LoadSnapshotHistory() {
	// Try loading persisted records (contains delta stats from actual backup runs)
	persisted := m.loadSnapshotHistoryFromFile()

	// Build a lookup map of persisted records by SnapshotID
	persistedByID := make(map[string]SnapshotRecord, len(persisted))
	for _, r := range persisted {
		persistedByID[r.SnapshotID] = r
	}

	// Query restic repos for any snapshots not in the persisted file
	drives := m.activeDrives()
	var allSnapshots []SnapshotInfo

	for _, drive := range drives {
		repoPath := PrimaryResticRepoPath(drive)
		if !m.restic.RepoExists(repoPath) {
			continue
		}
		snapshots, err := m.restic.ListSnapshots(repoPath, 20)
		if err != nil {
			m.logger.Printf("[WARN] Could not load snapshot history from %s: %v", repoPath, err)
			continue
		}
		allSnapshots = append(allSnapshots, snapshots...)
	}

	// Sort by time (oldest first for ring buffer)
	sort.Slice(allSnapshots, func(i, j int) bool {
		return allSnapshots[i].Time.Before(allSnapshots[j].Time)
	})

	m.mu.Lock()
	defer m.mu.Unlock()

	if len(persisted) > 0 {
		// Start from persisted records, add any restic snapshots not already there
		m.snapshotHistory = persisted
		for _, s := range allSnapshots {
			if _, found := persistedByID[s.ID]; !found {
				m.snapshotHistory = append(m.snapshotHistory, SnapshotRecord{
					SnapshotID: s.ID,
					Time:       s.Time,
					HasStats:   false,
					Success:    true,
				})
			}
		}
		// Re-sort by time after merge (oldest first for ring buffer)
		sort.Slice(m.snapshotHistory, func(i, j int) bool {
			return m.snapshotHistory[i].Time.Before(m.snapshotHistory[j].Time)
		})
		m.logger.Printf("[INFO] Loaded %d snapshots from persisted history (merged with %d restic entries)", len(persisted), len(allSnapshots))
	} else {
		// No persisted file — fall back to restic-only loading (first run)
		for _, s := range allSnapshots {
			m.snapshotHistory = append(m.snapshotHistory, SnapshotRecord{
				SnapshotID: s.ID,
				Time:       s.Time,
				HasStats:   false,
				Success:    true,
			})
		}
		m.logger.Printf("[INFO] Loaded %d historical snapshots from %d restic repos (no persisted history)", len(m.snapshotHistory), len(drives))
	}

	if len(m.snapshotHistory) > 20 {
		m.snapshotHistory = m.snapshotHistory[len(m.snapshotHistory)-20:]
	}
}

// RefreshCache updates the cached full status. Called by scheduler every 5 minutes
// and after each backup run.
func (m *Manager) RefreshCache(nextDBDump, nextBackup time.Time) {
	status := &FullBackupStatus{
		Enabled: m.cfg.Backup.Enabled,

		DBDumpSchedule: m.cfg.Backup.DBDumpSchedule,
		ResticSchedule: m.cfg.Backup.ResticSchedule,
		PruneSchedule:  m.cfg.Backup.PruneSchedule,
		NextDBDump:     nextDBDump,
		NextBackup:     nextBackup,
		Retention:      m.cfg.Backup.Retention,
	}

	// Expensive calls (outside lock)
	status.RepoStats = m.aggregateRepoStats()
	status.PerDriveRepoStats = m.perDriveRepoStats()

	// Scan dump files from per-drive per-stack paths
	files := m.listAllDumpFiles()
	status.DumpFiles = files

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if dbs, err := DiscoverDatabases(ctx, m.logger, m.isDebug()); err == nil {
		status.DiscoveredDBs = dbs
	}

	// Discover app data — all deployed stacks, backup is mandatory
	if m.stackProvider != nil {
		status.AppDataInfo = DiscoverAppData(m.stackProvider, status.DiscoveredDBs)
	}

	// Fill in dynamic fields under lock.
	// C1: lastDBDump mutation also happens here to prevent data races with GetFullStatus.
	// C2: snapshot history reversal happens before cachedStatus assignment (inside lock).
	m.mu.Lock()
	status.Running = m.running
	status.LastDBDump = m.lastDBDump
	status.LastBackup = m.lastBackup
	status.LastCheckTime = m.lastCheckTime
	status.LastCheckOK = m.lastCheckOK
	status.SnapshotHistory = make([]SnapshotRecord, len(m.snapshotHistory))
	copy(status.SnapshotHistory, m.snapshotHistory)

	// C1: Cross-check lastDBDump results inside lock to prevent torn writes.
	if m.lastDBDump != nil && len(files) > 0 {
		fileValidation := make(map[string]DumpValidation) // keyed by filename
		for _, f := range files {
			fileValidation[f.FileName] = f.Validation
		}
		for i, r := range m.lastDBDump.Results {
			if !r.Validation.Valid && r.Validation.Error == "" && r.FilePath != "" {
				filename := filepath.Base(r.FilePath)
				if fv, ok := fileValidation[filename]; ok {
					m.lastDBDump.Results[i].Validation = fv
					m.logger.Printf("[INFO] Re-validated %s from disk: valid=%v tables=%d",
						filename, fv.Valid, fv.TableCount)
				}
			}
		}
	}

	// C2: Reverse snapshot history before assigning to cachedStatus (inside lock).
	for i, j := 0, len(status.SnapshotHistory)-1; i < j; i, j = i+1, j-1 {
		status.SnapshotHistory[i], status.SnapshotHistory[j] = status.SnapshotHistory[j], status.SnapshotHistory[i]
	}

	m.cachedStatus = status
	m.cacheTime = time.Now()
	m.mu.Unlock()

	m.logger.Printf("[INFO] Backup status cache refreshed")
}

// GetFullStatus returns the cached backup status for page rendering.
// Returns instantly — no subprocess calls.
// Returns a deep copy so callers can safely append to slice fields without
// polluting the cache (which would cause duplicate entries on repeated calls).
func (m *Manager) GetFullStatus(nextDBDump, nextBackup time.Time) *FullBackupStatus {
	m.mu.Lock()
	defer m.mu.Unlock()

	if m.cachedStatus != nil {
		// Deep copy — callers (backupsHandler) append to CrossDriveSummary,
		// UnconfiguredApps, and CrossDriveWarnings. If we returned the cache
		// pointer directly, every page load would accumulate more entries.
		status := *m.cachedStatus
		status.AppDataInfo = make([]AppBackupInfo, len(m.cachedStatus.AppDataInfo))
		copy(status.AppDataInfo, m.cachedStatus.AppDataInfo)
		status.PerDriveRepoStats = make([]DriveRepoInfo, len(m.cachedStatus.PerDriveRepoStats))
		copy(status.PerDriveRepoStats, m.cachedStatus.PerDriveRepoStats)
		// These three slices are assembled by the handler from AppDataInfo + settings;
		// they must always start empty so the handler builds them fresh.
		status.CrossDriveSummary = nil
		status.UnconfiguredApps = nil
		status.CrossDriveWarnings = nil

		// Update dynamic fields that don't need subprocess calls
		status.Running = m.running
		status.NextDBDump = nextDBDump
		status.NextBackup = nextBackup
		// C4: Deep-copy lastDBDump and lastBackup so callers cannot mutate shared state.
		if m.lastDBDump != nil {
			copyDump := *m.lastDBDump
			if len(m.lastDBDump.Results) > 0 {
				copyDump.Results = make([]DumpResult, len(m.lastDBDump.Results))
				copy(copyDump.Results, m.lastDBDump.Results)
			}
			status.LastDBDump = &copyDump
		}
		if m.lastBackup != nil {
			copyBackup := *m.lastBackup
			status.LastBackup = &copyBackup
		}
		// Update snapshot history
		status.SnapshotHistory = make([]SnapshotRecord, len(m.snapshotHistory))
		copy(status.SnapshotHistory, m.snapshotHistory)
		// Reverse so newest first
		for i, j := 0, len(status.SnapshotHistory)-1; i < j; i, j = i+1, j-1 {
			status.SnapshotHistory[i], status.SnapshotHistory[j] = status.SnapshotHistory[j], status.SnapshotHistory[i]
		}

		// Synthesize LastBackup from snapshot history if not in memory (e.g., after restart)
		if status.LastBackup == nil && len(status.SnapshotHistory) > 0 {
			latest := status.SnapshotHistory[0] // already reversed, newest first
			status.LastBackup = &BackupStatus{
				LastRun: latest.Time,
				Success: latest.Success,
				Snapshot: &SnapshotResult{
					SnapshotID: latest.SnapshotID,
				},
			}
		}

		// Synthesize LastDBDump from DumpFiles on disk if not in memory
		if status.LastDBDump == nil && len(status.DumpFiles) > 0 {
			var results []DumpResult
			var latestTime time.Time
			for _, f := range status.DumpFiles {
				results = append(results, DumpResult{
					DB:         DiscoveredDB{StackName: f.StackName, DBType: f.DBType, ContainerName: f.StackName},
					FilePath:   f.FileName,
					Size:       f.Size,
					Validation: f.Validation,
				})
				if f.ModTime.After(latestTime) {
					latestTime = f.ModTime
				}
			}
			status.LastDBDump = &DBDumpStatus{
				LastRun: latestTime,
				Results: results,
				Success: true,
			}
		}

		return &status
	}

	// No cache yet — return a minimal status (first page load before cache is populated)
	return &FullBackupStatus{
		Enabled:        m.cfg.Backup.Enabled,
		Running:        m.running,
		LastDBDump:     m.lastDBDump,
		LastBackup:     m.lastBackup,
		DBDumpSchedule: m.cfg.Backup.DBDumpSchedule,
		ResticSchedule: m.cfg.Backup.ResticSchedule,
		PruneSchedule:  m.cfg.Backup.PruneSchedule,
		NextDBDump:     nextDBDump,
		NextBackup:     nextBackup,
		Retention:      m.cfg.Backup.Retention,
		LastCheckTime:  m.lastCheckTime,
		LastCheckOK:    m.lastCheckOK,
	}
}

// isDebug returns true if logging level is "debug".
func (m *Manager) isDebug() bool {
	return m.cfg.Logging.Level == "debug"
}

func dbNames(dbs []DiscoveredDB) string {
	var names []string
	for _, db := range dbs {
		names = append(names, fmt.Sprintf("%s(%s)", db.ContainerName, db.DBType))
	}
	return strings.Join(names, ", ")
}

// dedup removes duplicate strings from a slice, preserving order.
func dedup(items []string) []string {
	seen := make(map[string]bool)
	var result []string
	for _, item := range items {
		if !seen[item] {
			seen[item] = true
			result = append(result, item)
		}
	}
	return result
}