package sync

import (
	"fmt"
	"log/slog"
	"time"

	"git.mchus.pro/mchus/quoteforge/internal/localdb"
	"git.mchus.pro/mchus/quoteforge/internal/repository"
)

// Service handles synchronization between MariaDB and local SQLite
type Service struct {
	pricelistRepo *repository.PricelistRepository
	localDB       *localdb.LocalDB
}

// NewService creates a new sync service
func NewService(pricelistRepo *repository.PricelistRepository, localDB *localdb.LocalDB) *Service {
	return &Service{
		pricelistRepo: pricelistRepo,
		localDB:       localDB,
	}
}

// SyncStatus represents the current sync status
type SyncStatus struct {
	LastSyncAt       *time.Time `json:"last_sync_at"`
	ServerPricelists int        `json:"server_pricelists"`
	LocalPricelists  int        `json:"local_pricelists"`
	NeedsSync        bool       `json:"needs_sync"`
}

// GetStatus returns the current sync status
func (s *Service) GetStatus() (*SyncStatus, error) {
	lastSync := s.localDB.GetLastSyncTime()

	// Count server pricelists
	serverPricelists, _, err := s.pricelistRepo.List(0, 1)
	if err != nil {
		return nil, fmt.Errorf("counting server pricelists: %w", err)
	}

	// Count local pricelists
	localCount := s.localDB.CountLocalPricelists()

	needsSync, _ := s.NeedSync()

	return &SyncStatus{
		LastSyncAt:       lastSync,
		ServerPricelists: len(serverPricelists),
		LocalPricelists:  int(localCount),
		NeedsSync:        needsSync,
	}, nil
}

// NeedSync checks if synchronization is needed
// Returns true if there are new pricelists on server or last sync was >1 hour ago
func (s *Service) NeedSync() (bool, error) {
	lastSync := s.localDB.GetLastSyncTime()

	// If never synced, need sync
	if lastSync == nil {
		return true, nil
	}

	// If last sync was more than 1 hour ago, suggest sync
	if time.Since(*lastSync) > time.Hour {
		return true, nil
	}

	// Check if there are new pricelists on server
	latestServer, err := s.pricelistRepo.GetLatestActive()
	if err != nil {
		// If no pricelists on server, no need to sync
		return false, nil
	}

	latestLocal, err := s.localDB.GetLatestLocalPricelist()
	if err != nil {
		// No local pricelists, need to sync
		return true, nil
	}

	// If server has newer pricelist, need sync
	if latestServer.ID != latestLocal.ServerID {
		return true, nil
	}

	return false, nil
}

// SyncPricelists synchronizes all active pricelists from server to local SQLite
func (s *Service) SyncPricelists() (int, error) {
	slog.Info("starting pricelist sync")

	// Get all active pricelists from server (up to 100)
	serverPricelists, _, err := s.pricelistRepo.List(0, 100)
	if err != nil {
		return 0, fmt.Errorf("getting server pricelists: %w", err)
	}

	synced := 0
	for _, pl := range serverPricelists {
		// Check if pricelist already exists locally
		existing, _ := s.localDB.GetLocalPricelistByServerID(pl.ID)
		if existing != nil {
			// Already synced, skip
			continue
		}

		// Create local pricelist
		localPL := &localdb.LocalPricelist{
			ServerID:  pl.ID,
			Version:   pl.Version,
			Name:      pl.Notification, // Using notification as name
			CreatedAt: pl.CreatedAt,
			SyncedAt:  time.Now(),
			IsUsed:    false,
		}

		if err := s.localDB.SaveLocalPricelist(localPL); err != nil {
			slog.Warn("failed to save local pricelist", "version", pl.Version, "error", err)
			continue
		}

		synced++
		slog.Debug("synced pricelist", "version", pl.Version, "server_id", pl.ID)
	}

	// Update last sync time
	s.localDB.SetLastSyncTime(time.Now())

	slog.Info("pricelist sync completed", "synced", synced, "total", len(serverPricelists))
	return synced, nil
}

// SyncPricelistItems synchronizes items for a specific pricelist
func (s *Service) SyncPricelistItems(localPricelistID uint) (int, error) {
	// Get local pricelist
	localPL, err := s.localDB.GetLocalPricelistByID(localPricelistID)
	if err != nil {
		return 0, fmt.Errorf("getting local pricelist: %w", err)
	}

	// Check if items already exist
	existingCount := s.localDB.CountLocalPricelistItems(localPricelistID)
	if existingCount > 0 {
		slog.Debug("pricelist items already synced", "pricelist_id", localPricelistID, "count", existingCount)
		return int(existingCount), nil
	}

	// Get items from server
	serverItems, _, err := s.pricelistRepo.GetItems(localPL.ServerID, 0, 10000, "")
	if err != nil {
		return 0, fmt.Errorf("getting server pricelist items: %w", err)
	}

	// Convert and save locally
	localItems := make([]localdb.LocalPricelistItem, len(serverItems))
	for i, item := range serverItems {
		localItems[i] = localdb.LocalPricelistItem{
			PricelistID: localPricelistID,
			LotName:     item.LotName,
			Price:       item.Price,
		}
	}

	if err := s.localDB.SaveLocalPricelistItems(localItems); err != nil {
		return 0, fmt.Errorf("saving local pricelist items: %w", err)
	}

	slog.Info("synced pricelist items", "pricelist_id", localPricelistID, "items", len(localItems))
	return len(localItems), nil
}

// SyncPricelistItemsByServerID syncs items for a pricelist by its server ID
func (s *Service) SyncPricelistItemsByServerID(serverPricelistID uint) (int, error) {
	localPL, err := s.localDB.GetLocalPricelistByServerID(serverPricelistID)
	if err != nil {
		return 0, fmt.Errorf("local pricelist not found for server ID %d", serverPricelistID)
	}
	return s.SyncPricelistItems(localPL.ID)
}

// GetLocalPriceForLot returns the price for a lot from a local pricelist
func (s *Service) GetLocalPriceForLot(localPricelistID uint, lotName string) (float64, error) {
	return s.localDB.GetLocalPriceForLot(localPricelistID, lotName)
}

// GetPricelistForOffline returns a pricelist suitable for offline use
// If items are not synced, it will sync them first
func (s *Service) GetPricelistForOffline(serverPricelistID uint) (*localdb.LocalPricelist, error) {
	// Ensure pricelist is synced
	localPL, err := s.localDB.GetLocalPricelistByServerID(serverPricelistID)
	if err != nil {
		// Try to sync pricelists first
		if _, err := s.SyncPricelists(); err != nil {
			return nil, fmt.Errorf("syncing pricelists: %w", err)
		}

		// Try again
		localPL, err = s.localDB.GetLocalPricelistByServerID(serverPricelistID)
		if err != nil {
			return nil, fmt.Errorf("pricelist not found on server: %w", err)
		}
	}

	// Ensure items are synced
	if _, err := s.SyncPricelistItems(localPL.ID); err != nil {
		return nil, fmt.Errorf("syncing pricelist items: %w", err)
	}

	return localPL, nil
}