package sync

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

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

// PullPartnumberBooks synchronizes partnumber book snapshots from MariaDB to local SQLite.
// It only pulls books that don't exist locally yet (append-only).
func (s *Service) PullPartnumberBooks() (int, error) {
	slog.Info("starting partnumber book pull")

	mariaDB, err := s.getDB()
	if err != nil {
		return 0, fmt.Errorf("database not available: %w", err)
	}

	localBookRepo := repository.NewPartnumberBookRepository(s.localDB.DB())

	// Query server for all active partnumber books
	type serverBook struct {
		ID        int       `gorm:"column:id"`
		Version   string    `gorm:"column:version"`
		CreatedAt time.Time `gorm:"column:created_at"`
		IsActive  bool      `gorm:"column:is_active"`
	}
	var serverBooks []serverBook
	if err := mariaDB.Raw("SELECT id, version, created_at, is_active FROM qt_partnumber_books WHERE is_active = 1 ORDER BY created_at DESC, id DESC").Scan(&serverBooks).Error; err != nil {
		return 0, fmt.Errorf("querying server partnumber books: %w", err)
	}

	pulled := 0
	for _, sb := range serverBooks {
		// Check if already exists locally
		var existing localdb.LocalPartnumberBook
		err := s.localDB.DB().Where("server_id = ?", sb.ID).First(&existing).Error
		if err == nil {
			// Already exists
			continue
		}

		// Save the book
		localBook := &localdb.LocalPartnumberBook{
			ServerID:  sb.ID,
			Version:   sb.Version,
			CreatedAt: sb.CreatedAt,
			IsActive:  sb.IsActive,
		}
		if err := localBookRepo.SaveBook(localBook); err != nil {
			slog.Warn("failed to save local partnumber book", "server_id", sb.ID, "error", err)
			continue
		}

		// Pull items for this book
		type serverItem struct {
			Partnumber  string `gorm:"column:partnumber"`
			LotName     string `gorm:"column:lot_name"`
			IsPrimaryPN bool   `gorm:"column:is_primary_pn"`
			Description string `gorm:"column:description"`
		}
		var serverItems []serverItem
		if err := mariaDB.Raw("SELECT partnumber, lot_name, is_primary_pn, description FROM qt_partnumber_book_items WHERE book_id = ?", sb.ID).Scan(&serverItems).Error; err != nil {
			slog.Warn("failed to query server partnumber book items", "book_id", sb.ID, "error", err)
			continue
		}

		localItems := make([]localdb.LocalPartnumberBookItem, 0, len(serverItems))
		for _, si := range serverItems {
			localItems = append(localItems, localdb.LocalPartnumberBookItem{
				BookID:      localBook.ID,
				Partnumber:  si.Partnumber,
				LotName:     si.LotName,
				IsPrimaryPN: si.IsPrimaryPN,
				Description: si.Description,
			})
		}
		if err := localBookRepo.SaveBookItems(localItems); err != nil {
			slog.Warn("failed to save local partnumber book items", "book_id", localBook.ID, "error", err)
			continue
		}

		slog.Info("pulled partnumber book", "version", sb.Version, "items", len(localItems))
		pulled++
	}

	slog.Info("partnumber book pull completed", "pulled", pulled)
	return pulled, nil
}