package sync

import (
	"errors"
	"fmt"
	"time"

	"git.mchus.pro/mchus/priceforge/internal/localdb"
	"git.mchus.pro/mchus/priceforge/internal/repository"
	"gorm.io/gorm"
)

// ImportConfigurationsToLocal imports configurations from MariaDB into local SQLite.
// Existing local configs with pending local changes are skipped to avoid data loss.
func (s *Service) ImportConfigurationsToLocal() (*ConfigImportResult, error) {
	mariaDB, err := s.getDB()
	if err != nil {
		return nil, ErrOffline
	}

	configRepo := repository.NewConfigurationRepository(mariaDB)
	result := &ConfigImportResult{}

	offset := 0
	const limit = 200
	for {
		serverConfigs, _, err := configRepo.ListAll(offset, limit)
		if err != nil {
			return nil, fmt.Errorf("listing server configurations: %w", err)
		}
		if len(serverConfigs) == 0 {
			break
		}

		for i := range serverConfigs {
			cfg := serverConfigs[i]
			existing, err := s.localDB.GetConfigurationByUUID(cfg.UUID)
			if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
				return nil, fmt.Errorf("getting local configuration %s: %w", cfg.UUID, err)
			}

			if existing != nil && err == nil && existing.SyncStatus == "pending" {
				result.Skipped++
				continue
			}
			if existing != nil && err == nil && !existing.IsActive {
				// Keep local deactivation sticky: do not resurrect hidden entries from server pull.
				result.Skipped++
				continue
			}

			localCfg := localdb.ConfigurationToLocal(&cfg)
			now := time.Now()
			localCfg.SyncedAt = &now
			localCfg.SyncStatus = "synced"
			localCfg.UpdatedAt = now

			if existing != nil && err == nil {
				localCfg.ID = existing.ID
				result.Updated++
			} else {
				result.Imported++
			}

			if err := s.localDB.SaveConfiguration(localCfg); err != nil {
				return nil, fmt.Errorf("saving local configuration %s: %w", cfg.UUID, err)
			}
		}

		offset += len(serverConfigs)
	}

	return result, nil
}

// ImportProjectsToLocal imports projects from MariaDB into local SQLite.
// Existing local projects with pending local changes are skipped to avoid data loss.
func (s *Service) ImportProjectsToLocal() (*ProjectImportResult, error) {
	mariaDB, err := s.getDB()
	if err != nil {
		return nil, ErrOffline
	}

	projectRepo := repository.NewProjectRepository(mariaDB)
	result := &ProjectImportResult{}

	offset := 0
	const limit = 200
	for {
		serverProjects, _, err := projectRepo.List(offset, limit, true)
		if err != nil {
			return nil, fmt.Errorf("listing server projects: %w", err)
		}
		if len(serverProjects) == 0 {
			break
		}

		now := time.Now()
		for i := range serverProjects {
			project := serverProjects[i]

			existing, getErr := s.localDB.GetProjectByUUID(project.UUID)
			if getErr != nil && !errors.Is(getErr, gorm.ErrRecordNotFound) {
				return nil, fmt.Errorf("getting local project %s: %w", project.UUID, getErr)
			}

			if existing != nil && getErr == nil {
				// Keep unsynced local changes intact.
				if existing.SyncStatus == "pending" {
					result.Skipped++
					continue
				}

				existing.OwnerUsername = project.OwnerUsername
				existing.Name = project.Name
				existing.TrackerURL = project.TrackerURL
				existing.IsActive = project.IsActive
				existing.IsSystem = project.IsSystem
				existing.CreatedAt = project.CreatedAt
				existing.UpdatedAt = project.UpdatedAt
				serverID := project.ID
				existing.ServerID = &serverID
				existing.SyncStatus = "synced"
				existing.SyncedAt = &now

				if err := s.localDB.SaveProject(existing); err != nil {
					return nil, fmt.Errorf("saving local project %s: %w", project.UUID, err)
				}
				result.Updated++
				continue
			}

			localProject := localdb.ProjectToLocal(&project)
			localProject.SyncStatus = "synced"
			localProject.SyncedAt = &now
			if err := s.localDB.SaveProject(localProject); err != nil {
				return nil, fmt.Errorf("saving local project %s: %w", project.UUID, err)
			}
			result.Imported++
		}

		offset += len(serverProjects)
	}

	return result, nil
}