package service

import (
	"bugulma/backend/internal/domain"
	"bugulma/backend/internal/localization"
	"context"
	"fmt"
	"time"
)

// Note: SupportedLocales and DefaultLocale are defined in i18n_service.go
// They are shared constants used across all i18n-related services

// LocalizationService implements the domain.LocalizationService interface
type LocalizationService struct {
	repo domain.LocalizationRepository
}

// NewLocalizationService creates a new localization service
func NewLocalizationService(repo domain.LocalizationRepository) domain.LocalizationService {
	return &LocalizationService{repo: repo}
}

// GetLocalizedValue retrieves a localized value for a specific entity field and locale
func (s *LocalizationService) GetLocalizedValue(entityType, entityID, field, locale string) (string, error) {
	return s.GetLocalizedValueWithContext(context.Background(), entityType, entityID, field, locale)
}

// GetLocalizedValueWithContext retrieves a localized value with context support
func (s *LocalizationService) GetLocalizedValueWithContext(ctx context.Context, entityType, entityID, field, locale string) (string, error) {
	if entityType == "" || entityID == "" || field == "" || locale == "" {
		return "", fmt.Errorf("all parameters (entityType, entityID, field, locale) are required")
	}

	// Validate locale
	if !s.isValidLocale(locale) {
		return "", fmt.Errorf("invalid locale: %s. Supported locales: ru, en, tt", locale)
	}

	loc, err := s.repo.GetByEntityAndField(ctx, entityType, entityID, field, locale)
	if err != nil {
		return "", fmt.Errorf("failed to retrieve localization: %w", err)
	}

	if loc == nil {
		return "", nil // No localization found
	}

	return loc.Value, nil
}

// SetLocalizedValue sets or updates a localized value for a specific entity field and locale
func (s *LocalizationService) SetLocalizedValue(entityType, entityID, field, locale, value string) error {
	return s.SetLocalizedValueWithContext(context.Background(), entityType, entityID, field, locale, value)
}

// SetLocalizedValueWithContext sets or updates a localized value with context support
func (s *LocalizationService) SetLocalizedValueWithContext(ctx context.Context, entityType, entityID, field, locale, value string) error {
	if entityType == "" || entityID == "" || field == "" || locale == "" {
		return fmt.Errorf("all parameters (entityType, entityID, field, locale) are required")
	}

	// Validate locale
	if !s.isValidLocale(locale) {
		return fmt.Errorf("invalid locale: %s. Supported locales: ru, en, tt", locale)
	}

	// Validate entity type and field combination
	if !s.isValidEntityField(entityType, field) {
		return fmt.Errorf("invalid field '%s' for entity type '%s'", field, entityType)
	}

	// Check if localization already exists
	existing, err := s.repo.GetByEntityAndField(ctx, entityType, entityID, field, locale)
	if err != nil {
		return fmt.Errorf("failed to check existing localization: %w", err)
	}

	now := time.Now()

	if existing != nil {
		// Update existing
		existing.Value = value
		existing.UpdatedAt = now
		return s.repo.Update(ctx, existing)
	} else {
		// Create new
		loc := &domain.Localization{
			EntityType: entityType,
			EntityID:   entityID,
			Field:      field,
			Locale:     locale,
			Value:      value,
			CreatedAt:  now,
			UpdatedAt:  now,
		}
		return s.repo.Create(ctx, loc)
	}
}

// GetAllLocalizedValues retrieves all localized values for a specific entity
func (s *LocalizationService) GetAllLocalizedValues(entityType, entityID string) (map[string]map[string]string, error) {
	return s.GetAllLocalizedValuesWithContext(context.Background(), entityType, entityID)
}

// GetAllLocalizedValuesWithContext retrieves all localized values with context support
func (s *LocalizationService) GetAllLocalizedValuesWithContext(ctx context.Context, entityType, entityID string) (map[string]map[string]string, error) {
	if entityType == "" || entityID == "" {
		return nil, fmt.Errorf("entityType and entityID are required")
	}

	localizations, err := s.repo.GetAllByEntity(ctx, entityType, entityID)
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve localizations: %w", err)
	}

	result := make(map[string]map[string]string)
	for _, loc := range localizations {
		if result[loc.Field] == nil {
			result[loc.Field] = make(map[string]string)
		}
		result[loc.Field][loc.Locale] = loc.Value
	}

	return result, nil
}

// GetLocalizedEntity retrieves an entity with all its fields localized for a specific locale
func (s *LocalizationService) GetLocalizedEntity(entityType, entityID, locale string) (map[string]string, error) {
	return s.GetLocalizedEntityWithContext(context.Background(), entityType, entityID, locale)
}

// GetLocalizedEntityWithContext retrieves an entity with all its fields localized with context support
func (s *LocalizationService) GetLocalizedEntityWithContext(ctx context.Context, entityType, entityID, locale string) (map[string]string, error) {
	if entityType == "" || entityID == "" || locale == "" {
		return nil, fmt.Errorf("all parameters (entityType, entityID, locale) are required")
	}

	if !s.isValidLocale(locale) {
		return nil, fmt.Errorf("invalid locale: %s. Supported locales: ru, en, tt", locale)
	}

	localizations, err := s.repo.GetAllByEntity(ctx, entityType, entityID)
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve localizations: %w", err)
	}

	result := make(map[string]string)
	for _, loc := range localizations {
		if loc.Locale == locale {
			result[loc.Field] = loc.Value
		}
	}

	return result, nil
}

// GetSupportedLocalesForEntity returns all locales that have translations for a specific entity
func (s *LocalizationService) GetSupportedLocalesForEntity(entityType, entityID string) ([]string, error) {
	return s.GetSupportedLocalesForEntityWithContext(context.Background(), entityType, entityID)
}

// GetSupportedLocalesForEntityWithContext returns all locales with context support
func (s *LocalizationService) GetSupportedLocalesForEntityWithContext(ctx context.Context, entityType, entityID string) ([]string, error) {
	if entityType == "" || entityID == "" {
		return nil, fmt.Errorf("entityType and entityID are required")
	}

	return s.repo.GetSupportedLocalesForEntity(ctx, entityType, entityID)
}

// DeleteLocalizedValue deletes a specific localization
func (s *LocalizationService) DeleteLocalizedValue(entityType, entityID, field, locale string) error {
	return s.DeleteLocalizedValueWithContext(context.Background(), entityType, entityID, field, locale)
}

// DeleteLocalizedValueWithContext deletes a specific localization with context support
func (s *LocalizationService) DeleteLocalizedValueWithContext(ctx context.Context, entityType, entityID, field, locale string) error {
	if entityType == "" || entityID == "" || field == "" || locale == "" {
		return fmt.Errorf("all parameters (entityType, entityID, field, locale) are required")
	}

	loc, err := s.repo.GetByEntityAndField(ctx, entityType, entityID, field, locale)
	if err != nil {
		return fmt.Errorf("failed to find localization: %w", err)
	}

	if loc == nil {
		return fmt.Errorf("localization not found")
	}

	return s.repo.Delete(ctx, loc.ID)
}

// BulkSetLocalizedValues sets multiple localized values in a single operation
func (s *LocalizationService) BulkSetLocalizedValues(entityType, entityID string, values map[string]map[string]string) error {
	return s.BulkSetLocalizedValuesWithContext(context.Background(), entityType, entityID, values)
}

// BulkSetLocalizedValuesWithContext sets multiple localized values with context support
func (s *LocalizationService) BulkSetLocalizedValuesWithContext(ctx context.Context, entityType, entityID string, values map[string]map[string]string) error {
	if entityType == "" || entityID == "" {
		return fmt.Errorf("entityType and entityID are required")
	}

	if len(values) == 0 {
		return nil
	}

	var localizations []*domain.Localization
	now := time.Now()

	for field, localeValues := range values {
		for locale, value := range localeValues {
			if !s.isValidLocale(locale) {
				return fmt.Errorf("invalid locale: %s for field %s", locale, field)
			}
			if !s.isValidEntityField(entityType, field) {
				return fmt.Errorf("invalid field '%s' for entity type '%s'", field, entityType)
			}

			loc := &domain.Localization{
				EntityType: entityType,
				EntityID:   entityID,
				Field:      field,
				Locale:     locale,
				Value:      value,
				CreatedAt:  now,
				UpdatedAt:  now,
			}
			localizations = append(localizations, loc)
		}
	}

	// First delete existing localizations for these fields/locales
	for _, loc := range localizations {
		existing, _ := s.repo.GetByEntityAndField(ctx, loc.EntityType, loc.EntityID, loc.Field, loc.Locale)
		if existing != nil {
			s.repo.Delete(ctx, existing.ID) // Ignore errors, continue with creation
		}
	}

	return s.repo.BulkCreate(ctx, localizations)
}

// GetAllLocales returns all available locales in the system
func (s *LocalizationService) GetAllLocales() ([]string, error) {
	return s.GetAllLocalesWithContext(context.Background())
}

// GetAllLocalesWithContext returns all available locales with context support
func (s *LocalizationService) GetAllLocalesWithContext(ctx context.Context) ([]string, error) {
	return s.repo.GetAllLocales(ctx)
}

// SearchLocalizations searches for localizations containing specific text
func (s *LocalizationService) SearchLocalizations(query, locale string, limit int) ([]*domain.Localization, error) {
	return s.SearchLocalizationsWithContext(context.Background(), query, locale, limit)
}

// SearchLocalizationsWithContext searches for localizations with context support
func (s *LocalizationService) SearchLocalizationsWithContext(ctx context.Context, query, locale string, limit int) ([]*domain.Localization, error) {
	if query == "" {
		return nil, fmt.Errorf("search query cannot be empty")
	}

	if locale != "" && !s.isValidLocale(locale) {
		return nil, fmt.Errorf("invalid locale: %s", locale)
	}

	if limit <= 0 {
		limit = 50 // Default limit
	}
	if limit > 1000 {
		limit = 1000 // Max limit
	}

	return s.repo.SearchLocalizations(ctx, query, locale, limit)
}

// Helper methods for validation

func (s *LocalizationService) isValidLocale(locale string) bool {
	// Use the centralized locale constants from I18nService
	for _, supported := range SupportedLocales {
		if supported == locale {
			return true
		}
	}
	return false
}

func (s *LocalizationService) isValidEntityField(entityType, field string) bool {
	// Use registry to get valid fields for the entity type
	fields := localization.GetFieldsForEntityType(entityType)
	for _, f := range fields {
		if f == field {
			return true
		}
	}
	return false
}

// ApplyLocalizationToEntity applies localization to a localizable entity for a specific locale
func (s *LocalizationService) ApplyLocalizationToEntity(entity domain.Localizable, locale string) error {
	return s.ApplyLocalizationToEntityWithContext(context.Background(), entity, locale)
}

// ApplyLocalizationToEntityWithContext applies localization with context support
func (s *LocalizationService) ApplyLocalizationToEntityWithContext(ctx context.Context, entity domain.Localizable, locale string) error {
	if entity == nil {
		return fmt.Errorf("entity cannot be nil")
	}

	if locale == "ru" {
		// Russian is the primary language, no localization needed
		return nil
	}

	if !s.isValidLocale(locale) {
		return fmt.Errorf("invalid locale: %s", locale)
	}

	localizations, err := s.GetAllLocalizedValuesWithContext(ctx, entity.GetEntityType(), entity.GetEntityID())
	if err != nil {
		return fmt.Errorf("failed to get localizations: %w", err)
	}

	// Apply localizations based on entity type
	switch e := entity.(type) {
	case *domain.Site:
		if name, ok := localizations["name"][locale]; ok && name != "" {
			e.Name = name
		}
		if notes, ok := localizations["notes"][locale]; ok && notes != "" {
			e.Notes = notes
		}
		if builderOwner, ok := localizations["builder_owner"][locale]; ok && builderOwner != "" {
			e.BuilderOwner = builderOwner
		}
		if architect, ok := localizations["architect"][locale]; ok && architect != "" {
			e.Architect = architect
		}
		if originalPurpose, ok := localizations["original_purpose"][locale]; ok && originalPurpose != "" {
			e.OriginalPurpose = originalPurpose
		}
		if currentUse, ok := localizations["current_use"][locale]; ok && currentUse != "" {
			e.CurrentUse = currentUse
		}
		if style, ok := localizations["style"][locale]; ok && style != "" {
			e.Style = style
		}
		if materials, ok := localizations["materials"][locale]; ok && materials != "" {
			e.Materials = materials
		}
	case *domain.Organization:
		if name, ok := localizations["name"][locale]; ok && name != "" {
			e.Name = name
		}
		if description, ok := localizations["description"][locale]; ok && description != "" {
			e.Description = description
		}
	case *domain.User:
		if name, ok := localizations["name"][locale]; ok && name != "" {
			e.Name = name
		}
	}

	return nil
}