tercul-backend/internal/platform/search/weaviate_wrapper.go

package search

import (
	"context"
	"fmt"
	"log"
	"strconv"
	"tercul/internal/domain"
	domainsearch "tercul/internal/domain/search"
	"time"

	"github.com/weaviate/weaviate-go-client/v5/weaviate"
	"github.com/weaviate/weaviate-go-client/v5/weaviate/filters"
	"github.com/weaviate/weaviate-go-client/v5/weaviate/graphql"
)

type WeaviateWrapper interface {
	Search(ctx context.Context, params domainsearch.SearchParams) (*domain.SearchResults, error)
	IndexWork(ctx context.Context, work *domain.Work, content string) error
}

type weaviateWrapper struct {
	client      *weaviate.Client
	host        string
	searchAlpha float64
}

func NewWeaviateWrapper(client *weaviate.Client, host string, searchAlpha float64) WeaviateWrapper {
	return &weaviateWrapper{client: client, host: host, searchAlpha: searchAlpha}
}

const (
	DefaultLimit = 20
	MaxLimit     = 100
)

const (
	WorkClass        = "Work"
	AuthorClass      = "Author"
	TranslationClass = "Translation"
)

func sanitizeLimitOffset(limit, offset int) (int, int) {
	if limit <= 0 {
		limit = DefaultLimit
	}
	if limit > MaxLimit {
		limit = MaxLimit
	}
	if offset < 0 {
		offset = 0
	}
	return limit, offset
}

func (w *weaviateWrapper) hybridAlpha() float32 {
	if w.searchAlpha < 0 {
		return 0
	}
	if w.searchAlpha > 1 {
		return 1
	}
	return float32(w.searchAlpha)
}

func (w *weaviateWrapper) Search(ctx context.Context, params domainsearch.SearchParams) (*domain.SearchResults, error) {
	results := &domain.SearchResults{
		Works:        []domain.Work{},
		Translations: []domain.Translation{},
		Authors:      []domain.Author{},
	}

	limit, offset := sanitizeLimitOffset(params.Limit, params.Offset)

	workFields := []graphql.Field{
		{Name: "title"}, {Name: "description"}, {Name: "language"}, {Name: "status"}, {Name: "publishedAt"},
		{Name: "_additional", Fields: []graphql.Field{{Name: "id"}, {Name: "score"}, {Name: "meta", Fields: []graphql.Field{{Name: "count"}}}}},
	}
	authorFields := []graphql.Field{
		{Name: "name"},
		{Name: "_additional", Fields: []graphql.Field{{Name: "id"}, {Name: "score"}, {Name: "meta", Fields: []graphql.Field{{Name: "count"}}}}},
	}
	translationFields := []graphql.Field{
		{Name: "title"}, {Name: "language"},
		{Name: "_additional", Fields: []graphql.Field{{Name: "id"}, {Name: "score"}, {Name: "meta", Fields: []graphql.Field{{Name: "count"}}}}},
	}

	searcher := w.client.GraphQL().Get().
		WithFields(graphql.Field{Name: "... on Work", Fields: workFields}).
		WithFields(graphql.Field{Name: "... on Author", Fields: authorFields}).
		WithFields(graphql.Field{Name: "... on Translation", Fields: translationFields}).
		WithLimit(limit).
		WithOffset(offset)

	switch params.Mode {
	case domainsearch.SearchModeHybrid:
		hybrid := w.client.GraphQL().HybridArgumentBuilder().
			WithQuery(params.Query).
			WithAlpha(w.hybridAlpha()).
			WithProperties([]string{"title", "description", "name"})
		searcher.WithHybrid(hybrid)
	case domainsearch.SearchModeBM25:
		bm25 := w.client.GraphQL().Bm25ArgBuilder().
			WithQuery(params.Query).
			WithProperties([]string{"title", "description", "name"}...)
		searcher.WithBM25(bm25)
	}

	response, err := searcher.Do(ctx)
	if err != nil {
		return nil, err
	}

	get, ok := response.Data["Get"].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("invalid response data")
	}

	for className, classData := range get {
		for _, item := range classData.([]interface{}) {
			itemMap, ok := item.(map[string]interface{})
			if !ok {
				continue
			}
			switch className {
			case "Work":
				work, err := mapToWork(itemMap)
				if err != nil {
					log.Printf("Error mapping work: %v", err)
					continue
				}
				results.Works = append(results.Works, work)
			case "Author":
				author, err := mapToAuthor(itemMap)
				if err != nil {
					log.Printf("Error mapping author: %v", err)
					continue
				}
				results.Authors = append(results.Authors, author)
			case "Translation":
				translation, err := mapToTranslation(itemMap)
				if err != nil {
					log.Printf("Error mapping translation: %v", err)
					continue
				}
				results.Translations = append(results.Translations, translation)
			}
		}
	}

	meta, ok := response.Data["Meta"].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("invalid meta data")
	}
	count, ok := meta["count"].(float64)
	if !ok {
		return nil, fmt.Errorf("invalid count data")
	}
	results.Total = int64(count)

	return results, nil
}


func (w *weaviateWrapper) buildWhereFilter(searchFilters domain.SearchFilters, className string) *filters.WhereBuilder {
	operands := make([]*filters.WhereBuilder, 0)

	if len(searchFilters.Languages) > 0 {
		operands = append(operands, filters.Where().
			WithPath([]string{"language"}).
			WithOperator(filters.ContainsAny).
			WithValueText(searchFilters.Languages...))
	}

	if className == "Work" {
		if searchFilters.DateFrom != nil {
			operands = append(operands, filters.Where().
				WithPath([]string{"publishedAt"}).
				WithOperator(filters.GreaterThanEqual).
				WithValueDate(*searchFilters.DateFrom))
		}

		if searchFilters.DateTo != nil {
			operands = append(operands, filters.Where().
				WithPath([]string{"publishedAt"}).
				WithOperator(filters.LessThanEqual).
				WithValueDate(*searchFilters.DateTo))
		}

		if len(searchFilters.Authors) > 0 {
			authorOperands := make([]*filters.WhereBuilder, len(searchFilters.Authors))
			for i, author := range searchFilters.Authors {
				authorOperands[i] = filters.Where().
					WithPath([]string{"authors", "Author", "id"}).
					WithOperator(filters.Equal).
					WithValueText(fmt.Sprintf("weaviate://%s/Author/%s", w.host, author))
			}
			operands = append(operands, filters.Where().WithOperator(filters.Or).WithOperands(authorOperands))
		}

		if len(searchFilters.Tags) > 0 {
			tagOperands := make([]*filters.WhereBuilder, len(searchFilters.Tags))
			for i, tag := range searchFilters.Tags {
				tagOperands[i] = filters.Where().
					WithPath([]string{"tags", "Tag", "name"}).
					WithOperator(filters.Equal).
					WithValueText(tag)
			}
			operands = append(operands, filters.Where().WithOperator(filters.Or).WithOperands(tagOperands))
		}

		if len(searchFilters.Categories) > 0 {
			categoryOperands := make([]*filters.WhereBuilder, len(searchFilters.Categories))
			for i, category := range searchFilters.Categories {
				categoryOperands[i] = filters.Where().
					WithPath([]string{"categories", "Category", "name"}).
					WithOperator(filters.Equal).
					WithValueText(category)
			}
			operands = append(operands, filters.Where().WithOperator(filters.Or).WithOperands(categoryOperands))
		}
	}

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

	return filters.Where().WithOperator(filters.And).WithOperands(operands)
}

func mapToWork(data map[string]interface{}) (domain.Work, error) {
	work := domain.Work{}

	additional, ok := data["_additional"].(map[string]interface{})
	if !ok {
		return work, fmt.Errorf("missing _additional field")
	}

	idStr, ok := additional["id"].(string)
	if !ok {
		return work, fmt.Errorf("missing or invalid id")
	}
	id, err := strconv.ParseUint(idStr, 10, 64)
	if err != nil {
		return work, fmt.Errorf("failed to parse id: %w", err)
	}
	work.ID = uint(id)

	if title, ok := data["title"].(string); ok {
		work.Title = title
	}
	if description, ok := data["description"].(string); ok {
		work.Description = description
	}
	if language, ok := data["language"].(string); ok {
		work.Language = language
	}
	if status, ok := data["status"].(string); ok {
		work.Status = domain.WorkStatus(status)
	}
	if publishedAtStr, ok := data["publishedAt"].(string); ok {
		publishedAt, err := time.Parse(time.RFC3339, publishedAtStr)
		if err == nil {
			work.PublishedAt = &publishedAt
		}
	}
	if score, ok := additional["score"].(float64); ok {
		work.Score = score
	}

	return work, nil
}

func mapToAuthor(data map[string]interface{}) (domain.Author, error) {
	author := domain.Author{}

	additional, ok := data["_additional"].(map[string]interface{})
	if !ok {
		return author, fmt.Errorf("missing _additional field")
	}

	idStr, ok := additional["id"].(string)
	if !ok {
		return author, fmt.Errorf("missing or invalid id")
	}
	id, err := strconv.ParseUint(idStr, 10, 64)
	if err != nil {
		return author, fmt.Errorf("failed to parse id: %w", err)
	}
	author.ID = uint(id)

	if name, ok := data["name"].(string); ok {
		author.Name = name
	}
	if score, ok := additional["score"].(float64); ok {
		author.Score = score
	}

	return author, nil
}

func mapToTranslation(data map[string]interface{}) (domain.Translation, error) {
	translation := domain.Translation{}

	additional, ok := data["_additional"].(map[string]interface{})
	if !ok {
		return translation, fmt.Errorf("missing _additional field")
	}

	idStr, ok := additional["id"].(string)
	if !ok {
		return translation, fmt.Errorf("missing or invalid id")
	}
	id, err := strconv.ParseUint(idStr, 10, 64)
	if err != nil {
		return translation, fmt.Errorf("failed to parse id: %w", err)
	}
	translation.ID = uint(id)

	if title, ok := data["title"].(string); ok {
		translation.Title = title
	}
	if language, ok := data["language"].(string); ok {
		translation.Language = language
	}
	if score, ok := additional["score"].(float64); ok {
		translation.Score = score
	}

	return translation, nil
}


func (w *weaviateWrapper) IndexWork(ctx context.Context, work *domain.Work, content string) error {
	properties := map[string]interface{}{
		"language":    work.Language,
		"title":       work.Title,
		"description": work.Description,
		"status":      work.Status,
		"createdAt":   work.CreatedAt.Format(time.RFC3339),
		"updatedAt":   work.UpdatedAt.Format(time.RFC3339),
	}
	if content != "" {
		properties["content"] = content
	}

	_, err := w.client.Data().Creator().
		WithClassName("Work").
		WithID(fmt.Sprintf("%d", work.ID)).
		WithProperties(properties).
		Do(ctx)

	return err
}