package tender

import (
	"context"
	"fmt"
	"strings"
	"sync"

	"go.mongodb.org/mongo-driver/v2/bson"
	"golang.org/x/sync/errgroup"

	"tm/pkg/ai_summarizer"
)

type rankedRecommendedTender struct {
	tender    Tender
	rank      int
	analysis  string
	tenderRef string
}

type recommendationTranslationCache struct {
	mu    sync.Mutex
	items map[string]ai_summarizer.StoredTranslation
}

func newRecommendationTranslationCache() *recommendationTranslationCache {
	return &recommendationTranslationCache{
		items: make(map[string]ai_summarizer.StoredTranslation),
	}
}

func recommendationTranslationCacheKey(tenderID, language string) string {
	return strings.TrimSpace(tenderID) + "|" + strings.TrimSpace(language)
}

func (c *recommendationTranslationCache) get(tenderID, language string) (ai_summarizer.StoredTranslation, bool) {
	if c == nil {
		return ai_summarizer.StoredTranslation{}, false
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	stored, ok := c.items[recommendationTranslationCacheKey(tenderID, language)]
	return stored, ok
}

func (c *recommendationTranslationCache) set(tenderID, language string, stored ai_summarizer.StoredTranslation) {
	if c == nil {
		return
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	c.items[recommendationTranslationCacheKey(tenderID, language)] = stored
}

// buildRecommendedTenderListResponses builds list responses without MinIO translation lookups.
// Recommendation pages use MongoDB text; tender detail endpoints still enrich from storage.
func (s *tenderService) buildRecommendedTenderListResponses(items []rankedRecommendedTender, language string) []TenderResponse {
	if len(items) == 0 {
		return nil
	}

	out := make([]TenderResponse, len(items))
	for i, item := range items {
		resp := item.tender.ToResponseWithLanguage(language)
		resp.Rank = item.rank
		resp.Analysis = item.analysis
		resp.ProcedureRef = item.tenderRef
		out[i] = *resp
	}
	return out
}

func (s *tenderService) enrichRecommendedTenderResponsesParallel(ctx context.Context, responses []TenderResponse, language string) []TenderResponse {
	if len(responses) == 0 || s.aiSummarizerStorage == nil {
		return responses
	}

	out := make([]TenderResponse, len(responses))
	if len(responses) == 1 {
		out[0] = s.enrichRecommendedTenderResponse(ctx, responses[0], language, newRecommendationTranslationCache())
		return out
	}

	translationCache := newRecommendationTranslationCache()
	group, groupCtx := errgroup.WithContext(ctx)
	group.SetLimit(recommendationPageCacheConcurrency)

	for i := range responses {
		i := i
		group.Go(func() error {
			out[i] = s.enrichRecommendedTenderResponse(groupCtx, responses[i], language, translationCache)
			return nil
		})
	}

	if err := group.Wait(); err != nil {
		for i, resp := range responses {
			out[i] = s.enrichRecommendedTenderResponse(ctx, resp, language, translationCache)
		}
	}

	return out
}

func (s *tenderService) enrichRecommendedTenderResponse(
	ctx context.Context,
	resp TenderResponse,
	language string,
	cache *recommendationTranslationCache,
) TenderResponse {
	enriched := resp
	tender := tenderFromRecommendationResponse(resp)
	s.enrichWithTranslationTimeout(
		ctx,
		&tender,
		&enriched,
		language,
		cache,
		recommendTranslationEnrichmentTimeout,
	)
	return enriched
}

func tenderFromRecommendationResponse(item TenderResponse) Tender {
	var tender Tender
	if id, err := bson.ObjectIDFromHex(strings.TrimSpace(item.ID)); err == nil {
		tender.ID = id
	}
	tender.ContractFolderID = item.ContractFolderID
	tender.NoticePublicationID = item.NoticePublicationID
	tender.RelatedNoticePublicationIDs = append([]string(nil), item.RelatedNoticePublicationIDs...)
	tender.Status = item.Status
	tender.PublicationDate = item.PublicationDate
	tender.SubmissionDeadline = item.SubmissionDeadline
	tender.TenderDeadline = item.TenderDeadline
	return tender
}

func (s *tenderService) loadRecommendationExclusions(
	ctx context.Context,
	form *SearchForm,
	companyID string,
	companyIDs []string,
) (map[string]struct{}, map[string]map[string]struct{}, error) {
	if !form.ExcludeRejectedTenders {
		return nil, nil, nil
	}

	if len(companyIDs) > 0 {
		excludedByCompany, err := s.buildRejectedTenderIDSetsForCompanies(ctx, companyIDs)
		if err != nil {
			return nil, nil, fmt.Errorf("failed to build recommendation exclusions: %w", err)
		}
		return nil, excludedByCompany, nil
	}

	excluded, err := s.buildRejectedTenderIDSet(ctx, companyID)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to build recommendation exclusions: %w", err)
	}
	return excluded, nil, nil
}