package tender

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"
	"tm/internal/company"
	"tm/internal/customer"
	"tm/pkg/ai_summarizer"
	"tm/pkg/logger"
	"tm/pkg/response"
)

// AISummarizerClient defines the interface for on-demand AI summarization
type AISummarizerClient interface {
	FetchSummaryOnDemand(ctx context.Context, reqBody ai_summarizer.SummarizeRequest) (*ai_summarizer.SummarizeResponse, error)
}

// AISummarizerStorage defines the interface for fetching summaries from MinIO storage
type AISummarizerStorage interface {
	GetSummaryFromStorage(ctx context.Context, noticeID string) (string, error)
}

// TenderService interface defines tender business logic operations
type Service interface {
	// Tender operations
	GetByID(ctx context.Context, id string) (*TenderResponse, error)
	Update(ctx context.Context, req UpdateTenderRequest) (*TenderResponse, error)
	Delete(ctx context.Context, id string) error
	Search(ctx context.Context, req *SearchForm, pagination *response.Pagination) (*SearchResponse, error)
	Recommend(ctx context.Context, form *SearchForm, pagination *response.Pagination) (*SearchResponse, error)
	GetDocumentSummaries(ctx context.Context, id string) ([]DocumentSummary, error)

	// AI summarization operations
	GetAISummary(ctx context.Context, id string) (*AISummaryResponse, error)
	TriggerAISummarize(ctx context.Context, id string) (*AISummarizeResponse, error)
	GetAllAISummaries(ctx context.Context) ([]ai_summarizer.TenderSummaryItem, error)

	// Maintenance operations
	UpdateExpiredTenders(ctx context.Context) error
	CleanupOldData(ctx context.Context, olderThan time.Duration, pagination *response.Pagination) error
}

// tenderService implements TenderService interface
type tenderService struct {
	repository          TenderRepository
	companyService      company.Service
	customerService     customer.Service
	logger              logger.Logger
	aiSummarizerClient  AISummarizerClient
	aiSummarizerStorage AISummarizerStorage
}

// NewService creates a new tender service
func NewService(repository TenderRepository, companyService company.Service, customerService customer.Service, logger logger.Logger, aiClient AISummarizerClient, aiStorage AISummarizerStorage) Service {
	return &tenderService{
		repository:          repository,
		companyService:      companyService,
		customerService:     customerService,
		logger:              logger,
		aiSummarizerClient:  aiClient,
		aiSummarizerStorage: aiStorage,
	}
}

// GetTenderByID retrieves a tender by ID
func (s *tenderService) GetByID(ctx context.Context, id string) (*TenderResponse, error) {
	s.logger.Info("Retrieving tender by ID", map[string]interface{}{
		"tender_id": id,
	})

	tender, err := s.repository.GetByID(ctx, id)
	if err != nil {
		s.logger.Error("Failed to retrieve tender", map[string]interface{}{
			"tender_id": id,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to retrieve tender: %w", err)
	}

	resp := tender.ToResponse()

	// Enrich with AI summary from MinIO storage (best-effort, non-blocking)
	s.enrichWithAISummary(ctx, resp)

	return resp, nil
}

// enrichWithAISummary attempts to fetch the AI-generated overall summary from
// MinIO storage and attaches it to the response. Failures are logged but do not
// cause the request to fail — the field will simply be omitted.
func (s *tenderService) enrichWithAISummary(ctx context.Context, resp *TenderResponse) {
	if s.aiSummarizerStorage == nil || resp.NoticePublicationID == "" {
		return
	}

	summary, err := s.aiSummarizerStorage.GetSummaryFromStorage(ctx, resp.NoticePublicationID)
	if err != nil {
		s.logger.Debug("AI summary not available for tender", map[string]interface{}{
			"tender_id": resp.ID,
			"notice_id": resp.NoticePublicationID,
			"error":     err.Error(),
		})
		return
	}

	resp.OverallSummary = summary
}

// UpdateTender updates an existing tender
func (s *tenderService) Update(ctx context.Context, req UpdateTenderRequest) (*TenderResponse, error) {
	s.logger.Info("Updating tender", map[string]interface{}{
		"tender_id": req.ID,
	})

	// Get existing tender
	tender, err := s.repository.GetByID(ctx, req.ID)
	if err != nil {
		s.logger.Error("Failed to find tender for update", map[string]interface{}{
			"tender_id": req.ID,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to find tender: %w", err)
	}

	// Update fields if provided
	if req.Title != nil {
		tender.Title = *req.Title
	}
	if req.Description != nil {
		tender.Description = *req.Description
	}
	if req.Status != nil {
		tender.Status = *req.Status
	}
	if req.EstimatedValue != nil {
		tender.EstimatedValue = *req.EstimatedValue
	}
	if req.Currency != nil {
		tender.Currency = *req.Currency
	}
	if req.TenderDeadline != nil {
		tender.TenderDeadline = *req.TenderDeadline
	}

	if err := s.repository.Update(ctx, tender); err != nil {
		s.logger.Error("Failed to update tender", map[string]interface{}{
			"tender_id": req.ID,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to update tender: %w", err)
	}

	s.logger.Info("Tender updated successfully", map[string]interface{}{
		"tender_id": tender.ID,
	})

	return tender.ToResponse(), nil
}

// Delete deletes a tender
func (s *tenderService) Delete(ctx context.Context, id string) error {
	s.logger.Info("Deleting tender", map[string]interface{}{
		"tender_id": id,
	})

	if err := s.repository.Delete(ctx, id); err != nil {
		s.logger.Error("Failed to delete tender", map[string]interface{}{
			"tender_id": id,
			"error":     err.Error(),
		})
		return fmt.Errorf("failed to delete tender: %w", err)
	}

	s.logger.Info("Tender deleted successfully", map[string]interface{}{
		"tender_id": id,
	})

	return nil
}

// GetDocumentSummaries retrieves document summaries for a specific tender
func (s *tenderService) GetDocumentSummaries(ctx context.Context, id string) ([]DocumentSummary, error) {
	if id == "" {
		return nil, fmt.Errorf("tender ID cannot be empty")
	}

	// Get tender from repository
	tender, err := s.repository.GetByID(ctx, id)
	if err != nil {
		s.logger.Error("Failed to get tender for document summaries", map[string]interface{}{
			"tender_id": id,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to get tender: %w", err)
	}

	if tender == nil {
		return nil, fmt.Errorf("tender not found")
	}

	// Return document summaries (empty slice if none exist)
	if tender.DocumentSummaries == nil {
		return []DocumentSummary{}, nil
	}

	s.logger.Info("Retrieved document summaries for tender", map[string]interface{}{
		"tender_id":       id,
		"summaries_count": len(tender.DocumentSummaries),
	})

	return tender.DocumentSummaries, nil
}

// ListTenders retrieves tenders with pagination and filtering
func (s *tenderService) Search(ctx context.Context, form *SearchForm, pagination *response.Pagination) (*SearchResponse, error) {
	s.logger.Info("Listing tenders", map[string]interface{}{
		"limit":       pagination.Limit,
		"offset":      pagination.Offset,
		"company_id":  form.CompanyID,
		"customer_id": form.CustomerID,
		"from":        form.DeadlineFrom,
		"to":          form.DeadlineTo,
	})

	// If customer ID is provided, get customer keywords and add to search
	if form.CustomerID != nil && *form.CustomerID != "" {
		customerResp, err := s.customerService.GetByID(ctx, *form.CustomerID)
		if err == nil && customerResp != nil {
			// Only use keywords if status is ready
			if customerResp.KeywordsStatus == "ready" && len(customerResp.Keywords) > 0 {
				// Combine customer keywords with existing search query
				keywordsQuery := strings.Join(customerResp.Keywords, " ")
				if form.Search != nil && *form.Search != "" {
					combinedSearch := *form.Search + " " + keywordsQuery
					form.Search = &combinedSearch
				} else {
					form.Search = &keywordsQuery
				}
				s.logger.Info("Using customer keywords for search", map[string]interface{}{
					"customer_id": *form.CustomerID,
					"keywords":    customerResp.Keywords,
				})
			} else {
				s.logger.Info("Customer keywords not ready, skipping keyword-based search", map[string]interface{}{
					"customer_id":     *form.CustomerID,
					"keywords_status": customerResp.KeywordsStatus,
				})
			}
		}
	}

	tenders, total, err := s.repository.Search(ctx, form, pagination)
	if err != nil {
		s.logger.Error("Failed to list tenders", map[string]interface{}{
			"error": err.Error(),
		})
		return nil, fmt.Errorf("failed to list tenders: %w", err)
	}

	// If no company ID provided, return tenders without match percentage
	if form.CompanyID == nil || *form.CompanyID == "" {
		tenderResponses := make([]TenderResponse, 0, len(tenders))
		for _, tender := range tenders {
			tenderResponses = append(tenderResponses, *tender.ToResponse())
		}

		return &SearchResponse{
			Tenders:  tenderResponses,
			Metadata: pagination.Response(total),
		}, nil
	}

	// Get company CPV codes for match calculation
	comp, err := s.companyService.GetByID(ctx, *form.CompanyID)
	if err != nil {
		s.logger.Error("Failed to get company for match calculation", map[string]interface{}{
			"company_id": *form.CompanyID,
			"error":      err.Error(),
		})
		// Continue without match percentage if company not found
		tenderResponses := make([]TenderResponse, 0, len(tenders))
		for _, tender := range tenders {
			tenderResponses = append(tenderResponses, *tender.ToResponse())
		}

		return &SearchResponse{
				Tenders:  tenderResponses,
				Metadata: pagination.Response(total),
			},
			nil
	}

	var companyCPVCodes []string
	if comp.Tags != nil && comp.Tags.CPVCodes != nil {
		companyCPVCodes = comp.Tags.CPVCodes
	}

	s.logger.Info("Tenders sorted by match percentage", map[string]interface{}{
		"company_id":        *form.CompanyID,
		"company_cpv_codes": len(companyCPVCodes),
		"total_tenders":     len(tenders),
	})

	tenderResponses := make([]TenderResponse, 0, len(tenders))
	for _, tender := range tenders {
		tenderResponses = append(tenderResponses, *tender.ToResponse())
	}

	return &SearchResponse{
			Tenders:  tenderResponses,
			Metadata: pagination.Response(total),
		},
		nil
}

// Recommend retrieves tenders with pagination and filtering
func (s *tenderService) Recommend(ctx context.Context, form *SearchForm, pagination *response.Pagination) (*SearchResponse, error) {
	s.logger.Info("Recommend tenders", map[string]interface{}{
		"company_id":  form.CompanyID,
		"customer_id": form.CustomerID,
	})

	form.Status = []string{string(TenderStatusActive)}

	// Priority: Use customer keywords if available, otherwise use company CPV codes
	if form.CustomerID != nil && *form.CustomerID != "" {
		customerResp, err := s.customerService.GetByID(ctx, *form.CustomerID)
		if err == nil && customerResp != nil {
			// Only use keywords if status is ready
			if customerResp.KeywordsStatus == "ready" && len(customerResp.Keywords) > 0 {
				// Use customer keywords for recommendation
				keywordsQuery := strings.Join(customerResp.Keywords, " ")
				form.Search = &keywordsQuery
				s.logger.Info("Using customer keywords for recommendation", map[string]interface{}{
					"customer_id": *form.CustomerID,
					"keywords":    customerResp.Keywords,
				})
			} else {
				s.logger.Info("Customer keywords not ready, falling back to company CPV codes", map[string]interface{}{
					"customer_id":     *form.CustomerID,
					"keywords_status": customerResp.KeywordsStatus,
				})
			}
		}
	}

	// Fallback to company CPV codes if no customer keywords
	if form.Search == nil || *form.Search == "" {
		if form.CompanyID != nil && *form.CompanyID != "" {
			company, err := s.companyService.GetByID(ctx, *form.CompanyID)
			if err != nil {
				s.logger.Error("Failed to get company for CPV codes, skipping CPV-based filtering", map[string]interface{}{
					"company_id": form.CompanyID,
					"error":      err.Error(),
				})
				// Continue without CPV-based filtering instead of failing
			} else if company.Tags != nil && len(company.Tags.CPVCodes) > 0 {
				form.Classifications = company.Tags.CPVCodes
			}
		}
	}

	tenders, total, err := s.repository.Search(ctx, form, pagination)
	if err != nil {
		s.logger.Error("Failed to list tenders", map[string]interface{}{
			"error": err.Error(),
		})
		return nil, fmt.Errorf("failed to list tenders: %w", err)
	}

	tenderResponses := make([]TenderResponse, 0, len(tenders))
	for _, tender := range tenders {
		tenderResponses = append(tenderResponses, *tender.ToResponse())
	}

	return &SearchResponse{
		Tenders:  tenderResponses,
		Metadata: pagination.Response(total),
	}, nil
}

// Delete deletes a tender

// GetTenderStatistics retrieves tender statistics
func (s *tenderService) GetTenderStatistics(ctx context.Context) (*TenderStatistics, error) {
	s.logger.Info("Retrieving tender statistics", map[string]interface{}{})

	stats, err := s.repository.GetStatistics(ctx)
	if err != nil {
		s.logger.Error("Failed to retrieve tender statistics", map[string]interface{}{
			"error": err.Error(),
		})
		return nil, fmt.Errorf("failed to retrieve statistics: %w", err)
	}

	return stats, nil
}

// UpdateExpiredTenders updates status of expired tenders
func (s *tenderService) UpdateExpiredTenders(ctx context.Context) error {
	s.logger.Info("Updating expired tenders", map[string]interface{}{})

	// Get tenders that should be expired
	expiredTenders, err := s.repository.GetExpiredTenders(ctx, time.Now().Unix())
	if err != nil {
		s.logger.Error("Failed to get expired tenders", map[string]interface{}{
			"error": err.Error(),
		})
		return fmt.Errorf("failed to get expired tenders: %w", err)
	}

	updatedCount := 0
	for _, tender := range expiredTenders {
		if tender.Status != TenderStatusExpired {
			tender.UpdateStatus(TenderStatusExpired)
			if err := s.repository.Update(ctx, &tender); err != nil {
				s.logger.Error("Failed to update expired tender", map[string]interface{}{
					"tender_id": tender.ID,
					"error":     err.Error(),
				})
				continue
			}
			updatedCount++
		}
	}

	s.logger.Info("Expired tenders updated", map[string]interface{}{
		"total_expired": len(expiredTenders),
		"updated":       updatedCount,
	})

	return nil
}

// CleanupOldData removes old data based on retention policy
func (s *tenderService) CleanupOldData(ctx context.Context, olderThan time.Duration, pagination *response.Pagination) error {
	s.logger.Info("Cleaning up old data", map[string]interface{}{
		"older_than": olderThan.String(),
		"limit":      pagination.Limit,
		"offset":     pagination.Offset,
	})

	cutoffTime := time.Now().Add(-olderThan).Unix()

	// For now, we'll just log what would be cleaned up
	// In production, you might want to actually delete old data
	form := &SearchForm{
		Status: []string{string(TenderStatusExpired), string(TenderStatusCancelled), string(TenderStatusAwarded)},
	}

	oldTenders, _, err := s.repository.Search(ctx, form, pagination)
	if err != nil {
		s.logger.Error("Failed to find old tenders for cleanup", map[string]interface{}{
			"error": err.Error(),
		})
		return fmt.Errorf("failed to find old tenders: %w", err)
	}

	cleanupCount := 0
	for _, tender := range oldTenders {
		if tender.CreatedAt < cutoffTime {
			cleanupCount++
			// Here you would delete the tender if implementing actual cleanup
			// s.repository.Delete(ctx, tender.ID)
		}
	}

	s.logger.Info("Old data cleanup completed", map[string]interface{}{
		"found_old_tenders": cleanupCount,
		"cutoff_time":       cutoffTime,
	})

	return nil
}

// GetAISummary retrieves the AI-generated summary for a tender.
// It first tries to fetch from MinIO storage (async pipeline result).
// If not found or not ready, it returns an appropriate error.
func (s *tenderService) GetAISummary(ctx context.Context, id string) (*AISummaryResponse, error) {
	if id == "" {
		return nil, fmt.Errorf("tender ID cannot be empty")
	}

	// Get tender to find the notice_publication_id
	t, err := s.repository.GetByID(ctx, id)
	if err != nil {
		s.logger.Error("Failed to get tender for AI summary", map[string]interface{}{
			"tender_id": id,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to get tender: %w", err)
	}

	if t == nil {
		return nil, fmt.Errorf("tender not found")
	}

	noticeID := t.NoticePublicationID
	if noticeID == "" {
		return nil, fmt.Errorf("tender has no notice publication ID")
	}

	// Try to get summary from MinIO storage (async pipeline)
	if s.aiSummarizerStorage != nil {
		summary, err := s.aiSummarizerStorage.GetSummaryFromStorage(ctx, noticeID)
		if err == nil {
			return &AISummaryResponse{
				NoticeID:       noticeID,
				OverallSummary: summary,
				Source:         "storage",
			}, nil
		}

		// Log but don't fail — the summary might just not be ready yet
		s.logger.Info("AI summary not available from storage", map[string]interface{}{
			"tender_id": id,
			"notice_id": noticeID,
			"error":     err.Error(),
		})

		// Return specific error if summary not ready
		if errors.Is(err, ai_summarizer.ErrSummaryNotReady) {
			return nil, fmt.Errorf("AI summary is not ready yet, the pipeline is still processing")
		}
		if errors.Is(err, ai_summarizer.ErrObjectNotFound) {
			return nil, fmt.Errorf("AI summary not found — this tender has not been processed by the AI pipeline yet")
		}

		return nil, fmt.Errorf("failed to get AI summary: %w", err)
	}

	return nil, fmt.Errorf("AI summarizer storage is not configured")
}

// TriggerAISummarize triggers on-demand AI summarization for a tender.
// It calls the external AI service HTTP API to generate summaries.
func (s *tenderService) TriggerAISummarize(ctx context.Context, id string) (*AISummarizeResponse, error) {
	if id == "" {
		return nil, fmt.Errorf("tender ID cannot be empty")
	}

	if s.aiSummarizerClient == nil {
		return nil, fmt.Errorf("AI summarizer service is not configured")
	}

	// Get tender to build the request
	t, err := s.repository.GetByID(ctx, id)
	if err != nil {
		s.logger.Error("Failed to get tender for on-demand summarization", map[string]interface{}{
			"tender_id": id,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("failed to get tender: %w", err)
	}

	if t == nil {
		return nil, fmt.Errorf("tender not found")
	}

	noticeID := t.NoticePublicationID
	if noticeID == "" {
		return nil, fmt.Errorf("tender has no notice publication ID")
	}

	// Build the AI summarizer request
	reqBody := ai_summarizer.SummarizeRequest{
		NoticeID:           noticeID,
		DocumentURL:        t.DocumentURI,
		Title:              t.Title,
		Description:        t.Description,
		Country:            t.CountryCode,
		SubmissionDeadline: time.UnixMilli(t.SubmissionDeadline).Format(time.RFC3339),
	}

	if t.EstimatedValue > 0 {
		ev := t.EstimatedValue
		reqBody.EstimatedValue = &ev
	}
	if t.Currency != "" {
		reqBody.Currency = t.Currency
	}
	if t.BuyerOrganization != nil {
		reqBody.AuthorityName = t.BuyerOrganization.Name
	}

	s.logger.Info("Triggering on-demand AI summarization", map[string]interface{}{
		"tender_id": id,
		"notice_id": noticeID,
	})

	// Call the AI service
	resp, err := s.aiSummarizerClient.FetchSummaryOnDemand(ctx, reqBody)
	if err != nil {
		s.logger.Error("On-demand AI summarization failed", map[string]interface{}{
			"tender_id": id,
			"notice_id": noticeID,
			"error":     err.Error(),
		})
		return nil, fmt.Errorf("AI summarization request failed: %w", err)
	}

	// Map the response to our response type
	summaries := make([]AIDocumentSummary, 0, len(resp.Summaries))
	for _, s := range resp.Summaries {
		summaries = append(summaries, AIDocumentSummary{
			DocumentName: s.DocumentName,
			DocumentType: s.DocumentType,
			Summary:      s.Summary,
			SummaryModel: s.SummaryModel,
			Error:        s.Error,
		})
	}

	s.logger.Info("On-demand AI summarization completed", map[string]interface{}{
		"tender_id":       id,
		"notice_id":       noticeID,
		"summaries_count": len(summaries),
	})

	return &AISummarizeResponse{
		NoticeID:       resp.NoticeID,
		Summaries:      summaries,
		OverallSummary: resp.OverallSummary,
	}, nil
}

// GetAllAISummaries retrieves all AI-generated summaries from the MinIO storage.
// It lists all tender.json files in the bucket and returns summaries for tenders
// where the AI pipeline has completed processing.
func (s *tenderService) GetAllAISummaries(ctx context.Context) ([]ai_summarizer.TenderSummaryItem, error) {
	if s.aiSummarizerStorage == nil {
		return nil, fmt.Errorf("AI summarizer storage is not configured")
	}

	s.logger.Info("Retrieving all AI summaries from storage", map[string]interface{}{})

	// We need to access the underlying StorageClient to call GetAllSummaries.
	// Since aiSummarizerStorage is an interface, we type-assert to access GetAllSummaries.
	type allSummaries interface {
		GetAllSummaries(ctx context.Context) ([]ai_summarizer.TenderSummaryItem, error)
	}

	storage, ok := s.aiSummarizerStorage.(allSummaries)
	if !ok {
		return nil, fmt.Errorf("AI summarizer storage does not support batch retrieval")
	}

	results, err := storage.GetAllSummaries(ctx)
	if err != nil {
		s.logger.Error("Failed to get all AI summaries", map[string]interface{}{
			"error": err.Error(),
		})
		return nil, fmt.Errorf("failed to get all AI summaries: %w", err)
	}

	s.logger.Info("Retrieved all AI summaries", map[string]interface{}{
		"total_count": len(results),
	})

	return results, nil
}