package matching

import (
	"context"
	"fmt"
	"strings"

	"bugulma/backend/internal/analysis/regulatory"
	"bugulma/backend/internal/analysis/risk"
	"bugulma/backend/internal/analysis/transport"
	"bugulma/backend/internal/domain"
	"bugulma/backend/internal/geospatial"
	"bugulma/backend/internal/matching/engine"
	"bugulma/backend/internal/matching/manager"
	"bugulma/backend/internal/matching/plugins"
)

// Service orchestrates all matching functionality
type Service struct {
	engine    *engine.Engine
	manager   *manager.Manager
	pluginMgr *plugins.Manager
	matchRepo domain.MatchRepository

	// Dependencies for data access
	resourceFlowRepo     domain.ResourceFlowRepository
	siteRepo             domain.SiteRepository
	orgRepo              domain.OrganizationRepository
	productRepo          domain.ProductRepository
	serviceRepo          domain.ServiceRepository
	communityListingRepo domain.CommunityListingRepository
	eventBus             domain.EventBus

	// Geospatial calculator
	geoCalc geospatial.Calculator

	// Discovery matcher for products/services
	discoveryMatcher *DiscoveryMatcher
}

// EventBus is now defined in the domain package

// NewService creates a new matching service
func NewService(
	matchRepo domain.MatchRepository,
	negotiationRepo domain.NegotiationHistoryRepository,
	resourceFlowRepo domain.ResourceFlowRepository,
	siteRepo domain.SiteRepository,
	orgRepo domain.OrganizationRepository,
	productRepo domain.ProductRepository,
	serviceRepo domain.ServiceRepository,
	communityListingRepo domain.CommunityListingRepository,
	riskSvc *risk.Service,
	transportSvc *transport.Service,
	regulatorySvc *regulatory.Service,
	eventBus domain.EventBus,
) *Service {

	// Create engine with analysis services
	eng := engine.NewEngine(riskSvc, transportSvc, regulatorySvc)

	// Create manager for lifecycle operations
	mgr := manager.NewManager(matchRepo, negotiationRepo, eventBus)

	// Create plugin registry and register default plugins
	pluginRegistry := plugins.NewRegistry()
	if err := plugins.RegisterDefaultPlugins(pluginRegistry); err != nil {
		// Log error but continue - plugins are optional enhancement
		// In production, this would be logged properly
	}

	// Create plugin manager
	pluginMgr := plugins.NewManager(pluginRegistry, eng)

	// Create geospatial calculator
	geoCalc := geospatial.NewCalculatorWithDefaults()

	// Create discovery matcher for products/services
	discoveryMatcher := NewDiscoveryMatcher()

	return &Service{
		engine:               eng,
		manager:              mgr,
		pluginMgr:            pluginMgr,
		matchRepo:            matchRepo,
		resourceFlowRepo:     resourceFlowRepo,
		siteRepo:             siteRepo,
		orgRepo:              orgRepo,
		productRepo:          productRepo,
		serviceRepo:          serviceRepo,
		communityListingRepo: communityListingRepo,
		eventBus:             eventBus,
		geoCalc:              geoCalc,
		discoveryMatcher:     discoveryMatcher,
	}
}

// FindMatches finds potential matches based on criteria
func (s *Service) FindMatches(ctx context.Context, criteria Criteria) ([]*engine.Candidate, error) {
	// Find potential source and target flows
	sourceFlows, err := s.findSourceFlows(ctx, criteria)
	if err != nil {
		return nil, err
	}

	targetFlows, err := s.findTargetFlows(ctx, criteria)
	if err != nil {
		return nil, err
	}

	// Use engine to find initial matches
	candidates, err := s.engine.FindMatches(criteria, sourceFlows, targetFlows)
	if err != nil {
		return nil, err
	}

	// Enhance candidates with plugin logic
	var enhancedCandidates []*engine.Candidate
	for _, candidate := range candidates {
		// Calculate accurate distance using geospatial calculator
		sourceSite, err := s.siteRepo.GetByID(ctx, candidate.SourceFlow.SiteID)
		if err != nil {
			continue // Skip if we can't get site info
		}
		targetSite, err := s.siteRepo.GetByID(ctx, candidate.TargetFlow.SiteID)
		if err != nil {
			continue // Skip if we can't get site info
		}

		distanceResult, err := s.geoCalc.CalculateDistance(
			geospatial.Point{Latitude: sourceSite.Latitude, Longitude: sourceSite.Longitude},
			geospatial.Point{Latitude: targetSite.Latitude, Longitude: targetSite.Longitude},
		)
		if err != nil {
			continue // Skip if distance calculation fails
		}

		candidate.DistanceKm = distanceResult.DistanceKm

		// Enhance candidate with plugin logic
		if err := s.pluginMgr.EnhanceCandidate(candidate); err != nil {
			// Log error but continue with basic candidate
			continue
		}

		// Validate candidate with plugins
		if valid, _ := s.pluginMgr.ValidateWithPlugins(candidate); valid {
			enhancedCandidates = append(enhancedCandidates, candidate)
		}
	}

	// Re-rank enhanced candidates
	enhancedCandidates = s.rerankCandidates(enhancedCandidates)

	return enhancedCandidates, nil
}

// CreateMatch creates a new match from a candidate
func (s *Service) CreateMatch(ctx context.Context, candidate *engine.Candidate, creatorID string) (*domain.Match, error) {
	return s.manager.CreateMatch(ctx, candidate, creatorID)
}

// UpdateMatchStatus updates match status
func (s *Service) UpdateMatchStatus(ctx context.Context, matchID string, newStatus domain.MatchStatus, actorID string, notes string) error {
	return s.manager.UpdateMatchStatus(ctx, matchID, newStatus, actorID, notes)
}

// UpdateMatch updates match details
func (s *Service) UpdateMatch(ctx context.Context, match *domain.Match) error {
	return s.manager.UpdateMatch(ctx, match)
}

// DeleteMatch deletes a match
func (s *Service) DeleteMatch(ctx context.Context, matchID string, actorID string) error {
	return s.manager.DeleteMatch(ctx, matchID, actorID)
}

// GetMatchByID retrieves a match by ID
func (s *Service) GetMatchByID(ctx context.Context, matchID string) (*domain.Match, error) {
	return s.matchRepo.GetByID(ctx, matchID)
}

// GetTopMatches retrieves top matches
func (s *Service) GetTopMatches(ctx context.Context, limit int) ([]*domain.Match, error) {
	return s.matchRepo.GetTopMatches(ctx, limit)
}

// GetNegotiationHistory retrieves negotiation history for a match
func (s *Service) GetNegotiationHistory(ctx context.Context, matchID string) ([]*domain.NegotiationHistoryEntry, error) {
	return s.manager.GetNegotiationHistory(ctx, matchID)
}

// GetResourceFlowByID retrieves a resource flow by ID
func (s *Service) GetResourceFlowByID(ctx context.Context, id string) (*domain.ResourceFlow, error) {
	return s.resourceFlowRepo.GetByID(ctx, id)
}

// GetSiteByID retrieves a site by ID
func (s *Service) GetSiteByID(ctx context.Context, id string) (*domain.Site, error) {
	return s.siteRepo.GetByID(ctx, id)
}

// CalculateDistance calculates distance between two sites
func (s *Service) CalculateDistance(lat1, lon1, lat2, lon2 float64) float64 {
	result, err := s.geoCalc.CalculateDistance(
		geospatial.Point{Latitude: lat1, Longitude: lon1},
		geospatial.Point{Latitude: lat2, Longitude: lon2},
	)
	if err != nil {
		// Fallback to 0 if calculation fails (shouldn't happen with valid coordinates)
		return 0
	}
	return result.DistanceKm
}

// findSourceFlows finds resource flows that can be sources (outputs)
func (s *Service) findSourceFlows(ctx context.Context, criteria Criteria) ([]*domain.ResourceFlow, error) {
	// For output matching, we look for flows with opposite direction
	oppositeDirection := s.getOppositeDirection(criteria.ResourceType)

	flows, err := s.resourceFlowRepo.GetByTypeAndDirection(ctx, criteria.ResourceType, oppositeDirection)
	if err != nil {
		return nil, err
	}

	// Filter by organization if specified
	if criteria.OrganizationID != "" {
		var filtered []*domain.ResourceFlow
		for _, flow := range flows {
			if flow.OrganizationID == criteria.OrganizationID {
				filtered = append(filtered, flow)
			}
		}
		flows = filtered
	}

	return flows, nil
}

// findTargetFlows finds resource flows that can be targets (inputs)
func (s *Service) findTargetFlows(ctx context.Context, criteria Criteria) ([]*domain.ResourceFlow, error) {
	// For input matching, we look for flows in the specified direction
	flows, err := s.resourceFlowRepo.GetByTypeAndDirection(ctx, criteria.ResourceType, criteria.Direction)
	if err != nil {
		return nil, err
	}

	// Apply geographic filtering if site specified
	if criteria.SiteID != "" {
		flows = s.filterBySiteProximity(ctx, flows, criteria.SiteID, criteria.MaxDistanceKm)
	}

	return flows, nil
}

// filterBySiteProximity filters flows by distance from a reference site
func (s *Service) filterBySiteProximity(ctx context.Context, flows []*domain.ResourceFlow, siteID string, maxDistance float64) []*domain.ResourceFlow {
	if maxDistance <= 0 {
		return flows
	}

	refSite, err := s.siteRepo.GetByID(ctx, siteID)
	if err != nil {
		return flows // Return all if we can't get reference site
	}

	var filtered []*domain.ResourceFlow
	for _, flow := range flows {
		flowSite, err := s.siteRepo.GetByID(ctx, flow.SiteID)
		if err != nil {
			continue
		}

		result, err := s.geoCalc.CalculateDistance(
			geospatial.Point{Latitude: refSite.Latitude, Longitude: refSite.Longitude},
			geospatial.Point{Latitude: flowSite.Latitude, Longitude: flowSite.Longitude},
		)
		if err != nil {
			continue // Skip if distance calculation fails
		}
		distance := result.DistanceKm

		if distance <= maxDistance {
			filtered = append(filtered, flow)
		}
	}

	return filtered
}

// getOppositeDirection returns the opposite resource direction
func (s *Service) getOppositeDirection(resourceType domain.ResourceType) domain.ResourceDirection {
	return domain.DirectionOutput // Simplified - would depend on matching strategy
}

// rerankCandidates sorts candidates by enhanced overall score
func (s *Service) rerankCandidates(candidates []*engine.Candidate) []*engine.Candidate {
	// Simple sort by overall score (descending)
	for i := 0; i < len(candidates); i++ {
		for j := i + 1; j < len(candidates); j++ {
			if candidates[i].OverallScore < candidates[j].OverallScore {
				candidates[i], candidates[j] = candidates[j], candidates[i]
			}
		}
	}
	return candidates
}

// Import Criteria from engine package
type Criteria = engine.Criteria

// FindProductMatches finds products matching the discovery query
func (s *Service) FindProductMatches(ctx context.Context, query DiscoveryQuery) ([]*DiscoveryMatch, error) {
	if s.productRepo == nil {
		return nil, fmt.Errorf("product repository not available")
	}

	// Search products based on query
	var products []*domain.Product
	var err error

	if query.Location != nil && query.RadiusKm > 0 {
		products, err = s.productRepo.GetNearby(ctx, query.Location.Latitude, query.Location.Longitude, query.RadiusKm)
	} else {
		products, err = s.productRepo.GetAll(ctx)
	}
	if err != nil {
		return nil, fmt.Errorf("failed to fetch products: %w", err)
	}

	// Score and rank matches
	var matches []*DiscoveryMatch
	for _, product := range products {
		// Get organization and site
		var org *domain.Organization
		var site *domain.Site
		if product.OrganizationID != "" {
			org, _ = s.orgRepo.GetByID(ctx, product.OrganizationID)
		}
		if product.SiteID != nil {
			site, _ = s.siteRepo.GetByID(ctx, *product.SiteID)
		}

		match, err := s.discoveryMatcher.ScoreProductMatch(product, query, org, site)
		if err != nil {
			continue
		}

		// Apply filters
		if query.AvailabilityStatus != "" && product.AvailabilityStatus != query.AvailabilityStatus {
			continue
		}
		if len(query.Categories) > 0 {
			categoryMatched := false
			for _, cat := range query.Categories {
				if strings.EqualFold(cat, string(product.Category)) {
					categoryMatched = true
					break
				}
			}
			if !categoryMatched {
				continue
			}
		}

		matches = append(matches, match)
	}

	// Sort by relevance score
	for i := 0; i < len(matches); i++ {
		for j := i + 1; j < len(matches); j++ {
			if matches[i].RelevanceScore < matches[j].RelevanceScore {
				matches[i], matches[j] = matches[j], matches[i]
			}
		}
	}

	// Apply pagination
	start := query.Offset
	end := start + query.Limit
	if start >= len(matches) {
		return []*DiscoveryMatch{}, nil
	}
	if end > len(matches) {
		end = len(matches)
	}

	return matches[start:end], nil
}

// FindServiceMatches finds services matching the discovery query
func (s *Service) FindServiceMatches(ctx context.Context, query DiscoveryQuery) ([]*DiscoveryMatch, error) {
	if s.serviceRepo == nil {
		return nil, fmt.Errorf("service repository not available")
	}

	// Search services based on query
	var services []*domain.Service
	var err error

	if query.Location != nil && query.RadiusKm > 0 {
		services, err = s.serviceRepo.GetNearby(ctx, query.Location.Latitude, query.Location.Longitude, query.RadiusKm)
	} else {
		services, err = s.serviceRepo.GetAll(ctx)
	}
	if err != nil {
		return nil, fmt.Errorf("failed to fetch services: %w", err)
	}

	// Score and rank matches
	var matches []*DiscoveryMatch
	for _, service := range services {
		// Get organization and site
		var org *domain.Organization
		var site *domain.Site
		if service.OrganizationID != "" {
			org, _ = s.orgRepo.GetByID(ctx, service.OrganizationID)
		}
		if service.SiteID != nil {
			site, _ = s.siteRepo.GetByID(ctx, *service.SiteID)
		}

		match, err := s.discoveryMatcher.ScoreServiceMatch(service, query, org, site)
		if err != nil {
			continue
		}

		// Apply filters
		if query.AvailabilityStatus != "" && service.AvailabilityStatus != query.AvailabilityStatus {
			continue
		}

		matches = append(matches, match)
	}

	// Sort by relevance score
	for i := 0; i < len(matches); i++ {
		for j := i + 1; j < len(matches); j++ {
			if matches[i].RelevanceScore < matches[j].RelevanceScore {
				matches[i], matches[j] = matches[j], matches[i]
			}
		}
	}

	// Apply pagination
	start := query.Offset
	end := start + query.Limit
	if start >= len(matches) {
		return []*DiscoveryMatch{}, nil
	}
	if end > len(matches) {
		end = len(matches)
	}

	return matches[start:end], nil
}

// UniversalSearch performs a unified search across resources, products, services, and community listings
func (s *Service) UniversalSearch(ctx context.Context, query DiscoveryQuery) (*UniversalSearchResult, error) {
	result := &UniversalSearchResult{
		Query: query,
	}

	// Search products (soft match)
	if productMatches, err := s.FindProductMatches(ctx, query); err == nil {
		result.ProductMatches = productMatches
	}

	// Search services (soft match)
	if serviceMatches, err := s.FindServiceMatches(ctx, query); err == nil {
		result.ServiceMatches = serviceMatches
	}

	// Search community listings (soft match)
	if s.communityListingRepo != nil {
		var listings []*domain.CommunityListing
		var err error
		if query.Location != nil && query.RadiusKm > 0 {
			listings, err = s.communityListingRepo.GetNearby(ctx, query.Location.Latitude, query.Location.Longitude, query.RadiusKm)
		} else {
			listings, err = s.communityListingRepo.GetAll(ctx)
		}
		if err == nil {
			for _, listing := range listings {
				match, err := s.discoveryMatcher.ScoreCommunityListingMatch(listing, query)
				if err == nil {
					result.CommunityMatches = append(result.CommunityMatches, match)
				}
			}
			// Sort community matches
			for i := 0; i < len(result.CommunityMatches); i++ {
				for j := i + 1; j < len(result.CommunityMatches); j++ {
					if result.CommunityMatches[i].RelevanceScore < result.CommunityMatches[j].RelevanceScore {
						result.CommunityMatches[i], result.CommunityMatches[j] = result.CommunityMatches[j], result.CommunityMatches[i]
					}
				}
			}
		}
	}

	// Note: Resource flow matches (hard match) would be handled separately via FindMatches
	// This is the "soft match" layer as per concept's layered architecture

	return result, nil
}

// UniversalSearchResult contains results from universal search
type UniversalSearchResult struct {
	Query            DiscoveryQuery    `json:"query"`
	ProductMatches   []*DiscoveryMatch `json:"product_matches"`
	ServiceMatches   []*DiscoveryMatch `json:"service_matches"`
	CommunityMatches []*DiscoveryMatch `json:"community_matches"`
	// ResourceMatches would be added via separate FindMatches call (hard match)
}

// GetProductsByOrganization gets products for a specific organization (efficient method)
func (s *Service) GetProductsByOrganization(ctx context.Context, organizationID string) ([]*domain.Product, error) {
	if s.productRepo == nil {
		return nil, fmt.Errorf("product repository not available")
	}
	return s.productRepo.GetByOrganization(ctx, organizationID)
}

// GetServicesByOrganization gets services for a specific organization (efficient method)
func (s *Service) GetServicesByOrganization(ctx context.Context, organizationID string) ([]*domain.Service, error) {
	if s.serviceRepo == nil {
		return nil, fmt.Errorf("service repository not available")
	}
	return s.serviceRepo.GetByOrganization(ctx, organizationID)
}

// CreateProduct creates a new product with site linking support
func (s *Service) CreateProduct(ctx context.Context, product *domain.Product) error {
	if s.productRepo == nil {
		return fmt.Errorf("product repository not available")
	}

	// If SiteID is provided, populate location from site
	if product.SiteID != nil && *product.SiteID != "" {
		site, err := s.siteRepo.GetByID(ctx, *product.SiteID)
		if err == nil && site != nil {
			// Set location from site coordinates
			product.Location = domain.Point{
				Latitude:  site.Latitude,
				Longitude: site.Longitude,
				Valid:     true,
			}
		}
	}

	if err := s.productRepo.Create(ctx, product); err != nil {
		return err
	}

	// Sync to graph database if graph sync service is available
	// Note: This would require passing graph sync service to matching service
	// For now, we'll rely on event-driven sync

	return nil
}

// CreateService creates a new service with site linking support
func (s *Service) CreateService(ctx context.Context, service *domain.Service) error {
	if s.serviceRepo == nil {
		return fmt.Errorf("service repository not available")
	}

	// If SiteID is provided, populate location from site
	if service.SiteID != nil && *service.SiteID != "" {
		site, err := s.siteRepo.GetByID(ctx, *service.SiteID)
		if err == nil && site != nil {
			// Set location from site coordinates
			service.ServiceLocation = domain.Point{
				Latitude:  site.Latitude,
				Longitude: site.Longitude,
				Valid:     true,
			}
		}
	}

	if err := s.serviceRepo.Create(ctx, service); err != nil {
		return err
	}

	return nil
}

// CreateCommunityListing creates a new community listing
func (s *Service) CreateCommunityListing(ctx context.Context, listing *domain.CommunityListing) error {
	if s.communityListingRepo == nil {
		return fmt.Errorf("community listing repository not available")
	}

	// Validate the listing
	if err := listing.Validate(); err != nil {
		return fmt.Errorf("invalid listing: %w", err)
	}

	// Create the listing
	if err := s.communityListingRepo.Create(ctx, listing); err != nil {
		return fmt.Errorf("failed to create community listing: %w", err)
	}

	return nil
}