package service

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

// TrustService provides trust metrics and data quality services
type TrustService struct {
	trustRepo      domain.TrustMetricsRepository
	verifiedRepo   *repository.VerifiedDataRepository
	historicalRepo *repository.HistoricalSuccessRepository
}

// GetTrustRepository returns the trust metrics repository (for internal use)
func (s *TrustService) GetTrustRepository() domain.TrustMetricsRepository {
	return s.trustRepo
}

// NewTrustService creates a new trust service
func NewTrustService(
	trustRepo domain.TrustMetricsRepository,
	verifiedRepo *repository.VerifiedDataRepository,
	historicalRepo *repository.HistoricalSuccessRepository,
) *TrustService {
	return &TrustService{
		trustRepo:      trustRepo,
		verifiedRepo:   verifiedRepo,
		historicalRepo: historicalRepo,
	}
}

// AssessDataQuality performs comprehensive data quality assessment for an organization
func (s *TrustService) AssessDataQuality(ctx context.Context, orgID string) (*domain.DataQualityProfile, error) {
	profile, err := s.trustRepo.GetLatestProfile(ctx, orgID)
	if err != nil {
		return nil, fmt.Errorf("failed to get quality profile: %w", err)
	}

	// Enhance profile with additional calculations
	profile.Timeliness = s.calculateTimelinessScore(profile)
	profile.Consistency = s.calculateConsistencyScore(profile)

	// Recalculate overall score with all components
	profile.OverallScore = (profile.Completeness*0.3 + profile.Accuracy*0.3 +
		profile.Timeliness*0.2 + profile.Consistency*0.2)

	return profile, nil
}

// CalculateTrustScore calculates comprehensive trust score for an organization
func (s *TrustService) CalculateTrustScore(ctx context.Context, orgID string) (*domain.TrustScore, error) {
	return s.historicalRepo.CalculateTrustScore(ctx, orgID)
}

// UpdateTrustMetrics updates trust metrics for an organization
func (s *TrustService) UpdateTrustMetrics(ctx context.Context, orgID string, metrics []*domain.TrustMetrics) error {
	for _, metric := range metrics {
		metric.OrganizationID = orgID
		metric.LastUpdated = time.Now()

		// Calculate score based on value
		metric.Score = s.calculateScoreCategory(metric.Value)

		if err := s.trustRepo.Create(ctx, metric); err != nil {
			return fmt.Errorf("failed to create trust metric: %w", err)
		}
	}
	return nil
}

// SubmitForVerification submits data for verification
func (s *TrustService) SubmitForVerification(ctx context.Context, verifiedData *domain.VerifiedData) error {
	verifiedData.Status = domain.VerificationPending
	return s.verifiedRepo.Create(ctx, verifiedData)
}

// VerifyData marks data as verified
func (s *TrustService) VerifyData(ctx context.Context, dataID string, verifiedBy string, notes string) error {
	// Get existing verified data
	existing, err := s.verifiedRepo.GetByID(ctx, dataID)
	if err != nil {
		return fmt.Errorf("failed to get verified data: %w", err)
	}

	// Update verification status
	now := time.Now()
	existing.Status = domain.VerificationVerified
	existing.VerifiedBy = verifiedBy
	existing.VerifiedAt = &now
	existing.Notes = notes
	existing.ExpiresAt = &time.Time{} // Set expiration if needed

	return s.verifiedRepo.Update(ctx, existing)
}

// RecordHistoricalSuccess records historical success metrics
func (s *TrustService) RecordHistoricalSuccess(ctx context.Context, success *domain.HistoricalSuccess) error {
	success.RecordedAt = time.Now()
	return s.historicalRepo.Create(ctx, success)
}

// GetTrustDashboard returns trust dashboard data for an organization
func (s *TrustService) GetTrustDashboard(ctx context.Context, orgID string) (*TrustDashboard, error) {
	// Get trust score
	trustScore, err := s.CalculateTrustScore(ctx, orgID)
	if err != nil {
		return nil, fmt.Errorf("failed to calculate trust score: %w", err)
	}

	// Get quality profile
	qualityProfile, err := s.AssessDataQuality(ctx, orgID)
	if err != nil {
		return nil, fmt.Errorf("failed to assess data quality: %w", err)
	}

	// Get recent historical metrics
	historical, err := s.historicalRepo.GetByOrganization(ctx, orgID)
	if err != nil {
		return nil, fmt.Errorf("failed to get historical metrics: %w", err)
	}

	// Get verification status
	verifiedData, err := s.verifiedRepo.GetByOrganization(ctx, orgID)
	if err != nil {
		return nil, fmt.Errorf("failed to get verified data: %w", err)
	}

	dashboard := &TrustDashboard{
		OrganizationID:    orgID,
		TrustScore:        trustScore,
		QualityProfile:    qualityProfile,
		HistoricalMetrics: historical,
		VerifiedData:      verifiedData,
		LastUpdated:       time.Now(),
	}

	return dashboard, nil
}

// calculateTimelinessScore calculates how timely the data is
func (s *TrustService) calculateTimelinessScore(profile *domain.DataQualityProfile) float64 {
	// Check how recent the metrics are
	daysSinceAssessment := time.Since(profile.LastAssessed).Hours() / 24

	// Score decreases with age
	if daysSinceAssessment < 30 {
		return 0.9
	} else if daysSinceAssessment < 90 {
		return 0.7
	} else if daysSinceAssessment < 180 {
		return 0.5
	} else {
		return 0.3
	}
}

// calculateConsistencyScore calculates data consistency
func (s *TrustService) calculateConsistencyScore(profile *domain.DataQualityProfile) float64 {
	// Check for conflicting or inconsistent metrics
	// This is a simplified implementation
	if len(profile.Metrics) < 3 {
		return 0.5 // Not enough data to assess consistency
	}

	// Look for metrics with similar names but different values
	metricGroups := make(map[string][]float64)
	for _, metric := range profile.Metrics {
		metricGroups[metric.MetricName] = append(metricGroups[metric.MetricName], metric.Value)
	}

	// Check variance within groups
	consistentGroups := 0
	totalGroups := len(metricGroups)

	for _, values := range metricGroups {
		if len(values) > 1 {
			// Calculate simple variance
			avg := 0.0
			for _, v := range values {
				avg += v
			}
			avg /= float64(len(values))

			variance := 0.0
			for _, v := range values {
				diff := v - avg
				variance += diff * diff
			}
			variance /= float64(len(values))

			// Low variance indicates consistency
			if variance < 0.1 { // Threshold for consistency
				consistentGroups++
			}
		} else {
			consistentGroups++ // Single value is consistent by definition
		}
	}

	if totalGroups == 0 {
		return 0.5
	}

	return float64(consistentGroups) / float64(totalGroups)
}

// calculateScoreCategory converts numeric score to category
func (s *TrustService) calculateScoreCategory(value float64) string {
	switch {
	case value >= 0.9:
		return "excellent"
	case value >= 0.8:
		return "good"
	case value >= 0.6:
		return "fair"
	default:
		return "poor"
	}
}

// TrustDashboard represents comprehensive trust dashboard data
type TrustDashboard struct {
	OrganizationID    string                      `json:"organization_id"`
	TrustScore        *domain.TrustScore          `json:"trust_score"`
	QualityProfile    *domain.DataQualityProfile  `json:"quality_profile"`
	HistoricalMetrics []*domain.HistoricalSuccess `json:"historical_metrics"`
	VerifiedData      []*domain.VerifiedData      `json:"verified_data"`
	LastUpdated       time.Time                   `json:"last_updated"`
}