package manager

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"bugulma/backend/internal/domain"
	"bugulma/backend/internal/matching/engine"
)

// Context keys for extracting user/org info
type contextKey string

const (
	UserIDKey contextKey = "user_id"
	OrgIDKey  contextKey = "org_id"
)

// Helper functions to extract context values
func getUserIDFromContext(ctx context.Context) string {
	if userID, ok := ctx.Value(UserIDKey).(string); ok {
		return userID
	}
	return "system"
}

func getOrgIDFromContext(ctx context.Context) string {
	if orgID, ok := ctx.Value(OrgIDKey).(string); ok {
		return orgID
	}
	return ""
}

// EventPublisher interface for publishing events
type EventPublisher interface {
	Publish(event domain.Event) error
}

// Manager handles match lifecycle operations
type Manager struct {
	matchRepo       domain.MatchRepository
	negotiationRepo domain.NegotiationHistoryRepository
	eventBus        EventPublisher
}

// NewManager creates a new lifecycle manager
func NewManager(
	matchRepo domain.MatchRepository,
	negotiationRepo domain.NegotiationHistoryRepository,
	eventBus EventPublisher,
) *Manager {
	return &Manager{
		matchRepo:       matchRepo,
		negotiationRepo: negotiationRepo,
		eventBus:        eventBus,
	}
}

// CreateMatch creates a new match from a candidate
func (m *Manager) CreateMatch(ctx context.Context, candidate *engine.Candidate, creatorID string) (*domain.Match, error) {
	// Create match entity
	match := &domain.Match{
		ID:                   generateMatchID(),
		SourceResourceID:     candidate.SourceFlow.ID,
		TargetResourceID:     candidate.TargetFlow.ID,
		Status:               domain.MatchStatusSuggested,
		CompatibilityScore:   candidate.CompatibilityScore,
		TemporalOverlapScore: candidate.TemporalScore,
		QualityScore:         candidate.QualityScore,
		EconomicValue:        candidate.EstimatedAnnualSavings,
		DistanceKm:           candidate.DistanceKm,
		Priority:             candidate.Priority,
	}

	// Set contract details (embedded)
	now := time.Now()
	terminationDate := now.Add(365 * 24 * time.Hour) // 1 year default
	match.ContractDetails = &domain.ContractDetails{
		EffectiveFrom:   &now,
		TerminationDate: &terminationDate,
		ValuePerYear:    candidate.EstimatedAnnualSavings,
	}

	// Store economic data in JSONB field
	economicData, _ := json.Marshal(map[string]interface{}{
		"annual_savings":     candidate.EstimatedAnnualSavings,
		"npv":                0,
		"irr":                0,
		"payback_years":      0,
		"co2_avoided_tonnes": 0,
		"capex_required":     0,
		"opex_per_year":      0,
	})
	match.EconomicImpact = economicData

	// Store risk data in JSONB field
	riskData, _ := json.Marshal(map[string]interface{}{
		"technical_risk":  0.3,
		"regulatory_risk": 0.2,
		"market_risk":     0.1,
		"overall_risk":    0.2,
		"risk_level":      candidate.RiskLevel,
	})
	match.RiskAssessment = riskData

	// Create the match
	if err := m.matchRepo.Create(ctx, match); err != nil {
		return nil, fmt.Errorf("failed to create match: %w", err)
	}

	// Add initial negotiation entry
	negotiationEntry := &domain.NegotiationHistoryEntry{
		MatchID:   match.ID,
		Timestamp: time.Now(),
		ActorID:   creatorID,
		Action:    "created",
		Notes:     "Match created from automated matching process",
	}

	if err := m.negotiationRepo.Create(ctx, negotiationEntry); err != nil {
		fmt.Printf("Warning: Failed to create negotiation history: %v\n", err)
	}

	// Publish event
	if m.eventBus != nil {
		event := domain.Event{
			ID:        generateEventID(),
			Type:      domain.EventTypeMatchCreated,
			EntityID:  match.ID,
			OrgID:     getOrgIDFromContext(ctx), // Extract from request context
			UserID:    creatorID,
			Timestamp: time.Now(),
			Payload: map[string]interface{}{
				"match": match,
			},
		}
		if err := m.eventBus.Publish(event); err != nil {
			fmt.Printf("Warning: Failed to publish match created event: %v\n", err)
		}
	}

	return match, nil
}

// UpdateMatchStatus updates the status of a match with proper validation
func (m *Manager) UpdateMatchStatus(
	ctx context.Context,
	matchID string,
	newStatus domain.MatchStatus,
	actorID string,
	notes string,
) error {
	// Get current match
	match, err := m.matchRepo.GetByID(ctx, matchID)
	if err != nil {
		return fmt.Errorf("failed to get match: %w", err)
	}

	oldStatus := match.Status

	// Validate status transition
	if err := m.validateStatusTransition(oldStatus, newStatus); err != nil {
		return fmt.Errorf("invalid status transition: %w", err)
	}

	// Update match
	match.Status = newStatus

	// Handle status-specific logic
	switch newStatus {
	case domain.MatchStatusReserved:
		reservedUntil := time.Now().Add(24 * time.Hour)
		match.ReservedUntil = &reservedUntil
	case domain.MatchStatusCancelled:
		now := time.Now()
		match.CancelledAt = &now
		match.CancelledBy = actorID
	}

	if err := m.matchRepo.Update(ctx, match); err != nil {
		return fmt.Errorf("failed to update match: %w", err)
	}

	// Add negotiation history
	oldValue, _ := json.Marshal(string(oldStatus))
	newValue, _ := json.Marshal(string(newStatus))

	negotiationEntry := &domain.NegotiationHistoryEntry{
		MatchID:   matchID,
		Timestamp: time.Now(),
		ActorID:   actorID,
		Action:    "status_changed",
		Notes:     fmt.Sprintf("Status changed from %s to %s. %s", oldStatus, newStatus, notes),
		OldValue:  oldValue,
		NewValue:  newValue,
	}

	if err := m.negotiationRepo.Create(ctx, negotiationEntry); err != nil {
		fmt.Printf("Warning: Failed to create negotiation history: %v\n", err)
	}

	// Publish event
	if m.eventBus != nil {
		event := domain.Event{
			ID:        generateEventID(),
			Type:      domain.EventTypeMatchStatusChanged,
			EntityID:  matchID,
			OrgID:     getOrgIDFromContext(ctx), // Extract from request context
			UserID:    actorID,
			Timestamp: time.Now(),
			Payload: map[string]interface{}{
				"old_status": oldStatus,
				"new_status": newStatus,
				"match_id":   matchID,
			},
		}
		if err := m.eventBus.Publish(event); err != nil {
			fmt.Printf("Warning: Failed to publish status change event: %v\n", err)
		}
	}

	return nil
}

// UpdateMatch updates match details
func (m *Manager) UpdateMatch(ctx context.Context, match *domain.Match) error {
	match.UpdatedAt = time.Now()

	if err := m.matchRepo.Update(ctx, match); err != nil {
		return fmt.Errorf("failed to update match: %w", err)
	}

	// Publish event
	if m.eventBus != nil {
		event := domain.Event{
			ID:        generateEventID(),
			Type:      domain.EventTypeMatchUpdated,
			EntityID:  match.ID,
			OrgID:     getOrgIDFromContext(ctx),  // Extract from request context
			UserID:    getUserIDFromContext(ctx), // Extract from request context
			Timestamp: time.Now(),
			Payload: map[string]interface{}{
				"match": match,
			},
		}
		if err := m.eventBus.Publish(event); err != nil {
			fmt.Printf("Warning: Failed to publish match updated event: %v\n", err)
		}
	}

	return nil
}

// DeleteMatch marks a match as cancelled
func (m *Manager) DeleteMatch(ctx context.Context, matchID string, actorID string) error {
	match, err := m.matchRepo.GetByID(ctx, matchID)
	if err != nil {
		return fmt.Errorf("failed to get match: %w", err)
	}

	// Mark as cancelled if not already in terminal state
	if match.Status != domain.MatchStatusFailed && match.Status != domain.MatchStatusCancelled {
		now := time.Now()
		match.Status = domain.MatchStatusCancelled
		match.CancelledAt = &now
		match.CancelledBy = actorID

		if err := m.matchRepo.Update(ctx, match); err != nil {
			return fmt.Errorf("failed to update match status: %w", err)
		}
	}

	return nil
}

// GetNegotiationHistory retrieves negotiation history for a match
func (m *Manager) GetNegotiationHistory(ctx context.Context, matchID string) ([]*domain.NegotiationHistoryEntry, error) {
	return m.negotiationRepo.GetByMatchID(ctx, matchID)
}

// validateStatusTransition validates that a status transition is allowed
func (m *Manager) validateStatusTransition(from, to domain.MatchStatus) error {
	validTransitions := map[domain.MatchStatus][]domain.MatchStatus{
		domain.MatchStatusSuggested: {
			domain.MatchStatusNegotiating,
			domain.MatchStatusReserved,
			domain.MatchStatusFailed,
			domain.MatchStatusCancelled,
		},
		domain.MatchStatusNegotiating: {
			domain.MatchStatusReserved,
			domain.MatchStatusContracted,
			domain.MatchStatusFailed,
			domain.MatchStatusCancelled,
		},
		domain.MatchStatusReserved: {
			domain.MatchStatusContracted,
			domain.MatchStatusNegotiating,
			domain.MatchStatusFailed,
			domain.MatchStatusCancelled,
		},
		domain.MatchStatusContracted: {
			domain.MatchStatusLive,
			domain.MatchStatusFailed,
			domain.MatchStatusCancelled,
		},
		domain.MatchStatusLive: {
			domain.MatchStatusFailed,
			domain.MatchStatusCancelled,
		},
		// Terminal states
		domain.MatchStatusFailed:    {},
		domain.MatchStatusCancelled: {},
	}

	allowedTransitions, exists := validTransitions[from]
	if !exists {
		return fmt.Errorf("unknown status: %s", from)
	}

	for _, allowed := range allowedTransitions {
		if allowed == to {
			return nil
		}
	}

	return fmt.Errorf("invalid transition from %s to %s", from, to)
}

// generateMatchID generates a unique match ID
func generateMatchID() string {
	return fmt.Sprintf("match_%d", time.Now().UnixNano())
}

// generateNegotiationID generates a unique negotiation entry ID
func generateNegotiationID() string {
	return fmt.Sprintf("neg_%d", time.Now().UnixNano())
}

// generateEventID generates a unique event ID
func generateEventID() string {
	return fmt.Sprintf("evt_%d", time.Now().UnixNano())
}