package repository

import (
	"context"
	"errors"
	"time"

	"github.com/google/uuid"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"

	"tm/internal/domain"
	"tm/pkg/logger"
)

// CustomerRepositoryImpl implements the CustomerRepository interface
type CustomerRepositoryImpl struct {
	collection *mongo.Collection
	logger     logger.Logger
}

// NewCustomerRepository creates a new customer repository
func NewCustomerRepository(db *mongo.Database, logger logger.Logger) domain.CustomerRepository {
	collection := db.Collection("customers")

	// Create indexes
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

		// Email index (unique)
	emailIndex := mongo.IndexModel{
		Keys:    bson.D{{"email", 1}},
		Options: options.Index().SetUnique(true),
	}
	
	// Company ID index
	companyIndex := mongo.IndexModel{
		Keys: bson.D{{"company_id", 1}},
	}
	
	// Active status index
	activeIndex := mongo.IndexModel{
		Keys: bson.D{{"is_active", 1}},
	}
	
	// Created at index
	createdAtIndex := mongo.IndexModel{
		Keys: bson.D{{"created_at", -1}},
	}

	_, err := collection.Indexes().CreateMany(ctx, []mongo.IndexModel{
		emailIndex,
		companyIndex,
		activeIndex,
		createdAtIndex,
	})

	if err != nil {
		logger.Warn("Failed to create customer indexes", map[string]interface{}{
			"error": err.Error(),
		})
	}

	return &CustomerRepositoryImpl{
		collection: collection,
		logger:     logger,
	}
}

// Create creates a new customer
func (r *CustomerRepositoryImpl) Create(ctx context.Context, customer *domain.Customer) error {
	// Set created/updated timestamps
	now := time.Now()
	customer.CreatedAt = now
	customer.UpdatedAt = now

	// Insert customer
	_, err := r.collection.InsertOne(ctx, customer)
	if err != nil {
		if mongo.IsDuplicateKeyError(err) {
			return errors.New("customer already exists")
		}
		r.logger.Error("Failed to create customer", map[string]interface{}{
			"error":       err.Error(),
			"email":       customer.Email,
			"customer_id": customer.ID.String(),
		})
		return err
	}

	r.logger.Info("Customer created successfully", map[string]interface{}{
		"customer_id": customer.ID.String(),
		"email":       customer.Email,
	})

	return nil
}

// GetByID retrieves a customer by ID
func (r *CustomerRepositoryImpl) GetByID(ctx context.Context, id uuid.UUID) (*domain.Customer, error) {
	var customer domain.Customer

	filter := bson.M{"_id": id}
	err := r.collection.FindOne(ctx, filter).Decode(&customer)

	if err != nil {
		if err == mongo.ErrNoDocuments {
			return nil, errors.New("customer not found")
		}
		r.logger.Error("Failed to get customer by ID", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": id.String(),
		})
		return nil, err
	}

	return &customer, nil
}

// GetByEmail retrieves a customer by email
func (r *CustomerRepositoryImpl) GetByEmail(ctx context.Context, email string) (*domain.Customer, error) {
	var customer domain.Customer

	filter := bson.M{"email": email}
	err := r.collection.FindOne(ctx, filter).Decode(&customer)

	if err != nil {
		if err == mongo.ErrNoDocuments {
			return nil, errors.New("customer not found")
		}
		r.logger.Error("Failed to get customer by email", map[string]interface{}{
			"error": err.Error(),
			"email": email,
		})
		return nil, err
	}

	return &customer, nil
}

// Update updates a customer
func (r *CustomerRepositoryImpl) Update(ctx context.Context, customer *domain.Customer) error {
	// Set updated timestamp
	customer.UpdatedAt = time.Now()

	filter := bson.M{"_id": customer.ID}
	update := bson.M{"$set": customer}

	result, err := r.collection.UpdateOne(ctx, filter, update)
	if err != nil {
		r.logger.Error("Failed to update customer", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": customer.ID.String(),
		})
		return err
	}

	if result.MatchedCount == 0 {
		return errors.New("customer not found")
	}

	r.logger.Info("Customer updated successfully", map[string]interface{}{
		"customer_id": customer.ID.String(),
		"email":       customer.Email,
	})

	return nil
}

// Delete deletes a customer (soft delete by setting is_active to false)
func (r *CustomerRepositoryImpl) Delete(ctx context.Context, id uuid.UUID) error {
	filter := bson.M{"_id": id}
	update := bson.M{
		"$set": bson.M{
			"is_active":  false,
			"updated_at": time.Now(),
		},
	}

	result, err := r.collection.UpdateOne(ctx, filter, update)
	if err != nil {
		r.logger.Error("Failed to delete customer", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": id.String(),
		})
		return err
	}

	if result.MatchedCount == 0 {
		return errors.New("customer not found")
	}

	r.logger.Info("Customer deleted successfully", map[string]interface{}{
		"customer_id": id.String(),
	})

	return nil
}

// List retrieves customers with pagination
func (r *CustomerRepositoryImpl) List(ctx context.Context, limit, offset int) ([]*domain.Customer, error) {
	var customers []*domain.Customer

	// Build options
	opts := options.Find()
	opts.SetLimit(int64(limit))
	opts.SetSkip(int64(offset))
	opts.SetSort(bson.D{{"created_at", -1}}) // Sort by created_at desc

	// Only active customers by default
	filter := bson.M{"is_active": true}

	cursor, err := r.collection.Find(ctx, filter, opts)
	if err != nil {
		r.logger.Error("Failed to list customers", map[string]interface{}{
			"error":  err.Error(),
			"limit":  limit,
			"offset": offset,
		})
		return nil, err
	}
	defer cursor.Close(ctx)

	if err = cursor.All(ctx, &customers); err != nil {
		r.logger.Error("Failed to decode customers", map[string]interface{}{
			"error": err.Error(),
		})
		return nil, err
	}

	return customers, nil
}

// GetByCompanyID retrieves customers by company ID with pagination
func (r *CustomerRepositoryImpl) GetByCompanyID(ctx context.Context, companyID uuid.UUID, limit, offset int) ([]*domain.Customer, error) {
	var customers []*domain.Customer

	// Build options
	opts := options.Find()
	opts.SetLimit(int64(limit))
	opts.SetSkip(int64(offset))
	opts.SetSort(bson.D{{"created_at", -1}}) // Sort by created_at desc

	// Filter by company ID and active status
	filter := bson.M{
		"company_id": companyID,
		"is_active":  true,
	}

	cursor, err := r.collection.Find(ctx, filter, opts)
	if err != nil {
		r.logger.Error("Failed to get customers by company ID", map[string]interface{}{
			"error":      err.Error(),
			"company_id": companyID.String(),
			"limit":      limit,
			"offset":     offset,
		})
		return nil, err
	}
	defer cursor.Close(ctx)

	if err = cursor.All(ctx, &customers); err != nil {
		r.logger.Error("Failed to decode customers by company", map[string]interface{}{
			"error":      err.Error(),
			"company_id": companyID.String(),
		})
		return nil, err
	}

	return customers, nil
}

// UpdatePreferences updates customer preferences
func (r *CustomerRepositoryImpl) UpdatePreferences(ctx context.Context, id uuid.UUID, preferences *domain.CustomerPreferences) error {
	filter := bson.M{"_id": id}
	update := bson.M{
		"$set": bson.M{
			"preferences": preferences,
			"updated_at":  time.Now(),
		},
	}

	result, err := r.collection.UpdateOne(ctx, filter, update)
	if err != nil {
		r.logger.Error("Failed to update customer preferences", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": id.String(),
		})
		return err
	}

	if result.MatchedCount == 0 {
		return errors.New("customer not found")
	}

	r.logger.Info("Customer preferences updated successfully", map[string]interface{}{
		"customer_id": id.String(),
	})

	return nil
}

// AddDeviceToken adds a device token for push notifications
func (r *CustomerRepositoryImpl) AddDeviceToken(ctx context.Context, id uuid.UUID, token string) error {
	filter := bson.M{"_id": id}
	update := bson.M{
		"$addToSet": bson.M{"device_tokens": token}, // Use $addToSet to avoid duplicates
		"$set":      bson.M{"updated_at": time.Now()},
	}

	result, err := r.collection.UpdateOne(ctx, filter, update)
	if err != nil {
		r.logger.Error("Failed to add device token", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": id.String(),
			"token":       token,
		})
		return err
	}

	if result.MatchedCount == 0 {
		return errors.New("customer not found")
	}

	r.logger.Info("Device token added successfully", map[string]interface{}{
		"customer_id": id.String(),
		"token":       token,
	})

	return nil
}

// RemoveDeviceToken removes a device token
func (r *CustomerRepositoryImpl) RemoveDeviceToken(ctx context.Context, id uuid.UUID, token string) error {
	filter := bson.M{"_id": id}
	update := bson.M{
		"$pull": bson.M{"device_tokens": token}, // Use $pull to remove the token
		"$set":  bson.M{"updated_at": time.Now()},
	}

	result, err := r.collection.UpdateOne(ctx, filter, update)
	if err != nil {
		r.logger.Error("Failed to remove device token", map[string]interface{}{
			"error":       err.Error(),
			"customer_id": id.String(),
			"token":       token,
		})
		return err
	}

	if result.MatchedCount == 0 {
		return errors.New("customer not found")
	}

	r.logger.Info("Device token removed successfully", map[string]interface{}{
		"customer_id": id.String(),
		"token":       token,
	})

	return nil
}