package services

import (
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"os"

	"github.com/stripe/stripe-go/v76"
	"github.com/stripe/stripe-go/v76/checkout/session"
	"github.com/stripe/stripe-go/v76/webhook"
)

type SubscriptionService struct {
	DB *sql.DB
}

func NewSubscriptionService(db *sql.DB) *SubscriptionService {
	// Initialize Stripe
	stripe.Key = os.Getenv("STRIPE_SECRET_KEY")
	return &SubscriptionService{DB: db}
}

// CreateCheckoutSession создает сессию checkout для подписки
func (s *SubscriptionService) CreateCheckoutSession(companyID int, planID string, userEmail string) (string, error) {
	// Define price ID based on plan
	var priceID string
	switch planID {
	case "professional":
		priceID = os.Getenv("STRIPE_PRICE_PROFESSIONAL")
	case "enterprise":
		priceID = os.Getenv("STRIPE_PRICE_ENTERPRISE")
	default: // starter
		priceID = os.Getenv("STRIPE_PRICE_STARTER")
	}

	if priceID == "" {
		// Fallback for demo/development if envs are missing
		// In production this should error out
		if planID == "starter" {
			return "", errors.New("starter plan is free")
		}
		return "", fmt.Errorf("price id not configured for plan %s", planID)
	}

	frontendURL := os.Getenv("FRONTEND_URL")
	if frontendURL == "" {
		frontendURL = "http://localhost:8963"
	}

	params := &stripe.CheckoutSessionParams{
		CustomerEmail: stripe.String(userEmail),
		PaymentMethodTypes: stripe.StringSlice([]string{
			"card",
		}),
		LineItems: []*stripe.CheckoutSessionLineItemParams{
			{
				Price:    stripe.String(priceID),
				Quantity: stripe.Int64(1),
			},
		},
		Mode:       stripe.String(string(stripe.CheckoutSessionModeSubscription)),
		SuccessURL: stripe.String(frontendURL + "/dashboard?payment=success&session_id={CHECKOUT_SESSION_ID}"),
		CancelURL:  stripe.String(frontendURL + "/dashboard?payment=cancelled"),
		Metadata: map[string]string{
			"company_id": fmt.Sprintf("%d", companyID),
			"plan_id":    planID,
		},
	}

	// Add Pix if configured (usually requires BRL currency and specialized setup)
	// checking if we should add it dynamically or just rely on Stripe Dashboard settings
	// For API 2022-11-15+ payment_method_types is often inferred from dashboard
	// but adding it explicitly if we want to force it.
	// Note: Pix for subscriptions might have limitations.
	// Standard approach: use "card" and "boleto" or others if supported by the price currency (BRL).

	// If we want to support Pix, we might need to check if it's a one-time payment or subscription.
	// Recurring Pix is not fully standard in Stripe Checkout yet for all regions.
	// Let's stick generic for now and user can enable methods in Dashboard.

	sess, err := session.New(params)
	if err != nil {
		return "", err
	}

	return sess.URL, nil
}

// HandleWebhook processes Stripe events
func (s *SubscriptionService) HandleWebhook(payload []byte, signature string) error {
	endpointSecret := os.Getenv("STRIPE_WEBHOOK_SECRET")
	event, err := webhook.ConstructEvent(payload, signature, endpointSecret)
	if err != nil {
		return err
	}

	switch event.Type {
	case "checkout.session.completed":
		var session stripe.CheckoutSession
		if err := json.Unmarshal(event.Data.Raw, &session); err != nil {
			return err
		}

		// Extract company ID from metadata
		companyIDStr := session.Metadata["company_id"]
		planID := session.Metadata["plan_id"]

		if companyIDStr != "" && planID != "" {
			// Update company status
			_, err := s.DB.Exec(`
				UPDATE companies 
				SET stripe_customer_id = $1, 
					subscription_plan = $2, 
					subscription_status = 'active',
					updated_at = NOW()
				WHERE id = $3
			`, session.Customer.ID, planID, companyIDStr)

			if err != nil {
				log.Printf("Error updating company subscription: %v", err)
				return err
			}
		}

	case "invoice.payment_succeeded":
		var invoice stripe.Invoice
		if err := json.Unmarshal(event.Data.Raw, &invoice); err != nil {
			return err
		}
		if invoice.Subscription != nil {
			// Maintain active status
			// In a more complex system, we'd lookup company by stripe_customer_id
			_, err := s.DB.Exec(`
				UPDATE companies 
				SET subscription_status = 'active', updated_at = NOW()
				WHERE stripe_customer_id = $1
			`, invoice.Customer.ID)
			if err != nil {
				log.Printf("Error updating subscription status: %v", err)
			}
		}

	case "invoice.payment_failed":
		var invoice stripe.Invoice
		if err := json.Unmarshal(event.Data.Raw, &invoice); err != nil {
			return err
		}
		if invoice.Subscription != nil {
			// Mark as past_due or canceled
			_, err := s.DB.Exec(`
				UPDATE companies 
				SET subscription_status = 'past_due', updated_at = NOW()
				WHERE stripe_customer_id = $1
			`, invoice.Customer.ID)
			if err != nil {
				log.Printf("Error updating subscription status: %v", err)
			}
		}
	}

	return nil
}