package checkout

import (
	"encoding/json"
	"fmt"

	"git.k6n.net/go-cart-actor/pkg/cart"
	messages "git.k6n.net/go-cart-actor/proto/checkout"
)

// mutation_initialize_checkout.go
//
// Registers the InitializeCheckout mutation.
// This mutation is invoked AFTER an external checkout session
// has been successfully created or updated. It persists the
// order reference / status and marks the checkout as having a payment in progress.
//
// Behavior:
//   - Sets OrderId to the order ID.
//   - Sets Status to the current status.
//   - Sets PaymentInProgress flag.
//   - Assumes inventory is already reserved.
//
// Validation:
//   - Returns an error if payload is nil.
//   - Returns an error if orderId is empty.

func HandleInitializeCheckout(g *CheckoutGrain, m *messages.InitializeCheckout) error {
	if m == nil {
		return fmt.Errorf("InitializeCheckout: nil payload")
	}
	// if g.OrderId == "" {
	// 	return fmt.Errorf("InitializeCheckout: missing orderId")
	// }
	if g.CartState != nil {
		if g.CartId != cart.CartId(m.CartId) {
			return fmt.Errorf("InitializeCheckout: cart ID mismatch")
		}
		if g.PaymentInProgress > 0 || g.OrderId != nil {
			return fmt.Errorf("InitializeCheckout: payment already in progress")
		}
	}

	err := json.Unmarshal(m.CartState.Value, &g.CartState)
	if err != nil {
		return err
	}

	g.CartTotalPrice = g.CartState.TotalPrice

	return nil
}