refactor/checkout (#8)

Co-authored-by: matst80 <mats.tornberg@gmail.com>
Reviewed-on: #8
Co-authored-by: Mats Törnberg <mats@tornberg.me>
Co-committed-by: Mats Törnberg <mats@tornberg.me>

cmd/checkout/cart-client.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	"git.k6n.net/go-cart-actor/pkg/cart"
+)
+
+type CartClient struct {
+	httpClient *http.Client
+	baseUrl    string
+}
+
+func NewCartClient(baseUrl string) *CartClient {
+	return &CartClient{
+		httpClient: &http.Client{Timeout: 10 * time.Second},
+		baseUrl:    baseUrl,
+	}
+}
+
+// func (c *CartClient) ApplyMutation(cartId cart.CartId, mutation proto.Message) error {
+// 	url := fmt.Sprintf("%s/internal/cart/%s/mutation", c.baseUrl, cartId.String())
+// 	data, err := proto.Marshal(mutation)
+// 	if err != nil {
+// 		return err
+// 	}
+// 	req, err := http.NewRequest("POST", url, bytes.NewReader(data))
+// 	if err != nil {
+// 		return err
+// 	}
+// 	req.Header.Set("Content-Type", "application/protobuf")
+// 	resp, err := c.httpClient.Do(req)
+// 	if err != nil {
+// 		return err
+// 	}
+// 	defer resp.Body.Close()
+// 	if resp.StatusCode != http.StatusOK {
+// 		return fmt.Errorf("cart mutation failed: %s", resp.Status)
+// 	}
+// 	return nil
+// }
+
+func (s *CartClient) getCartGrain(ctx context.Context, cartId cart.CartId) (*cart.CartGrain, error) {
+	// Call cart service to get grain
+	url := fmt.Sprintf("%s/cart/byid/%d", s.baseUrl, cartId.String())
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := s.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to get cart: %s", resp.Status)
+	}
+	var grain cart.CartGrain
+	err = json.NewDecoder(resp.Body).Decode(&grain)
+	return &grain, err
+}