Initial Marktplaats SDK scaffold

Clone the twdehands SDK into mrktplaats and retarget naming and defaults for app.marktplaats.nl while keeping the same request/response bodies and endpoint behavior.

favorites.go

@@ -0,0 +1,62 @@
+package mrktplaats
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+)
+
+// FavoritesService handles saved/favorite ads.
+type FavoritesService struct {
+	t *transport
+}
+
+// FavoriteItem is a saved ad.
+type FavoriteItem struct {
+	ItemID       string `json:"itemId"`
+	CreationDate string `json:"creationDate"`
+}
+
+// FavoritesResponse is the response from listing favorite ads.
+type FavoritesResponse struct {
+	Items              []FavoriteItem `json:"items"`
+	MoreItemsAvailable bool           `json:"moreItemsAvailable"`
+	Total              int            `json:"total"`
+}
+
+type modifyFavoritesRequest struct {
+	AdURNs []string `json:"adUrns"`
+}
+
+type modifyFavoritesResponse struct {
+	Items []FavoriteItem `json:"items"`
+}
+
+// List returns the authenticated user's favorite ads.
+func (s *FavoritesService) List(ctx context.Context, limit int) (*FavoritesResponse, error) {
+	params := url.Values{}
+	if limit > 0 {
+		params.Set("limit", fmt.Sprintf("%d", limit))
+	}
+	var resp FavoritesResponse
+	if err := s.t.get(ctx, "/app/favorites/v1/favorite-ads", params, &resp); err != nil {
+		return nil, err
+	}
+	return &resp, nil
+}
+
+// Add saves one or more ads to favorites by their URNs.
+func (s *FavoritesService) Add(ctx context.Context, urns ...string) ([]FavoriteItem, error) {
+	body := modifyFavoritesRequest{AdURNs: urns}
+	var resp modifyFavoritesResponse
+	if err := s.t.postJSON(ctx, "/app/favorites/v2/favorite-ads", nil, nil, body, &resp); err != nil {
+		return nil, err
+	}
+	return resp.Items, nil
+}
+
+// Remove deletes one or more ads from favorites by their URNs.
+func (s *FavoritesService) Remove(ctx context.Context, urns ...string) error {
+	body := modifyFavoritesRequest{AdURNs: urns}
+	return s.t.postJSON(ctx, "/app/favorites/v2/favorite-ads/delete", nil, nil, body, nil)
+}