stickers: page owned packs by count received

pkg/line/stickers.go

@@ -28,9 +28,9 @@ type StickerSummary struct {
 func (c *Client) GetOwnedStickerProducts(ctx context.Context, country string) ([]ShopProduct, error) {
 	const pageSize, maxProducts = 1000, 100000
 	var products []ShopProduct
-	for offset := 0; offset < maxProducts; {
+	for len(products) < maxProducts {
 		resp, err := c.callRPCWithBaseURLContext(ctx, ShopBaseURL, "ShopService", "getOwnedProductSummaries",
-			"stickershop", offset, pageSize, map[string]string{"language": "en", "country": country})
+			"stickershop", len(products), pageSize, map[string]string{"language": "en", "country": country})
 		if err != nil {
 			return nil, err
 		}
@@ -39,7 +39,6 @@ func (c *Client) GetOwnedStickerProducts(ctx context.Context, country string) ([
 			Message string `json:"message"`
 			Data    *struct {
 				Products []ShopProduct `json:"productList"`
-				Offset   int           `json:"offset"`
 				Total    int           `json:"totalSize"`
 			} `json:"data"`
 		}
@@ -48,19 +47,20 @@ func (c *Client) GetOwnedStickerProducts(ctx context.Context, country string) ([
 		}
 		if result.Code != 0 {
 			return nil, fmt.Errorf("getOwnedProductSummaries failed: code %d: %s", result.Code, result.Message)
+		} else if result.Data == nil {
+			return nil, fmt.Errorf("getOwnedProductSummaries returned no data")
 		}
-		data := result.Data
-		if data == nil || data.Offset != offset || data.Total < offset || data.Total > maxProducts {
-			return nil, fmt.Errorf("invalid LINE shop pagination")
-		}
-		products = append(products, data.Products...)
-		offset += len(data.Products)
-		if offset >= data.Total {
+		page := result.Data.Products
+		products = append(products, page...)
+		if result.Data.Total > 0 {
+			if len(products) >= result.Data.Total {
+				return products, nil
+			} else if len(page) == 0 {
+				return nil, fmt.Errorf("getOwnedProductSummaries returned empty page at %d of %d products", len(products), result.Data.Total)
+			}
+		} else if len(page) < pageSize {
 			return products, nil
 		}
-		if len(data.Products) == 0 {
-			return nil, fmt.Errorf("empty LINE shop page before end of catalog")
-		}
 	}
 	return nil, fmt.Errorf("LINE shop catalog exceeded pagination limit")
 }

pkg/line/stickers_test.go

@@ -0,0 +1,76 @@
+package line
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"slices"
+	"strings"
+	"testing"
+)
+
+func TestGetOwnedStickerProductsPaging(t *testing.T) {
+	page := func(total int, ids ...string) string {
+		products := make([]string, len(ids))
+		for i, id := range ids {
+			products[i] = fmt.Sprintf(`{"id":%q}`, id)
+		}
+		totalField := ""
+		if total >= 0 {
+			totalField = fmt.Sprintf(`,"totalSize":%d`, total)
+		}
+		return fmt.Sprintf(`{"code":0,"data":{"offset":0%s,"productList":[%s]}}`, totalField, strings.Join(products, ","))
+	}
+	fullPage := make([]string, 1000)
+	for i := range fullPage {
+		fullPage[i] = fmt.Sprint(i)
+	}
+	tests := []struct {
+		name        string
+		pages       []string
+		wantIDs     []string
+		wantOffsets []int
+		wantErr     bool
+	}{
+		{"ignores echoed offset and short pages", []string{page(3, "1", "2"), page(3, "3")}, []string{"1", "2", "3"}, []int{0, 2}, false},
+		{"errors on empty page before total", []string{page(5, "1", "2"), page(5)}, nil, []int{0, 2}, true},
+		{"errors on null data", []string{`{"code":0,"data":null}`}, nil, []int{0}, true},
+		{"missing total", []string{page(-1, "1")}, []string{"1"}, []int{0}, false},
+		{"zero total stops on empty page", []string{page(0)}, nil, []int{0}, false},
+		{"missing total pages until short page", []string{page(-1, fullPage...), page(-1, "1000")}, append(slices.Clone(fullPage), "1000"), []int{0, 1000}, false},
+		{"zero total pages until empty page", []string{page(0, fullPage...), page(0)}, fullPage, []int{0, 1000}, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var offsets []int
+			client := NewClient("token")
+			client.HTTPClient = &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+				var args []json.RawMessage
+				body, _ := io.ReadAll(req.Body)
+				if err := json.Unmarshal(body, &args); err != nil || len(args) != 4 || string(args[0]) != `"stickershop"` {
+					t.Fatalf("unexpected request body %s", body)
+				}
+				var offset int
+				_ = json.Unmarshal(args[1], &offset)
+				offsets = append(offsets, offset)
+				if len(offsets) > len(tt.pages) {
+					t.Fatalf("too many requests")
+				}
+				return obsResponse(http.StatusOK, tt.pages[len(offsets)-1]), nil
+			})}
+			products, err := client.GetOwnedStickerProducts(context.Background(), "JP")
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("err = %v, wantErr %v", err, tt.wantErr)
+			}
+			var ids []string
+			for _, product := range products {
+				ids = append(ids, product.ID)
+			}
+			if !slices.Equal(ids, tt.wantIDs) || !slices.Equal(offsets, tt.wantOffsets) {
+				t.Fatalf("ids = %v offsets = %v, want %v %v", ids, offsets, tt.wantIDs, tt.wantOffsets)
+			}
+		})
+	}
+}