feat(attachments): align list pagination

internal/handler/api/v1/conversation_handler_test.go

@@ -9,6 +9,7 @@ import (
 	"net/http/httptest"
 	"strconv"
 	"testing"
+	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/stretchr/testify/assert"
@@ -446,6 +447,41 @@ func (s *ConversationHandlerTestSuite) TestListAttachmentsReturnsChatwootPayload
 	assert.Contains(s.T(), item, "created_at")
 }
 
+func (s *ConversationHandlerTestSuite) TestListAttachmentsUsesChatwootFixedPageSize() {
+	conversation := &model.Conversation{AccountID: s.testAccount.ID, InboxID: s.testConv.InboxID, ContactID: s.testConv.ContactID, Status: "open", ChannelType: "web_widget", Channel: "web_widget"}
+	s.Require().NoError(s.db.Create(conversation).Error)
+	message := &model.Message{AccountID: s.testAccount.ID, InboxID: conversation.InboxID, ConversationID: conversation.ID, Content: "files", MessageType: "incoming", ContentType: "text", Status: "sent"}
+	s.Require().NoError(s.db.Create(message).Error)
+
+	baseTime := time.Now().Add(-time.Hour)
+	var newestID uint
+	for i := 0; i < 30; i++ {
+		attachment := &model.Attachment{
+			Base:      model.Base{CreatedAt: baseTime.Add(time.Duration(i) * time.Minute), UpdatedAt: baseTime.Add(time.Duration(i) * time.Minute)},
+			AccountID: s.testAccount.ID,
+			MessageID: message.ID,
+			FileType:  "file",
+			FileURL:   fmt.Sprintf("https://cdn.example.com/file-%02d.txt", i),
+			FileName:  fmt.Sprintf("file-%02d.txt", i),
+		}
+		s.Require().NoError(s.db.Create(attachment).Error)
+		newestID = attachment.ID
+	}
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest("GET", fmt.Sprintf("%s/conversations/%d/attachments?per_page=5", s.accountURL(), conversation.ID), nil)
+	s.router.ServeHTTP(w, req)
+
+	assert.Equal(s.T(), http.StatusOK, w.Code, w.Body.String())
+	var resp map[string]any
+	assert.NoError(s.T(), json.Unmarshal(w.Body.Bytes(), &resp))
+	assert.Equal(s.T(), float64(30), resp["meta"].(map[string]any)["total_count"])
+	payload := resp["payload"].([]any)
+	assert.Len(s.T(), payload, 30)
+	first := payload[0].(map[string]any)
+	assert.Equal(s.T(), float64(newestID), first["id"])
+}
+
 func (s *ConversationHandlerTestSuite) TestToggleTyping_InvalidAccountID() {
 	w := httptest.NewRecorder()
 	req, _ := http.NewRequest("POST", "/api/v1/accounts/abc/conversations/1/toggle_typing", bytes.NewBufferString(`{"typing_status":"on"}`))