fix(zalo): correct json field mappings (#924)

Fixes #922 - Zalo OA bot was silently dropping all incoming messages due to JSON field mapping mismatches.

- Align zaloBotInfo/zaloFrom/zaloChat JSON tags with live API (display_name, chat_type)
- Change getUpdates to decode single-object response (API returns one update, not an array)
- Add dedicated pollClient with Timeout=0 + per-call context timeout for long-polling
- Update tests accordingly

internal/channels/zalo/zalo.go

@@ -44,6 +44,7 @@ type Channel struct {
 	blockReply *bool
 	stopCh     chan struct{}
 	client     *http.Client
+	pollClient *http.Client
 	// pairingService, pairingDebounce are inherited from channels.BaseChannel.
 }
 
@@ -74,6 +75,7 @@ func New(cfg config.ZaloConfig, msgBus *bus.MessageBus, pairingSvc store.Pairing
 		blockReply:  cfg.BlockReply,
 		stopCh:      make(chan struct{}),
 		client:      &http.Client{Timeout: 60 * time.Second},
+		pollClient:  &http.Client{Timeout: 0},
 	}
 	ch.SetPairingService(pairingSvc)
 	return ch, nil
@@ -398,7 +400,7 @@ type zaloAPIResponse struct {
 
 type zaloBotInfo struct {
 	ID   string `json:"id"`
-	Name string `json:"name"`
+	Name string `json:"display_name"`
 }
 
 type zaloMessage struct {
@@ -414,12 +416,12 @@ type zaloMessage struct {
 
 type zaloFrom struct {
 	ID       string `json:"id"`
-	Username string `json:"username"`
+	Username string `json:"display_name"`
 }
 
 type zaloChat struct {
 	ID   string `json:"id"`
-	Type string `json:"type"`
+	Type string `json:"chat_type"`
 }
 
 type zaloUpdate struct {
@@ -428,6 +430,10 @@ type zaloUpdate struct {
 }
 
 func (c *Channel) callAPI(method string, body any) (json.RawMessage, error) {
+	return c.callAPIWith(context.Background(), c.client, method, body)
+}
+
+func (c *Channel) callAPIWith(ctx context.Context, client *http.Client, method string, body any) (json.RawMessage, error) {
 	url := fmt.Sprintf("%s/bot%s/%s", apiBase, c.token, method)
 
 	var reqBody io.Reader
@@ -439,7 +445,7 @@ func (c *Channel) callAPI(method string, body any) (json.RawMessage, error) {
 		reqBody = bytes.NewReader(data)
 	}
 
-	req, err := http.NewRequest("POST", url, reqBody)
+	req, err := http.NewRequestWithContext(ctx, "POST", url, reqBody)
 	if err != nil {
 		return nil, fmt.Errorf("create request: %w", err)
 	}
@@ -447,7 +453,7 @@ func (c *Channel) callAPI(method string, body any) (json.RawMessage, error) {
 		req.Header.Set("Content-Type", "application/json")
 	}
 
-	resp, err := c.client.Do(req)
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("api call %s: %w", method, err)
 	}
@@ -488,16 +494,22 @@ func (c *Channel) getUpdates(timeout int) ([]zaloUpdate, error) {
 		"timeout": timeout,
 	}
 
-	result, err := c.callAPI("getUpdates", params)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout+7)*time.Second)
+	defer cancel()
+
+	result, err := c.callAPIWith(ctx, c.pollClient, "getUpdates", params)
 	if err != nil {
 		return nil, err
 	}
 
-	var updates []zaloUpdate
-	if err := json.Unmarshal(result, &updates); err != nil {
+	var update zaloUpdate
+	if err := json.Unmarshal(result, &update); err != nil {
 		return nil, fmt.Errorf("unmarshal updates: %w", err)
 	}
-	return updates, nil
+	if update.EventName == "" {
+		return nil, nil
+	}
+	return []zaloUpdate{update}, nil
 }
 
 func (c *Channel) sendMessage(chatID, text string) error {

internal/channels/zalo/zalo_test.go

@@ -115,7 +115,7 @@ func TestCallAPI_MalformedJSONReturnsError(t *testing.T) {
 // TestGetMe_ParsesBotInfo verifies getMe returns the zaloBotInfo struct.
 func TestGetMe_ParsesBotInfo(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, _ = w.Write([]byte(`{"ok":true,"result":{"id":"bot-xyz","name":"TestBot"}}`))
+		_, _ = w.Write([]byte(`{"ok":true,"result":{"id":"bot-xyz","display_name":"TestBot"}}`))
 	}))
 	defer srv.Close()
 
@@ -142,10 +142,10 @@ func TestGetMe_UnmarshalError(t *testing.T) {
 	}
 }
 
-// TestGetUpdates_ParsesUpdateArray verifies getUpdates decodes the updates array.
-func TestGetUpdates_ParsesUpdateArray(t *testing.T) {
+// TestGetUpdates_ParsesSingleUpdate verifies getUpdates decodes the single-object API response.
+func TestGetUpdates_ParsesSingleUpdate(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, _ = w.Write([]byte(`{"ok":true,"result":[{"event_name":"message.text.received","message":{"message_id":"m1","text":"hi","from":{"id":"user1"},"chat":{"id":"user1"}}}]}`))
+		_, _ = w.Write([]byte(`{"ok":true,"result":{"event_name":"message.text.received","message":{"message_id":"m1","text":"hi","from":{"id":"user1"},"chat":{"id":"user1"}}}}`))
 	}))
 	defer srv.Close()
 
@@ -168,7 +168,7 @@ func TestGetUpdates_ParsesUpdateArray(t *testing.T) {
 // TestGetUpdates_UnmarshalError verifies a malformed result surfaces an error.
 func TestGetUpdates_UnmarshalError(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, _ = w.Write([]byte(`{"ok":true,"result":"string-instead-of-array"}`))
+		_, _ = w.Write([]byte(`{"ok":true,"result":"not-an-object"}`))
 	}))
 	defer srv.Close()