wip: add long message helpers and payload type controls

- add centralized message validation errors
- switch command handlers to return error
- add explicit long plain-text reply helpers
- support strict payload type policy with debug logging
- document versioning and changelog workflow

msg_context_test.go

@@ -2,8 +2,10 @@ package laniakea
 
 import (
 	"encoding/json"
+	"errors"
 	"io"
 	"net/http"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -62,3 +64,146 @@ func TestAnswerPhotoIncludesDirectMessagesTopicID(t *testing.T) {
 		t.Fatalf("unexpected direct_messages_topic_id: %v", got)
 	}
 }
+
+func TestAnswerRejectsEmptyMessage(t *testing.T) {
+	ctx := &MsgContext{
+		Msg:    &tgapi.Message{Chat: &tgapi.Chat{ID: 42, Type: string(tgapi.ChatTypePrivate)}},
+		Logger: slog.CreateLogger(),
+	}
+
+	if answer := ctx.Answer(""); answer != nil {
+		t.Fatal("expected nil answer for empty message")
+	}
+}
+
+func TestAnswerRejectsLongMessageWithoutSendingRequest(t *testing.T) {
+	client := &http.Client{
+		Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+			t.Fatal("unexpected HTTP request")
+			return nil, nil
+		}),
+	}
+
+	api := tgapi.NewAPI(
+		tgapi.NewAPIOpts("token").
+			SetAPIUrl("https://example.test").
+			SetHTTPClient(client),
+	)
+	defer func() {
+		if err := api.Close(); err != nil {
+			t.Fatalf("Close returned error: %v", err)
+		}
+	}()
+
+	ctx := &MsgContext{
+		Api:    api,
+		Msg:    &tgapi.Message{Chat: &tgapi.Chat{ID: 42, Type: string(tgapi.ChatTypePrivate)}},
+		Logger: slog.CreateLogger(),
+	}
+
+	if answer := ctx.Answer(strings.Repeat("a", maxMessageTextLen+1)); answer != nil {
+		t.Fatal("expected nil answer for long message")
+	}
+}
+
+func TestValidateMessageText(t *testing.T) {
+	if err := validateMessageText(""); !errors.Is(err, ErrEmptyMessage) {
+		t.Fatalf("expected ErrEmptyMessage, got %v", err)
+	}
+	if err := validateMessageText(strings.Repeat("a", maxMessageTextLen+1)); !errors.Is(err, ErrMessageTooLong) {
+		t.Fatalf("expected ErrMessageTooLong, got %v", err)
+	}
+	if err := validateMessageText("ok"); err != nil {
+		t.Fatalf("expected nil error, got %v", err)
+	}
+}
+
+func TestValidateCaptionText(t *testing.T) {
+	if err := validateCaptionText(strings.Repeat("a", maxMessageCaptionLen+1)); !errors.Is(err, ErrCaptionTooLong) {
+		t.Fatalf("expected ErrCaptionTooLong, got %v", err)
+	}
+	if err := validateCaptionText(""); err != nil {
+		t.Fatalf("expected nil error, got %v", err)
+	}
+}
+
+func TestSplitMessageTextPreservesContent(t *testing.T) {
+	text := "alpha beta\n" + strings.Repeat("x", maxMessageTextLen) + " omega"
+
+	parts := SplitMessageText(text)
+	if len(parts) < 2 {
+		t.Fatalf("expected multiple parts, got %d", len(parts))
+	}
+
+	for i, part := range parts {
+		if got := len([]rune(part)); got > maxMessageTextLen {
+			t.Fatalf("part %d exceeded limit: %d", i, got)
+		}
+	}
+
+	if got := strings.Join(parts, ""); got != text {
+		t.Fatalf("split/join mismatch: got %q want %q", got, text)
+	}
+}
+
+func TestAnswerLongSplitsRequestsAndAttachesKeyboardToLastChunk(t *testing.T) {
+	var requests []map[string]any
+
+	client := &http.Client{
+		Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+			body, err := io.ReadAll(req.Body)
+			if err != nil {
+				t.Fatalf("failed to read request body: %v", err)
+			}
+			var got map[string]any
+			if err := json.Unmarshal(body, &got); err != nil {
+				t.Fatalf("failed to decode request body: %v", err)
+			}
+			requests = append(requests, got)
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Header:     http.Header{"Content-Type": []string{"application/json"}},
+				Body:       io.NopCloser(strings.NewReader(`{"ok":true,"result":{"message_id":9,"date":1}}`)),
+			}, nil
+		}),
+	}
+
+	api := tgapi.NewAPI(
+		tgapi.NewAPIOpts("token").
+			SetAPIUrl("https://example.test").
+			SetHTTPClient(client),
+	)
+	defer func() {
+		if err := api.Close(); err != nil {
+			t.Fatalf("Close returned error: %v", err)
+		}
+	}()
+
+	ctx := &MsgContext{
+		Api:    api,
+		Msg:    &tgapi.Message{Chat: &tgapi.Chat{ID: 42, Type: string(tgapi.ChatTypePrivate)}},
+		Logger: slog.CreateLogger(),
+	}
+	kb := NewInlineKeyboardJson(1).AddCallbackButton("A", "cmd")
+	text := strings.Repeat("a", maxMessageTextLen) + " " + strings.Repeat("b", 32)
+
+	messages := ctx.KeyboardLong(text, kb)
+	if got := len(messages); got != 2 {
+		t.Fatalf("expected 2 sent messages, got %d", got)
+	}
+	if got := len(requests); got != 2 {
+		t.Fatalf("expected 2 requests, got %d", got)
+	}
+	if _, ok := requests[0]["reply_markup"]; ok {
+		t.Fatal("did not expect keyboard on first chunk")
+	}
+	if _, ok := requests[1]["reply_markup"]; !ok {
+		t.Fatal("expected keyboard on final chunk")
+	}
+
+	gotTexts := []string{requests[0]["text"].(string), requests[1]["text"].(string)}
+	wantTexts := SplitMessageText(text)
+	if !reflect.DeepEqual(gotTexts, wantTexts) {
+		t.Fatalf("unexpected chunk texts: got %q want %q", gotTexts, wantTexts)
+	}
+}