fix(channels): deliver long Telegram and Discord replies

src/channels/channel.h

@@ -37,6 +37,19 @@ typedef struct channel_incoming_msg {
 /** Clear and free incoming message fields. Safe to call repeatedly or on zeroed. */
 void channel_incoming_msg_clear(channel_incoming_msg_t *msg);
 
+/**
+ * Byte length of the next outbound piece of @p text.
+ * The piece is at most @p max_bytes and stops before a multibyte UTF-8
+ * character that would not fit, so chat APIs do not see a split code point.
+ *
+ * Example: `channel_outbound_chunk_len("hello", 2)` returns 2.
+ *
+ * @param text      NUL-terminated text. NULL returns 0.
+ * @param max_bytes Maximum piece size in bytes. 0 returns 0.
+ * @return Byte length of the next piece, or 0 when @p text is empty.
+ */
+size_t channel_outbound_chunk_len(const char *text, size_t max_bytes);
+
 /**
  * Channel vtable: init, poll, send, cleanup. CLI and Telegram implement this.
  */

src/channels/channel_common.c

@@ -31,6 +31,23 @@ const channel_t *channel_get_by_name(const char *name)
 	return NULL;
 }
 
+size_t channel_outbound_chunk_len(const char *text, size_t max_bytes)
+{
+	size_t len;
+	size_t n;
+
+	if (!text || max_bytes == 0)
+		return 0;
+	len = strlen(text);
+	if (len <= max_bytes)
+		return len;
+	/* Walk back over UTF-8 continuation bytes so the cut sits on a boundary. */
+	n = max_bytes;
+	while (n > 0 && ((unsigned char)text[n] & 0xC0) == 0x80)
+		n--;
+	return n > 0 ? n : max_bytes;
+}
+
 void channel_incoming_msg_clear(channel_incoming_msg_t *msg)
 {
 	if (!msg) return;

src/channels/discord.c

@@ -862,25 +862,13 @@ static int discord_recipient_channel_id(const char *recipient, char *out, size_t
 	return 0;
 }
 
-static int discord_send(const char *recipient, const char *text,
-                        const channel_attachment_t *attachments, size_t att_count)
+static int discord_post_text(const char *channel_id, const char *text, const char *auth_hdr)
 {
-	struct discord_ctx *dc = &g_dc;
-	char channel_id[DISCORD_CHANNEL_ID_CAP];
 	cJSON *root;
 	char *json_body;
 	char url[DISCORD_URL_CAP];
-	char auth_hdr[DISCORD_AUTH_HDR_CAP];
 	int attempt;
-	(void)attachments;
-	if (att_count > 0)
-		return -1;
-	if (!dc->token || !recipient || !text || text[0] == '\0')
-		return -1;
-	if (strlen(text) > (size_t)DISCORD_MSG_MAX_LEN)
-		return -1;
-	if (discord_recipient_channel_id(recipient, channel_id, sizeof(channel_id)) != 0)
-		return -1;
+
 	root = cJSON_CreateObject();
 	if (!root)
 		return -1;
@@ -893,10 +881,6 @@ static int discord_send(const char *recipient, const char *text,
 		free(json_body);
 		return -1;
 	}
-	if (snprintf(auth_hdr, sizeof(auth_hdr), "Authorization: Bot %s", dc->token) >= (int)sizeof(auth_hdr)) {
-		free(json_body);
-		return -1;
-	}
 	for (attempt = 0; attempt < DISCORD_SEND_MAX_ATTEMPTS; attempt++) {
 		struct discord_hdr_ud hd = { -1.0 };
 		struct curl_slist *hdrs = NULL;
@@ -949,9 +933,46 @@ static int discord_send(const char *recipient, const char *text,
 		free(json_body);
 		return -1;
 	}
+	free(json_body);
 	return -1;
 }
 
+static int discord_send(const char *recipient, const char *text,
+                        const channel_attachment_t *attachments, size_t att_count)
+{
+	struct discord_ctx *dc = &g_dc;
+	char channel_id[DISCORD_CHANNEL_ID_CAP];
+	char auth_hdr[DISCORD_AUTH_HDR_CAP];
+	const char *cursor;
+
+	(void)attachments;
+	if (att_count > 0)
+		return -1;
+	if (!dc->token || !recipient || !text || text[0] == '\0')
+		return -1;
+	if (discord_recipient_channel_id(recipient, channel_id, sizeof(channel_id)) != 0)
+		return -1;
+	if (snprintf(auth_hdr, sizeof(auth_hdr), "Authorization: Bot %s", dc->token) >=
+	    (int)sizeof(auth_hdr))
+		return -1;
+	/* A single REST message is 2000 characters. Longer replies used to fail
+	 * the whole send, so cron kept re-running the agent and the user saw nothing. */
+	cursor = text;
+	while (cursor[0] != '\0') {
+		char piece[DISCORD_MSG_MAX_LEN + 1];
+		size_t n = channel_outbound_chunk_len(cursor, (size_t)DISCORD_MSG_MAX_LEN);
+
+		if (n == 0 || n > (size_t)DISCORD_MSG_MAX_LEN)
+			return -1;
+		memcpy(piece, cursor, n);
+		piece[n] = '\0';
+		if (discord_post_text(channel_id, piece, auth_hdr) != 0)
+			return -1;
+		cursor += n;
+	}
+	return 0;
+}
+
 static void discord_cleanup(void)
 {
 	struct discord_pending *pending;

src/channels/telegram.c

@@ -21,6 +21,8 @@
 #define POLL_TIMEOUT_SEC 30
 #define RESP_BUF_SIZE (256 * 1024)
 #define RESP_BUF_INIT 4096
+/* Bot API sendMessage text limit. Longer agent replies are sent as several messages. */
+#define TG_TEXT_MAX 4096
 
 struct telegram_ctx {
 	char *token;
@@ -261,43 +263,129 @@ static int tg_poll(channel_incoming_msg_t *out, int timeout_ms)
 	return 0;
 }
 
-static int tg_send(const char *recipient, const char *text,
-                   const channel_attachment_t *attachments, size_t att_count)
+/* Curl success is not delivery. sendMessage reports refusal in HTTP status and ok. */
+static int telegram_response_ok(long http_code, const char *body)
+{
+	cJSON *root;
+	cJSON *ok_item;
+
+	if (http_code < 200 || http_code >= 300)
+		return 0;
+	if (!body || body[0] == '\0')
+		return 0;
+	root = cJSON_Parse(body);
+	if (!root || !cJSON_IsObject(root)) {
+		if (root)
+			cJSON_Delete(root);
+		return 0;
+	}
+	ok_item = cJSON_GetObjectItemCaseSensitive(root, "ok");
+	if (!cJSON_IsBool(ok_item) || !cJSON_IsTrue(ok_item)) {
+		cJSON_Delete(root);
+		return 0;
+	}
+	cJSON_Delete(root);
+	return 1;
+}
+
+static int telegram_perform_post(CURL *curl, const char *url, const char *postfields)
+{
+	tg_buf_t resp;
+	long http_code = 0;
+	int ret = -1;
+
+	resp.buf = malloc(RESP_BUF_INIT);
+	if (!resp.buf)
+		return -1;
+	resp.len = 0;
+	resp.cap = RESP_BUF_INIT;
+	resp.buf[0] = '\0';
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postfields);
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_cb);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &resp);
+	if (tg_curl_perform(curl, "sendMessage") == 0) {
+		curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
+		if (telegram_response_ok(http_code, resp.buf))
+			ret = 0;
+		else
+			fprintf(stderr, "shellclaw: telegram: sendMessage rejected HTTP %ld\n",
+			        http_code);
+	}
+	free(resp.buf);
+	return ret;
+}
+
+static int telegram_post_chunk(const char *chat_id, const char *text)
 {
-	(void)attachments;
-	(void)att_count;
-	if (!g_tg.initialized || !g_tg.token || !recipient || !text) return -1;
-	const char *chat_id = strchr(recipient, ':');
-	if (chat_id) chat_id++;
-	else chat_id = recipient;
 	char url[512];
-	snprintf(url, sizeof(url), "%s%s/%s", TG_API_BASE, g_tg.token, TG_SEND_MSG);
-	CURL *curl = curl_easy_init();
-	if (!curl) return -1;
+	CURL *curl;
+	char *escaped;
+	char *postfields;
+	int ret;
+	size_t need;
+
+	curl = curl_easy_init();
+	if (!curl)
+		return -1;
 	tg_curl_harden(curl);
 	curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);
 	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10L);
 	curl_easy_setopt(curl, CURLOPT_TIMEOUT, 30L);
-	char *escaped = curl_easy_escape(curl, text, (int)strlen(text));
+	snprintf(url, sizeof(url), "%s%s/%s", TG_API_BASE, g_tg.token, TG_SEND_MSG);
+	escaped = curl_easy_escape(curl, text, (int)strlen(text));
 	if (!escaped) {
 		curl_easy_cleanup(curl);
 		return -1;
 	}
-	size_t need = strlen(chat_id) + strlen(escaped) + 32;
-	char *postfields = malloc(need);
-	int ret = -1;
-	if (postfields) {
-		snprintf(postfields, need, "chat_id=%s&text=%s", chat_id, escaped);
-		curl_easy_setopt(curl, CURLOPT_URL, url);
-		curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postfields);
-		ret = (tg_curl_perform(curl, "sendMessage") == 0) ? 0 : -1;
-		free(postfields);
+	need = strlen(chat_id) + strlen(escaped) + 32;
+	postfields = malloc(need);
+	if (!postfields) {
+		curl_free(escaped);
+		curl_easy_cleanup(curl);
+		return -1;
 	}
+	snprintf(postfields, need, "chat_id=%s&text=%s", chat_id, escaped);
+	ret = telegram_perform_post(curl, url, postfields);
+	free(postfields);
 	curl_free(escaped);
 	curl_easy_cleanup(curl);
 	return ret;
 }
 
+static int tg_send(const char *recipient, const char *text,
+                   const channel_attachment_t *attachments, size_t att_count)
+{
+	const char *chat_id;
+	const char *cursor;
+
+	(void)attachments;
+	(void)att_count;
+	if (!g_tg.initialized || !g_tg.token || !recipient || !text || text[0] == '\0')
+		return -1;
+	chat_id = strchr(recipient, ':');
+	if (chat_id)
+		chat_id++;
+	else
+		chat_id = recipient;
+	if (chat_id[0] == '\0')
+		return -1;
+	cursor = text;
+	while (cursor[0] != '\0') {
+		char piece[TG_TEXT_MAX + 1];
+		size_t n = channel_outbound_chunk_len(cursor, TG_TEXT_MAX);
+
+		if (n == 0 || n > TG_TEXT_MAX)
+			return -1;
+		memcpy(piece, cursor, n);
+		piece[n] = '\0';
+		if (telegram_post_chunk(chat_id, piece) != 0)
+			return -1;
+		cursor += n;
+	}
+	return 0;
+}
+
 static void tg_cleanup(void)
 {
 	free(g_tg.token);
@@ -335,4 +423,9 @@ void telegram_set_test_config(const config_t *cfg)
 {
 	g_tg.cfg = cfg;
 }
+
+int telegram_response_ok_for_test(long http_code, const char *body)
+{
+	return telegram_response_ok(http_code, body);
+}
 #endif

tests/test_channel.c

@@ -74,6 +74,22 @@ static void test_stub_cleanup(void)
 	MU_ASSERT(1, "stub cleanup does not crash");
 }
 
+static void test_outbound_chunk_len(void)
+{
+	/* U+20AC EURO SIGN is the three-byte sequence e2 82 ac. */
+	const char euro[] = "x\xE2\x82\xAC" "y";
+	size_t n;
+
+	MU_ASSERT(channel_outbound_chunk_len(NULL, 10) == 0, "NULL text is empty");
+	MU_ASSERT(channel_outbound_chunk_len("", 10) == 0, "empty text is empty");
+	MU_ASSERT(channel_outbound_chunk_len("hi", 0) == 0, "zero cap is empty");
+	MU_ASSERT(channel_outbound_chunk_len("hello", 5) == 5, "exact fit stays one piece");
+	MU_ASSERT(channel_outbound_chunk_len("hello", 2) == 2, "ascii splits on the cap");
+	n = channel_outbound_chunk_len(euro, 2);
+	MU_ASSERT(n == 1, "multibyte character is not split");
+	MU_ASSERT(channel_outbound_chunk_len(euro + n, 3) == 3, "next piece is the whole euro sign");
+}
+
 int main(void)
 {
 	MU_RUN(test_stub_channel_exists);
@@ -82,6 +98,7 @@ int main(void)
 	MU_RUN(test_incoming_msg_clear_safe);
 	MU_RUN(test_stub_send_succeeds);
 	MU_RUN(test_stub_cleanup);
+	MU_RUN(test_outbound_chunk_len);
 	printf("%d tests run, %d failed\n", tests_run, tests_failed);
 	return tests_failed ? 1 : 0;
 }

tests/test_telegram.c

@@ -13,6 +13,7 @@
 /* Test-only entry points from telegram.c (compiled with -DSHELLCLAW_TEST) */
 extern int telegram_parse_update_for_test(const char *json, channel_incoming_msg_t *out, long *update_id);
 extern void telegram_set_test_config(const config_t *cfg);
+extern int telegram_response_ok_for_test(long http_code, const char *body);
 
 static int tests_run = 0;
 static int tests_failed = 0;
@@ -207,6 +208,24 @@ static void test_parse_missing_from_field(void)
 	remove("/tmp/test_tg_nofrom.toml");
 }
 
+static void test_send_response_requires_ok(void)
+{
+	const char *too_long = "{\"ok\":false,\"error_code\":400,"
+		"\"description\":\"Bad Request: message is too long\"}";
+	const char *accepted = "{\"ok\":true,\"result\":{\"message_id\":1}}";
+
+	MU_ASSERT(telegram_response_ok_for_test(400, too_long) == 0,
+		"HTTP 400 message-too-long is not delivery");
+	MU_ASSERT(telegram_response_ok_for_test(200, "{\"ok\":false}") == 0,
+		"HTTP 200 with ok false is not delivery");
+	MU_ASSERT(telegram_response_ok_for_test(200, "") == 0,
+		"empty body is not delivery");
+	MU_ASSERT(telegram_response_ok_for_test(429, "{\"ok\":false}") == 0,
+		"HTTP 429 is not delivery");
+	MU_ASSERT(telegram_response_ok_for_test(200, accepted) == 1,
+		"HTTP 200 with ok true is delivery");
+}
+
 static void test_vtable_fields_set(void)
 {
 	const channel_t *ch = channel_telegram_get();
@@ -227,6 +246,7 @@ int main(void)
 	MU_RUN(test_parse_photo_with_caption);
 	MU_RUN(test_parse_no_message_key);
 	MU_RUN(test_parse_missing_from_field);
+	MU_RUN(test_send_response_requires_ok);
 	MU_RUN(test_vtable_fields_set);
 	printf("%d tests run, %d failed\n", tests_run, tests_failed);
 	return tests_failed ? 1 : 0;