modem: chat: Add runtime API to modem_chat_script_chat

Add APIs allowing for modifying the modem_chat_script_chat
safely at runtime.

Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>

include/zephyr/modem/chat.h

@@ -426,6 +426,45 @@ void modem_chat_match_set_partial(struct modem_chat_match *chat_match, bool part
  */
 void modem_chat_match_enable_wildcards(struct modem_chat_match *chat_match, bool enable);
 
+/**
+ * @brief Initialize modem chat script chat
+ * @param script_chat Modem chat script chat instance
+ */
+void modem_chat_script_chat_init(struct modem_chat_script_chat *script_chat);
+
+/**
+ * @brief Set request of modem chat script chat instance
+ * @param script_chat Modem chat script chat instance
+ * @param request Request to set
+ * @note The lifetime of request must match or exceed the lifetime of script_chat
+ * @warning Always call this API after request is modified
+ *
+ * @retval 0 if successful, negative errno code otherwise
+ */
+int modem_chat_script_chat_set_request(struct modem_chat_script_chat *script_chat,
+				       const char *request);
+
+/**
+ * @brief Set modem chat script chat matches
+ * @param script_chat Modem chat script chat instance
+ * @param response_matches Response match array to set
+ * @param response_matches_size Size of response match array
+ * @note The lifetime of response_matches must match or exceed the lifetime of script_chat
+ *
+ * @retval 0 if successful, negative errno code otherwise
+ */
+int modem_chat_script_chat_set_response_matches(struct modem_chat_script_chat *script_chat,
+						const struct modem_chat_match *response_matches,
+						uint16_t response_matches_size);
+
+/**
+ * @brief Set modem chat script chat timeout
+ * @param script_chat Modem chat script chat instance
+ * @param timeout_ms Timeout in milliseconds
+ */
+void modem_chat_script_chat_set_timeout(struct modem_chat_script_chat *script_chat,
+					uint16_t timeout_ms);
+
 #ifdef __cplusplus
 }
 #endif

subsys/modem/modem_chat.c

@@ -764,6 +764,12 @@ static void modem_chat_pipe_callback(struct modem_pipe *pipe, enum modem_pipe_ev
 	}
 }
 
+static bool modem_chat_validate_array(const void *array, size_t size)
+{
+	return ((array == NULL) && (size == 0)) ||
+	       ((array != NULL) && (size > 0));
+}
+
 #if CONFIG_MODEM_STATS
 static uint32_t get_receive_buf_size(struct modem_chat *chat)
 {
@@ -983,3 +989,43 @@ void modem_chat_match_enable_wildcards(struct modem_chat_match *match, bool enab
 {
 	match->wildcards = enable;
 }
+
+void modem_chat_script_chat_init(struct modem_chat_script_chat *script_chat)
+{
+	memset(script_chat, 0, sizeof(struct modem_chat_script_chat));
+}
+
+int modem_chat_script_chat_set_request(struct modem_chat_script_chat *script_chat,
+				       const char *request)
+{
+	size_t size;
+
+	size = strnlen(request, UINT16_MAX + 1);
+
+	if (size == (UINT16_MAX + 1)) {
+		return -ENOMEM;
+	}
+
+	script_chat->request = request;
+	script_chat->request_size = (uint16_t)size;
+	return 0;
+}
+
+int modem_chat_script_chat_set_response_matches(struct modem_chat_script_chat *script_chat,
+						const struct modem_chat_match *response_matches,
+						uint16_t response_matches_size)
+{
+	if (!modem_chat_validate_array(response_matches, response_matches_size)) {
+		return -EINVAL;
+	}
+
+	script_chat->response_matches = response_matches;
+	script_chat->response_matches_size = response_matches_size;
+	return 0;
+}
+
+void modem_chat_script_chat_set_timeout(struct modem_chat_script_chat *script_chat,
+					uint16_t timeout)
+{
+	script_chat->timeout = timeout;
+}

tests/subsys/modem/modem_chat/src/main.c

@@ -704,6 +704,36 @@ ZTEST(modem_chat, test_runtime_match)
 	zassert_equal(test_match.wildcards, false);
 }
 
+ZTEST(modem_chat, test_runtime_script_chat)
+{
+	int ret;
+	struct modem_chat_script_chat test_script_chat;
+	struct modem_chat_match test_response_matches[2];
+
+	modem_chat_script_chat_init(&test_script_chat);
+
+	ret = modem_chat_script_chat_set_request(&test_script_chat, "AT345");
+	zassert_ok(ret, "Failed to set request");
+	zassert_ok(strcmp(test_script_chat.request, "AT345"), "Failed to set script_chat");
+	zassert_equal(test_script_chat.request_size, 5, "Failed to set size of script_chat");
+
+	ret = modem_chat_script_chat_set_response_matches(&test_script_chat,
+							  test_response_matches,
+							  ARRAY_SIZE(test_response_matches));
+	zassert_ok(ret, "Failed to set response matches");
+	zassert_equal(test_script_chat.response_matches, test_response_matches,
+		      "Failed to set response_matches");
+	zassert_equal(test_script_chat.response_matches_size, ARRAY_SIZE(test_response_matches),
+		      "Failed to set response_matches");
+
+	ret = modem_chat_script_chat_set_response_matches(&test_script_chat,
+							  test_response_matches, 0);
+	zassert_equal(ret, -EINVAL, "Should have failed to set response matches");
+
+	ret = modem_chat_script_chat_set_response_matches(&test_script_chat, NULL, 1);
+	zassert_equal(ret, -EINVAL, "Should have failed to set response matches");
+}
+
 /*************************************************************************************************/
 /*                                         Test suite                                            */
 /*************************************************************************************************/