feat: Home Assistant MQTT Auto-Discovery Integration

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.10)
-project(LightNVR VERSION 0.23.1 LANGUAGES C CXX)
+project(LightNVR VERSION 0.23.2 LANGUAGES C CXX)
 
 # Set C/C++ standards
 set(CMAKE_C_STANDARD 11)

config/lightnvr.ini

@@ -124,6 +124,19 @@ qos = 1
 ; Retain detection messages on the broker (default: false)
 retain = false
 
+; Home Assistant MQTT auto-discovery
+; When enabled, cameras and sensors automatically appear in Home Assistant
+; Requires MQTT broker shared with Home Assistant
+ha_discovery = false
+
+; Discovery topic prefix (default: homeassistant)
+; Must match Home Assistant's MQTT discovery prefix setting
+ha_discovery_prefix = homeassistant
+
+; Snapshot publish interval in seconds (default: 30, 0=disabled)
+; Publishes JPEG camera snapshots via MQTT for HA camera entities
+ha_snapshot_interval = 30
+
 [onvif]
 ; ONVIF camera discovery settings
 ; Enable automatic discovery of ONVIF cameras on the network

include/core/config.h

@@ -192,6 +192,11 @@ typedef struct {
     int mqtt_keepalive;                   // MQTT keepalive interval in seconds (default: 60)
     int mqtt_qos;                         // MQTT QoS level 0, 1, or 2 (default: 1)
     bool mqtt_retain;                     // Retain detection messages (default: false)
+
+    // Home Assistant MQTT auto-discovery settings
+    bool mqtt_ha_discovery;               // Enable HA MQTT auto-discovery (default: false)
+    char mqtt_ha_discovery_prefix[128];   // HA discovery topic prefix (default: "homeassistant")
+    int mqtt_ha_snapshot_interval;        // Snapshot publish interval in seconds (default: 30, 0=disabled)
 } config_t;
 
 /**

include/core/mqtt_client.h

@@ -47,14 +47,58 @@ int mqtt_publish_detection(const char *stream_name, const detection_result_t *re
 
 /**
  * Publish a raw message to a custom topic
- * 
+ *
  * @param topic Full topic path (topic_prefix is NOT automatically prepended)
  * @param payload Message payload (null-terminated string)
  * @param retain Whether to set the retain flag
  * @return 0 on success, -1 on failure
  */
 int mqtt_publish_raw(const char *topic, const char *payload, bool retain);
 
+/**
+ * Publish binary data to a topic (e.g., JPEG snapshots)
+ *
+ * @param topic Full topic path
+ * @param data Binary data buffer
+ * @param len Length of data in bytes
+ * @param retain Whether to set the retain flag
+ * @return 0 on success, -1 on failure
+ */
+int mqtt_publish_binary(const char *topic, const void *data, size_t len, bool retain);
+
+/**
+ * Publish Home Assistant MQTT discovery messages for all configured streams.
+ * Publishes camera, binary_sensor (motion), and sensor (object counts) entities.
+ * Called on connect and when stream configuration changes.
+ *
+ * @return 0 on success, -1 on failure
+ */
+int mqtt_publish_ha_discovery(void);
+
+/**
+ * Update the motion state for a camera stream.
+ * Publishes ON to the motion topic when detection occurs.
+ * After a timeout with no new detections, publishes OFF.
+ *
+ * @param stream_name Name of the stream
+ * @param result Detection results (NULL to force OFF)
+ */
+void mqtt_set_motion_state(const char *stream_name, const detection_result_t *result);
+
+/**
+ * Start Home Assistant services (snapshot timer, motion timeout checker).
+ * Should be called after MQTT is connected and HA discovery is published.
+ *
+ * @return 0 on success, -1 on failure
+ */
+int mqtt_start_ha_services(void);
+
+/**
+ * Stop Home Assistant services.
+ * Should be called before MQTT cleanup.
+ */
+void mqtt_stop_ha_services(void);
+
 /**
  * Disconnect from the MQTT broker gracefully
  */
@@ -66,6 +110,16 @@ void mqtt_disconnect(void);
  */
 void mqtt_cleanup(void);
 
+/**
+ * Reinitialize MQTT client with current configuration.
+ * Performs cleanup → init → connect → HA discovery/services.
+ * Used for hot-reload when settings change from the web UI.
+ *
+ * @param config Pointer to the (updated) application configuration
+ * @return 0 on success, -1 on failure
+ */
+int mqtt_reinit(const config_t *config);
+
 #else /* ENABLE_MQTT not defined */
 
 /* Stub implementations when MQTT is disabled */
@@ -78,8 +132,18 @@ static inline int mqtt_publish_detection(const char *stream_name, const detectio
 static inline int mqtt_publish_raw(const char *topic, const char *payload, bool retain) {
     (void)topic; (void)payload; (void)retain; return 0;
 }
+static inline int mqtt_publish_binary(const char *topic, const void *data, size_t len, bool retain) {
+    (void)topic; (void)data; (void)len; (void)retain; return 0;
+}
+static inline int mqtt_publish_ha_discovery(void) { return 0; }
+static inline void mqtt_set_motion_state(const char *stream_name, const detection_result_t *result) {
+    (void)stream_name; (void)result;
+}
+static inline int mqtt_start_ha_services(void) { return 0; }
+static inline void mqtt_stop_ha_services(void) {}
 static inline void mqtt_disconnect(void) {}
 static inline void mqtt_cleanup(void) {}
+static inline int mqtt_reinit(const config_t *config) { (void)config; return 0; }
 
 #endif /* ENABLE_MQTT */
 

include/core/version.h

@@ -3,8 +3,8 @@
 
 #define LIGHTNVR_VERSION_MAJOR 0
 #define LIGHTNVR_VERSION_MINOR 23
-#define LIGHTNVR_VERSION_PATCH 1
-#define LIGHTNVR_VERSION_STRING "0.23.1"
+#define LIGHTNVR_VERSION_PATCH 2
+#define LIGHTNVR_VERSION_STRING "0.23.2"
 
 #define LIGHTNVR_BUILD_DATE ""
 #define LIGHTNVR_GIT_COMMIT ""

src/core/config.c

@@ -352,6 +352,11 @@ void load_default_config(config_t *config) {
     config->mqtt_keepalive = 60;                // 60 seconds keepalive
     config->mqtt_qos = 1;                       // QoS 1 (at least once)
     config->mqtt_retain = false;                // Don't retain messages by default
+
+    // Home Assistant MQTT auto-discovery settings
+    config->mqtt_ha_discovery = false;          // Disabled by default
+    snprintf(config->mqtt_ha_discovery_prefix, sizeof(config->mqtt_ha_discovery_prefix), "homeassistant");
+    config->mqtt_ha_snapshot_interval = 30;     // 30 seconds default
 }
 
 // Create directory if it doesn't exist
@@ -810,6 +815,19 @@ static int config_ini_handler(void* user, const char* section, const char* name,
             }
         } else if (strcmp(name, "retain") == 0) {
             config->mqtt_retain = (strcmp(value, "true") == 0 || strcmp(value, "1") == 0);
+        } else if (strcmp(name, "ha_discovery") == 0 || strcmp(name, "ha_discovery_enabled") == 0) {
+            config->mqtt_ha_discovery = (strcmp(value, "true") == 0 || strcmp(value, "1") == 0);
+        } else if (strcmp(name, "ha_discovery_prefix") == 0) {
+            strncpy(config->mqtt_ha_discovery_prefix, value, sizeof(config->mqtt_ha_discovery_prefix) - 1);
+            config->mqtt_ha_discovery_prefix[sizeof(config->mqtt_ha_discovery_prefix) - 1] = '\0';
+        } else if (strcmp(name, "ha_snapshot_interval") == 0) {
+            config->mqtt_ha_snapshot_interval = atoi(value);
+            if (config->mqtt_ha_snapshot_interval < 0) {
+                config->mqtt_ha_snapshot_interval = 0; // 0 = disabled
+            }
+            if (config->mqtt_ha_snapshot_interval > 300) {
+                config->mqtt_ha_snapshot_interval = 300; // Maximum 5 minutes
+            }
         }
     }
 
@@ -1336,6 +1354,30 @@ int save_config(const config_t *config, const char *path) {
         fprintf(file, "turn_password = %s\n", config->turn_password);
     }
 
+    // Write MQTT settings
+    fprintf(file, "\n[mqtt]\n");
+    fprintf(file, "enabled = %s\n", config->mqtt_enabled ? "true" : "false");
+    if (config->mqtt_broker_host[0] != '\0') {
+        fprintf(file, "broker_host = %s\n", config->mqtt_broker_host);
+    }
+    fprintf(file, "broker_port = %d\n", config->mqtt_broker_port);
+    if (config->mqtt_username[0] != '\0') {
+        fprintf(file, "username = %s\n", config->mqtt_username);
+    }
+    if (config->mqtt_password[0] != '\0') {
+        fprintf(file, "password = %s\n", config->mqtt_password);
+    }
+    fprintf(file, "client_id = %s\n", config->mqtt_client_id);
+    fprintf(file, "topic_prefix = %s\n", config->mqtt_topic_prefix);
+    fprintf(file, "tls_enabled = %s\n", config->mqtt_tls_enabled ? "true" : "false");
+    fprintf(file, "keepalive = %d\n", config->mqtt_keepalive);
+    fprintf(file, "qos = %d\n", config->mqtt_qos);
+    fprintf(file, "retain = %s\n", config->mqtt_retain ? "true" : "false");
+    fprintf(file, "; Home Assistant MQTT auto-discovery\n");
+    fprintf(file, "ha_discovery = %s\n", config->mqtt_ha_discovery ? "true" : "false");
+    fprintf(file, "ha_discovery_prefix = %s\n", config->mqtt_ha_discovery_prefix);
+    fprintf(file, "ha_snapshot_interval = %d\n", config->mqtt_ha_snapshot_interval);
+
     // Write ONVIF settings
     fprintf(file, "\n[onvif]\n");
     fprintf(file, "discovery_enabled = %s\n", config->onvif_discovery_enabled ? "true" : "false");

src/core/main.c

@@ -846,6 +846,12 @@ int main(int argc, char *argv[]) {
                 log_warn("Failed to connect to MQTT broker, will retry automatically");
             } else {
                 log_info("Connected to MQTT broker");
+
+                // Publish Home Assistant discovery and start HA services if enabled
+                if (config.mqtt_ha_discovery) {
+                    mqtt_publish_ha_discovery();
+                    mqtt_start_ha_services();
+                }
             }
         }
     }