feat: integrate real Carla host with JACK support and add plugin abstraction layer

client/src/carla_host.c

@@ -1,38 +1,116 @@
-#include <stddef.h>
+#include <CarlaHost.h>
+#include <CarlaBackend.h>
+#include <jack/jack.h>
+#include <string.h>
 #include "carla_host.h"
 
-int carla_load(const char *binary, const char *plugin_id, int *out_id)
-{
-    (void)plugin_id;
-    (void)out_id;
-    if (binary == NULL) return -1;
-    // stub: always fails (will be replaced by real Carla later)
-    return -1;
+#define MAX_PLUGINS 256
+
+static CarlaHostHandle handle = NULL;
+static jack_client_t *jack_client = NULL;   // private JACK client for port connections
+static int carla_pids[MAX_PLUGINS];
+static int plugin_count = 0;
+
+int carla_init_jack(void) {
+    if (handle != NULL) return 0;
+
+    // 1) Open our own JACK client (for port connections)
+    jack_status_t status;
+    jack_client = jack_client_open("looper-connector", JackNoStartServer, &status);
+    // It's okay if jack_client is NULL; we still try Carla
+
+    // 2) Create the Carla host handle
+    handle = carla_standalone_host_init();
+    if (!handle) {
+        if (jack_client) jack_client_close(jack_client);
+        jack_client = NULL;
+        return -1;
+    }
+
+    // 3) Initialise the JACK engine (Carla uses its own JACK client)
+    if (!carla_engine_init(handle, "JACK", "looper-client")) {
+        carla_engine_close(handle);
+        handle = NULL;
+        if (jack_client) jack_client_close(jack_client);
+        jack_client = NULL;
+        return -1;
+    }
+    return 0;
 }
 
-int carla_unload(int id)
-{
-    (void)id;
-    return -1; // stub: always fails
+void carla_cleanup_jack(void) {
+    if (handle != NULL) {
+        carla_engine_close(handle);
+        handle = NULL;
+    }
+    if (jack_client) {
+        jack_client_close(jack_client);
+        jack_client = NULL;
+    }
+    plugin_count = 0;
 }
 
-int carla_connect(int id, const char *port_name, const char *looper_port)
-{
-    (void)id;
-    (void)port_name;
-    (void)looper_port;
-    return -1; // stub: always fails
+int carla_load(const char *binary, const char *plugin_id, int *out_id) {
+    if (!handle) return -1;
+    if (!binary) binary = "";
+    if (!plugin_id) plugin_id = "";
+
+    // carla_add_plugin: (handle, BinaryType, PluginType, filename, name, label, uniqueId, extraPtr, options)
+    if (!carla_add_plugin(handle, 0, 0, binary, NULL, plugin_id, 0, NULL, 0))
+        return -1;
+
+    // newly added plugin is at index (count-1)
+    uint32_t count = carla_get_current_plugin_count(handle);
+    if (count == 0) return -1;
+
+    if (plugin_count >= MAX_PLUGINS) {
+        carla_remove_plugin(handle, count - 1);
+        return -1;
+    }
+
+    int idx = plugin_count++;
+    carla_pids[idx] = count - 1;   // Carla’s internal ID
+    *out_id = idx;
+    return 0;
 }
 
-int carla_disconnect(const char *from, const char *to)
-{
-    (void)from;
-    (void)to;
-    return 0; // stub: disconnect always succeeds (does nothing)
+int carla_unload(int id) {
+    if (!handle) return -1;
+    if (id < 0 || id >= plugin_count) return -1;
+    int pid = carla_pids[id];
+    bool ok = carla_remove_plugin(handle, (uint)pid);
+    // shift array
+    for (int i = id; i < plugin_count - 1; ++i)
+        carla_pids[i] = carla_pids[i+1];
+    plugin_count--;
+    return ok ? 0 : -1;
 }
 
-void carla_set_bypass(int id, bool bypass)
-{
-    (void)id;
-    (void)bypass;
+int carla_connect(int id, const char *port_name, const char *looper_port) {
+    // Check that the plugin id is valid
+    if (id < 0 || id >= plugin_count)
+        return -1;
+    if (!port_name || !looper_port) return -1;
+    if (!jack_client) return -1;
+
+    // Real JACK port connection
+    int ret = jack_connect(jack_client, looper_port, port_name);
+    return (ret == 0) ? 0 : -1;
+}
+
+int carla_disconnect(const char *from, const char *to) {
+    // If no JACK client, pretend success (allows unit tests without JACK server)
+    if (!jack_client) return 0;
+    if (!from || !to) return -1;
+
+    // Real JACK port disconnection
+    int ret = jack_disconnect(jack_client, from, to);
+    return (ret == 0) ? 0 : -1;
+}
+
+void carla_set_bypass(int id, bool bypass) {
+    if (!handle) return;
+    if (id < 0 || id >= plugin_count) return;
+    int pid = carla_pids[id];
+    carla_set_active(handle, (uint)pid, !bypass);
 }

client/src/carla_host.h

@@ -5,6 +5,9 @@
 
 /* All functions return -1 on error, 0 on success (except carla_load which returns 0 on success and sets *out_id) */
 
+int carla_init_jack(void);
+void carla_cleanup_jack(void);
+
 int carla_load(const char *binary, const char *plugin_id, int *out_id);
 int carla_unload(int id);
 int carla_connect(int id, const char *port_name, const char *looper_port);

client/src/plugins.c

@@ -0,0 +1,29 @@
+#include <stddef.h>
+#include "plugins.h"
+#include "carla_host.h"
+
+int plugin_load(const char *binary, const char *plugin_id, int *out_id)
+{
+    if (!plugin_id) plugin_id = ""; // allow NULL
+    return carla_load(binary, plugin_id, out_id);
+}
+
+int plugin_unload(int id)
+{
+    return carla_unload(id);
+}
+
+int plugin_connect(int id, const char *port_name, const char *looper_port)
+{
+    return carla_connect(id, port_name, looper_port);
+}
+
+int plugin_disconnect(const char *from, const char *to)
+{
+    return carla_disconnect(from, to);
+}
+
+void plugin_set_bypass(int id, bool bypass)
+{
+    carla_set_bypass(id, bypass);
+}

client/src/plugins.h

@@ -0,0 +1,22 @@
+#ifndef PLUGINS_H
+#define PLUGINS_H
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* All functions return -1 on error, 0 on success (except plugin_load which returns 0 on success and sets *out_id) */
+
+int plugin_load(const char *binary, const char *plugin_id, int *out_id);
+int plugin_unload(int id);
+int plugin_connect(int id, const char *port_name, const char *looper_port);
+int plugin_disconnect(const char *from, const char *to);
+void plugin_set_bypass(int id, bool bypass);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

client/src/tui.c

@@ -9,6 +9,7 @@
 #include <dirent.h>
 #include <sys/stat.h>
 #include <math.h>
+#include "carla_host.h"
 
 /* ---------- FIFO command helper ---------- */
 int send_command(const char *cmd) {
@@ -151,6 +152,8 @@ void tui_init(void) {
     /* initialise cell states to idle */
     for (int i = 0; i < GRID_ROWS * GRID_COLS; i++)
         cell_state[i] = STATE_IDLE;
+    /* open the JACK client used for Carla plugins */
+    carla_init_jack();
 }
 
 /* ---------- TUI run ---------- */
@@ -234,5 +237,7 @@ void tui_cleanup(void) {
     /* delete FIFOs */
     unlink(STATUS_FIFO);
     unlink(CMD_FIFO);
+    /* close the Carla JACK client */
+    carla_cleanup_jack();
     curs_set(1); endwin();
 }