feat: implement URI-based plugin loading and GUI text input for Carla

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

carla.c

@@ -81,10 +81,88 @@ static int add_gain_plugin(CarlaHost *host, int channel) {
 int carla_add_plugin(CarlaHost *host, int channel, const char *uri, PluginType type) {
     if (!host || !host->initialized) return -1;
     if (channel < 0 || channel >= 8) return -1;
+    if (!uri) return -1;
     
-    (void)uri;
+    ChannelRack *rack = &host->channel_racks[channel];
-    (void)type;
+    if (rack->num_plugins >= 16) return -1;
-    return add_gain_plugin(host, channel);
+    
+    PluginInfo *plugin = &rack->plugins[rack->num_plugins];
+    
+    // Parse URI to determine plugin type and name
+    if (strstr(uri, "internal://") == uri) {
+        // Internal plugin
+        plugin->type = PLUGIN_TYPE_INTERNAL;
+        strncpy(plugin->uri, uri, sizeof(plugin->uri) - 1);
+        plugin->uri[sizeof(plugin->uri) - 1] = '\0';
+        
+        const char *name = uri + strlen("internal://");
+        if (strcmp(name, "gain") == 0) {
+            strcpy(plugin->name, "Gain");
+            plugin->num_parameters = 1;
+            plugin->parameters = malloc(sizeof(float));
+            plugin->parameters[0] = 1.0f;
+            plugin->parameter_names = malloc(sizeof(char*));
+            plugin->parameter_names[0] = strdup("Gain");
+        } else if (strcmp(name, "reverb") == 0) {
+            strcpy(plugin->name, "Reverb");
+            plugin->num_parameters = 2;
+            plugin->parameters = malloc(2 * sizeof(float));
+            plugin->parameters[0] = 0.5f; // Mix
+            plugin->parameters[1] = 0.5f; // Decay
+            plugin->parameter_names = malloc(2 * sizeof(char*));
+            plugin->parameter_names[0] = strdup("Mix");
+            plugin->parameter_names[1] = strdup("Decay");
+        } else if (strcmp(name, "delay") == 0) {
+            strcpy(plugin->name, "Delay");
+            plugin->num_parameters = 2;
+            plugin->parameters = malloc(2 * sizeof(float));
+            plugin->parameters[0] = 0.3f; // Feedback
+            plugin->parameters[1] = 0.5f; // Mix
+            plugin->parameter_names = malloc(2 * sizeof(char*));
+            plugin->parameter_names[0] = strdup("Feedback");
+            plugin->parameter_names[1] = strdup("Mix");
+        } else if (strcmp(name, "filter") == 0) {
+            strcpy(plugin->name, "Filter");
+            plugin->num_parameters = 2;
+            plugin->parameters = malloc(2 * sizeof(float));
+            plugin->parameters[0] = 1000.0f; // Cutoff
+            plugin->parameters[1] = 1.0f;    // Resonance
+            plugin->parameter_names = malloc(2 * sizeof(char*));
+            plugin->parameter_names[0] = strdup("Cutoff");
+            plugin->parameter_names[1] = strdup("Resonance");
+        } else {
+            // Unknown internal plugin, default to gain
+            strcpy(plugin->name, "Unknown Internal");
+            plugin->num_parameters = 0;
+            plugin->parameters = NULL;
+            plugin->parameter_names = NULL;
+        }
+    } else {
+        // External plugin (LV2, VST, etc.) - store URI for future Carla integration
+        plugin->type = type;
+        strncpy(plugin->uri, uri, sizeof(plugin->uri) - 1);
+        plugin->uri[sizeof(plugin->uri) - 1] = '\0';
+        
+        // Extract a display name from the URI
+        const char *last_slash = strrchr(uri, '/');
+        if (last_slash) {
+            strncpy(plugin->name, last_slash + 1, sizeof(plugin->name) - 1);
+        } else {
+            strncpy(plugin->name, uri, sizeof(plugin->name) - 1);
+        }
+        plugin->name[sizeof(plugin->name) - 1] = '\0';
+        
+        plugin->num_parameters = 0;
+        plugin->parameters = NULL;
+        plugin->parameter_names = NULL;
+    }
+    
+    plugin->carla_plugin_id = -1;
+    rack->num_plugins++;
+    
+    printf("Added plugin '%s' (URI: %s) to channel %d\n", plugin->name, plugin->uri, channel);
+    
+    return rack->num_plugins - 1;
 }
 
 int carla_remove_plugin(CarlaHost *host, int channel, int plugin_index) {

gui.c

@@ -9,6 +9,7 @@
 #include "engine.h"
 #include "gui.h"
 #include "dispatcher.h"
+#include "carla.h"
 
 /* microui includes */
 #define MU_IMPLEMENTATION
@@ -44,6 +45,12 @@ static float bpm = 120.0f;
 static int loop_length = 8;          /* beats */
 static int current_beat = 0;
 
+/* Carla host and plugin URI input */
+static CarlaHost carla_host;
+static char plugin_uri_input[256];
+static int plugin_uri_input_len = 0;
+static int selected_channel = 0;
+
 /* ---------------------------------------------------------------------------
  *  drawing helpers (stubs for microui)
  * ------------------------------------------------------------------------- */
@@ -114,6 +121,27 @@ static void gui_update(void)
             }
         }
 
+        /* Plugin URI input */
+        mu_layout_row(ctx, 2, (int[]) { 60, -1 }, 0);
+        mu_label(ctx, "URI:");
+        {
+            char display[256];
+            if (plugin_uri_input_len > 0) {
+                snprintf(display, sizeof(display), "%s_", plugin_uri_input);
+            } else {
+                snprintf(display, sizeof(display), "type URI here...");
+            }
+            mu_label(ctx, display);
+        }
+        mu_layout_row(ctx, 1, (int[]) { -1 }, 0);
+        if (mu_button(ctx, "Add Plugin")) {
+            if (plugin_uri_input_len > 0) {
+                carla_add_plugin(&carla_host, selected_channel, plugin_uri_input, PLUGIN_TYPE_INTERNAL);
+                plugin_uri_input_len = 0;
+                plugin_uri_input[0] = '\0';
+            }
+        }
+
         mu_end_window(ctx);
     }
 
@@ -127,6 +155,9 @@ int gui_main(Engine *engine)
 {
     g_engine = engine;
 
+    /* Initialize Carla host */
+    carla_init(&carla_host, engine->client);
+
     /* initialise microui */
     ctx = malloc(sizeof(mu_Context));
     if (!ctx) return -1;
@@ -148,6 +179,22 @@ int gui_main(Engine *engine)
         /* handle input */
         int ch = getch();
         if (ch != ERR) {
+            /* Handle text input for plugin URI */
+            if (ch >= 32 && ch <= 126 && plugin_uri_input_len < 255) {
+                plugin_uri_input[plugin_uri_input_len++] = (char)ch;
+                plugin_uri_input[plugin_uri_input_len] = '\0';
+            } else if (ch == 127 || ch == KEY_BACKSPACE) {
+                if (plugin_uri_input_len > 0) {
+                    plugin_uri_input[--plugin_uri_input_len] = '\0';
+                }
+            } else if (ch == '\n' || ch == '\r') {
+                /* Submit plugin URI */
+                if (plugin_uri_input_len > 0) {
+                    carla_add_plugin(&carla_host, selected_channel, plugin_uri_input, PLUGIN_TYPE_INTERNAL);
+                    plugin_uri_input_len = 0;
+                    plugin_uri_input[0] = '\0';
+                }
+            }
             switch (ch) {
                 case 'q':
                 case 'Q':
@@ -212,6 +259,7 @@ int gui_main(Engine *engine)
     }
 
     /* cleanup */
+    carla_cleanup(&carla_host);
     endwin();
     free(ctx);
     return 0;