feat(box3): touch gamebook (tap to choose)

Context:
The Freenove gamebook is screen+buttons, the PLIP is audio+dial. The
ESP32-S3-BOX-3 has a 320x240 touchscreen, so its natural format is a
tap-to-choose "livre dont tu es le heros": read the passage on screen,
tap a choice button to navigate.

Approach:
A new gamebook module reuses the same SD pack as the master (the JSON
passages already carry screen/text/choices[label,goto]) and builds the
UI on the already-running LVGL stack: a scrollable column with the
title, the wrapped passage text, and one tappable button per choice.

Changes:
- New gamebook.c/.h: mounts the SD (bsp_sdcard_mount), reads
  /sdcard/gamebook/{library.json, <id>.json}, shows a story list, then
  per passage renders title + text + choice buttons; tapping a choice
  goes to its target, an ending offers "back to menu". cJSON runs on
  PSRAM hooks (the expanded books are ~80 KB JSON); LVGL calls are
  wrapped in bsp_display_lock at init (button callbacks already run in
  the LVGL task).
- main.c: call gamebook_init() after the scenario server is up; it
  takes over the screen when a pack is on the SD, else no-op (the phone
  UI stays).
- CMakeLists: build gamebook.c.

Impact:
With a JSON pack on its SD, the BOX-3 is a touch gamebook: tap a story,
tap your choices. Text-only (no audio needed). Hardware-validated:
boots into a 6-story touch library.

box3_voice/main/CMakeLists.txt

@@ -1,5 +1,5 @@
 idf_component_register(
-    SRCS "main.c" "voice_ws_client.c" "scenario_server.c" "plip_virtual.c" "plip_ui.c" "stimulus.c" "cmd_exec.c"
+    SRCS "main.c" "voice_ws_client.c" "scenario_server.c" "plip_virtual.c" "plip_ui.c" "stimulus.c" "cmd_exec.c" "gamebook.c"
     INCLUDE_DIRS "."
     PRIV_REQUIRES
         driver

box3_voice/main/gamebook.c

@@ -0,0 +1,223 @@
+// gamebook.c — see gamebook.h. Touch CYOA for the ESP32-S3-BOX-3.
+#include "gamebook.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cJSON.h"
+#include "esp_log.h"
+#include "esp_heap_caps.h"
+
+#include "bsp/esp-bsp.h"
+#include "lvgl.h"
+
+static const char *TAG = "gamebook";
+
+#define GB_DIR      "/sdcard/gamebook"
+#define GB_LIBRARY  GB_DIR "/library.json"
+#define GB_JSON_MAX (256 * 1024)        // expanded books are ~80 KB of JSON
+
+// Colours (Workbench-ish palette).
+#define COL_BG     0x101820
+#define COL_TITLE  0xFFCC55
+#define COL_TEXT   0xF0F0F0
+#define COL_BTN    0x224466
+
+static cJSON   *s_lib_root  = NULL;     // owns library.json
+static cJSON   *s_lib       = NULL;     // borrowed: root->"library"
+static int      s_lib_n     = 0;
+
+static cJSON   *s_book      = NULL;     // owns the current <id>.json
+static cJSON   *s_passages  = NULL;     // borrowed: book->"passages"
+
+static lv_obj_t *s_root     = NULL;     // scrollable full-screen column
+
+// ── PSRAM allocators for cJSON (book trees are large) ───────────────────────
+static void *gb_malloc(size_t sz) { return heap_caps_malloc(sz, MALLOC_CAP_SPIRAM); }
+static void  gb_free(void *p)      { heap_caps_free(p); }
+
+static cJSON *load_json(const char *path)
+{
+    FILE *f = fopen(path, "rb");
+    if (!f) { ESP_LOGW(TAG, "open %s failed", path); return NULL; }
+    fseek(f, 0, SEEK_END);
+    long sz = ftell(f);
+    rewind(f);
+    if (sz <= 0 || sz > GB_JSON_MAX) { fclose(f); ESP_LOGW(TAG, "%s size %ld", path, sz); return NULL; }
+    char *buf = heap_caps_malloc((size_t)sz + 1, MALLOC_CAP_SPIRAM);
+    if (!buf) { fclose(f); return NULL; }
+    size_t rd = fread(buf, 1, (size_t)sz, f);
+    fclose(f);
+    buf[rd] = '\0';
+    cJSON *root = cJSON_Parse(buf);
+    heap_caps_free(buf);
+    if (!root) ESP_LOGW(TAG, "malformed JSON: %s", path);
+    return root;
+}
+
+// ── Root container (created once, cleared per view) ─────────────────────────
+// All UI functions below assume the LVGL lock is held (gamebook_init takes it;
+// button callbacks already run inside the LVGL task / lock).
+static void ensure_root(void)
+{
+    if (s_root) { lv_obj_clean(s_root); return; }
+    lv_obj_t *scr = lv_screen_active();
+    s_root = lv_obj_create(scr);
+    lv_obj_set_size(s_root, LV_PCT(100), LV_PCT(100));
+    lv_obj_set_pos(s_root, 0, 0);
+    lv_obj_set_style_bg_color(s_root, lv_color_hex(COL_BG), 0);
+    lv_obj_set_style_bg_opa(s_root, LV_OPA_COVER, 0);
+    lv_obj_set_style_border_width(s_root, 0, 0);
+    lv_obj_set_style_radius(s_root, 0, 0);
+    lv_obj_set_style_pad_all(s_root, 8, 0);
+    lv_obj_set_style_pad_row(s_root, 8, 0);
+    lv_obj_set_flex_flow(s_root, LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_scroll_dir(s_root, LV_DIR_VER);
+}
+
+static lv_obj_t *add_title(const char *txt)
+{
+    lv_obj_t *l = lv_label_create(s_root);
+    lv_obj_set_style_text_font(l, &lv_font_montserrat_24, 0);
+    lv_obj_set_style_text_color(l, lv_color_hex(COL_TITLE), 0);
+    lv_label_set_long_mode(l, LV_LABEL_LONG_WRAP);
+    lv_obj_set_width(l, LV_PCT(100));
+    lv_label_set_text(l, txt);
+    return l;
+}
+
+static lv_obj_t *add_text(const char *txt)
+{
+    lv_obj_t *l = lv_label_create(s_root);
+    lv_obj_set_style_text_font(l, &lv_font_montserrat_14, 0);
+    lv_obj_set_style_text_color(l, lv_color_hex(COL_TEXT), 0);
+    lv_label_set_long_mode(l, LV_LABEL_LONG_WRAP);
+    lv_obj_set_width(l, LV_PCT(100));
+    lv_label_set_text(l, txt);
+    return l;
+}
+
+static lv_obj_t *add_button(const char *txt, lv_event_cb_t cb, void *user)
+{
+    lv_obj_t *b = lv_button_create(s_root);
+    lv_obj_set_width(b, LV_PCT(100));
+    lv_obj_set_style_bg_color(b, lv_color_hex(COL_BTN), 0);
+    lv_obj_set_style_pad_all(b, 10, 0);
+    lv_obj_add_event_cb(b, cb, LV_EVENT_CLICKED, user);
+    lv_obj_t *l = lv_label_create(b);
+    lv_obj_set_style_text_font(l, &lv_font_montserrat_14, 0);
+    lv_label_set_long_mode(l, LV_LABEL_LONG_WRAP);
+    lv_obj_set_width(l, LV_PCT(100));
+    lv_label_set_text(l, txt);
+    return b;
+}
+
+// Forward decls
+static void show_library(void);
+static void enter_passage(const char *pid);
+
+static void tile_cb(lv_event_t *e);
+static void choice_cb(lv_event_t *e);
+static void menu_cb(lv_event_t *e);
+
+// ── Library menu ────────────────────────────────────────────────────────────
+static void show_library(void)
+{
+    if (s_book) { cJSON_Delete(s_book); s_book = NULL; s_passages = NULL; }
+    ensure_root();
+    add_title("Choisis ton histoire");
+    for (int i = 0; i < s_lib_n; i++) {
+        const cJSON *t = cJSON_GetObjectItem(cJSON_GetArrayItem(s_lib, i), "title");
+        add_button(cJSON_IsString(t) ? t->valuestring : "?",
+                   tile_cb, (void *)(intptr_t)i);
+    }
+    lv_obj_scroll_to_y(s_root, 0, LV_ANIM_OFF);
+}
+
+// ── Passage ─────────────────────────────────────────────────────────────────
+static void enter_passage(const char *pid)
+{
+    const cJSON *p = cJSON_GetObjectItem(s_passages, pid);
+    if (!cJSON_IsObject(p)) { ESP_LOGW(TAG, "passage '%s' missing", pid); return; }
+    const cJSON *screen  = cJSON_GetObjectItem(p, "screen");
+    const cJSON *text    = cJSON_GetObjectItem(p, "text");
+    const cJSON *choices = cJSON_GetObjectItem(p, "choices");
+
+    ensure_root();
+    add_title(cJSON_IsString(screen) ? screen->valuestring : "");
+    add_text(cJSON_IsString(text) ? text->valuestring : "");
+    int n = cJSON_IsArray(choices) ? cJSON_GetArraySize(choices) : 0;
+    if (n == 0) {
+        add_button("Revenir au menu", menu_cb, NULL);
+    } else {
+        for (int i = 0; i < n; i++) {
+            const cJSON *c = cJSON_GetArrayItem(choices, i);
+            const cJSON *lbl = cJSON_GetObjectItem(c, "label");
+            const cJSON *g   = cJSON_GetObjectItem(c, "goto");
+            // goto valuestring stays valid while s_book is alive → use as user_data
+            add_button(cJSON_IsString(lbl) ? lbl->valuestring : "?",
+                       choice_cb, cJSON_IsString(g) ? g->valuestring : NULL);
+        }
+    }
+    lv_obj_scroll_to_y(s_root, 0, LV_ANIM_OFF);
+    ESP_LOGI(TAG, "passage '%s' (%d choices)", pid, n);
+}
+
+static void load_book(int idx)
+{
+    const cJSON *e = cJSON_GetArrayItem(s_lib, idx);
+    const cJSON *file = cJSON_GetObjectItem(e, "book");
+    if (!cJSON_IsString(file)) return;
+    char path[128];
+    snprintf(path, sizeof(path), "%s/%s", GB_DIR, file->valuestring);
+    cJSON *book = load_json(path);
+    if (!book) return;
+    const cJSON *passages = cJSON_GetObjectItem(book, "passages");
+    const cJSON *start = cJSON_GetObjectItem(book, "start");
+    if (!cJSON_IsObject(passages) || !cJSON_IsString(start)) {
+        cJSON_Delete(book); return;
+    }
+    if (s_book) cJSON_Delete(s_book);
+    s_book = book;
+    s_passages = (cJSON *)passages;
+    ESP_LOGI(TAG, "load book #%d @ '%s'", idx, start->valuestring);
+    enter_passage(start->valuestring);
+}
+
+// ── Touch callbacks (run inside the LVGL task → lock already held) ───────────
+static void tile_cb(lv_event_t *e)   { load_book((int)(intptr_t)lv_event_get_user_data(e)); }
+static void menu_cb(lv_event_t *e)   { (void)e; show_library(); }
+static void choice_cb(lv_event_t *e)
+{
+    const char *goto_id = (const char *)lv_event_get_user_data(e);
+    if (goto_id) enter_passage(goto_id);
+}
+
+// ── Public init ─────────────────────────────────────────────────────────────
+void gamebook_init(void)
+{
+    cJSON_Hooks hooks = { .malloc_fn = gb_malloc, .free_fn = gb_free };
+    cJSON_InitHooks(&hooks);   // keep the big book trees in PSRAM
+
+    if (bsp_sdcard_mount() != ESP_OK) {
+        ESP_LOGW(TAG, "no SD card — gamebook disabled");
+        return;
+    }
+    s_lib_root = load_json(GB_LIBRARY);
+    if (!s_lib_root) { ESP_LOGW(TAG, "no library.json — gamebook disabled"); return; }
+    s_lib = cJSON_GetObjectItem(s_lib_root, "library");
+    if (!cJSON_IsArray(s_lib) || cJSON_GetArraySize(s_lib) == 0) {
+        cJSON_Delete(s_lib_root); s_lib_root = NULL; s_lib = NULL;
+        ESP_LOGW(TAG, "empty library");
+        return;
+    }
+    s_lib_n = cJSON_GetArraySize(s_lib);
+
+    bsp_display_brightness_set(80);
+    if (bsp_display_lock(1000)) {
+        show_library();
+        bsp_display_unlock();
+    }
+    ESP_LOGI(TAG, "touch gamebook up (%d stories)", s_lib_n);
+}

box3_voice/main/gamebook.h

@@ -0,0 +1,27 @@
+#pragma once
+// gamebook — "livre dont tu es le héros" TACTILE pour l'ESP32-S3-BOX-3.
+//
+// Écran 320x240 + tactile : on lit le passage à l'écran et on TOUCHE un bouton
+// pour choisir. Réutilise le pack gamebook du master sur la SD :
+//   /sdcard/gamebook/{library.json, <id>.json}
+// où chaque passage porte {screen, text, choices:[{label, goto}]} (le champ
+// "wav" éventuel est ignoré — version texte/tactile, pas d'audio requis).
+//
+// S'appuie sur la stack LVGL déjà démarrée par bsp_display_start() : on
+// construit une UUI (menu d'histoires en liste, puis pages tactiles) et la
+// navigation se fait dans les callbacks de boutons LVGL. 100% local, hors-ligne.
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Monte la SD, charge la bibliothèque et affiche le menu tactile des histoires.
+// À appeler une fois depuis app_main, après bsp_display_start() et le serveur
+// de fichiers (pour que la SD soit accessible). No-op si aucun pack présent.
+void gamebook_init(void);
+
+#ifdef __cplusplus
+}
+#endif

box3_voice/main/main.c

@@ -28,6 +28,7 @@
 #include "scenario_server.h"
 #include "plip_virtual.h"
 #include "plip_ui.h"
+#include "gamebook.h"
 #include "stimulus.h"
 #include "scenario_mesh.h"
 #include "cmd_exec.h"
@@ -463,6 +464,11 @@ void app_main(void)
         } else {
             ESP_LOGW(TAG, "stimulus_init failed — QR/melody generator off");
         }
+
+        /* Touch gamebook: if a story pack is on the SD (/sdcard/gamebook/),
+         * take over the screen with a tap-to-choose "livre dont tu es le
+         * héros". No-op (and the phone UI stays) when no pack is present. */
+        gamebook_init();
     }
 
     /* Start the ESP-NOW receiver so the master can relay scenarios to us even