feat: remove previous back button and add a switching validate/back button for better UX

app/build.gradle

@@ -10,8 +10,8 @@ android {
         applicationId "com.stock.pignon"
         minSdkVersion 17
         targetSdkVersion 36
-        versionCode 2
+        versionCode 5
-        versionName "0.2.0"
+        versionName "0.5.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/java/com/stock/pignon/CartActionHelper.java

@@ -3,7 +3,6 @@ package com.stock.pignon;
 
 import android.app.AlertDialog;
 import android.content.Context;
-import android.content.Intent;
 import android.os.Handler;
 import android.os.Environment;
 import android.text.Html;
@@ -22,9 +21,8 @@ import java.io.FileOutputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.lang.reflect.Type;
-import java.util.HashMap;
+import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
 
 /**
  * Action on shopping cart: validation, clearing, and persistence
@@ -33,6 +31,21 @@ public class CartActionHelper {
 
     private static final String TAG = "CartActionHelper";
 
+    /**
+     * Data structure for JSON and CSV
+     */
+    private static class StockEntry {
+        String date;
+        String name;
+        int qty;
+
+        StockEntry(String date, String name, int qty) {
+            this.date = date;
+            this.name = name;
+            this.qty = qty;
+        }
+    }
+
     /**
      * Resets the cart data and refreshes UI
      */
@@ -90,6 +103,74 @@ public class CartActionHelper {
                 .show();
     }
 
+
+
+    /**
+     * Merges current cart items with the existing stock file (json and csv) on the SD Card.
+     */
+    private static void saveCartToExternalFile(List<CartItem> cartItems) {
+        File dir = new File(Environment.getExternalStorageDirectory(), Config.EXTERNAL_DIR_NAME);
+        File stockFile = new File(dir, Config.OUTPUT_JSON_NAME);
+        File csvFile = new File(dir, Config.OUTPUT_CSV_NAME);
+
+        String today = DateHelper.getTodayIso();
+        Gson gson = new Gson();
+
+        // Load previous list
+        List<StockEntry> history = loadHistory(stockFile, gson);
+
+        // Merge current cart items in previous list
+        for (CartItem cartItem : cartItems) {
+            boolean merged = false;
+            for (StockEntry entry : history) {
+                // Same date same name ? Add it
+                if (entry.date.equals(today) && entry.name.equals(cartItem.getName())) {
+                    entry.qty += cartItem.getQuantity();
+                    merged = true;
+                    break;
+                }
+            }
+            // Not found on the same date ? Create it
+            if (!merged) {
+                history.add(new StockEntry(today, cartItem.getName(), cartItem.getQuantity()));
+            }
+        }
+        // Save to JSON
+        try (FileOutputStream fos = new FileOutputStream(stockFile);
+             OutputStreamWriter writer = new OutputStreamWriter(fos, "UTF-8")) {
+            gson.newBuilder().setPrettyPrinting().create().toJson(history, writer);
+        } catch (Exception e) {
+            Log.e(TAG, "Error writing JSON", e);
+        }
+
+        // Save to CSV, french format with ";"
+        try (FileOutputStream fos = new FileOutputStream(csvFile);
+             OutputStreamWriter writer = new OutputStreamWriter(fos, "UTF-8")) {
+            writer.write('\ufeff');
+            writer.write("Date;Article;Quantité\n");
+            for (StockEntry entry : history) {
+                writer.write(entry.date + ";" + entry.name.replace(";", ",") + ";" + entry.qty + "\n");
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "Error writing CSV", e);
+        }
+    }
+
+    /**
+     * Load JSON history
+     */
+    private static List<StockEntry> loadHistory(File file, Gson gson) {
+        if (!file.exists()) return new ArrayList<>();
+        try (InputStreamReader reader = new InputStreamReader(new FileInputStream(file), "UTF-8")) {
+            Type type = new TypeToken<List<StockEntry>>(){}.getType();
+            List<StockEntry> result = gson.fromJson(reader, type);
+            return (result != null) ? result : new ArrayList<>();
+        } catch (Exception e) {
+            Log.e(TAG, "Error reading json history", e);
+            return new ArrayList<>();
+        }
+    }
+
     /**
      * Displays a thank you popup and returns to the main menu after 2 seconds.
      */
@@ -101,80 +182,21 @@ public class CartActionHelper {
                 .create();
         merciDialog.show();
 
-
         new Handler().postDelayed(() -> {
             // Close dialog
             merciDialog.dismiss();
+
+            if (activity instanceof MainActivity) {
+                MainActivity main = (MainActivity) activity;
                 // Go to home if not already
-            if (!(activity instanceof MainActivity)) {
+                main.showHome();
-                Intent intent = new Intent(activity, MainActivity.class);
                 // Clear the backstack so the user can't "go back" to a validated cart
-                intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
+                GridLayout grid = main.findViewById(R.id.gridPieces);
-                activity.startActivity(intent);
+                refreshGridQuantities(grid);
             }
         }, 2000);
     }
 
-    /**
-     * Merges current cart items with the existing stock file on the SD Card.
-     */
-    private static void saveCartToExternalFile(List<CartItem> cartItems) {
-        File dir = new File(Environment.getExternalStorageDirectory(), Config.EXTERNAL_DIR_NAME);
-        File stockFile = new File(dir, Config.STOCK_FILE_NAME);
-
-        Gson gson = new Gson();
-        Map<String, Integer> stockMap;
-
-        // Load data into a Map (Key: Item Name, Value: Total Quantity)
-        stockMap = loadExistingStock(stockFile, gson);
-
-        // Merge with new items from current cart
-        for (CartItem item : cartItems) {
-            // Get previous quantity
-            Integer qtyObj = stockMap.get(item.getName());
-            int currentQty = (qtyObj != null) ? qtyObj : 0;
-            // Add
-            stockMap.put(item.getName(), currentQty + item.getQuantity());
-        }
-
-        // Overwrite the file with updated data
-        // Needs WRITE_EXTERNAL_STORAGE permission
-        try (FileOutputStream fos = new FileOutputStream(stockFile);
-             @SuppressWarnings("CharsetObjectCanBeUsed")
-             OutputStreamWriter writer = new OutputStreamWriter(fos, "UTF-8")) {
-
-            // Writing directly to the stream
-            gson.toJson(stockMap, writer);
-            Log.i(TAG, "Stock updated successfully at: " + stockFile.getAbsolutePath());
-
-        } catch (Exception e) {
-            Log.e(TAG, "Failed to write stock file", e);
-        }
-    }
-
-    /**
-     * Reads the current stock file. If the file is missing or corrupted, returns an empty map.
-     */
-    private static Map<String, Integer> loadExistingStock(File stockFile, Gson gson) {
-        if (!stockFile.exists()) return new HashMap<>();
-
-        try (FileInputStream fis = new FileInputStream(stockFile);
-             @SuppressWarnings("CharsetObjectCanBeUsed")
-             InputStreamReader reader = new InputStreamReader(fis, "UTF-8")) {
-
-            // Type definition for Map required by GSON : <String, Integer>
-            Type type = new TypeToken<Map<String, Integer>>(){}.getType();
-            // Read and fill map
-            Map<String, Integer> result = gson.fromJson(reader, type);
-
-            return (result != null) ? result : new HashMap<>();
-
-        } catch (Exception e) {
-            Log.e(TAG, "Error reading existing stock, starting fresh", e);
-            return new HashMap<>();
-        }
-    }
-
     /**
      * Updates the UI grid to reflect quantities.
      */

app/src/main/java/com/stock/pignon/CartViewHelper.java

@@ -22,17 +22,23 @@ import java.util.List;
 public class CartViewHelper {
 
     /**
-     * Refreshes the entire cart side-panel or list
+     * Short version for app resume : update without changing validate/back button state
-     * Clears everything and rebuild on current CartManager data
      */
     public static void updateCartView(LinearLayout cartList, Context context) {
+        updateCartView(cartList, context, false, false);
+    }
+
+    /**
+     * Full version with validate/back button management
+     */
+    public static void updateCartView(LinearLayout cartList, Context context, boolean updateButton, boolean isHome) {
         if (cartList == null) return;
 
-        // Clear and get current items
+        // Clean item lists
         cartList.removeAllViews();
         List<CartItem> cartItems = CartManager.getItems();
 
-        // If empty cart, show it to user
+        // Manage empty cart
         if (cartItems.isEmpty()) {
             TextView empty = new TextView(context);
             empty.setText(context.getString(R.string.cart_empty));
@@ -40,35 +46,24 @@ public class CartViewHelper {
             empty.setGravity(Gravity.CENTER);
             empty.setPadding(0, 50, 0, 0);
             cartList.addView(empty);
-
             updateTotalDisplay(context, 0, 0);
-            return;
+        } else {
-        }
+            // Create list if not empty
-
-        // Build list and calculate total at the same time
             int totalMin = 0;
             int totalMax = 0;
-
             for (CartItem item : cartItems) {
                 totalMin += item.getTotalMin();
                 totalMax += item.getTotalMax();
 
-            // Create and add the row view
+                // Create a line for each item
                 cartList.addView(createCartItemView(item, cartList, context));
             }
-
-        // Display global price range at the end
             updateTotalDisplay(context, totalMin, totalMax);
         }
 
-    /**
+        // Update validate/back button
-     * Updates the global price range at the bottom of the screen
+        if (updateButton && context instanceof MainActivity) {
-     */
+            ((MainActivity) context).updateActionButton(isHome);
-    private static void updateTotalDisplay(Context context, int min, int max) {
-        TextView totalView = ((Activity) context).findViewById(R.id.totalView);
-        if (totalView != null) {
-            // Using string resources
-            totalView.setText(context.getString(R.string.price_range, min, max, "€"));
         }
     }
 
@@ -81,7 +76,6 @@ public class CartViewHelper {
         row.setOrientation(LinearLayout.HORIZONTAL);
         row.setGravity(Gravity.CENTER_VERTICAL);
 
-        // Layout parameters
         LinearLayout.LayoutParams rowParams = new LinearLayout.LayoutParams(
                 LinearLayout.LayoutParams.MATCH_PARENT,
                 LinearLayout.LayoutParams.WRAP_CONTENT);
@@ -90,13 +84,13 @@ public class CartViewHelper {
 
         // Image
         ImageView image = new ImageView(context);
-        ImageLoader.loadImage(image, item.getImageFile(),200,200);
+        ImageLoader.loadImage(image, item.getImageFile(), 200, 200);
         LinearLayout.LayoutParams imgParams = new LinearLayout.LayoutParams(100, 100);
         imgParams.setMargins(0, 0, 20, 0);
         image.setLayoutParams(imgParams);
         row.addView(image);
 
-        // Sublayout for name + [quantity + price]
+        // Sublayout infos
         LinearLayout infoLayout = new LinearLayout(context);
         infoLayout.setOrientation(LinearLayout.VERTICAL);
         infoLayout.setLayoutParams(new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 1f));
@@ -108,7 +102,7 @@ public class CartViewHelper {
         nameView.setTypeface(null, Typeface.BOLD);
         infoLayout.addView(nameView);
 
-        // Quantity and price range
+        // Quantity / price
         TextView detailsView = new TextView(context);
         String details = context.getString(R.string.cart_item, item.getQuantity(), item.getTotalMin(), item.getTotalMax());
         detailsView.setText(details);
@@ -124,42 +118,35 @@ public class CartViewHelper {
     }
 
     /**
-     * Creates the delete button
+     * Creates the delete button for each item
     */
     private static Button createRemoveButton(CartItem item, LinearLayout cartList, Context context) {
         Button btn = new Button(context);
         btn.setText("✖");
-        btn.setTextSize(18);
         btn.setTextColor(Color.WHITE);
-        btn.setGravity(Gravity.CENTER);
-
-        // Conversion DP to PX for consistent size on all screens
         float scale = context.getResources().getDisplayMetrics().density;
         int sizePx = (int) (48 * scale + 0.5f);
+        btn.setLayoutParams(new LinearLayout.LayoutParams(sizePx, sizePx));
 
-        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(sizePx, sizePx);
-        btn.setLayoutParams(params);
-
-        // Background: grey rounded rectangle (API 17 fallback)
         GradientDrawable shape = new GradientDrawable();
-        shape.setColor(Color.parseColor("#E53935")); // Reddish to indicate delete
+        shape.setColor(Color.parseColor("#E53935"));
         shape.setCornerRadius(4 * scale);
         btn.setBackground(shape);
 
         btn.setOnClickListener(v -> {
-            // setting quantity to 0 removes the item
+            CartManager.addOrUpdateItem(item.getName(), item.getMinPrice(), item.getMaxPrice(), 0, item.getImageFile());
-            CartManager.addOrUpdateItem(
-                    item.getName(),
-                    item.getMinPrice(),
-                    item.getMaxPrice(),
-                    0, // Setting quantity to 0 triggers removal
-                    item.getImageFile()
-            );
-
-            // visual refresh of the cart list
             updateCartView(cartList, context);
         });
-
         return btn;
     }
+
+    /**
+     * Manage price range for whole cart
+     */
+    private static void updateTotalDisplay(Context context, int min, int max) {
+        TextView totalView = ((Activity) context).findViewById(R.id.totalView);
+        if (totalView != null) {
+            totalView.setText(context.getString(R.string.price_range, min, max, "€"));
+        }
+    }
 }

app/src/main/java/com/stock/pignon/Config.java

@@ -9,8 +9,11 @@ public class Config {
     public static final String IMAGES_SUBDIR_NAME = "images";
 
     // Input json
-    public static final String PIECES_FILE_NAME = "pieces.json";
+    public static final String INPUT_JSON_NAME = "pieces.json";
 
     // Output json
-    public static final String STOCK_FILE_NAME = "stock.json";
+    public static final String OUTPUT_JSON_NAME = "stock.json";
+
+    // Output json
+    public static final String OUTPUT_CSV_NAME = "stock.csv";
 }

app/src/main/java/com/stock/pignon/ControlServer.java

@@ -37,12 +37,25 @@ public class ControlServer extends NanoHTTPD {
         // Get requested address
         String uri = session.getUri();
 
-        // Adapt URL to find the file : /stock.json become stock.json
+        switch (uri) {
-        if (uri.equals("/download_orders")) {
+            case "/download_input":
-            return downloadFile(Config.STOCK_FILE_NAME);
+                return downloadFile(Config.INPUT_JSON_NAME);
-        }
+
-        if (uri.equals("/download_json")) {
+            case "/output_json":
-            return downloadFile(Config.PIECES_FILE_NAME);
+                return viewFile(Config.OUTPUT_JSON_NAME);
+
+            case "/download_output_json":
+                return downloadFile(Config.OUTPUT_JSON_NAME);
+
+            case "/output_csv":
+                return viewFile(Config.OUTPUT_CSV_NAME);
+
+            case "/download_output_csv":
+                return downloadFile(Config.OUTPUT_CSV_NAME);
+
+            case "/":
+            case "/index.html":
+                return newFixedLengthResponse(getHtmlResponse());
         }
 
         // File upload management
@@ -54,8 +67,7 @@ public class ControlServer extends NanoHTTPD {
             }
         }
 
-        // Return UI
+        return newFixedLengthResponse(Response.Status.NOT_FOUND, MIME_PLAINTEXT, "❌ Page non trouvée");
-        return newFixedLengthResponse(getHtmlResponse());
     }
 
     /**
@@ -71,7 +83,7 @@ public class ControlServer extends NanoHTTPD {
                 "h1 { color: #0049AF; border-bottom: 2px solid #0049AF; }" +
                 "h2 { color: #555; margin-top: 30px; }" +
                 ".card { background: #f4f4f4; padding: 15px; border-radius: 8px; margin-bottom: 20px; border: 1px solid #ddd; }" +
-                ".btn { display: inline-block; width: 280px; height: 45px; line-height: 45px; text-align: center; background: #0049AF; color: white; text-decoration: none; border-radius: 4px; border: none; cursor: pointer; font-weight: bold; box-sizing: border-box; padding: 0; -webkit-appearance: none; font-family: inherit; font-size: 14px; font-style: normal; letter-spacing: normal; }" +
+                ".btn { display: inline-block; width: 280px; height: 45px; line-height: 45px; text-align: center; background: #0049AF; color: white; text-decoration: none; border-radius: 4px; border: none; cursor: pointer; font-weight: bold; box-sizing: border-box; padding: 0; -webkit-appearance: none; font-family: inherit; font-size: 14px; font-style: normal; letter-spacing: normal; margin: 10px 5px; vertical-align: middle;}" +
                 ".btn-download { background: #2E7D32; }" +
                 "input[type='file'] { margin: 10px 0; }" +
                 ".status { font-weight: bold; color: green; }" +
@@ -84,13 +96,16 @@ public class ControlServer extends NanoHTTPD {
                 "<div class='card'>" +
                 "<h3>Récupérer les sacoches des adhérent·es</h3>" +
                 "<p>Télécharger le décompte des pièces sorties de l'atelier.</p>" +
-                "<a href='/download_orders' class='btn'>Télécharger stock.json</a>" +
+                "<a href='/output_json' class='btn'>Voir stock.json</a>" +
+                "<a href='/output_csv' class='btn'>Voir stock.csv</a>" +
+                "<a href='/download_output_json' class='btn'>Télécharger stock.json</a>" +
+                "<a href='/download_output_csv' class='btn'>Télécharger stock.csv</a>" +
                 "</div>" +
 
                 "<h2>Modifier le catalogue</h2>" +
                 "<div class='card'>" +
                 "<h3>Gestion du fichier JSON</h3>" +
-                "<p>Catalogue actuel : <a href='/download_json' class='btn'>Télécharger pieces.json</a></p>" +
+                "<p>Catalogue actuel : <a href='/download_input' class='btn'>Télécharger pieces.json</a></p>" +
                 "<hr>" +
                 "<form action='/upload_json' method='post' enctype='multipart/form-data'>" +
                 "<p><strong>Envoyer un nouveau catalogue :</strong></p>" +
@@ -124,7 +139,7 @@ public class ControlServer extends NanoHTTPD {
             if (tmpPath == null) return newFixedLengthResponse("❌ Aucun fichier reçu.");
 
             File src = new File(tmpPath);
-            File dest = new File(baseDir, Config.PIECES_FILE_NAME);
+            File dest = new File(baseDir, Config.INPUT_JSON_NAME);
 
             copyFile(src, dest);
             return newFixedLengthResponse("✅ Catalogue mis à jour ! <a href='/'>Retour</a>");
@@ -179,20 +194,43 @@ public class ControlServer extends NanoHTTPD {
     }
 
     /**
-     * Prepare local file to send it to remote.
+     * Prepare file and offer as download
      */
     private Response downloadFile(String filename) {
         File file = new File(baseDir, filename);
         if (!file.exists()) {
-            return newFixedLengthResponse(Response.Status.NOT_FOUND, MIME_PLAINTEXT, "❌ Fichier non trouvé : " + filename);
+            return newFixedLengthResponse(Response.Status.NOT_FOUND, MIME_PLAINTEXT, "❌ Fichier non trouvé.");
         }
         try {
             InputStream is = new FileInputStream(file);
+
+            // Force download
             Response res = newChunkedResponse(Response.Status.OK, "application/octet-stream", is);
 
-            // Force file download name
             res.addHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
+            return res;
+        } catch (IOException e) {
+            return newFixedLengthResponse("❌ Erreur de lecture.");
+        }
+    }
 
+    /**
+     * Prepare file and print it in browser
+     */
+    private Response viewFile(String filename) {
+        File file = new File(baseDir, filename);
+        if (!file.exists()) {
+            return newFixedLengthResponse(Response.Status.NOT_FOUND, MIME_PLAINTEXT, "❌ Fichier non trouvé.");
+        }
+        try {
+            InputStream is = new FileInputStream(file);
+
+            // Force Mime type to print file inside browser
+            String mimeType = "text/plain";
+
+            Response res = newChunkedResponse(Response.Status.OK, mimeType + "; charset=utf-8", is);
+
+            res.addHeader("Content-Disposition", "inline");
             return res;
         } catch (IOException e) {
             return newFixedLengthResponse("❌ Erreur de lecture.");

app/src/main/java/com/stock/pignon/DataLoader.java

@@ -13,7 +13,7 @@ import java.util.List;
 public class DataLoader {
     private static final String TAG = "DataLoader"; // For readable logs
     private static final String EXTERNAL_DIR = Config.EXTERNAL_DIR_NAME;
-    private static final String PIECES_FILE = Config.PIECES_FILE_NAME;
+    private static final String PIECES_FILE = Config.INPUT_JSON_NAME;
 
     // Raw data
     private static List<Category> cachedCategories = new ArrayList<>();

app/src/main/java/com/stock/pignon/DateHelper.java

@@ -0,0 +1,15 @@
+// DateHelper.java
+package com.stock.pignon;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+
+public class DateHelper {
+    /**
+     * Return ISO format date (AAAA-MM-JJ)
+     */
+    public static String getTodayIso() {
+        return new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault()).format(new Date());
+    }
+}

app/src/main/java/com/stock/pignon/MainActivity.java

@@ -61,12 +61,6 @@ public class MainActivity extends AppCompatActivity {
         gridPieces = findViewById(R.id.gridPieces);
         mainImage = findViewById(R.id.mainImage);
 
-        // Setup Back Button
-        Button backBtn = findViewById(R.id.backToHomeBtn);
-        if (backBtn != null) {
-            backBtn.setOnClickListener(v -> showHome());
-        }
-
         // Copy assets to sd card if not founded
         copyAssetsIfEmpty();
         // Get data from sd card
@@ -85,6 +79,14 @@ public class MainActivity extends AppCompatActivity {
             getSupportActionBar().setTitle(" 🚲 Atelier du Pignon - Gestion du stock à prix libre");
         }
 
+        // Get app version
+        String versionName;
+        try {
+            versionName = "App v" + getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
+        } catch (Exception e) {
+            versionName = ""; // Fallback
+        }
+
         // Launch server
         server = new ControlServer(8080);
         try {
@@ -93,12 +95,12 @@ public class MainActivity extends AppCompatActivity {
 
             // On met l'URL directement dans le sous-titre de l'ActionBar
             if (getSupportActionBar() != null) {
-                getSupportActionBar().setSubtitle("🟢 Serveur actif : " + url);
+                getSupportActionBar().setSubtitle("Serveur en ligne : " + url + " - " + versionName);
             }
-            Log.i(TAG, "Serveur démarré sur : " + url);
+            Log.i(TAG, "Server started on : " + url);
         } catch (IOException e) {
             if (getSupportActionBar() != null) {
-                getSupportActionBar().setSubtitle("🔴 Erreur serveur : Port 8080 occupé");
+                getSupportActionBar().setSubtitle("Erreur serveur" + " - " + versionName);
             }
         }
     }
@@ -115,7 +117,7 @@ public class MainActivity extends AppCompatActivity {
         super.onDestroy();
         if (server != null) {
             server.stop();
-            Log.i(TAG, "Serveur arrêté.");
+            Log.i(TAG, "Server stopped.");
         }
     }
 
@@ -192,6 +194,8 @@ public class MainActivity extends AppCompatActivity {
         homeLayout.setVisibility(View.GONE);
         categoryItemsLayout.setVisibility(View.VISIBLE);
 
+        updateActionButton(false);
+
         gridPieces.removeAllViews();
 
         // Calculate item width for a 4-column grid
@@ -258,9 +262,11 @@ public class MainActivity extends AppCompatActivity {
         CartViewHelper.updateCartView(cartList, this);
     }
 
-    private void showHome() {
+    public void showHome() {
         categoryItemsLayout.setVisibility(View.GONE);
         homeLayout.setVisibility(View.VISIBLE);
+
+        updateActionButton(true);
     }
 
     private void loadMainImage() {
@@ -268,8 +274,6 @@ public class MainActivity extends AppCompatActivity {
         ImageLoader.loadImage(mainImage, "_velo", 800,800);
     }
 
-    // --- Button Actions (linked via android:onClick in XML) ---
-
     public void emptyCart(View view) {
         CartActionHelper.emptyCart(cartList, this);
     }
@@ -278,29 +282,87 @@ public class MainActivity extends AppCompatActivity {
         CartActionHelper.validateCart(cartList, this);
     }
 
+    public void updateActionButton(boolean isHome) {
+        Button btn = findViewById(R.id.validateCartBtn);
+        if (btn == null) return;
+
+        if (isHome) {
+            // Home mode : validate button
+            btn.setText(getString(R.string.cart_validate_btn));
+            btn.setBackgroundColor(Color.parseColor("#43A047")); // Vert
+            btn.setOnClickListener(v -> validateCart(v));
+        } else {
+            // Category mode : back button
+            btn.setText(getString(R.string.cart_back_btn));
+            btn.setBackgroundColor(Color.parseColor("#1E88E5")); // Bleu
+            btn.setOnClickListener(v -> showHome());
+        }
+    }
+
     private int dpToPx(int dp) {
         return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, getResources().getDisplayMetrics());
     }
 
     private void copyAssetsIfEmpty() {
-        File folder = new File(Environment.getExternalStorageDirectory(), Config.EXTERNAL_DIR_NAME);
+        File rootDir = new File(Environment.getExternalStorageDirectory(), Config.EXTERNAL_DIR_NAME);
 
-        // First safety : is folder already in sdcard ?
+        // Create root folder if not found
-        if (!folder.exists()) {
+        if (!rootDir.exists()) {
-            // Second safety : are we able to create folder ?
+            if (!rootDir.mkdirs()) {
-            if (folder.mkdirs()) {
+                Log.e("MainActivity", "Can't create root dir." + rootDir.getAbsolutePath());
-                // Copy JSON file
+                return;
-                copyFileFromAssets(Config.PIECES_FILE_NAME, new File(folder, Config.PIECES_FILE_NAME));
-
-                // Copy images subfolder
-                File imgFolder = new File(folder, Config.IMAGES_SUBDIR_NAME);
-                if (imgFolder.mkdirs()) {
-                    copyFolderFromAssets(Config.IMAGES_SUBDIR_NAME, imgFolder);
             }
         }
+
+        // Check pieces.json
+        File inputJson = new File(rootDir, Config.INPUT_JSON_NAME);
+        if (!inputJson.exists()) {
+            Log.i("MainActivity", "pieces.json not found, copying it...");
+            copyFileFromAssets(Config.INPUT_JSON_NAME, inputJson);
+        } else {
+            Log.d("MainActivity", "Keep existing pieces.json");
+        }
+
+        // Check stock.json and stock.csv output files to avoid control server error
+        checkOrCreateEmptyFile(new File(rootDir, Config.OUTPUT_JSON_NAME), "[]");
+        checkOrCreateEmptyFile(new File(rootDir, Config.OUTPUT_CSV_NAME), "");
+
+        // Check images folder
+        File imgDir = new File(rootDir, Config.IMAGES_SUBDIR_NAME);
+        if (!imgDir.exists()) {
+            if (!imgDir.mkdirs()) {
+                Log.e("MainActivity", "Can't create images dir.");
+                return;
+            }
+        }
+
+        // Copy images only if not found
+        String[] filesInImgDir = imgDir.list();
+        if (filesInImgDir == null || filesInImgDir.length == 0) {
+            Log.i("MainActivity", "Images folder empty. Installing images...");
+            copyFolderFromAssets(Config.IMAGES_SUBDIR_NAME, imgDir);
+        } else {
+            Log.d("MainActivity", "Keep existing images.");
+        }
+    }
+
+    /**
+     * Create a file with default content if not found
+     */
+    private void checkOrCreateEmptyFile(File file, String defaultContent) {
+        if (!file.exists()) {
+            try (FileOutputStream fos = new FileOutputStream(file)) {
+                fos.write(defaultContent.getBytes());
+                Log.d(TAG, "Initialisation de : " + file.getName());
+            } catch (IOException e) {
+                Log.e(TAG, "Erreur lors de l'initialisation de " + file.getName(), e);
+            }
         }
     }
 
+    /**
+     * Copy folder from assets
+     */
     private void copyFolderFromAssets(String assetDirName, File destDir) {
         try {
             String[] files = getAssets().list(assetDirName);
@@ -316,25 +378,28 @@ public class MainActivity extends AppCompatActivity {
                 }
             }
         } catch (IOException e) {
-            Log.e("MainActivity", "Erreur listing assets: " + assetDirName, e);
+            Log.e("MainActivity", "Listing assets error: " + assetDirName, e);
         }
     }
 
+    /**
+     * Copy file from assets
+     */
     private void copyFileFromAssets(String assetName, File destFile) {
         // Optimized read
         // Try-with-resources ensures streams are automatically closed, avoid memory leaks
         try (InputStream in = getAssets().open(assetName);
              OutputStream out = new FileOutputStream(destFile)) {
 
-            byte[] buffer = new byte[1024];
+            byte[] buffer = new byte[8192];
             int read;
             while ((read = in.read(buffer)) != -1) {
                 out.write(buffer, 0, read);
             }
-            Log.d("MainActivity", "Succès : " + assetName + " copié.");
+            Log.d("MainActivity", "Success : " + assetName + " copied.");
 
         } catch (IOException e) {
-            Log.e("MainActivity", "Erreur copie asset: " + assetName, e);
+            Log.e("MainActivity", "Can't copy asset: " + assetName, e);
         }
     }
 
@@ -355,7 +420,7 @@ public class MainActivity extends AppCompatActivity {
                 }
             }
         } catch (Exception e) {
-            Log.e(TAG, "Erreur IP", e);
+            Log.e(TAG, "IP error", e);
         }
         return "127.0.0.1";
     }

app/src/main/res/layout/activity_main.xml

@@ -42,12 +42,6 @@
             android:visibility="gone"
             android:padding="10dp">
 
-            <Button
-                android:id="@+id/backToHomeBtn"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:text="← Retour" />
-
             <ScrollView
                 android:layout_width="match_parent"
                 android:layout_height="match_parent">

app/src/main/res/values/strings.xml

@@ -3,8 +3,9 @@
 
     <string name="cart_name">Mes sacoches</string>
     <string name="cart_validate_btn">Valider</string>
+    <string name="cart_back_btn">Retour</string>
     <string name="cart_empty_btn">Vider</string>
-    <string name="cart_empty">Sacoches vides</string>
+    <string name="cart_empty">C\'est vide !</string>
     <string name="cart_item">Quantité : %1$d (%2$d - %3$d €)</string>
 
     <string name="currency">€</string>
@@ -13,6 +14,6 @@
     <string name="popup_name">Mes sacoches</string>
     <string name="popup_item"><![CDATA[<b>%1$d x %2$s</b> : %3$d - %4$d €<br>]]></string>
     <string name="popup_total"><![CDATA[<br><b>Contribution consciente dans la petite boîte : %1$d - %2$d €</b>]]></string>
-    <string name="popup_end">Sacoches sauvegardées, merci !</string>
+    <string name="popup_end">Sacoches sauvegardées, merci ! ❤️</string>
 
 </resources>