fix(modbus_tool): Improve UI stability and readability

- Refactor the curses drawing loop to be state-based, eliminating screen flicker after user input.
- Add a helper function to format uptime from seconds into a human-readable string (d/h/m/s).

software/tools/modbus_tool/modbus_tool.py

@@ -24,6 +24,30 @@ client = None
 status_data = {}
 status_lock = threading.Lock()
 
+def format_uptime(seconds):
+    """Formats seconds into a human-readable d/h/m/s string."""
+    if not isinstance(seconds, (int, float)) or seconds < 0:
+        return "N/A"
+    if seconds == 0:
+        return "0s"
+
+    days, remainder = divmod(seconds, 86400)
+    hours, remainder = divmod(remainder, 3600)
+    minutes, secs = divmod(remainder, 60)
+
+    parts = []
+    if days > 0:
+        parts.append(f"{int(days)}d")
+    if hours > 0:
+        parts.append(f"{int(hours)}h")
+    if minutes > 0:
+        parts.append(f"{int(minutes)}m")
+    # Always show seconds if it's the only unit or if other units are present
+    if secs > 0 or not parts:
+        parts.append(f"{int(secs)}s")
+
+    return " ".join(parts)
+
 def poll_status(slave_id, interval):
     """Periodically polls the status of the node and updates the global status_data dict."""
     global status_data
@@ -53,9 +77,9 @@ def poll_status(slave_id, interval):
             fw_patch = rr_sys.registers[1]
             uptime_low = rr_sys.registers[3]
             uptime_high = rr_sys.registers[4]
-            uptime = (uptime_high << 16) | uptime_low
+            uptime_seconds = (uptime_high << 16) | uptime_low
             new_data["firmware"] = f"v{fw_major}.{fw_minor}.{fw_patch}"
-            new_data["uptime"] = f"{uptime}s"
+            new_data["uptime"] = format_uptime(uptime_seconds)
 
         except ModbusException as e:
             new_data["error"] = f"Modbus Error: {e}"
@@ -69,141 +93,132 @@ def poll_status(slave_id, interval):
 def draw_button(stdscr, y, x, text, selected=False):
     """Draws a button with a border, handling selection highlight."""
     button_width = len(text) + 4
-    if selected:
+    color = curses.color_pair(2) if selected else curses.color_pair(1)
-        color = curses.color_pair(2)  # Highlighted (blue on white)
-    else:
-        color = curses.color_pair(1)  # Normal (white on blue)
 
-    # Draw the button background and text
     stdscr.addstr(y, x, " " * button_width, color)
     stdscr.addstr(y, x + 2, text, color)
-    # Draw the border with the same color attribute
     stdscr.addstr(y - 1, x, "┌" + "─" * (button_width - 2) + "┐", color)
     stdscr.addstr(y, x, "│", color)
     stdscr.addstr(y, x + button_width - 1, "│", color)
     stdscr.addstr(y + 1, x, "└" + "─" * (button_width - 2) + "┘", color)
 
-def get_user_input(stdscr, h, w, prompt):
-    """Safely get user input in a curses window."""
-    curses.echo()
-    curses.curs_set(1)
-    stdscr.nodelay(0)
-    input_line_y = h - 2
-    stdscr.addstr(input_line_y, 0, " " * (w - 1), curses.color_pair(1))
-    stdscr.addstr(input_line_y, 0, prompt, curses.color_pair(1) | curses.A_BOLD)
-    stdscr.refresh()
-    # Input should be on a white background for readability
-    input_win = curses.newwin(1, w - len(prompt) - 1, input_line_y, len(prompt))
-    input_win.bkgd(' ', curses.color_pair(4)) # Black on white
-    input_str = input_win.getstr().decode('utf-8')
-
-    stdscr.nodelay(1)
-    curses.noecho()
-    curses.curs_set(0)
-    return input_str
-
-def show_message(stdscr, h, w, message, is_error=False, duration=1.5):
-    """Display a message for a short duration."""
-    msg_y = h - 2
-    color = curses.color_pair(3) if is_error else curses.color_pair(1)
-    stdscr.addstr(msg_y, 0, " " * (w - 1), color)
-    stdscr.addstr(msg_y, 0, message, color | curses.A_BOLD)
-    stdscr.refresh()
-    time.sleep(duration)
-
 def main_menu(stdscr, slave_id):
-    """The main curses UI with a full blue background."""
+    """The main curses UI with a flicker-free, state-based drawing loop."""
     global status_data
     curses.curs_set(0)
     stdscr.nodelay(1)
     stdscr.timeout(100)
 
-    # Initialize colors
+    # --- Color Pairs ---
     curses.start_color()
     curses.init_pair(1, curses.COLOR_WHITE, curses.COLOR_BLUE)  # Main: white on blue
     curses.init_pair(2, curses.COLOR_BLUE, curses.COLOR_WHITE)  # Selected: blue on white
     curses.init_pair(3, curses.COLOR_RED, curses.COLOR_BLUE)    # Error: red on blue
-    curses.init_pair(4, curses.COLOR_BLACK, curses.COLOR_WHITE) # Input: black on white
-
-    # Set the background for the whole screen
     stdscr.bkgd(' ', curses.color_pair(1))
 
+    # --- UI State ---
     menu = ["Open Valve", "Close Valve", "Stop Valve", "Set Max Opening Time", "Set Max Closing Time", "Exit"]
     current_row_idx = 0
+    
+    # State for transient messages
+    message = ""
+    message_time = 0
+    
+    # State for user input
+    input_mode = False
+    input_prompt = ""
+    input_str = ""
+    input_target_reg = 0
 
     while not stop_event.is_set():
-        stdscr.clear() # Clear screen with the background color
         h, w = stdscr.getmaxyx()
+        
+        # --- Handle Input and State Changes ---
+        key = stdscr.getch()
 
-        # --- Draw Status Area ---
+        if input_mode:
+            if key in [10, 13]: # Enter
+                try:
+                    seconds = int(input_str)
+                    client.write_register(input_target_reg, seconds, slave=slave_id)
+                    message = f"-> Set time to {seconds}s"
+                except ValueError:
+                    message = "-> Invalid input. Please enter a number."
+                except Exception as e:
+                    message = f"-> Error: {e}"
+                message_time = time.time()
+                input_mode = False
+                input_str = ""
+            elif key == curses.KEY_BACKSPACE or key == 127:
+                input_str = input_str[:-1]
+            elif key != -1 and chr(key).isprintable():
+                input_str += chr(key)
+        else: # Navigation mode
+            if key == curses.KEY_UP and current_row_idx > 0:
+                current_row_idx -= 1
+            elif key == curses.KEY_DOWN and current_row_idx < len(menu) - 1:
+                current_row_idx += 1
+            elif key == curses.KEY_ENTER or key in [10, 13]:
+                selected_option = menu[current_row_idx]
+                message_time = time.time() # Set time for all actions
+
+                if selected_option == "Exit":
+                    stop_event.set()
+                    continue
+                elif selected_option == "Open Valve":
+                    client.write_register(REG_HOLDING_VALVE_COMMAND, 1, slave=slave_id)
+                    message = "-> Sent OPEN command"
+                elif selected_option == "Close Valve":
+                    client.write_register(REG_HOLDING_VALVE_COMMAND, 2, slave=slave_id)
+                    message = "-> Sent CLOSE command"
+                elif selected_option == "Stop Valve":
+                    client.write_register(REG_HOLDING_VALVE_COMMAND, 0, slave=slave_id)
+                    message = "-> Sent STOP command"
+                elif "Set Max" in selected_option:
+                    input_mode = True
+                    input_prompt = f"Enter new value for '{selected_option}' (seconds): "
+                    input_target_reg = REG_HOLDING_MAX_OPENING_TIME_S if "Opening" in selected_option else REG_HOLDING_MAX_CLOSING_TIME_S
+
+        # --- Drawing Logic (Single Source of Truth) ---
+        stdscr.clear()
+
+        # 1. Draw Status Area
         with status_lock:
             current_data = status_data.copy()
-
+        
         if current_data.get("error"):
             stdscr.addstr(0, 0, current_data["error"], curses.color_pair(3) | curses.A_BOLD)
         else:
-            # Use a single color pair, bold for labels
             bold = curses.color_pair(1) | curses.A_BOLD
             normal = curses.color_pair(1)
             col1_x, col2_x, col3_x = 2, 35, 70
-            stdscr.addstr(1, col1_x, "Valve State:", bold)
+            stdscr.addstr(1, col1_x, "Valve State:", bold); stdscr.addstr(1, col1_x + 14, str(current_data.get('state', 'N/A')), normal)
-            stdscr.addstr(1, col1_x + 14, str(current_data.get('state', 'N/A')), normal)
+            stdscr.addstr(2, col1_x, "Movement:", bold); stdscr.addstr(2, col1_x + 14, str(current_data.get('movement', 'N/A')), normal)
-            stdscr.addstr(2, col1_x, "Movement:", bold)
+            stdscr.addstr(3, col1_x, "Motor Current:", bold); stdscr.addstr(3, col1_x + 14, str(current_data.get('motor_current', 'N/A')), normal)
-            stdscr.addstr(2, col1_x + 14, str(current_data.get('movement', 'N/A')), normal)
+            stdscr.addstr(1, col2_x, "Max Open Time:", bold); stdscr.addstr(1, col2_x + 16, str(current_data.get('open_time', 'N/A')), normal)
-            stdscr.addstr(3, col1_x, "Motor Current:", bold)
+            stdscr.addstr(2, col2_x, "Max Close Time:", bold); stdscr.addstr(2, col2_x + 16, str(current_data.get('close_time', 'N/A')), normal)
-            stdscr.addstr(3, col1_x + 14, str(current_data.get('motor_current', 'N/A')), normal)
+            stdscr.addstr(1, col3_x, "Firmware:", bold); stdscr.addstr(1, col3_x + 11, str(current_data.get('firmware', 'N/A')), normal)
-
+            stdscr.addstr(2, col3_x, "Uptime:", bold); stdscr.addstr(2, col3_x + 11, str(current_data.get('uptime', 'N/A')), normal)
-            stdscr.addstr(1, col2_x, "Max Open Time:", bold)
-            stdscr.addstr(1, col2_x + 16, str(current_data.get('open_time', 'N/A')), normal)
-            stdscr.addstr(2, col2_x, "Max Close Time:", bold)
-            stdscr.addstr(2, col2_x + 16, str(current_data.get('close_time', 'N/A')), normal)
-
-            stdscr.addstr(1, col3_x, "Firmware:", bold)
-            stdscr.addstr(1, col3_x + 11, str(current_data.get('firmware', 'N/A')), normal)
-            stdscr.addstr(2, col3_x, "Uptime:", bold)
-            stdscr.addstr(2, col3_x + 11, str(current_data.get('uptime', 'N/A')), normal)
         stdscr.addstr(5, 0, "─" * (w - 1), normal)
 
-        # --- Draw Menu Buttons ---
+        # 2. Draw Menu Buttons
         for idx, row in enumerate(menu):
             x = w // 2 - (len(row) + 4) // 2
-            y = h // 2 - (len(menu)) + (idx * 3)
+            y = h // 2 - len(menu) + (idx * 3)
             draw_button(stdscr, y, x, row, idx == current_row_idx)
 
+        # 3. Draw Transient Message or Input Prompt
+        if time.time() - message_time < 2.0:
+            stdscr.addstr(h - 2, 0, message.ljust(w - 1), curses.color_pair(1) | curses.A_BOLD)
+        
+        if input_mode:
+            curses.curs_set(1)
+            stdscr.addstr(h - 2, 0, (input_prompt + input_str).ljust(w-1), curses.color_pair(2))
+            stdscr.move(h - 2, len(input_prompt) + len(input_str))
+        else:
+            curses.curs_set(0)
+
         stdscr.refresh()
-        key = stdscr.getch()
-
-        if key == curses.KEY_UP and current_row_idx > 0:
-            current_row_idx -= 1
-        elif key == curses.KEY_DOWN and current_row_idx < len(menu) - 1:
-            current_row_idx += 1
-        elif key == curses.KEY_ENTER or key in [10, 13]:
-            selected_option = menu[current_row_idx]
-
-            if selected_option == "Exit":
-                stop_event.set()
-                break
-            elif selected_option == "Open Valve":
-                client.write_register(REG_HOLDING_VALVE_COMMAND, 1, slave=slave_id)
-                show_message(stdscr, h, w, "-> Sent OPEN command")
-            elif selected_option == "Close Valve":
-                client.write_register(REG_HOLDING_VALVE_COMMAND, 2, slave=slave_id)
-                show_message(stdscr, h, w, "-> Sent CLOSE command")
-            elif selected_option == "Stop Valve":
-                client.write_register(REG_HOLDING_VALVE_COMMAND, 0, slave=slave_id)
-                show_message(stdscr, h, w, "-> Sent STOP command")
-            elif "Set Max" in selected_option:
-                prompt = f"Enter new value for '{selected_option}' (seconds): "
-                input_str = get_user_input(stdscr, h, w, prompt)
-                try:
-                    seconds = int(input_str)
-                    reg = REG_HOLDING_MAX_OPENING_TIME_S if "Opening" in selected_option else REG_HOLDING_MAX_CLOSING_TIME_S
-                    client.write_register(reg, seconds, slave=slave_id)
-                    show_message(stdscr, h, w, f"-> Set '{selected_option}' to {seconds}s")
-                except ValueError:
-                    show_message(stdscr, h, w, "-> Invalid input. Please enter a number.", is_error=True)
-                except Exception as e:
-                    show_message(stdscr, h, w, f"-> Error: {e}", is_error=True)
 
 def main():
     global client