multiple updates

- colour theme implemented. ThemeService based global switching for future light detection triggers
- test flipflop service for various fun
- navigator widget class with state switching

scripts/generate_theme.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+"""Theme generator for Smart Serow Flutter UI.
+
+Reads navigator from config, loads corresponding theme JSON,
+and generates app_colors.dart with the colour palette.
+
+Fallback chain: {navigator}.json -> default.json -> hardcoded defaults
+"""
+
+import json
+import sys
+from pathlib import Path
+
+
+SCRIPT_DIR = Path(__file__).parent.resolve()
+PROJECT_ROOT = SCRIPT_DIR.parent
+UI_DIR = PROJECT_ROOT / "pi" / "ui"
+THEMES_DIR = PROJECT_ROOT / "extra" / "themes"
+CONFIG_FILE = UI_DIR / "config.json"
+OUTPUT_FILE = UI_DIR / "lib" / "theme" / "app_colors.dart"
+
+# Hardcoded fallback if no theme files exist at all
+HARDCODED_THEME = {
+    "dark": {
+        "background": "#000000",
+        "foreground": "#FFFFFF",
+        "highlight": "#FF5555",
+        "subdued": "#808080",
+    },
+    "bright": {
+        "background": "#F0F0F0",
+        "foreground": "#1A1A1A",
+        "highlight": "#CC0000",
+        "subdued": "#606060",
+    },
+}
+
+
+def hex_to_flutter(hex_color: str) -> str:
+    """Convert #RRGGBB to 0xFFRRGGBB format."""
+    hex_clean = hex_color.lstrip("#").upper()
+    return f"0xFF{hex_clean}"
+
+
+def load_config() -> dict:
+    """Load UI config, return empty dict if missing."""
+    if CONFIG_FILE.exists():
+        with open(CONFIG_FILE) as f:
+            return json.load(f)
+    return {}
+
+
+def load_theme(navigator: str) -> dict:
+    """Load theme for navigator with fallback chain."""
+    # Try navigator-specific theme
+    nav_theme = THEMES_DIR / f"{navigator}.json"
+    if nav_theme.exists():
+        print(f"  Using theme: {nav_theme.name}")
+        with open(nav_theme) as f:
+            return json.load(f)
+
+    # Try default theme
+    default_theme = THEMES_DIR / "default.json"
+    if default_theme.exists():
+        print(f"  Fallback to: default.json")
+        with open(default_theme) as f:
+            return json.load(f)
+
+    # Last resort: hardcoded
+    print(f"  Using hardcoded defaults")
+    return HARDCODED_THEME
+
+
+def generate_dart(theme: dict) -> str:
+    """Generate Dart source from theme dict."""
+    dark = theme["dark"]
+    bright = theme["bright"]
+
+    return f'''import 'package:flutter/material.dart';
+
+/// Auto-generated from theme config. Do not edit manually.
+/// Run scripts/generate_theme.py to regenerate.
+class AppColors {{
+  AppColors._();
+
+  // Dark theme (low ambient light)
+  static const darkBackground = Color({hex_to_flutter(dark["background"])});
+  static const darkForeground = Color({hex_to_flutter(dark["foreground"])});
+  static const darkHighlight = Color({hex_to_flutter(dark["highlight"])});
+  static const darkSubdued = Color({hex_to_flutter(dark["subdued"])});
+
+  // Bright theme (high ambient light)
+  static const brightBackground = Color({hex_to_flutter(bright["background"])});
+  static const brightForeground = Color({hex_to_flutter(bright["foreground"])});
+  static const brightHighlight = Color({hex_to_flutter(bright["highlight"])});
+  static const brightSubdued = Color({hex_to_flutter(bright["subdued"])});
+}}
+'''
+
+
+def main():
+    print("=== Theme Generation ===")
+
+    # Get navigator from config
+    config = load_config()
+    navigator = config.get("navigator", "default")
+    print(f"  Navigator: {navigator}")
+
+    # Load theme
+    theme = load_theme(navigator)
+
+    # Generate Dart
+    dart_source = generate_dart(theme)
+
+    # Ensure output directory exists
+    OUTPUT_FILE.parent.mkdir(parents=True, exist_ok=True)
+
+    # Write output
+    with open(OUTPUT_FILE, "w") as f:
+        f.write(dart_source)
+
+    print(f"  Generated: {OUTPUT_FILE.relative_to(PROJECT_ROOT)}")
+    return True
+
+
+if __name__ == "__main__":
+    success = main()
+    sys.exit(0 if success else 1)