sxchnge/frontend/packages/sxchnge_theme/lib/src/theme.dart

import 'package:flutter/material.dart';

import 'brand.dart';

/// Install with `MaterialApp(theme: SxchngeTheme.light(),
/// darkTheme: SxchngeTheme.dark())`.
abstract final class SxchngeTheme {
  static const packageName = 'sxchnge_theme';

  static ThemeData light() => _build(Brightness.light);
  static ThemeData dark() => _build(Brightness.dark);

  static ThemeData _build(Brightness brightness) {
    final dark = brightness == Brightness.dark;
    // Seed supplies complete Material roles; explicit overrides preserve brand
    // colors and readable foregrounds rather than approximating the palette.
    final scheme =
        ColorScheme.fromSeed(
          seedColor: SxchngeBrand.forest,
          brightness: brightness,
        ).copyWith(
          primary: dark ? SxchngeBrand.mint : SxchngeBrand.ink,
          onPrimary: dark ? SxchngeBrand.ink : SxchngeBrand.mint,
          primaryContainer: SxchngeBrand.mint,
          onPrimaryContainer: SxchngeBrand.ink,
          secondary: dark ? SxchngeBrand.mint : SxchngeBrand.forest,
          onSecondary: dark ? SxchngeBrand.ink : SxchngeBrand.paper,
          secondaryContainer: dark
              ? SxchngeBrand.darkReceive
              : SxchngeBrand.sageSurface,
          onSecondaryContainer: dark ? SxchngeBrand.mint : SxchngeBrand.ink,
          tertiary: dark ? SxchngeBrand.lime : SxchngeBrand.forest,
          onTertiary: dark ? SxchngeBrand.ink : SxchngeBrand.paper,
          tertiaryContainer: SxchngeBrand.lime,
          onTertiaryContainer: SxchngeBrand.ink,
          surface: dark ? SxchngeBrand.ink : SxchngeBrand.paper,
          onSurface: dark ? SxchngeBrand.paper : SxchngeBrand.ink,
          onSurfaceVariant: dark ? const Color(0xFFB6C6B9) : SxchngeBrand.muted,
          surfaceContainerLowest: dark ? const Color(0xFF101B17) : Colors.white,
          surfaceContainerLow: dark
              ? const Color(0xFF1B2B23)
              : SxchngeBrand.paper,
          surfaceContainer: dark
              ? SxchngeBrand.darkField
              : SxchngeBrand.sageSurface,
          surfaceContainerHigh: dark
              ? SxchngeBrand.darkReceive
              : SxchngeBrand.line,
          surfaceContainerHighest: dark
              ? const Color(0xFF324A3C)
              : const Color(0xFFCFD9CE),
          outline: dark ? const Color(0xFF8CA291) : SxchngeBrand.muted,
          outlineVariant: dark ? const Color(0xFF405A48) : SxchngeBrand.line,
          inverseSurface: dark ? SxchngeBrand.paper : SxchngeBrand.ink,
          onInverseSurface: dark ? SxchngeBrand.ink : SxchngeBrand.paper,
          inversePrimary: dark ? SxchngeBrand.forest : SxchngeBrand.mint,
          surfaceTint: Colors.transparent,
        );
    final base = ThemeData(
      useMaterial3: true,
      colorScheme: scheme,
      fontFamily: SxchngeBrand.fontFamily,
      package: packageName,
      scaffoldBackgroundColor: scheme.surface,
      visualDensity: VisualDensity.standard,
      materialTapTargetSize: MaterialTapTargetSize.padded,
    );
    final text = base.textTheme.copyWith(
      displayLarge: base.textTheme.displayLarge!.copyWith(
        fontSize: 48,
        fontWeight: FontWeight.w600,
        letterSpacing: -2,
        height: 1.1,
      ),
      displayMedium: base.textTheme.displayMedium!.copyWith(
        fontSize: 40,
        fontWeight: FontWeight.w600,
        letterSpacing: -1.5,
        height: 1.15,
      ),
      displaySmall: base.textTheme.displaySmall!.copyWith(
        fontSize: 36,
        fontWeight: FontWeight.w600,
        letterSpacing: -1,
        height: 1.2,
      ),
      headlineLarge: base.textTheme.headlineLarge!.copyWith(
        fontWeight: FontWeight.w600,
        letterSpacing: -1,
      ),
      headlineMedium: base.textTheme.headlineMedium!.copyWith(
        fontWeight: FontWeight.w600,
        letterSpacing: -0.5,
      ),
      headlineSmall: base.textTheme.headlineSmall!.copyWith(
        fontWeight: FontWeight.w600,
      ),
      bodyLarge: base.textTheme.bodyLarge!.copyWith(fontSize: 16, height: 1.65),
      bodyMedium: base.textTheme.bodyMedium!.copyWith(
        fontSize: 16,
        height: 1.5,
      ),
      bodySmall: base.textTheme.bodySmall!.copyWith(fontSize: 14, height: 1.5),
      labelLarge: base.textTheme.labelLarge!.copyWith(
        fontSize: 16,
        fontWeight: FontWeight.w600,
      ),
      labelMedium: base.textTheme.labelMedium!.copyWith(
        fontSize: 14,
        fontWeight: FontWeight.w600,
      ),
      labelSmall: base.textTheme.labelSmall!.copyWith(fontSize: 14),
    );
    final border = OutlineInputBorder(
      borderRadius: BorderRadius.circular(14),
      borderSide: BorderSide(color: scheme.outline),
    );
    return base.copyWith(
      textTheme: text,
      appBarTheme: AppBarThemeData(
        backgroundColor: scheme.surface,
        foregroundColor: scheme.onSurface,
        surfaceTintColor: Colors.transparent,
        elevation: 0,
        centerTitle: false,
        titleTextStyle: text.titleLarge,
      ),
      cardTheme: CardThemeData(
        color: scheme.surfaceContainer,
        elevation: 0,
        margin: EdgeInsets.zero,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
      ),
      filledButtonTheme: FilledButtonThemeData(
        style: FilledButton.styleFrom(
          minimumSize: const Size(64, 48),
          padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 14),
          shape: const StadiumBorder(),
          textStyle: text.labelLarge,
        ),
      ),
      elevatedButtonTheme: ElevatedButtonThemeData(
        style: ElevatedButton.styleFrom(
          minimumSize: const Size(64, 48),
          padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 14),
          shape: const StadiumBorder(),
          textStyle: text.labelLarge,
          elevation: 0,
        ),
      ),
      outlinedButtonTheme: OutlinedButtonThemeData(
        style: OutlinedButton.styleFrom(
          minimumSize: const Size(64, 48),
          padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 14),
          shape: const StadiumBorder(),
          textStyle: text.labelLarge,
        ),
      ),
      textButtonTheme: TextButtonThemeData(
        style: TextButton.styleFrom(
          minimumSize: const Size(48, 48),
          textStyle: text.labelLarge,
        ),
      ),
      inputDecorationTheme: InputDecorationThemeData(
        filled: true,
        fillColor: scheme.surfaceContainerLowest,
        contentPadding: const EdgeInsets.all(16),
        border: border,
        enabledBorder: border,
        focusedBorder: border.copyWith(
          borderSide: BorderSide(
            color: dark ? SxchngeBrand.mint : SxchngeBrand.focus,
            width: 2,
          ),
        ),
        errorBorder: border.copyWith(
          borderSide: BorderSide(color: scheme.error),
        ),
        focusedErrorBorder: border.copyWith(
          borderSide: BorderSide(color: scheme.error, width: 2),
        ),
      ),
      dialogTheme: DialogThemeData(
        backgroundColor: scheme.surface,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
      ),
      dividerTheme: DividerThemeData(
        color: scheme.outlineVariant,
        thickness: 1,
      ),
      navigationBarTheme: NavigationBarThemeData(
        backgroundColor: scheme.surface,
        indicatorColor: scheme.primaryContainer,
      ),
      textSelectionTheme: TextSelectionThemeData(
        cursorColor: scheme.primary,
        selectionColor: SxchngeBrand.lime.withValues(alpha: dark ? 0.3 : 0.5),
        selectionHandleColor: scheme.primary,
      ),
    );
  }
}