/// Material 3 light and dark themes, including typography and component styles.
library;

import 'package:flutter/material.dart';

/// Builds the [ThemeData] used by [MaterialApp] for light and dark mode.
///
/// Colors are generated from a single seed so both schemes stay consistent
/// with Material 3 tonal palettes.
abstract final class AppTheme {
  static const Color seed = Color(0xFF0F766E);

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

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

  static ThemeData _build(Brightness brightness) {
    final colorScheme = ColorScheme.fromSeed(
      seedColor: seed,
      brightness: brightness,
    );

    final isDark = brightness == Brightness.dark;
    final textTheme = _textTheme(colorScheme);

    return ThemeData(
      useMaterial3: true,
      colorScheme: colorScheme,
      textTheme: textTheme,
      scaffoldBackgroundColor: colorScheme.surface,
      appBarTheme: AppBarTheme(
        centerTitle: false,
        elevation: 0,
        scrolledUnderElevation: 1,
        backgroundColor: colorScheme.surface,
        foregroundColor: colorScheme.onSurface,
        titleTextStyle: textTheme.titleLarge,
      ),
      cardTheme: CardThemeData(
        elevation: 0,
        color: colorScheme.surfaceContainerLow,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16),
        ),
        clipBehavior: Clip.antiAlias,
        margin: EdgeInsets.zero,
      ),
      navigationBarTheme: NavigationBarThemeData(
        elevation: 0,
        height: 72,
        backgroundColor: colorScheme.surfaceContainer,
        indicatorColor: colorScheme.secondaryContainer,
        labelTextStyle: WidgetStateProperty.resolveWith((states) {
          final selected = states.contains(WidgetState.selected);
          return textTheme.labelMedium?.copyWith(
            fontWeight: selected ? FontWeight.w600 : FontWeight.w500,
          );
        }),
      ),
      inputDecorationTheme: InputDecorationTheme(
        filled: true,
        fillColor: colorScheme.surfaceContainerHighest.withValues(alpha: 0.6),
        border: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
        ),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: BorderSide(color: colorScheme.outlineVariant),
        ),
        focusedBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: BorderSide(color: colorScheme.primary, width: 2),
        ),
        contentPadding: const EdgeInsets.symmetric(
          horizontal: 16,
          vertical: 14,
        ),
      ),
      filledButtonTheme: FilledButtonThemeData(
        style: FilledButton.styleFrom(
          minimumSize: const Size.fromHeight(48),
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
          textStyle: textTheme.labelLarge,
        ),
      ),
      floatingActionButtonTheme: FloatingActionButtonThemeData(
        backgroundColor: colorScheme.primary,
        foregroundColor: colorScheme.onPrimary,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16),
        ),
      ),
      dividerTheme: DividerThemeData(
        color: colorScheme.outlineVariant,
        space: 1,
      ),
      snackBarTheme: SnackBarThemeData(
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(12),
        ),
      ),
      listTileTheme: ListTileThemeData(
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(12),
        ),
        iconColor: colorScheme.primary,
      ),
      shadowColor: isDark ? Colors.black : const Color(0x1A0F172A),
    );
  }

  /// Slightly tighter, more editorial type scale than the Material defaults.
  static TextTheme _textTheme(ColorScheme colors) {
    const family = 'Roboto';
    return TextTheme(
      displaySmall: TextStyle(
        fontFamily: family,
        fontSize: 36,
        fontWeight: FontWeight.w700,
        letterSpacing: -0.5,
        color: colors.onSurface,
      ),
      headlineMedium: TextStyle(
        fontFamily: family,
        fontSize: 28,
        fontWeight: FontWeight.w600,
        letterSpacing: -0.3,
        color: colors.onSurface,
      ),
      titleLarge: TextStyle(
        fontFamily: family,
        fontSize: 22,
        fontWeight: FontWeight.w600,
        color: colors.onSurface,
      ),
      titleMedium: TextStyle(
        fontFamily: family,
        fontSize: 16,
        fontWeight: FontWeight.w600,
        color: colors.onSurface,
      ),
      bodyLarge: TextStyle(
        fontFamily: family,
        fontSize: 16,
        height: 1.45,
        color: colors.onSurface,
      ),
      bodyMedium: TextStyle(
        fontFamily: family,
        fontSize: 14,
        height: 1.4,
        color: colors.onSurfaceVariant,
      ),
      labelLarge: TextStyle(
        fontFamily: family,
        fontSize: 14,
        fontWeight: FontWeight.w600,
        letterSpacing: 0.1,
        color: colors.onPrimary,
      ),
      labelMedium: TextStyle(
        fontFamily: family,
        fontSize: 12,
        fontWeight: FontWeight.w500,
        letterSpacing: 0.4,
        color: colors.onSurfaceVariant,
      ),
    );
  }
}