import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'app_colors.dart'; // Import Extension

enum AppFontStyle {
  sans,      // Noto Sans JP (ゴシック)
  serif,     // Noto Serif JP (明朝)
  pottaOne,  // Potta One (髭文字)
  digital,   // DotGothic16 (ドット)
}

enum ColorVariant {
  washiSumiKohaku,  // 和紙×墨×琥珀 (Theme A)
  current,          // Current theme (Theme B)
}

class AppTheme {
  static const Color posimaiBlue = Color(0xFF376495);

  // ===== Theme A: 和紙×墨×琥珀 (Washi × Sumi × Kohaku) =====
  // 日本酒の世界観を反映した洗練された配色
  static const Color washiWhite = Color(0xFFFDFBF7);      // 和紙の温かみのある白
  static const Color sumiBlack = Color(0xFF4A3B32);       // 墨色（温かみのある焦げ茶）
  static const Color kohakuGold = Color(0xFFD4A574);      // 琥珀色（酒の黄金色）
  static const Color kohakuDeep = Color(0xFFB8860B);      // 深い琥珀（アクセント用）

  // ===== Theme B: Current (Original) =====
  // 既存のPosimai Blueベースのテーマ

  // Padding Constants
  static const double spacingEmpty = 0.0;
  static const double spacingTiny = 4.0;
  static const double spacingSmall = 8.0;
  static const double spacingMedium = 16.0;
  static const double spacingLarge = 24.0;
  static const double spacingXLarge = 32.0;

  static ThemeData createTheme(
    AppFontStyle fontStyle,
    Brightness brightness,
    ColorVariant colorVariant,
  ) {
    /*
      Why GoogleFonts is safe:
      1. Downloads dynamically (no asset size increase).
      2. Caches locally (fast 2nd load).
      3. Fallback exists during download.
    */
    final TextTheme textTheme;
    switch (fontStyle) {
      case AppFontStyle.sans:
        textTheme = GoogleFonts.notoSansJpTextTheme();
      case AppFontStyle.serif:
        textTheme = GoogleFonts.notoSerifJpTextTheme();
      case AppFontStyle.pottaOne:
        textTheme = GoogleFonts.pottaOneTextTheme();
      case AppFontStyle.digital:
        textTheme = GoogleFonts.dotGothic16TextTheme();
    }

    // Get AppColors for this theme variant
    final appColors = _getAppColors(colorVariant, brightness);

    // Color scheme based on variant
    final ColorScheme colorScheme;

    if (colorVariant == ColorVariant.washiSumiKohaku) {
      // Theme A: 和紙×墨×琥珀
      colorScheme = ColorScheme.fromSeed(
        seedColor: kohakuGold,
        brightness: brightness,
      ).copyWith(
        primary: brightness == Brightness.dark
            ? kohakuGold              // 琥珀色 for dark mode
            : sumiBlack,              // 墨色 for light mode

        surface: brightness == Brightness.dark
            ? const Color(0xFF1E1E1E)
            : washiWhite,             // 和紙ホワイト

        secondary: brightness == Brightness.dark
            ? kohakuDeep              // 深い琥珀 for dark mode
            : kohakuGold,             // 琥珀色 for light mode
      );
    } else {
      // Theme B: Current (Original)
      colorScheme = ColorScheme.fromSeed(
        seedColor: posimaiBlue,
        brightness: brightness,
      ).copyWith(
        primary: brightness == Brightness.dark
            ? const Color(0xFF8AB4F8)  // Bright blue for dark mode
            : posimaiBlue,             // Original blue for light mode

        surface: brightness == Brightness.dark
            ? const Color(0xFF1E1E1E)
            : Colors.white,

        secondary: brightness == Brightness.dark
            ? const Color(0xFFFFB74D)  // Warm orange for dark mode accents
            : const Color(0xFFFF6F00), // Deep orange for light mode
      );
    }

    return ThemeData(
      useMaterial3: true,
      colorScheme: colorScheme,
      textTheme: textTheme.apply(
        bodyColor: (brightness == Brightness.dark) ? Colors.white : Colors.black87,
        displayColor: (brightness == Brightness.dark) ? Colors.white : Colors.black87,
      ).copyWith(
        // Ensure headers/labels are visible
        titleMedium: TextStyle(color: (brightness == Brightness.dark) ? Colors.white : Colors.black87),
        titleSmall: TextStyle(color: (brightness == Brightness.dark) ? Colors.white70 : Colors.black54),
        labelLarge: TextStyle(color: (brightness == Brightness.dark) ? Colors.white : Colors.black87),
      ),
      scaffoldBackgroundColor: (brightness == Brightness.dark)
          ? const Color(0xFF121212)
          : (colorVariant == ColorVariant.washiSumiKohaku
              ? washiWhite
              : const Color(0xFFFAFAFA)),

      cardTheme: CardThemeData(
        elevation: 0,
        margin: EdgeInsets.zero,
        color: (brightness == Brightness.dark)
            ? const Color(0xFF1E1E1E)
            : (colorVariant == ColorVariant.washiSumiKohaku
                ? Colors.white
                : Colors.white),
      ),
      
      appBarTheme: AppBarTheme(
        // UI/UX Consistency: AppBarとNavigationBarの背景色を統一（ダークモードのみ）
        backgroundColor: (brightness == Brightness.dark) ? const Color(0xFF1E1E1E) : null,
        foregroundColor: (brightness == Brightness.dark) ? Colors.white : Colors.black87,
        actionsIconTheme: IconThemeData(
          color: (brightness == Brightness.dark) ? Colors.white : Colors.black87,
        ),
        iconTheme: IconThemeData(
          color: (brightness == Brightness.dark) ? Colors.white : Colors.black87,
        ),
      ),
      
      iconTheme: IconThemeData(
        color: (brightness == Brightness.dark)
            ? Colors.white
            : (colorVariant == ColorVariant.washiSumiKohaku
                ? sumiBlack
                : posimaiBlue),
      ),
      
      navigationBarTheme: NavigationBarThemeData(
        backgroundColor: (brightness == Brightness.dark) ? const Color(0xFF1E1E1E) : null,
         indicatorColor: brightness == Brightness.dark
            ? appColors.brandPrimary.withValues(alpha: 0.4)
            : appColors.brandPrimary.withValues(alpha: 0.25),
      ),
      extensions: [
        _getAppColors(colorVariant, brightness),
      ],
    );
  }

  /// AppColorsインスタンスを取得（テーマバリアントとブライトネスに基づく）
  static AppColors _getAppColors(ColorVariant colorVariant, Brightness brightness) {
    if (colorVariant == ColorVariant.washiSumiKohaku) {
      return brightness == Brightness.dark
          ? AppColors.washiDark()
          : AppColors.washiLight();
    } else {
      return brightness == Brightness.dark
          ? AppColors.currentDark()
          : AppColors.currentLight();
    }
  }
}