import 'dart:io';

import 'package:flutter/material.dart';

/// 应用级语义色扩展（浅色/深色各一套，随主题自动切换）
///
/// 用法：`context.appColors.cardBackground`
/// 原理：颜色挂载在 ThemeData.extensions 上，主题切换时组件树自动重建，
///       页面无需写 `isDark ? A : B` 判断
@immutable
class AppColors extends ThemeExtension<AppColors> {
  const AppColors({
    required this.pageBackground,
    required this.cardBackground,
    required this.fillBackground,
    required this.textPrimary,
    required this.textSecondary,
    required this.textTertiary,
    required this.divider,
    required this.cardShadow,
    required this.primary,
    required this.danger,
    required this.warning,
    required this.success,
  });

  /// 页面背景色
  final Color pageBackground;

  /// 卡片背景色
  final Color cardBackground;

  /// 卡片内嵌块填充色（输入框、上传按钮等）
  final Color fillBackground;

  /// 主要文字色
  final Color textPrimary;

  /// 次要文字色
  final Color textSecondary;

  /// 辅助文字色（占位、说明）
  final Color textTertiary;

  /// 分割线/浅色边框
  final Color divider;

  /// 卡片阴影色
  final Color cardShadow;

  /// 品牌主色（两种模式下保持一致）
  final Color primary;

  /// 危险/错误色（两种模式下保持一致）
  final Color danger;

  /// 警告色（两种模式下保持一致）
  final Color warning;

  /// 成功/完成色（两种模式下保持一致）
  final Color success;

  /// 浅色语义色（取自设计稿）
  static const AppColors light = AppColors(
    pageBackground: Color(0xFFF5F7FA),
    cardBackground: Color(0xFFFFFFFF),
    fillBackground: Color(0xFFF8F9FA),
    textPrimary: Color(0xFF1D2129),
    textSecondary: Color(0xFF4E5969),
    textTertiary: Color(0xFF86909C),
    divider: Color(0xFFF0F0F0),
    cardShadow: Color(0x0D000000),
    primary: Color(0xFF165DFF),
    danger: Color(0xFFF53F3F),
    warning: Color(0xFFFF7D00),
    success: Color(0xFF00B42A),
  );

  /// 深色语义色（与 AppTheme.darkTheme 的 surface 色保持一致）
  static const AppColors dark = AppColors(
    pageBackground: Color(0xFF1C1C1E),
    cardBackground: Color(0xFF2C2C2E),
    fillBackground: Color(0xFF3A3A3C),
    textPrimary: Color(0xFFF2F3F5),
    textSecondary: Color(0xFFC9CDD4),
    textTertiary: Color(0xFF86909C),
    divider: Color(0xFF3A3A3C),
    cardShadow: Color(0x00000000), // 深色下无阴影，靠色差分层级
    primary: Color(0xFF165DFF),
    danger: Color(0xFFF53F3F),
    warning: Color(0xFFFF7D00),
    success: Color(0xFF00B42A),
  );

  @override
  AppColors copyWith({
    Color? pageBackground,
    Color? cardBackground,
    Color? fillBackground,
    Color? textPrimary,
    Color? textSecondary,
    Color? textTertiary,
    Color? divider,
    Color? cardShadow,
    Color? primary,
    Color? danger,
    Color? warning,
    Color? success,
  }) {
    return AppColors(
      pageBackground: pageBackground ?? this.pageBackground,
      cardBackground: cardBackground ?? this.cardBackground,
      fillBackground: fillBackground ?? this.fillBackground,
      textPrimary: textPrimary ?? this.textPrimary,
      textSecondary: textSecondary ?? this.textSecondary,
      textTertiary: textTertiary ?? this.textTertiary,
      divider: divider ?? this.divider,
      cardShadow: cardShadow ?? this.cardShadow,
      primary: primary ?? this.primary,
      danger: danger ?? this.danger,
      warning: warning ?? this.warning,
      success: success ?? this.success,
    );
  }

  @override
  AppColors lerp(AppColors? other, double t) {
    if (other == null) return this;
    return AppColors(
      pageBackground: Color.lerp(pageBackground, other.pageBackground, t)!,
      cardBackground: Color.lerp(cardBackground, other.cardBackground, t)!,
      fillBackground: Color.lerp(fillBackground, other.fillBackground, t)!,
      textPrimary: Color.lerp(textPrimary, other.textPrimary, t)!,
      textSecondary: Color.lerp(textSecondary, other.textSecondary, t)!,
      textTertiary: Color.lerp(textTertiary, other.textTertiary, t)!,
      divider: Color.lerp(divider, other.divider, t)!,
      cardShadow: Color.lerp(cardShadow, other.cardShadow, t)!,
      primary: Color.lerp(primary, other.primary, t)!,
      danger: Color.lerp(danger, other.danger, t)!,
      warning: Color.lerp(warning, other.warning, t)!,
      success: Color.lerp(success, other.success, t)!,
    );
  }
}

/// 便捷访问扩展：`context.appColors`
extension AppColorsX on BuildContext {
  AppColors get appColors => Theme.of(this).extension<AppColors>()!;
}

class AppTheme {
  // 基础色值定义
  static const Color _pureWhite = Color(0xFFFFFFFF);
  static const Color _offWhite = Color(0xFFfafafc); // 稍微带点灰的白，用于背景增加层次感
  static const Color _pureBlack = Color(0xFF000000);
  static const Color _darkGrey = Color(0xFF1C1C1E); // iOS 风格的深灰黑色
  static const Color _surfaceDark = Color(0xFF2C2C2E); // 深色模式下卡片、弹窗表面色

  static ThemeData get lightTheme {
    return ThemeData(
      useMaterial3: true,
      brightness: Brightness.light,
      fontFamily: (Platform.isWindows) ? 'Microsoft YaHei' : null,

      // 语义色扩展
      extensions: const [AppColors.light],

      // 1. 整体背景色
      scaffoldBackgroundColor: _offWhite,

      // 2. 核心颜色方案
      colorScheme: const ColorScheme.light(
        primary: _pureBlack, // 主色设为黑色
        onPrimary: _pureWhite, // 黑色背景上的文字设为白色
        surface: _pureWhite, // 卡片、弹窗等表面颜色
        onSurface: _pureBlack, // 表面上的文字色
        background: _offWhite,
      ),

      // 3. 全局按钮主题
      elevatedButtonTheme: ElevatedButtonThemeData(
        style: ElevatedButton.styleFrom(
          backgroundColor: _pureBlack,
          foregroundColor: _pureWhite,
          elevation: 0,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
          padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 24),
        ),
      ),

      // 4. 填充按钮主题 (常用语 Material 3)
      filledButtonTheme: FilledButtonThemeData(
        style: FilledButton.styleFrom(
          backgroundColor: _pureBlack,
          foregroundColor: _pureWhite,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
        ),
      ),

      // 5. AppBar 主题 (纯白背景，黑色文字)
      appBarTheme: const AppBarTheme(
        backgroundColor: _pureWhite,
        surfaceTintColor: Colors.transparent,
        elevation: 0,
        centerTitle: true,
        iconTheme: IconThemeData(color: _pureBlack),
        titleTextStyle: TextStyle(
          color: _pureBlack,
          fontSize: 18,
          fontWeight: FontWeight.w700,
          letterSpacing: -0.5,
        ),
      ),

      // 6. 输入框主题 (黑白简约)
      inputDecorationTheme: InputDecorationTheme(
        filled: true,
        fillColor: _pureWhite,
        border: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: Colors.black12),
        ),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: Colors.black12),
        ),
        focusedBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: _pureBlack, width: 1.5),
        ),
      ),
    );
  }

  /// 深色主题 (与浅色主题对称的黑白简约风格)
  static ThemeData get darkTheme {
    return ThemeData(
      useMaterial3: true,
      brightness: Brightness.dark,
      fontFamily: (Platform.isWindows) ? 'Microsoft YaHei' : null,

      // 语义色扩展
      extensions: const [AppColors.dark],

      // 1. 整体背景色 (iOS 风格深灰黑)
      scaffoldBackgroundColor: _darkGrey,

      // 2. 核心颜色方案 (与浅色主题反色：主色白色)
      colorScheme: const ColorScheme.dark(
        primary: _pureWhite, // 主色设为白色
        onPrimary: _pureBlack, // 白色背景上的文字设为黑色
        surface: _surfaceDark, // 卡片、弹窗等表面颜色
        onSurface: _pureWhite, // 表面上的文字色
      ),

      // 3. 全局按钮主题 (白底黑字)
      elevatedButtonTheme: ElevatedButtonThemeData(
        style: ElevatedButton.styleFrom(
          backgroundColor: _pureWhite,
          foregroundColor: _pureBlack,
          elevation: 0,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
          padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 24),
        ),
      ),

      // 4. 填充按钮主题 (常用语 Material 3)
      filledButtonTheme: FilledButtonThemeData(
        style: FilledButton.styleFrom(
          backgroundColor: _pureWhite,
          foregroundColor: _pureBlack,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(12),
          ),
        ),
      ),

      // 5. AppBar 主题 (深灰黑背景，白色文字)
      appBarTheme: const AppBarTheme(
        backgroundColor: _darkGrey,
        surfaceTintColor: Colors.transparent,
        elevation: 0,
        centerTitle: true,
        iconTheme: IconThemeData(color: _pureWhite),
        titleTextStyle: TextStyle(
          color: _pureWhite,
          fontSize: 18,
          fontWeight: FontWeight.w700,
          letterSpacing: -0.5,
        ),
      ),

      // 6. 输入框主题 (深色填充，白色边框)
      inputDecorationTheme: InputDecorationTheme(
        filled: true,
        fillColor: _surfaceDark,
        border: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: Colors.white12),
        ),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: Colors.white12),
        ),
        focusedBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(12),
          borderSide: const BorderSide(color: _pureWhite, width: 1.5),
        ),
      ),
    );
  }
}