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

class AppTheme {
  static ThemeData get lightTheme {
    // Base text theme with DM Sans (PRD: 正文/UI 字体)
    final baseTextTheme = GoogleFonts.dmSansTextTheme(const TextTheme(
      // h1 / Large Headings
      displayLarge: TextStyle(
        color: AppColors.textPrimary,
        fontSize: 32,
        fontWeight: FontWeight.w700,
        letterSpacing: -0.5,
      ),
      // h2 / Subheadings
      displayMedium: TextStyle(
        color: AppColors.textPrimary,
        fontSize: 24,
        fontWeight: FontWeight.w600,
      ),
      // Body Text
      bodyLarge: TextStyle(
        color: AppColors.textPrimary,
        fontSize: 16,
        fontWeight: FontWeight.w400,
        height: 1.5,
      ),
      bodyMedium: TextStyle(
        color: AppColors.textSecondary,
        fontSize: 14,
        fontWeight: FontWeight.w400,
      ),
      // Small captions
      bodySmall: TextStyle(color: AppColors.textLight, fontSize: 12),
      // Button Text
      labelLarge: TextStyle(
        color: Colors.white,
        fontSize: 16,
        fontWeight: FontWeight.w600,
        letterSpacing: 0.5,
      ),
    ));

    // Apply Outfit to heading styles (PRD: 标题/Display 字体)
    final textTheme = baseTextTheme.copyWith(
      displayLarge: GoogleFonts.outfit(textStyle: baseTextTheme.displayLarge),
      displayMedium: GoogleFonts.outfit(textStyle: baseTextTheme.displayMedium),
      displaySmall: GoogleFonts.outfit(textStyle: baseTextTheme.displaySmall),
      headlineLarge: GoogleFonts.outfit(textStyle: baseTextTheme.headlineLarge),
      headlineMedium: GoogleFonts.outfit(textStyle: baseTextTheme.headlineMedium),
      headlineSmall: GoogleFonts.outfit(textStyle: baseTextTheme.headlineSmall),
      titleLarge: GoogleFonts.outfit(textStyle: baseTextTheme.titleLarge),
      titleMedium: GoogleFonts.outfit(textStyle: baseTextTheme.titleMedium),
      titleSmall: GoogleFonts.outfit(textStyle: baseTextTheme.titleSmall),
    );

    return ThemeData(
      useMaterial3: true,
      scaffoldBackgroundColor: AppColors.bgBase,
      primaryColor: AppColors.primaryIndigo,
      colorScheme: ColorScheme.fromSeed(
        seedColor: AppColors.primaryIndigo,
        primary: AppColors.primaryIndigo,
        secondary: AppColors.primaryPurple,
        surface: AppColors.bgBase,
        background: AppColors.bgBase,
      ),
      // PRD: DM Sans 为默认正文字体，回退到系统字体
      fontFamily: GoogleFonts.dmSans().fontFamily,
      fontFamilyFallback: const [
        'Roboto',
        'PingFang SC',
        'Helvetica Neue',
      ],
      textTheme: textTheme,
      snackBarTheme: SnackBarThemeData(
        backgroundColor: const Color(0xFFF9FAFB),
        contentTextStyle: const TextStyle(
          color: Color(0xFF374151),
          fontSize: 14,
        ),
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16),
        ),
        behavior: SnackBarBehavior.floating,
        elevation: 4,
        insetPadding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
      ),
    );
  }

  // Animation Curves from CSS
  // --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
  static const Curve easeSmooth = Cubic(0.4, 0, 0.2, 1);

  // --ease-bounce: cubic-bezier(0.34, 1.56, 0.64, 1);
  static const Curve easeBounce = Cubic(0.34, 1.56, 0.64, 1);
}