import 'package:flutter/material.dart';

import 'app_colors.dart';
import 'app_data_styles.dart';
import 'status_colors.dart';

/// Builds the app's light/dark [ThemeData]. Colors are constructed
/// explicitly from [AppColors] rather than via [ColorScheme.fromSeed] so the
/// approved mockup's exact hex values can't drift through algorithmic tone
/// generation.
abstract final class AppTheme {
  static ThemeData light() => _build(brightness: Brightness.light);
  static ThemeData dark() => _build(brightness: Brightness.dark);

  static ThemeData _build({required Brightness brightness}) {
    final isDark = brightness == Brightness.dark;

    final colorScheme = isDark
        ? const ColorScheme.dark(
            surface: AppColors.darkBg,
            onSurface: AppColors.darkText,
            surfaceContainerHighest: AppColors.darkSurfaceAlt,
            primary: AppColors.darkAccent,
            onPrimary: AppColors.darkAccentInk,
            secondary: AppColors.darkAccentStrong,
            onSecondary: AppColors.darkAccentInk,
            error: AppColors.critical,
            onError: Colors.white,
            outline: AppColors.darkBorder,
            outlineVariant: AppColors.darkBorder,
          )
        : const ColorScheme.light(
            surface: AppColors.lightBg,
            onSurface: AppColors.lightText,
            surfaceContainerHighest: AppColors.lightSurfaceAlt,
            primary: AppColors.lightAccent,
            onPrimary: AppColors.lightAccentInk,
            secondary: AppColors.lightAccentStrong,
            onSecondary: AppColors.lightAccentInk,
            error: AppColors.critical,
            onError: Colors.white,
            outline: AppColors.lightBorder,
            outlineVariant: AppColors.lightBorder,
          );

    final surfaceCard = isDark ? AppColors.darkSurface : AppColors.lightSurface;
    final textColor = isDark ? AppColors.darkText : AppColors.lightText;
    final textMuted = isDark ? AppColors.darkTextMuted : AppColors.lightTextMuted;
    final textFaint = isDark ? AppColors.darkTextFaint : AppColors.lightTextFaint;
    final border = isDark ? AppColors.darkBorder : AppColors.lightBorder;

    final textTheme = TextTheme(
      displaySmall: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 30, color: textColor, letterSpacing: -0.2),
      headlineSmall: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 22, color: textColor, letterSpacing: -0.1),
      titleLarge: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 17, color: textColor, letterSpacing: -0.1),
      titleMedium: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w600, fontSize: 14, color: textColor),
      titleSmall: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 11, color: textFaint, letterSpacing: 0.6),
      bodyLarge: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w400, fontSize: 15, color: textColor, height: 1.5),
      bodyMedium: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w400, fontSize: 13.5, color: textColor, height: 1.45),
      bodySmall: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w500, fontSize: 12, color: textMuted),
      labelLarge: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w600, fontSize: 13, color: textColor),
      labelMedium: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w600, fontSize: 12, color: textMuted),
      labelSmall: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 11, color: textFaint, letterSpacing: 0.5),
    );

    return ThemeData(
      useMaterial3: true,
      brightness: brightness,
      colorScheme: colorScheme,
      scaffoldBackgroundColor: colorScheme.surface,
      canvasColor: colorScheme.surface,
      dividerColor: border,
      fontFamily: 'Inter',
      textTheme: textTheme,
      cardTheme: CardThemeData(
        color: surfaceCard,
        elevation: 0,
        margin: EdgeInsets.zero,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(10),
          side: BorderSide(color: border),
        ),
      ),
      appBarTheme: AppBarTheme(
        backgroundColor: colorScheme.surface,
        foregroundColor: textColor,
        elevation: 0,
        surfaceTintColor: Colors.transparent,
      ),
      navigationRailTheme: NavigationRailThemeData(
        backgroundColor: isDark ? AppColors.darkSurfaceAlt : AppColors.lightSurfaceAlt,
        indicatorColor: colorScheme.primary.withValues(alpha: 0.16),
        selectedIconTheme: IconThemeData(color: colorScheme.secondary),
        unselectedIconTheme: IconThemeData(color: textMuted),
        selectedLabelTextStyle: TextStyle(color: colorScheme.secondary, fontWeight: FontWeight.w700, fontSize: 12.5),
        unselectedLabelTextStyle: TextStyle(color: textMuted, fontWeight: FontWeight.w500, fontSize: 12.5),
      ),
      elevatedButtonTheme: ElevatedButtonThemeData(
        style: ElevatedButton.styleFrom(
          backgroundColor: colorScheme.primary,
          foregroundColor: colorScheme.onPrimary,
          elevation: 0,
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(7)),
          textStyle: const TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w600, fontSize: 13),
        ),
      ),
      outlinedButtonTheme: OutlinedButtonThemeData(
        style: OutlinedButton.styleFrom(
          foregroundColor: textColor,
          side: BorderSide(color: border),
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(7)),
          textStyle: const TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w600, fontSize: 13),
        ),
      ),
      inputDecorationTheme: InputDecorationTheme(
        filled: true,
        fillColor: colorScheme.surface,
        contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
        border: OutlineInputBorder(
          borderRadius: BorderRadius.circular(7),
          borderSide: BorderSide(color: border),
        ),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(7),
          borderSide: BorderSide(color: border),
        ),
        focusedBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(7),
          borderSide: BorderSide(color: colorScheme.primary, width: 1.5),
        ),
        labelStyle: TextStyle(color: textMuted, fontSize: 12.5, fontWeight: FontWeight.w600),
      ),
      dataTableTheme: DataTableThemeData(
        headingTextStyle: TextStyle(fontFamily: 'Inter', fontWeight: FontWeight.w700, fontSize: 11, color: textFaint, letterSpacing: 0.5),
        dataTextStyle: TextStyle(fontFamily: 'Inter', fontSize: 13, color: textColor),
        dividerThickness: 1,
      ),
      extensions: [
        isDark ? StatusColors.dark : StatusColors.light,
        AppDataStyles.resolve(textColor: textColor, mutedColor: textMuted),
      ],
    );
  }
}