// Theme assembly. ColorScheme + typography + component themes.

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

import 'tokens.dart';

class FaiTheme {
  FaiTheme._();

  /// Inter for UI, JetBrains Mono for technical strings (IDs,
  /// paths, capability refs). Both via google_fonts so they
  /// bundle on first run; for production we'd ship them as
  /// app assets.
  static TextTheme _textTheme(Brightness b) {
    final base = b == Brightness.dark
        ? Typography.whiteCupertino
        : Typography.blackCupertino;
    return GoogleFonts.interTextTheme(base).copyWith(
      displaySmall: GoogleFonts.inter(
        fontSize: 28,
        fontWeight: FontWeight.w600,
        letterSpacing: -0.4,
      ),
      headlineSmall: GoogleFonts.inter(
        fontSize: 20,
        fontWeight: FontWeight.w600,
        letterSpacing: -0.2,
      ),
      titleMedium: GoogleFonts.inter(
        fontSize: 15,
        fontWeight: FontWeight.w600,
        letterSpacing: 0,
      ),
      titleSmall: GoogleFonts.inter(
        fontSize: 13,
        fontWeight: FontWeight.w500,
      ),
      bodyLarge: GoogleFonts.inter(
        fontSize: 14,
        fontWeight: FontWeight.w400,
        height: 1.45,
      ),
      bodyMedium: GoogleFonts.inter(
        fontSize: 13,
        fontWeight: FontWeight.w400,
        height: 1.4,
      ),
      bodySmall: GoogleFonts.inter(
        fontSize: 12,
        fontWeight: FontWeight.w400,
        height: 1.4,
      ),
      labelMedium: GoogleFonts.inter(
        fontSize: 12,
        fontWeight: FontWeight.w500,
      ),
      labelSmall: GoogleFonts.inter(
        fontSize: 11,
        fontWeight: FontWeight.w500,
        letterSpacing: 0.2,
      ),
    );
  }

  /// JetBrains Mono for monospaced technical content. Used by
  /// FaiMono helper.
  static TextStyle mono({
    double size = 12,
    FontWeight weight = FontWeight.w400,
    Color? color,
  }) =>
      GoogleFonts.jetBrainsMono(
        fontSize: size,
        fontWeight: weight,
        color: color,
        height: 1.4,
      );

  static ThemeData dark() {
    final scheme = ColorScheme(
      brightness: Brightness.dark,
      primary: FaiColors.accent,
      onPrimary: FaiColors.black,
      primaryContainer: FaiColors.accentMuted,
      onPrimaryContainer: FaiColors.textStrong,
      secondary: FaiColors.accentDeep,
      onSecondary: FaiColors.black,
      secondaryContainer: FaiColors.surfaceHigh,
      onSecondaryContainer: FaiColors.text,
      tertiary: FaiColors.accent,
      onTertiary: FaiColors.black,
      tertiaryContainer: FaiColors.surfaceHigh,
      onTertiaryContainer: FaiColors.text,
      error: FaiColors.danger,
      onError: FaiColors.textStrong,
      errorContainer: const Color(0xFF3F1518),
      onErrorContainer: const Color(0xFFFCA5A5),
      surface: FaiColors.black,
      onSurface: FaiColors.text,
      onSurfaceVariant: FaiColors.muted,
      outline: FaiColors.border,
      outlineVariant: FaiColors.border,
      surfaceContainerLowest: FaiColors.black,
      surfaceContainerLow: FaiColors.surface,
      surfaceContainer: FaiColors.surface,
      surfaceContainerHigh: FaiColors.surfaceHigh,
      surfaceContainerHighest: FaiColors.surfaceHigh,
    );
    return _build(scheme);
  }

  static ThemeData light() {
    final scheme = ColorScheme(
      brightness: Brightness.light,
      primary: FaiColors.accentDeep,
      onPrimary: FaiColors.lightSurface,
      primaryContainer: const Color(0xFFE0F2FE),
      onPrimaryContainer: FaiColors.accentMuted,
      secondary: FaiColors.accentMuted,
      onSecondary: FaiColors.lightSurface,
      secondaryContainer: FaiColors.lightSurfaceHigh,
      onSecondaryContainer: FaiColors.lightText,
      tertiary: FaiColors.accentDeep,
      onTertiary: FaiColors.lightSurface,
      tertiaryContainer: const Color(0xFFE0F2FE),
      onTertiaryContainer: FaiColors.accentMuted,
      error: FaiColors.danger,
      onError: FaiColors.lightSurface,
      errorContainer: const Color(0xFFFEE2E2),
      onErrorContainer: const Color(0xFF7F1D1D),
      surface: FaiColors.lightCanvas,
      onSurface: FaiColors.lightText,
      onSurfaceVariant: FaiColors.lightMuted,
      outline: FaiColors.lightBorder,
      outlineVariant: FaiColors.lightBorder,
      surfaceContainerLowest: FaiColors.lightCanvas,
      surfaceContainerLow: FaiColors.lightSurface,
      surfaceContainer: FaiColors.lightSurface,
      surfaceContainerHigh: FaiColors.lightSurfaceHigh,
      surfaceContainerHighest: FaiColors.lightSurfaceHigh,
    );
    return _build(scheme);
  }

  static ThemeData _build(ColorScheme scheme) {
    final textTheme = _textTheme(scheme.brightness);
    return ThemeData(
      useMaterial3: true,
      colorScheme: scheme,
      scaffoldBackgroundColor: scheme.surface,
      textTheme: textTheme,
      primaryTextTheme: textTheme,
      appBarTheme: AppBarTheme(
        backgroundColor: scheme.surface,
        foregroundColor: scheme.onSurface,
        elevation: 0,
        scrolledUnderElevation: 0,
        centerTitle: false,
        titleTextStyle: textTheme.headlineSmall,
        toolbarHeight: 64,
      ),
      cardTheme: CardThemeData(
        color: scheme.surfaceContainer,
        elevation: 0,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(FaiRadius.md),
          side: BorderSide(color: scheme.outlineVariant),
        ),
        margin: EdgeInsets.zero,
      ),
      filledButtonTheme: FilledButtonThemeData(
        style: FilledButton.styleFrom(
          backgroundColor: scheme.primary,
          foregroundColor: scheme.onPrimary,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(FaiRadius.sm),
          ),
          padding: const EdgeInsets.symmetric(
            horizontal: FaiSpace.lg,
            vertical: FaiSpace.md,
          ),
          textStyle: textTheme.labelMedium,
          animationDuration: FaiMotion.fast,
        ),
      ),
      outlinedButtonTheme: OutlinedButtonThemeData(
        style: OutlinedButton.styleFrom(
          foregroundColor: scheme.onSurface,
          side: BorderSide(color: scheme.outline),
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(FaiRadius.sm),
          ),
          padding: const EdgeInsets.symmetric(
            horizontal: FaiSpace.lg,
            vertical: FaiSpace.md,
          ),
          textStyle: textTheme.labelMedium,
          animationDuration: FaiMotion.fast,
        ),
      ),
      iconButtonTheme: IconButtonThemeData(
        style: IconButton.styleFrom(
          foregroundColor: scheme.onSurfaceVariant,
        ),
      ),
      navigationRailTheme: NavigationRailThemeData(
        backgroundColor: scheme.surfaceContainerLow,
        indicatorColor: scheme.primaryContainer,
        selectedIconTheme: IconThemeData(color: scheme.primary, size: 22),
        unselectedIconTheme:
            IconThemeData(color: scheme.onSurfaceVariant, size: 22),
        selectedLabelTextStyle:
            textTheme.labelMedium?.copyWith(color: scheme.primary),
        unselectedLabelTextStyle: textTheme.labelMedium
            ?.copyWith(color: scheme.onSurfaceVariant),
        useIndicator: true,
      ),
      dividerColor: scheme.outlineVariant,
      dividerTheme: DividerThemeData(
        color: scheme.outlineVariant,
        thickness: 1,
        space: 1,
      ),
      snackBarTheme: SnackBarThemeData(
        backgroundColor: scheme.surfaceContainerHigh,
        contentTextStyle:
            textTheme.bodyMedium?.copyWith(color: scheme.onSurface),
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(FaiRadius.sm),
        ),
      ),
    );
  }
}