import 'package:flutter/material.dart';

import '../focus/focusable_chip_mixin.dart';
import '../focus/input_mode_tracker.dart';
import '../utils/platform_detector.dart';
import 'focus_builders.dart';

/// Horizontally scrollable host for a row of [FocusableTabChip]s.
///
/// App-bar titles and header rows give the strip a bounded width; a plain
/// Row overflows it on narrow windows (visible as the striped overflow
/// indicator). The strip shrink-wraps like `mainAxisSize: min` and scrolls
/// instead. D-pad stays correct: chips center themselves on focus via the
/// chip mixin, so LEFT/RIGHT reaches off-screen tabs.
class TabChipStrip extends StatelessWidget {
  final List<Widget> children;

  const TabChipStrip({super.key, required this.children});

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(mainAxisSize: .min, children: children),
    );
  }
}

/// A focusable tab chip that shows a color change when focused or selected.
///
/// Used for tab navigation in LibrariesScreen. Handles:
/// - SELECT key to activate the tab
/// - LEFT/RIGHT arrows to switch between tabs
/// - DOWN arrow to navigate to tab content
/// - BACK key to navigate to sidenav
class FocusableTabChip extends StatefulWidget {
  final String label;
  final bool isSelected;
  final VoidCallback onSelect;

  /// Optional external focus node for programmatic focus control.
  final FocusNode? focusNode;

  /// Called when the user presses LEFT from this chip.
  /// Should switch to the previous tab.
  final VoidCallback? onNavigateLeft;

  /// Called when the user presses RIGHT from this chip.
  /// Should switch to the next tab.
  final VoidCallback? onNavigateRight;

  /// Called when the user presses DOWN from this chip.
  final VoidCallback? onNavigateDown;

  /// Called when the user presses UP from this chip.
  final VoidCallback? onNavigateUp;

  /// Called when the user presses BACK from this chip.
  final VoidCallback? onBack;

  /// Called when SELECT key is held (D-pad long press).
  final VoidCallback? onLongPress;

  /// Optional image to show above the label (e.g. a poster).
  /// When provided, the chip lays out vertically with image on top, label below.
  final Widget? topImage;

  const FocusableTabChip({
    super.key,
    required this.label,
    required this.isSelected,
    required this.onSelect,
    this.focusNode,
    this.onNavigateLeft,
    this.onNavigateRight,
    this.onNavigateDown,
    this.onNavigateUp,
    this.onBack,
    this.onLongPress,
    this.topImage,
  });

  @override
  State<FocusableTabChip> createState() => _FocusableTabChipState();
}

class _FocusableTabChipState extends State<FocusableTabChip> with FocusableChipStateMixin<FocusableTabChip> {
  @override
  FocusNode? get widgetFocusNode => widget.focusNode;

  @override
  String get debugLabel => 'tab_chip_${widget.label}';

  @override
  void initState() {
    super.initState();
    initFocusNode();
  }

  @override
  void didUpdateWidget(FocusableTabChip oldWidget) {
    super.didUpdateWidget(oldWidget);
    updateFocusNode(oldWidget.focusNode);
  }

  @override
  void dispose() {
    disposeFocusNode();
    super.dispose();
  }

  KeyEventResult _handleKeyEvent(FocusNode node, KeyEvent event) {
    return handleChipKeyEvent(
      node,
      event,
      ChipKeyCallbacks(
        onSelect: widget.onSelect,
        onLongPress: widget.onLongPress,
        onNavigateLeft: widget.onNavigateLeft,
        onNavigateRight: widget.onNavigateRight,
        onNavigateDown: widget.onNavigateDown,
        onNavigateUp: widget.onNavigateUp,
        onBack: widget.onBack,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    // Only show focus effects during keyboard/d-pad navigation
    final showFocus = isFocused && InputModeTracker.isKeyboardMode(context);

    // Determine background color based on focus and selection state
    // - Selected + Focused: slightly dimmed primary (to show focus distinction)
    // - Selected only: primary color
    // - Focused only: primary color
    // - Neither: surface color
    Color backgroundColor;
    Color foregroundColor;

    if (widget.isSelected && showFocus) {
      // Selected + focused: dim the primary color slightly
      backgroundColor = Color.lerp(colorScheme.primary, colorScheme.surface, 0.25)!;
      foregroundColor = colorScheme.onPrimary;
    } else if (widget.isSelected || showFocus) {
      // Selected or focused (but not both): full primary
      backgroundColor = colorScheme.primary;
      foregroundColor = colorScheme.onPrimary;
    } else {
      // Neither selected nor focused
      if (PlatformDetector.isTV()) {
        backgroundColor = colorScheme.secondaryContainer.withValues(alpha: 0.38);
        foregroundColor = colorScheme.onSecondaryContainer;
      } else {
        backgroundColor = colorScheme.surfaceContainerHighest;
        foregroundColor = colorScheme.onSurfaceVariant;
      }
    }

    final isHighlighted = showFocus || widget.isSelected;

    final label = Text(
      widget.label,
      style: Theme.of(context).textTheme.labelLarge?.copyWith(
        color: foregroundColor,
        fontWeight: isHighlighted ? FontWeight.w600 : FontWeight.normal,
      ),
    );

    final hasImage = widget.topImage != null;
    return FocusBuilders.buildFocusableChip(
      context: context,
      focusNode: focusNode,
      onKeyEvent: _handleKeyEvent,
      onTap: widget.onSelect,
      semanticLabel: widget.label,
      selected: widget.isSelected,
      padding: hasImage ? const EdgeInsets.all(8) : const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      backgroundColor: backgroundColor,
      borderRadius: hasImage ? 12 : 20,
      child: hasImage
          ? Column(
              mainAxisSize: .min,
              children: [
                ClipRRect(borderRadius: BorderRadius.circular(6), child: widget.topImage!),
                const SizedBox(height: 6),
                label,
              ],
            )
          : label,
    );
  }
}