import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../config/app_config.dart';
import 'scan_mode_provider.dart';

/// DO / Product Scan mode toggle pill rendered in the [CameraDrawer].
///
/// Extracted from [CameraDrawer] to keep that file under the 256-line §3
/// threshold (AGENTS.md §3, touched during task 8.1). Reads and writes
/// [scanModeProvider] directly — the global source of truth shared with
/// [DocumentsScreen] (task 8.1, docs/api-contract-map.md G11).
///
/// Color convention:
///   - DO active      → [AppConfig.doModeColor] (orange)
///   - Product active → [AppConfig.primaryColor] (green)
class CameraDrawerModeToggle extends ConsumerWidget {
  const CameraDrawerModeToggle({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final activeMode = ref.watch(scanModeProvider);

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 24.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            'Mode',
            style: AppConfig.bodySmall.copyWith(
              color: Colors.grey.shade500,
              fontWeight: FontWeight.w600,
              letterSpacing: 0.5,
            ),
          ),
          const SizedBox(height: 8),
          Container(
            height: 48,
            decoration: BoxDecoration(
              color: Colors.grey.shade100,
              borderRadius: BorderRadius.circular(12),
            ),
            child: Padding(
              padding: const EdgeInsets.all(4.0),
              child: Row(
                children: [
                  _buildSegment(
                    ref: ref,
                    value: 'DO',
                    label: 'DO Scan',
                    activeIcon: Icons.description,
                    inactiveIcon: Icons.description_outlined,
                    activeMode: activeMode,
                    activeColor: AppConfig.doModeColor,
                  ),
                  _buildSegment(
                    ref: ref,
                    value: 'Product',
                    label: 'Product Scan',
                    activeIcon: Icons.inventory_2,
                    inactiveIcon: Icons.inventory_2_outlined,
                    activeMode: activeMode,
                    activeColor: AppConfig.primaryColor,
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildSegment({
    required WidgetRef ref,
    required String value,
    required String label,
    required IconData activeIcon,
    required IconData inactiveIcon,
    required String activeMode,
    required Color activeColor,
  }) {
    final isActive = activeMode == value;
    return Expanded(
      child: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTap: () => ref.read(scanModeProvider.notifier).state = value,
        child: Container(
          decoration: BoxDecoration(
            color: isActive ? activeColor : Colors.transparent,
            borderRadius: BorderRadius.circular(8),
            boxShadow: isActive
                ? [
                    BoxShadow(
                      color: activeColor.withOpacity(0.2),
                      blurRadius: 4,
                      offset: const Offset(0, 2),
                    )
                  ]
                : [],
          ),
          alignment: Alignment.center,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(
                isActive ? activeIcon : inactiveIcon,
                size: 16,
                color: isActive ? Colors.white : Colors.grey.shade500,
              ),
              const SizedBox(width: 6),
              Text(
                label,
                style: AppConfig.bodyMedium.copyWith(
                  fontWeight: isActive ? FontWeight.bold : FontWeight.normal,
                  color: isActive ? Colors.white : Colors.grey.shade600,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}