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

import '../../../providers/bill_provider.dart';
import '../../../utils/date_util.dart';

/// 月份切换条：‹ 2026年9月 ›
class MonthSwitcher extends ConsumerWidget {
  const MonthSwitcher({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final anchor = ref.watch(monthAnchorProvider);
    final notifier = ref.read(monthAnchorProvider.notifier);

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.85),
        borderRadius: BorderRadius.circular(20),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          _iconButton(
            icon: Icons.chevron_left,
            tooltip: '上一月',
            onTap: notifier.prev,
          ),
          GestureDetector(
            onTap: () => _pickMonth(context, ref),
            child: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Text(
                    formatMonthTitle(anchor),
                    style: const TextStyle(
                      fontSize: 14,
                      fontWeight: FontWeight.w600,
                      color: Color(0xFF5D4037),
                    ),
                  ),
                  const SizedBox(width: 4),
                  const Icon(Icons.arrow_drop_down, size: 18, color: Color(0xFF8D6E63)),
                ],
              ),
            ),
          ),
          _iconButton(
            icon: Icons.chevron_right,
            tooltip: '下一月',
            // 不允许超过当前月
            onTap: notifier.canGoNext ? notifier.next : null,
          ),
        ],
      ),
    );
  }

  Widget _iconButton({
    required IconData icon,
    required String tooltip,
    VoidCallback? onTap,
  }) {
    final enabled = onTap != null;
    return IconButton(
      icon: Icon(icon),
      iconSize: 20,
      visualDensity: VisualDensity.compact,
      padding: EdgeInsets.zero,
      constraints: const BoxConstraints(minWidth: 32, minHeight: 32),
      color: enabled ? const Color(0xFF5D4037) : const Color(0xFFBCAAA4),
      tooltip: tooltip,
      onPressed: onTap,
    );
  }

  Future<void> _pickMonth(BuildContext context, WidgetRef ref) async {
    final anchor = ref.read(monthAnchorProvider);
    final picked = await showDatePicker(
      context: context,
      initialDate: anchor,
      initialDatePickerMode: DatePickerMode.year,
      firstDate: DateTime(2000),
      lastDate: DateTime(2100),
    );
    if (picked != null) {
      ref.read(monthAnchorProvider.notifier).pick(picked);
    }
  }
}