import 'dart:async';

import 'package:flutter/material.dart';
import 'package:lszlgl/base/base_state.dart';
import 'package:lszlgl/page/home/home_page.dart';
import 'package:lszlgl/page/user_center/user_center_page.dart';

/// 主页tab页面
class MainTabPage extends StatefulWidget {
  const MainTabPage({Key? key}) : super(key: key);

  @override
  State<MainTabPage> createState() => _MainTabPageState();
}

class _MainTabPageState extends State<MainTabPage> {
  late List<String> tabTextList;

  late List<String> tabIconList;
  late List<String> tabIconSelectList;

  late List<Widget> pageList;

  late PageController ctrl;

  int selectedIndex = 0;

  DateTime? lastTime;

  ValueNotifier<bool> popState = ValueNotifier(false);

  void refreshTab(int index, {bool refreshPage = false}) {
    if (index == selectedIndex) return;
    setState(() {
      selectedIndex = index;
    });
    if (refreshPage) ctrl.jumpToPage(index);
  }

  @override
  void initState() {
    super.initState();
    tabTextList = ['首页', '用户中心'];
    tabIconList = [imgNavHome, imgNavUserCenter];
    tabIconSelectList = [imgNavHomeSelect, imgNavUserCenterSelect];
    pageList = [const HomePage(), const UserCenterPage()];
    ctrl = PageController(initialPage: selectedIndex);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFFF3F3F3),
      body: buildPop(buildBody()),
      bottomNavigationBar: buildNavigation(),
    );
  }

  Widget buildPop(Widget child) {
    return ValueListenableBuilder<bool>(
      valueListenable: popState,
      builder: (_, value, __) {
        return PopScope(
          canPop: value,
          child: child,
          onPopInvoked: (didPop) {
            if (didPop) return;
            MyNavigator.showToast('再试一次退出');
            popState.value = true;
            // 2秒后不可退出
            Timer(
              const Duration(seconds: 2),
              () => popState.value = false,
            );
          },
        );
      },
    );
  }

  Widget buildBody() {
    return PageView.builder(
      controller: ctrl,
      // physics: const BouncingScrollPhysics(),
      onPageChanged: refreshTab,
      itemCount: pageList.length,
      itemBuilder: (_, index) => pageList[index],
    );
  }

  Widget buildNavigation() {
    return NavigationBar(
      height: 56,
      selectedIndex: selectedIndex,
      surfaceTintColor: Colors.white,
      onDestinationSelected: (index) => refreshTab(index, refreshPage: true),
      backgroundColor: Colors.white,
      destinations: List.generate(
        tabTextList.length,
        (index) => GestureDetector(
          behavior: HitTestBehavior.opaque,
          onTap: () => refreshTab(index, refreshPage: true),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              Image.asset(
                index == selectedIndex ? tabIconSelectList[index] : tabIconList[index],
                height: 18,
              ),
              Text(
                tabTextList[index],
                style: TextStyle(
                  fontSize: 12,
                  fontWeight: FontWeight.w500,
                  color: index == selectedIndex ? const Color(0xFF333333) : const Color(0xFF888888),
                ),
              ),
            ],
          ),
        ),
      ).toList(),
    );
  }
}