import 'package:comunic/ui/screens/conversations_screen.dart';
import 'package:comunic/ui/screens/menus_screen.dart';
import 'package:comunic/ui/tiles/custom_bottom_navigation_bar_item.dart';
import 'package:flutter/material.dart';

/// Main route of the application
///
/// @author Pierre HUBERT

class HomeRoute extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _HomeRouteState();
}

class _HomeRouteState extends State<HomeRoute> {
  int _currTab = 0;
  List<int> history = List();


  /// Change currently visible tab
  void _changeTab(int newTabNumber) {
    setState(() {
      _currTab = newTabNumber;
    });
  }

  /// Allows to go to previous tab
  Future<bool> _willPop() async {
    if (history.length == 1) return true;

    history.removeLast();
    _changeTab(history[history.length - 1]);
    return false;
  }

  /// Handles a new tab being tapped
  void _onTap(int number, BuildContext context) {
    if (_currTab != number) history.add(number);
    _changeTab(number);
  }

  @override
  void initState() {
    super.initState();
    history.add(_currTab);
  }

  /// Build the body of the application
  Widget _buildBody(BuildContext context) {
    switch (_currTab) {
      case 0:
        return ConversationsScreen();

      case 1:
        return MenuScreen();

      default:
        throw "Invalid tab number : " + _currTab.toString();
    }
  }

  /// Build navigation bar items
  List<BottomNavigationBarItem> _buildNavigationBarItems() {
    return <BottomNavigationBarItem>[
      CustomNavigationBarItem(
        icon: Icon(Icons.chat),
        title: Text("Conversations"),
      ),
      CustomNavigationBarItem(
        icon: Icon(Icons.menu),
        title: Text("Menu"),
      ),
    ];
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: _willPop,
      child: Scaffold(
        body: SafeArea(
          child: _buildBody(context),
        ),
        bottomNavigationBar: BottomNavigationBar(
          currentIndex: _currTab,
          items: _buildNavigationBarItems(),
          onTap: (i) => _onTap(i, context),
        ),
      ),
    );
  }
}