import 'dart:math' as math;

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

import 'package:mini_tias/screens/capture_screen.dart';
import 'package:mini_tias/screens/gallery_screen.dart';

/// BottomNavigationBar で撮影画面と一覧画面を切り替えるホーム画面．
///
/// UI 全体を 180° 回転して表示する（端末を逆さに置いて使用するため）．
class HomeScreen extends StatefulWidget {
  const HomeScreen({super.key});

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  int _currentIndex = 0;
  double _brightness = 0.8;

  static const _screens = [CaptureScreen(), GalleryScreen()];

  @override
  void initState() {
    super.initState();
    _setBrightness(_brightness);
  }

  @override
  void dispose() {
    ScreenBrightness.instance.resetApplicationScreenBrightness();
    super.dispose();
  }

  Future<void> _setBrightness(double value) async {
    await ScreenBrightness.instance.setApplicationScreenBrightness(value);
  }

  @override
  Widget build(BuildContext context) {
    final screenHeight = MediaQuery.of(context).size.height;
    final attachmentPadding = screenHeight / 3;

    return Transform.rotate(
      angle: math.pi,
      child: Scaffold(
        body: Padding(
          padding: EdgeInsets.only(bottom: attachmentPadding),
          child: _screens[_currentIndex],
        ),
        bottomNavigationBar: Padding(
          padding: EdgeInsets.only(bottom: attachmentPadding),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16),
                child: Row(
                  children: [
                    const Icon(Icons.brightness_low, size: 20),
                    Expanded(
                      child: Slider(
                        value: _brightness,
                        onChanged: (value) {
                          setState(() => _brightness = value);
                          _setBrightness(value);
                        },
                      ),
                    ),
                    const Icon(Icons.brightness_high, size: 20),
                  ],
                ),
              ),
              BottomNavigationBar(
                currentIndex: _currentIndex,
                onTap: (index) => setState(() => _currentIndex = index),
                items: const [
                  BottomNavigationBarItem(
                    icon: Icon(Icons.camera_alt),
                    label: '撮影',
                  ),
                  BottomNavigationBarItem(
                    icon: Icon(Icons.photo_library),
                    label: '一覧',
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}