import 'dart:async';

import 'package:feet/notifications/tasks.dart';
import 'package:feet/util.dart';
import 'package:feet/widgets/centered_page_hint.dart';
import 'package:feet/widgets/filter_menu.dart';
import 'package:feet/widgets/homepage_post.dart';
import 'package:feet/widgets/login_prompt.dart';
import 'package:flutter/material.dart';
import 'package:dynamic_color/dynamic_color.dart';
import 'package:flutter/services.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'api/api.dart';

// Limit the maximum amount of posts to fetch so we don't wait forever when
// fetching a large list
const FETCH_MAX_POSTS = 1000;

void main() {
  setupBackgroundTasks();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  final api = FeverAPI();
  SharedPreferences? prefs;

  MyApp({super.key});

  Future<bool> _loadPrefs() async {
    var prefs = await SharedPreferences.getInstance();
    this.prefs = prefs;
    api.sharedPrefs = prefs;
    var apiKey = prefs.getString('apiKey'), apiUrl = prefs.getString('apiUrl');

    if (apiUrl != null && apiKey != null) {
      api.apiUrl = apiUrl;
      api.apiKey = apiKey;
      return true;
    }

    return false;
  }

  @override
  Widget build(BuildContext context) {
    return DynamicColorBuilder(
      builder: ((lightDynamic, darkDynamic) => MaterialApp(
            title: 'Feet',
            theme: ThemeData(
              brightness: Brightness.light,
              useMaterial3: true,
              colorScheme: lightDynamic,
            ),
            darkTheme: ThemeData(
              brightness: Brightness.dark,
              useMaterial3: true,
              colorScheme: darkDynamic,
            ),
            themeMode: ThemeMode.system,
            home: FutureBuilder<bool>(
              builder: (context, snapshot) {
                if (snapshot.hasData && prefs != null) {
                  return MyHomePage(title: 'Feet', api: api, prefs: prefs!);
                }
                return const SizedBox();
              },
              future: _loadPrefs(),
            ),
          )),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;
  final FeverAPI api;
  final SharedPreferences prefs;
  const MyHomePage(
      {super.key, required this.title, required this.api, required this.prefs});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var _index = 0;
  var _fetched = false;
  var _fetchedCount = 0;
  var _knownPostsSize = -1;
  var _isDemoUser = false;
  List<int> _feedFilter = [];

  Future<void> refresh() async {
    widget.api.cache.clear();
    setState(() {
      _fetchedCount = 0;
      _knownPostsSize = -1;
      _feedFilter = [];
    });

    print("Starting refresh");

    var data = await widget.api
        .request()
        .withFeeds()
        .withGroups()
        .withFavicons()
        .withItems()
        .sinceId(0)
        .execute();

    while ((data['items'] as List<dynamic>).isNotEmpty &&
        _fetchedCount < FETCH_MAX_POSTS) {
      print("Fetching more items");

      var ids = widget.api.cache.items
          .getAll()
          .values
          .map((value) => value.id)
          .toList()
        ..sort((a, b) => b - a);

      setState(() {
        _fetchedCount = ids.length;
        _knownPostsSize = data['total_items'] ?? -1;
      });

      data =
          await widget.api.request().withItems().sinceId(ids.first).execute();

      print(
          "Item cache size is now ${widget.api.cache.items.size} ${ids.first} ${ids.last}");
    }
  }

  @override
  void initState() {
    super.initState();

    setState(() {
      _isDemoUser = widget.prefs.getBool("isDemo") ?? false;
    });

    refresh().then((_) => setState(() {
          _fetched = true;
        }));
  }

  @override
  Widget build(BuildContext context) {
    var loggedIn = widget.api.loggedIn();
    var posts = widget.api.cache.items.getAll().values.where((element) =>
        _feedFilter.isEmpty || _feedFilter.contains(element.feedId));

    var savedPosts = posts.where((element) => element.isSaved);
    var unreadPosts = posts.where((element) => !element.isRead);

    final pages = [
      /* Posts list */
      posts.isNotEmpty
          ? ListView(
              children: posts.map((value) => HomepagePost(post: value)).toList()
                ..sort((a, b) => b.post.createdOnTime.millisecondsSinceEpoch
                    .compareTo(a.post.createdOnTime.millisecondsSinceEpoch)),
            )
          : const CenteredPageHint(
              icon: Icons.coffee, text: "Your feed is currently empty."),
      /* Unread */
      unreadPosts.isNotEmpty
          ? ListView(
              children: unreadPosts
                  .map((value) => HomepagePost(post: value))
                  .toList()
                ..sort((a, b) => b.post.createdOnTime.millisecondsSinceEpoch
                    .compareTo(a.post.createdOnTime.millisecondsSinceEpoch)),
            )
          : const CenteredPageHint(
              icon: Icons.check, text: "Nothing new here!"),
      /* Saved posts */
      savedPosts.isNotEmpty
          ? ListView(
              children: savedPosts
                  .map((value) => HomepagePost(post: value))
                  .toList()
                ..sort((a, b) => b.post.createdOnTime.millisecondsSinceEpoch
                    .compareTo(a.post.createdOnTime.millisecondsSinceEpoch)),
            )
          : const CenteredPageHint(
              icon: Icons.bookmarks_outlined,
              text: "Nothing here yet. Try saving some posts!"),
    ];

    // I'm aware that this is stupid, but I'm sick and tired and
    // really don't care as long as it works
    if (!loggedIn) {
      Timer.periodic(const Duration(seconds: 1), (timer) {
        setState(() {
          loggedIn = widget.api.loggedIn();
        });

        if (loggedIn) {
          timer.cancel();
          refresh().then((_) => setState(() => _fetched = true));
        }
      });
    }

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        actions: [
          _isDemoUser
            ? ElevatedButton(
              onPressed: () {
                showDialog(
                  context: context,
                  builder: (context) => AlertDialog(
                    title: const Text("Connected to demo server"),
                    content: RichText(text: TextSpan(
                      children: [
                        const TextSpan(
                          text: "You are currently connected to the demo server.\n"
                          "Use the"
                        ),
                        WidgetSpan(child: Icon(Icons.adaptive.more, size: 20),
                        ),
                        const TextSpan(
                          text: "button in the top right to log out and switch "
                                "to your own instance once you're done exploring."
                        ),
                      ],
                    )),
                    actions: [
                      TextButton(
                        onPressed: () => Navigator.of(context).pop(),
                        child: const Text("Got it!"),
                      ),
                    ],
                  ),
                );
              },
              style: ElevatedButton.styleFrom(
                backgroundColor: const Color.fromARGB(255, 114, 77, 7),
                foregroundColor: Colors.amber,
              ),
              child: Row(children: const [
                Icon(Icons.warning),
                SizedBox(width: 8),
                Text("Demo"),
              ])
            )
            : Container(),
          IconButton(
            onPressed: () {
              var theme = Theme.of(context);

              HapticFeedback.heavyImpact();
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(
                  content: Text('Refreshing feeds',
                      style: TextStyle(color: theme.colorScheme.onBackground)),
                  duration: const Duration(seconds: 2),
                  backgroundColor: theme.colorScheme.secondaryContainer,
                ),
              );
              refresh().then((_) {
                setState(() {});
              });
            },
            icon: const Icon(Icons.replay_outlined),
          ), // Refresh
          PopupMenuButton(
              itemBuilder: (context) => [
                    PopupMenuItem(
                      value: "log_out",
                      child: const Text("Log out"),
                      onTap: () {
                        Future.delayed(
                          const Duration(seconds: 0),
                          () => showDialog(
                            context: context,
                            builder: (context) => AlertDialog(
                              title: const Text("Log out"),
                              content: const Text(
                                  "Are you sure you want to log out?"),
                              actions: [
                                TextButton(
                                    onPressed: () async {
                                      Navigator.pop(context);
                                      await widget.prefs.clear();

                                      setState(() {
                                        widget.api.apiKey = null;
                                        widget.api.apiUrl = null;
                                        widget.api.cache.clear();
                                      });
                                    },
                                    child: const Text("Do it!")),
                                TextButton(
                                  onPressed: () {
                                    Navigator.pop(context);
                                  },
                                  child: const Text("Nevermind"),
                                ),
                              ],
                            ),
                          ),
                        );
                      },
                    ),
                    PopupMenuItem(
                      value: "filter",
                      child: Text(_feedFilter.isEmpty
                          ? "Filter..."
                          : "Filter (${_feedFilter.length}/${widget.api.cache.feeds.size})"),
                      onTap: () {
                        Future.delayed(
                          Duration.zero,
                          () => showDialog(
                            context: context,
                            barrierDismissible: false,
                            builder: (context) => FilterMenu(
                              api: widget.api,
                              initData: _feedFilter,
                              onConfirm: (items) {
                                setState(() {
                                  _feedFilter = items;
                                });
                              },
                            ),
                          ),
                        );
                      },
                    ),
                    PopupMenuItem(
                      value: "feedback",
                      child: const Text("Feedback"),
                      onTap: () async {
                        await openUrl(context,
                            "https://git.amogus.cloud/Lea/feet/issues");
                      },
                    ),
                  ]),
        ],
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _index,
        onTap: (value) => setState(() => _index = value),
        items: const [
          BottomNavigationBarItem(
            icon: Icon(Icons.list),
            label: 'Feed',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.lens_blur),
            label: 'Unread',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.bookmark_outline),
            activeIcon: Icon(Icons.bookmark),
            label: 'Saved',
          ),
        ],
      ),
      body: loggedIn
          ? (_fetched
              ? pages[_index]
              : CenteredPageHint(
                  icon: Icons.downloading,
                  text:
                      "Fetching your feeds...\n${_fetchedCount > 0 && _knownPostsSize > -1 ? "$_fetchedCount / $_knownPostsSize" : ""}"))
          : Center(child: LoginPrompt(api: widget.api)),
    );
  }
}