import 'dart:io';

import 'package:fluent_reader_lite/generated/l10n.dart';
import 'package:fluent_reader_lite/models/feeds_model.dart';
import 'package:fluent_reader_lite/models/item.dart';
import 'package:fluent_reader_lite/models/items_model.dart';
import 'package:fluent_reader_lite/models/source.dart';
import 'package:fluent_reader_lite/models/sources_model.dart';
import 'package:fluent_reader_lite/utils/colors.dart';
import 'package:fluent_reader_lite/utils/font_manager.dart';
import 'package:fluent_reader_lite/utils/global.dart';
import 'package:fluent_reader_lite/utils/store.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:intl/intl.dart';
import 'package:http/http.dart' as http;
import 'package:provider/provider.dart';
import 'package:tuple/tuple.dart';
import 'package:share_plus/share_plus.dart';
import 'package:fluent_reader_lite/components/cupertino_toolbar.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:webview_flutter/webview_flutter.dart';

class ArticlePage extends StatefulWidget {
  static final GlobalKey<ArticlePageState> state = GlobalKey();

  ArticlePage() : super(key: state);

  @override
  ArticlePageState createState() => ArticlePageState();
}

enum _ArticleLoadState { Loading, Success, Failure }

class ArticlePageState extends State<ArticlePage> {
  WebViewController? _controller;
  int requestId = 0;
  _ArticleLoadState loaded = _ArticleLoadState.Loading;
  bool navigated = false;
  SourceOpenTarget? _target;
  String? iid;
  bool? isSourceFeed;

  WebViewController _createController() {
    final controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setNavigationDelegate(NavigationDelegate(
        onNavigationRequest: _onNavigate,
        onPageStarted: _onPageReady,
        onPageFinished: _onWebpageReady,
      ));
    return controller;
  }

  void loadNewItem(String id, {bool? isSource}) {
    if (!Global.itemsModel.getItem(id)!.hasRead) {
      Global.itemsModel.updateItem(id, read: true);
    }
    setState(() {
      iid = id;
      loaded = _ArticleLoadState.Loading;
      navigated = false;
      _target = null;
      if (isSource != null) isSourceFeed = isSource;
    });
  }

  NavigationDecision _onNavigate(NavigationRequest request) {
    if (navigated && request.isMainFrame) {
      final internal = Global.globalModel.inAppBrowser;
      launchUrl(
        Uri.parse(request.url),
        mode: internal ? LaunchMode.inAppWebView : LaunchMode.externalApplication,
      );
      return NavigationDecision.prevent;
    } else {
      return NavigationDecision.navigate;
    }
  }

  void _loadHtml(RSSItem item, RSSSource source, {bool loadFull = false}) async {
    var localUrl = "http://127.0.0.1:9000/article/article.html";
    var currId = requestId;
    String a;
    if (loadFull) {
      try {
        var uri = Uri.parse(item.link);
        var html = (await http.get(uri)).body;
        a = Uri.encodeComponent(html);
      } catch (exp) {
        if (mounted && currId == requestId) {
          setState(() {
            loaded = _ArticleLoadState.Failure;
          });
        }
        return;
      }
    } else {
      a = Uri.encodeComponent(item.content);
    }
    if (!mounted || currId != requestId) return;
    var h =
        '<p id="source">${source.name}${item.creator.isNotEmpty ? ' / ' + item.creator : ''}</p>';
    h += '<p id="title">${item.title}</p>';
    h +=
        '<p id="date">${DateFormat.yMd(Localizations.localeOf(context).toString()).add_Hm().format(item.date)}</p>';
    h += '<article></article>';
    h = Uri.encodeComponent(h);
    var s = Store.getArticleFontSize();
    var f = Uri.encodeComponent(Global.globalModel.fontFamily);
    localUrl += "?a=$a&h=$h&s=$s&f=$f&u=${item.link}&m=${loadFull ? 1 : 0}";
    // Pass custom font URL for non-built-in fonts
    if (!FontManager.builtInFonts.contains(Global.globalModel.fontFamily)) {
      final fontUrl = await FontManager.getCustomFontUrl(Global.globalModel.fontFamily);
      if (fontUrl != null) {
        localUrl += "&fp=${Uri.encodeComponent(fontUrl)}";
      }
    }
    if (Platform.isAndroid || Global.globalModel.getBrightness() != null) {
      var brightness = Global.currentBrightness(context);
      localUrl += "&t=${brightness.index}";
    }
    _controller?.loadRequest(Uri.parse(localUrl));
  }

  void _onPageReady(String url) async {
    if (Platform.isAndroid || Global.globalModel.getBrightness() != null) {
      await Future.delayed(Duration(milliseconds: 300));
    }
    setState(() {
      loaded = _ArticleLoadState.Success;
    });
    if (_target == SourceOpenTarget.Local ||
        _target == SourceOpenTarget.FullContent) {
      navigated = true;
    }
  }

  void _onWebpageReady(String url) {
    if (loaded == _ArticleLoadState.Success) navigated = true;
  }

  void _setOpenTarget(RSSItem item, RSSSource source, {SourceOpenTarget? target}) {
    _target = target ?? Global.resolveOpenTarget(source);
    _loadOpenTarget(item, source);
  }

  void _loadOpenTarget(RSSItem item, RSSSource source) {
    setState(() {
      requestId += 1;
      loaded = _ArticleLoadState.Loading;
      navigated = false;
    });
    switch (_target!) {
      case SourceOpenTarget.Local:
        _loadHtml(item, source);
        break;
      case SourceOpenTarget.FullContent:
        _loadHtml(item, source, loadFull: true);
        break;
      case SourceOpenTarget.Webpage:
      case SourceOpenTarget.External:
        _controller?.loadRequest(Uri.parse(item.link));
        break;
      case SourceOpenTarget.Inherit:
        _loadHtml(item, source);
        break;
    }
  }

  @override
  Widget build(BuildContext context) {
    final Tuple2<String, bool> arguments =
        ModalRoute.of(context)!.settings.arguments as Tuple2<String, bool>;
    iid ??= arguments.item1;
    isSourceFeed ??= arguments.item2;
    final resolvedDarkGrey = MyColors.dynamicDarkGrey.resolveFrom(context);
    final viewOptions = {
      0: Padding(
        child: Icon(
          Icons.rss_feed,
          color: resolvedDarkGrey,
          semanticLabel: S.of(context).rssText,
        ),
        padding: EdgeInsets.symmetric(horizontal: 8),
      ),
      1: Icon(
        Icons.article_outlined,
        color: resolvedDarkGrey,
        semanticLabel: S.of(context).loadFull,
      ),
      2: Icon(
        Icons.language,
        color: resolvedDarkGrey,
        semanticLabel: S.of(context).loadWebpage,
      ),
    };
    return Selector2<ItemsModel, SourcesModel, Tuple2<RSSItem, RSSSource>>(
      selector: (context, itemsModel, sourcesModel) {
        var item = itemsModel.getItem(iid!)!;
        var source = sourcesModel.getSource(item.source)!;
        return Tuple2(item, source);
      },
      builder: (context, tuple, child) {
        var item = tuple.item1;
        var source = tuple.item2;
        _target ??= Global.resolveOpenTarget(source);
        if (_controller == null) {
          _controller = _createController();
          Future.microtask(() => _loadOpenTarget(item, source));
        }
        final body = SafeArea(
          child: IndexedStack(
            index: loaded.index,
            children: [
              Center(child: CupertinoActivityIndicator()),
              WebViewWidget(
                key: Key("a-$iid-${_target!.index}"),
                controller: _controller!,
              ),
              Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text(
                      S.of(context).wentWrong,
                      style: TextStyle(
                          color: CupertinoColors.label.resolveFrom(context)),
                    ),
                    CupertinoButton(
                      child: Text(S.of(context).retry),
                      onPressed: () {
                        _loadOpenTarget(item, source);
                      },
                    ),
                  ],
                ),
              )
            ],
          ),
          bottom: false,
        );
        return CupertinoPageScaffold(
          navigationBar: CupertinoNavigationBar(
            backgroundColor: CupertinoColors.systemBackground,
            middle: CupertinoSlidingSegmentedControl<int>(
              children: viewOptions,
              onValueChanged: (v) {
                _setOpenTarget(item, source, target: SourceOpenTarget.values[v!]);
              },
              groupValue: _target!.index > 2 ? 2 : _target!.index,
            ),
          ),
          child: Consumer<FeedsModel>(
            child: body,
            builder: (context, feedsModel, child) {
              final feed = isSourceFeed! ? feedsModel.source! : feedsModel.all;
              var idx = feed.iids.indexOf(iid!);
              return CupertinoToolbar(
                items: [
                  CupertinoToolbarItem(
                    icon: item.hasRead
                        ? CupertinoIcons.circle
                        : CupertinoIcons.smallcircle_fill_circle,
                    semanticLabel: item.hasRead
                        ? S.of(context).markUnread
                        : S.of(context).markRead,
                    onPressed: () {
                      HapticFeedback.mediumImpact();
                      Global.itemsModel
                          .updateItem(item.id, read: !item.hasRead);
                    },
                  ),
                  CupertinoToolbarItem(
                    icon: item.starred
                        ? CupertinoIcons.star_fill
                        : CupertinoIcons.star,
                    semanticLabel: item.starred
                        ? S.of(context).star
                        : S.of(context).unstar,
                    onPressed: () {
                      HapticFeedback.mediumImpact();
                      Global.itemsModel
                          .updateItem(item.id, starred: !item.starred);
                    },
                  ),
                  CupertinoToolbarItem(
                    icon: CupertinoIcons.share,
                    semanticLabel: S.of(context).share,
                    onPressed: () {
                      final media = MediaQuery.of(context);
                      Share.share(item.link,
                          sharePositionOrigin: Rect.fromLTWH(
                              media.size.width -
                                  (ArticlePage.state.currentContext?.size?.width ??
                                      0) /
                                      2,
                              media.size.height - media.padding.bottom - 54,
                              0,
                              0));
                    },
                  ),
                  CupertinoToolbarItem(
                    icon: CupertinoIcons.chevron_up,
                    semanticLabel: S.of(context).prev,
                    onPressed: idx <= 0
                        ? null
                        : () {
                            loadNewItem(feed.iids[idx - 1]);
                          },
                  ),
                  CupertinoToolbarItem(
                    icon: CupertinoIcons.chevron_down,
                    semanticLabel: S.of(context).next,
                    onPressed: (idx == -1 ||
                            (idx == feed.iids.length - 1 && feed.allLoaded))
                        ? null
                        : () async {
                            if (idx == feed.iids.length - 1) {
                              await feed.loadMore();
                            }
                            idx = feed.iids.indexOf(iid!);
                            if (idx != feed.iids.length - 1) {
                              loadNewItem(feed.iids[idx + 1]);
                            }
                          },
                  ),
                ],
                body: child!,
              );
            },
          ),
        );
      },
    );
  }
}