import 'dart:math' as math;

import 'package:collection/collection.dart';
import 'package:dropdown_button2/dropdown_button2.dart';
import 'package:easy_localization/easy_localization.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:gap/gap.dart';
import 'package:go_router/go_router.dart';
import 'package:image_picker/image_picker.dart';
import 'package:material_symbols_icons/symbols.dart';
import 'package:styled_widget/styled_widget.dart';
import 'package:surface/controllers/post_write_controller.dart';
import 'package:surface/providers/sn_network.dart';
import 'package:surface/types/post.dart';
import 'package:surface/widgets/account/account_image.dart';
import 'package:surface/widgets/loading_indicator.dart';
import 'package:surface/widgets/navigation/app_scaffold.dart';
import 'package:surface/widgets/post/post_item.dart';
import 'package:surface/widgets/post/post_media_pending_list.dart';
import 'package:surface/widgets/post/post_meta_editor.dart';
import 'package:surface/widgets/dialog.dart';
import 'package:provider/provider.dart';

class PostEditorScreen extends StatefulWidget {
  final String mode;
  final int? postEditId;
  final int? postReplyId;
  final int? postRepostId;
  const PostEditorScreen({
    super.key,
    required this.mode,
    required this.postEditId,
    required this.postReplyId,
    required this.postRepostId,
  });

  @override
  State<PostEditorScreen> createState() => _PostEditorScreenState();
}

class _PostEditorScreenState extends State<PostEditorScreen> {
  final PostWriteController _writeController = PostWriteController();

  bool _isFetching = false;
  bool get _isLoading => _isFetching || _writeController.isLoading;

  List<SnPublisher>? _publishers;

  Future<void> _fetchPublishers() async {
    setState(() => _isFetching = true);

    try {
      final sn = context.read<SnNetworkProvider>();
      final resp = await sn.client.get('/cgi/co/publishers');
      _publishers = List<SnPublisher>.from(
        resp.data?.map((e) => SnPublisher.fromJson(e)) ?? [],
      );
      _writeController.setPublisher(_publishers?.firstOrNull);
    } catch (err) {
      if (!mounted) return;
      context.showErrorDialog(err);
    } finally {
      setState(() => _isFetching = false);
    }
  }

  void _updateMeta() {
    showModalBottomSheet(
      context: context,
      builder: (context) => PostMetaEditor(controller: _writeController),
      useRootNavigator: true,
    );
  }

  final _imagePicker = ImagePicker();

  void _selectMedia() async {
    final result = await _imagePicker.pickMultipleMedia();
    if (result.isEmpty) return;
    _writeController.addAttachments(
      result.map((e) => PostWriteMedia.fromFile(e)),
    );
    setState(() {});
  }

  @override
  void dispose() {
    _writeController.dispose();
    super.dispose();
  }

  @override
  void initState() {
    super.initState();
    if (!PostWriteController.kTitleMap.keys.contains(widget.mode)) {
      context.showErrorDialog('Unknown post type');
      Navigator.pop(context);
    }
    _fetchPublishers();
    _writeController.fetchRelatedPost(
      context,
      editing: widget.postEditId,
      replying: widget.postReplyId,
      reposting: widget.postRepostId,
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: _writeController,
      builder: (context, _) {
        return AppScaffold(
          appBar: AppBar(
            leading: BackButton(
              onPressed: () {
                Navigator.pop(context);
              },
            ),
            flexibleSpace: Column(
              children: [
                Text(_writeController.title.isNotEmpty
                        ? _writeController.title
                        : 'untitled'.tr())
                    .textStyle(Theme.of(context).textTheme.titleLarge!)
                    .textColor(Colors.white),
                Text(PostWriteController.kTitleMap[widget.mode]!)
                    .tr()
                    .textColor(Colors.white.withAlpha((255 * 0.9).round())),
              ],
            ).padding(top: math.max(MediaQuery.of(context).padding.top, 8)),
            actions: [
              IconButton(
                icon: const Icon(Symbols.tune),
                onPressed: _writeController.isBusy ? null : _updateMeta,
              ),
            ],
          ),
          body: Column(
            children: [
              DropdownButtonHideUnderline(
                child: DropdownButton2<SnPublisher>(
                  isExpanded: true,
                  hint: Text(
                    'fieldPostPublisher',
                    style: TextStyle(
                      fontSize: 14,
                      color: Theme.of(context).hintColor,
                    ),
                  ).tr(),
                  items: <DropdownMenuItem<SnPublisher>>[
                    ...(_publishers?.map(
                          (item) => DropdownMenuItem<SnPublisher>(
                            enabled: _writeController.editingPost == null,
                            value: item,
                            child: Row(
                              children: [
                                AccountImage(content: item.avatar, radius: 16),
                                const Gap(8),
                                Expanded(
                                  child: Column(
                                    mainAxisSize: MainAxisSize.min,
                                    crossAxisAlignment:
                                        CrossAxisAlignment.start,
                                    children: [
                                      Text(item.nick).textStyle(
                                          Theme.of(context)
                                              .textTheme
                                              .bodyMedium!),
                                      Text('@${item.name}')
                                          .textStyle(Theme.of(context)
                                              .textTheme
                                              .bodySmall!)
                                          .fontSize(12),
                                    ],
                                  ),
                                ),
                              ],
                            ),
                          ),
                        ) ??
                        []),
                    DropdownMenuItem<SnPublisher>(
                      value: null,
                      child: Row(
                        children: [
                          CircleAvatar(
                            radius: 16,
                            backgroundColor: Colors.transparent,
                            foregroundColor:
                                Theme.of(context).colorScheme.onSurface,
                            child: const Icon(Symbols.add),
                          ),
                          const Gap(8),
                          Expanded(
                            child: Column(
                              mainAxisSize: MainAxisSize.min,
                              crossAxisAlignment: CrossAxisAlignment.start,
                              children: [
                                Text('publishersNew').tr().textStyle(
                                    Theme.of(context).textTheme.bodyMedium!),
                              ],
                            ),
                          ),
                        ],
                      ),
                    ),
                  ],
                  value: _writeController.publisher,
                  onChanged: (SnPublisher? value) {
                    if (value == null) {
                      GoRouter.of(context)
                          .pushNamed('accountPublisherNew')
                          .then((value) {
                        if (value == true) {
                          _publishers = null;
                          _fetchPublishers();
                        }
                      });
                    } else {
                      _writeController.setPublisher(value);
                    }
                  },
                  buttonStyleData: const ButtonStyleData(
                    padding: EdgeInsets.only(right: 16),
                    height: 48,
                  ),
                  menuItemStyleData: const MenuItemStyleData(
                    height: 48,
                  ),
                ),
              ),
              const Divider(height: 1),
              Expanded(
                child: SingleChildScrollView(
                  padding: EdgeInsets.only(bottom: 8),
                  child: Column(
                    children: [
                      // Replying Notice
                      if (_writeController.replyingPost != null)
                        Column(
                          children: [
                            Theme(
                              data: Theme.of(context).copyWith(
                                dividerColor: Colors.transparent,
                              ),
                              child: ExpansionTile(
                                minTileHeight: 48,
                                leading:
                                    const Icon(Symbols.reply).padding(left: 4),
                                title: Text('postReplyingNotice')
                                    .fontSize(15)
                                    .tr(args: [
                                  '@${_writeController.replyingPost!.publisher.name}'
                                ]),
                                children: <Widget>[
                                  PostItem(data: _writeController.replyingPost!)
                                ],
                              ),
                            ),
                            const Divider(height: 1),
                          ],
                        ),
                      // Reposting Notice
                      if (_writeController.repostingPost != null)
                        Column(
                          children: [
                            Theme(
                              data: Theme.of(context).copyWith(
                                dividerColor: Colors.transparent,
                              ),
                              child: ExpansionTile(
                                minTileHeight: 48,
                                leading: const Icon(Symbols.forward)
                                    .padding(left: 4),
                                title: Text('postRepostingNotice')
                                    .fontSize(15)
                                    .tr(args: [
                                  '@${_writeController.repostingPost!.publisher.name}'
                                ]),
                                children: <Widget>[
                                  PostItem(
                                      data: _writeController.repostingPost!)
                                ],
                              ),
                            ),
                            const Divider(height: 1),
                          ],
                        ),
                      // Editing Notice
                      if (_writeController.editingPost != null)
                        Column(
                          children: [
                            Theme(
                              data: Theme.of(context).copyWith(
                                dividerColor: Colors.transparent,
                              ),
                              child: ExpansionTile(
                                minTileHeight: 48,
                                leading: const Icon(Symbols.edit_note)
                                    .padding(left: 4),
                                title: Text('postEditingNotice')
                                    .fontSize(15)
                                    .tr(args: [
                                  '@${_writeController.editingPost!.publisher.name}'
                                ]),
                                children: <Widget>[
                                  PostItem(data: _writeController.editingPost!)
                                ],
                              ),
                            ),
                            const Divider(height: 1),
                          ],
                        ),
                      // Content Input Area
                      TextField(
                        controller: _writeController.contentController,
                        maxLines: null,
                        decoration: InputDecoration(
                          hintText: 'fieldPostContent'.tr(),
                          hintStyle: TextStyle(fontSize: 14),
                          isCollapsed: true,
                          contentPadding: const EdgeInsets.symmetric(
                            horizontal: 16,
                          ),
                          border: InputBorder.none,
                        ),
                        onTapOutside: (_) =>
                            FocusManager.instance.primaryFocus?.unfocus(),
                      )
                    ]
                        .expandIndexed(
                          (idx, ele) => [
                            if (idx != 0 || _writeController.isRelatedNull)
                              const Gap(8),
                            ele,
                          ],
                        )
                        .toList(),
                  ),
                ),
              ),
              if (_writeController.attachments.isNotEmpty)
                PostMediaPendingList(
                  data: _writeController.attachments,
                  onRemove: (idx) {
                    _writeController.removeAttachmentAt(idx);
                  },
                ).padding(bottom: 8),
              Material(
                elevation: 2,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    LoadingIndicator(isActive: _isLoading),
                    if (_writeController.isBusy &&
                        _writeController.progress != null)
                      TweenAnimationBuilder<double>(
                        tween: Tween(begin: 0, end: _writeController.progress),
                        duration: Duration(milliseconds: 300),
                        builder: (context, value, _) =>
                            LinearProgressIndicator(value: value, minHeight: 2),
                      )
                    else if (_writeController.isBusy)
                      const LinearProgressIndicator(value: null, minHeight: 2),
                    Row(
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: [
                        Expanded(
                          child: ScrollConfiguration(
                            behavior: _PostEditorActionScrollBehavior(),
                            child: SingleChildScrollView(
                              scrollDirection: Axis.vertical,
                              child: Row(
                                children: [
                                  IconButton(
                                    onPressed: _writeController.isBusy
                                        ? null
                                        : _selectMedia,
                                    icon: Icon(
                                      Symbols.add_photo_alternate,
                                      color:
                                          Theme.of(context).colorScheme.primary,
                                    ),
                                  ),
                                ],
                              ),
                            ),
                          ),
                        ),
                        TextButton.icon(
                          onPressed: (_writeController.isBusy ||
                                  _writeController.publisher == null)
                              ? null
                              : () => _writeController.post(context),
                          icon: const Icon(Symbols.send),
                          label: Text('postPublish').tr(),
                        ),
                      ],
                    ).padding(horizontal: 16),
                  ],
                ).padding(
                  bottom: MediaQuery.of(context).padding.bottom,
                  top: 4,
                ),
              ),
            ],
          ),
        );
      },
    );
  }
}

class _PostEditorActionScrollBehavior extends MaterialScrollBehavior {
  @override
  Set<PointerDeviceKind> get dragDevices => {
        PointerDeviceKind.touch,
        PointerDeviceKind.mouse,
      };
}