import 'package:flutter/material.dart';
import 'package:lucide_icons/lucide_icons.dart';
import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/exceptions.dart';
import '../../core/theme.dart';
import '../../core/wikilink_syntax.dart';
import '../../providers/api_client_provider.dart';
import '../../providers/notes_provider.dart';
import '../../widgets/project_selector.dart';

class NoteEditScreen extends ConsumerStatefulWidget {
  final int? noteId;
  final String? noteType; // passed when creating a typed note from KnowledgeScreen
  const NoteEditScreen({super.key, this.noteId, this.noteType});

  @override
  ConsumerState<NoteEditScreen> createState() => _NoteEditScreenState();
}

class _NoteEditScreenState extends ConsumerState<NoteEditScreen> {
  final _titleController = TextEditingController();
  final _contentController = TextEditingController();
  final _tagController = TextEditingController();
  List<String> _tags = [];
  int? _projectId;
  bool _preview = false;
  bool _saving = false;
  late String _noteType;

  late final Future<void> _initFuture;

  @override
  void initState() {
    super.initState();
    _noteType = widget.noteType ?? 'note';
    _initFuture =
        widget.noteId != null ? _loadExisting() : Future.value();
  }

  @override
  void dispose() {
    _titleController.dispose();
    _contentController.dispose();
    _tagController.dispose();
    super.dispose();
  }

  Future<void> _loadExisting() async {
    final note =
        await ref.read(notesRepositoryProvider).getOne(widget.noteId!);
    _titleController.text = note.title;
    _contentController.text = note.body;
    _tags = List<String>.from(note.tags);
    _projectId = note.projectId;
    _noteType = note.noteType;
  }

  void _addTag(String raw) {
    final tag = raw.trim().replaceAll(',', '').toLowerCase();
    if (tag.isEmpty || _tags.contains(tag)) {
      _tagController.clear();
      return;
    }
    setState(() {
      _tags = [..._tags, tag];
      _tagController.clear();
    });
  }

  void _removeTag(String tag) {
    setState(() => _tags = _tags.where((t) => t != tag).toList());
  }

  Future<void> _delete() async {
    final confirm = await showDialog<bool>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: const Text('Delete note?'),
        content: Text(_titleController.text),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(dialogContext, false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(dialogContext, true),
            style: TextButton.styleFrom(
              foregroundColor: Theme.of(dialogContext).extension<ActionColors>()!.destructive,
            ),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (confirm == true) {
      await ref.read(notesProvider.notifier).delete(widget.noteId!);
      if (mounted) context.pop();
    }
  }

  Future<void> _save() async {
    final title = _titleController.text.trim();
    final body = _contentController.text;
    if (title.isEmpty) {
      ScaffoldMessenger.of(context)
          .showSnackBar(const SnackBar(content: Text('Title is required.')));
      return;
    }
    setState(() => _saving = true);
    try {
      if (widget.noteId == null) {
        await ref.read(notesProvider.notifier).create(
              title,
              body,
              tags: _tags,
              projectId: _projectId,
              noteType: _noteType,
            );
        if (mounted) context.pop();
      } else {
        await ref.read(notesProvider.notifier).updateNote(
              widget.noteId!,
              title,
              body,
              tags: _tags,
              projectId: _projectId,
              clearProject: _projectId == null,
              noteType: _noteType,
            );
        if (mounted) context.pop();
      }
    } on AppException catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context)
            .showSnackBar(SnackBar(content: Text(e.message)));
      }
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _initFuture,
      builder: (context, snapshot) {
        return Scaffold(
          appBar: AppBar(
            title: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(widget.noteId == null ? 'New Note' : 'Edit Note'),
                if (_noteType != 'note')
                  Chip(
                    label: Text(
                      _noteType,
                      style: const TextStyle(fontSize: 11),
                    ),
                    padding: EdgeInsets.zero,
                    visualDensity: VisualDensity.compact,
                    materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                  ),
              ],
            ),
            actions: [
              if (widget.noteId != null)
                IconButton(
                  icon: const Icon(LucideIcons.trash2),
                  tooltip: 'Delete',
                  onPressed: _delete,
                ),
              IconButton(
                icon: Icon(_preview ? LucideIcons.pencil : LucideIcons.eye),
                tooltip: _preview ? 'Edit' : 'Preview',
                onPressed: () => setState(() => _preview = !_preview),
              ),
              IconButton(
                icon: _saving
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Icon(LucideIcons.check),
                onPressed: _saving ? null : _save,
              ),
            ],
          ),
          body: snapshot.connectionState == ConnectionState.waiting
              ? const Center(child: CircularProgressIndicator())
              : Column(
                  children: [
                    Padding(
                      padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
                      child: TextField(
                        controller: _titleController,
                        decoration: const InputDecoration(
                          hintText: 'Title',
                          border: InputBorder.none,
                        ),
                        style: Theme.of(context).textTheme.titleLarge,
                        textInputAction: TextInputAction.next,
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.fromLTRB(16, 0, 16, 8),
                      child: _TagInput(
                        tags: _tags,
                        controller: _tagController,
                        onAdd: _addTag,
                        onRemove: _removeTag,
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.fromLTRB(16, 0, 16, 8),
                      child: ProjectSelector(
                        value: _projectId,
                        onChanged: (id) => setState(() => _projectId = id),
                      ),
                    ),
                    const Divider(height: 1),
                    Expanded(
                      child: _preview
                          ? Markdown(
                              data: _contentController.text,
                              extensionSet: wikilinkExtensionSet,
                            )
                          : Padding(
                              padding:
                                  const EdgeInsets.symmetric(horizontal: 16),
                              child: TextField(
                                controller: _contentController,
                                decoration: const InputDecoration(
                                  hintText: 'Write in markdown...',
                                  border: InputBorder.none,
                                ),
                                maxLines: null,
                                expands: true,
                                keyboardType: TextInputType.multiline,
                                textAlignVertical: TextAlignVertical.top,
                              ),
                            ),
                    ),
                  ],
                ),
        );
      },
    );
  }
}

class _TagInput extends StatelessWidget {
  final List<String> tags;
  final TextEditingController controller;
  final ValueChanged<String> onAdd;
  final ValueChanged<String> onRemove;

  const _TagInput({
    required this.tags,
    required this.controller,
    required this.onAdd,
    required this.onRemove,
  });

  @override
  Widget build(BuildContext context) {
    return Wrap(
      spacing: 6,
      runSpacing: 4,
      crossAxisAlignment: WrapCrossAlignment.center,
      children: [
        ...tags.map(
          (tag) => Chip(
            label: Text('#$tag', style: const TextStyle(fontSize: 12)),
            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
            padding: const EdgeInsets.symmetric(horizontal: 4),
            deleteIcon: const Icon(LucideIcons.x, size: 14),
            onDeleted: () => onRemove(tag),
          ),
        ),
        SizedBox(
          width: 120,
          child: TextField(
            controller: controller,
            decoration: const InputDecoration(
              hintText: 'Add tag…',
              border: InputBorder.none,
              isDense: true,
              contentPadding: EdgeInsets.symmetric(vertical: 4),
            ),
            style: const TextStyle(fontSize: 13),
            textInputAction: TextInputAction.done,
            onSubmitted: onAdd,
            onChanged: (v) {
              if (v.endsWith(',') || v.endsWith(' ')) {
                onAdd(v.replaceAll(RegExp(r'[, ]+$'), ''));
              }
            },
          ),
        ),
      ],
    );
  }
}