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

import '../../core/exceptions.dart';
import '../../providers/api_client_provider.dart';
import '../../providers/notes_provider.dart';

class NoteEditScreen extends ConsumerStatefulWidget {
  final int? noteId;
  const NoteEditScreen({super.key, this.noteId});

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

class _NoteEditScreenState extends ConsumerState<NoteEditScreen> {
  final _titleController = TextEditingController();
  final _contentController = TextEditingController();
  bool _preview = false;
  bool _saving = false;
  bool _loaded = false;

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

  Future<void> _loadExisting() async {
    if (_loaded || widget.noteId == null) {
      _loaded = true;
      return;
    }
    final note =
        await ref.read(notesRepositoryProvider).getOne(widget.noteId!);
    _titleController.text = note.title;
    _contentController.text = note.body;
    _loaded = true;
  }

  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),
            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);
        if (mounted) context.pop();
      } else {
        await ref
            .read(notesProvider.notifier)
            .updateNote(widget.noteId!, title, body);
        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: _loadExisting(),
      builder: (context, snapshot) {
        return Scaffold(
          appBar: AppBar(
            title: Text(widget.noteId == null ? 'New Note' : 'Edit Note'),
            actions: [
              if (widget.noteId != null)
                IconButton(
                  icon: const Icon(Icons.delete_outline),
                  tooltip: 'Delete',
                  onPressed: _delete,
                ),
              IconButton(
                icon: Icon(_preview ? Icons.edit : Icons.preview),
                tooltip: _preview ? 'Edit' : 'Preview',
                onPressed: () => setState(() => _preview = !_preview),
              ),
              IconButton(
                icon: _saving
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Icon(Icons.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,
                      ),
                    ),
                    const Divider(),
                    Expanded(
                      child: _preview
                          ? Markdown(data: _contentController.text)
                          : 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,
                                onChanged: (_) => setState(() {}),
                              ),
                            ),
                    ),
                  ],
                ),
        );
      },
    );
  }
}