import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';
import '../../core/theme/app_theme.dart';
import '../../core/widgets/loading_button.dart';
import '../../core/api/api_client.dart';
import '../../shared/providers/lookup_providers.dart';
import 'surat_provider.dart';

class SuratFormScreen extends ConsumerStatefulWidget {
  final int? editId;
  final int? prefillTaskId;
  const SuratFormScreen({super.key, this.editId, this.prefillTaskId});

  @override
  ConsumerState<SuratFormScreen> createState() => _SuratFormScreenState();
}

class _SuratFormScreenState extends ConsumerState<SuratFormScreen> {
  final _formKey = GlobalKey<FormState>();
  final _subjectCtrl = TextEditingController();
  final _perihalCtrl = TextEditingController();
  final _bodyCtrl = TextEditingController();
  DateTime? _tanggal;
  int? _companyId;
  int? _vendorId;
  int? _categoryId;
  bool _loading = false;
  bool _initDone = false;

  bool get isEdit => widget.editId != null;

  @override
  void initState() {
    super.initState();
    if (widget.prefillTaskId != null) _loadPrefill();
  }

  @override
  void dispose() {
    _subjectCtrl.dispose();
    _perihalCtrl.dispose();
    _bodyCtrl.dispose();
    super.dispose();
  }

  Future<void> _loadPrefill() async {
    try {
      final resp = await apiDio.get('/tasks/${widget.prefillTaskId}/letter-prefill');
      setState(() {
        _subjectCtrl.text = resp.data['subject'] ?? '';
        if (resp.data['body'] != null) _bodyCtrl.text = resp.data['body'];
      });
    } catch (_) {}
  }

  Future<void> _initEdit() async {
    if (!isEdit || _initDone) return;
    _initDone = true;
    try {
      final resp = await apiDio.get('/surat/${widget.editId}');
      final d = resp.data as Map<String, dynamic>;
      setState(() {
        _subjectCtrl.text = d['subject'] ?? '';
        _perihalCtrl.text = d['perihal'] ?? '';
        _bodyCtrl.text = (d['body'] ?? '').replaceAll(RegExp(r'<[^>]*>'), '');
        _companyId = d['company_id'];
        _vendorId = d['vendor_id'];
        _categoryId = d['category_id'];
        if (d['tanggal'] != null) _tanggal = DateTime.tryParse(d['tanggal']);
      });
    } catch (_) {}
  }

  Future<void> _submit() async {
    if (!_formKey.currentState!.validate()) return;
    setState(() => _loading = true);
    try {
      final data = <String, dynamic>{
        'subject': _subjectCtrl.text.trim(),
        'perihal': _perihalCtrl.text.trim(),
        'body': _bodyCtrl.text.trim(),
        'company_id': _companyId,
        'vendor_id': _vendorId,
        'category_id': _categoryId,
        if (_tanggal != null) 'tanggal': DateFormat('yyyy-MM-dd').format(_tanggal!),
        if (widget.prefillTaskId != null && !isEdit) 'task_id': widget.prefillTaskId,
      };
      if (isEdit) {
        await updateSurat(widget.editId!, data);
      } else {
        await createSurat(data);
      }
      if (mounted) context.pop();
    } on ApiException catch (e) {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(e.message), backgroundColor: AppColors.danger));
    } finally {
      if (mounted) setState(() => _loading = false);
    }
  }

  Future<void> _pickDate() async {
    final picked = await showDatePicker(
      context: context,
      initialDate: _tanggal ?? DateTime.now(),
      firstDate: DateTime(2020), lastDate: DateTime(2030),
    );
    if (picked != null) setState(() => _tanggal = picked);
  }

  @override
  Widget build(BuildContext context) {
    if (isEdit) _initEdit();
    final companiesAsync = ref.watch(companiesProvider);
    final vendorsAsync = ref.watch(vendorsProvider);
    final categoriesAsync = ref.watch(categoriesProvider);

    return Scaffold(
      appBar: AppBar(title: Text(isEdit ? 'Edit Letter' : 'Create Letter')),
      body: Form(
        key: _formKey,
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            _label('Subject'),
            TextFormField(
              controller: _subjectCtrl,
              decoration: const InputDecoration(hintText: 'Letter subject'),
              validator: (v) => (v == null || v.isEmpty) ? 'Subject is required' : null,
            ),
            const SizedBox(height: 16),

            _label('Notes (optional)'),
            TextFormField(controller: _perihalCtrl,
                decoration: const InputDecoration(hintText: 'Additional notes')),
            const SizedBox(height: 16),

            _label('Company'),
            companiesAsync.when(
              loading: () => const LinearProgressIndicator(),
              error: (_, __) => const Text('Failed to load companies'),
              data: (list) => DropdownButtonFormField<int>(
                value: _companyId,
                decoration: const InputDecoration(hintText: 'Select company'),
                items: list.map((c) => DropdownMenuItem(value: c.id, child: Text(c.name))).toList(),
                onChanged: (v) => setState(() => _companyId = v),
                validator: (v) => v == null ? 'Company is required' : null,
              ),
            ),
            const SizedBox(height: 16),

            _label('Vendor (optional)'),
            vendorsAsync.when(
              loading: () => const LinearProgressIndicator(),
              error: (_, __) => const Text('Failed to load vendors'),
              data: (list) => DropdownButtonFormField<int>(
                value: _vendorId,
                decoration: const InputDecoration(hintText: 'Select vendor'),
                items: [
                  const DropdownMenuItem(value: null, child: Text('None')),
                  ...list.map((v) => DropdownMenuItem(value: v.id, child: Text(v.name))),
                ],
                onChanged: (v) => setState(() => _vendorId = v),
              ),
            ),
            const SizedBox(height: 16),

            _label('Category'),
            categoriesAsync.when(
              loading: () => const LinearProgressIndicator(),
              error: (_, __) => const Text('Failed to load categories'),
              data: (list) => DropdownButtonFormField<int>(
                value: _categoryId,
                decoration: const InputDecoration(hintText: 'Select category'),
                items: list.map((c) => DropdownMenuItem(value: c.id, child: Text(c.name))).toList(),
                onChanged: (v) => setState(() => _categoryId = v),
                validator: (v) => v == null ? 'Category is required' : null,
              ),
            ),
            const SizedBox(height: 16),

            _label('Letter Date'),
            GestureDetector(
              onTap: _pickDate,
              child: Container(
                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
                decoration: BoxDecoration(
                  color: AppColors.surface,
                  border: Border.all(color: AppColors.border),
                  borderRadius: BorderRadius.circular(10),
                ),
                child: Row(children: [
                  const Icon(Icons.calendar_today_outlined, size: 16, color: AppColors.textSub),
                  const SizedBox(width: 10),
                  Text(
                    _tanggal != null ? DateFormat('d MMMM yyyy').format(_tanggal!) : 'Select date',
                    style: TextStyle(color: _tanggal != null ? AppColors.text : AppColors.textSub, fontSize: 14),
                  ),
                ]),
              ),
            ),
            const SizedBox(height: 16),

            _label('Letter Content'),
            TextFormField(
              controller: _bodyCtrl,
              maxLines: 8,
              decoration: const InputDecoration(
                hintText: 'Write letter content here...',
                alignLabelWithHint: true,
              ),
            ),
            const SizedBox(height: 32),
            LoadingButton(loading: _loading, label: isEdit ? 'Save' : 'Create Letter', onPressed: _submit),
          ],
        ),
      ),
    );
  }

  Widget _label(String text) => Padding(
    padding: const EdgeInsets.only(bottom: 6),
    child: Text(text, style: const TextStyle(fontSize: 13, fontWeight: FontWeight.w600, color: AppColors.text)),
  );
}