import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flux/features/attachments/blocs/operation_files_bloc.dart';
import 'package:image_picker/image_picker.dart';
import 'package:file_picker/file_picker.dart';

class OperationMobileUploadScreen extends StatefulWidget {
  final String operationId;
  final String operationName;

  const OperationMobileUploadScreen({
    super.key,
    required this.operationId,
    required this.operationName,
  });

  @override
  State<OperationMobileUploadScreen> createState() =>
      _OperationMobileUploadScreenState();
}

class _OperationMobileUploadScreenState
    extends State<OperationMobileUploadScreen> {
  // 1. LA NOSTRA STAGING AREA (Il "Carrello")
  final List<PlatformFile> _stagedFiles = [];

  // 2. STATO DI CARICAMENTO GLOBALE
  bool _isUploading = false;

  // Funzione magica per capire se è un'immagine o un PDF dall'estensione
  bool _isImage(String path) {
    final ext = path.split('.').last.toLowerCase();
    return ['jpg', 'jpeg', 'png', 'webp'].contains(ext);
  }

  @override
  Widget build(BuildContext context) {
    return BlocListener<OperationFilesBloc, OperationFilesState>(
      listener: (context, state) {
        // Quando il BLoC ci dice che ha finito l'upload (Success), chiudiamo la pagina!
        if (state.status == OperationFilesStatus.success && _isUploading) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(
              content: Text("Tutti i file caricati con successo! ✅"),
            ),
          );
          Navigator.of(context).pop();
        }
        if (state.status == OperationFilesStatus.failure) {
          setState(() => _isUploading = false);
          ScaffoldMessenger.of(
            context,
          ).showSnackBar(SnackBar(content: Text("Errore: ${state.error}")));
        }
      },
      child: Scaffold(
        appBar: AppBar(
          title: Text("Upload Pratica:\n${widget.operationName}"),
          automaticallyImplyLeading: !_isUploading,
        ),
        body: Stack(
          children: [
            Column(
              children: [
                // --- SEZIONE PULSANTI (Fotocamera / Galleria) ---
                Padding(
                  padding: const EdgeInsets.all(16.0),
                  child: Row(
                    children: [
                      Expanded(
                        child: ElevatedButton.icon(
                          onPressed: _isUploading ? null : _handleCamera,
                          icon: const Icon(Icons.camera_alt),
                          label: const Text("SCATTA"),
                          style: ElevatedButton.styleFrom(
                            padding: const EdgeInsets.symmetric(vertical: 16),
                          ),
                        ),
                      ),
                      const SizedBox(width: 12),
                      Expanded(
                        child: OutlinedButton.icon(
                          onPressed: _isUploading ? null : _handleFilePicker,
                          icon: const Icon(Icons.folder),
                          label: const Text("GALLERIA"),
                          style: OutlinedButton.styleFrom(
                            padding: const EdgeInsets.symmetric(vertical: 16),
                          ),
                        ),
                      ),
                    ],
                  ),
                ),

                const Divider(),

                // --- SEZIONE ANTEPRIME (La GridView Magica) ---
                Expanded(
                  child: _stagedFiles.isEmpty
                      ? const Center(
                          child: Text(
                            "Nessun file selezionato.\nScatta una foto o scegli dalla galleria.",
                            textAlign: TextAlign.center,
                            style: TextStyle(color: Colors.grey),
                          ),
                        )
                      : GridView.builder(
                          padding: const EdgeInsets.all(16),
                          gridDelegate:
                              const SliverGridDelegateWithFixedCrossAxisCount(
                                crossAxisCount:
                                    3, // 3 colonne come la galleria dell'iPhone
                                crossAxisSpacing: 12,
                                mainAxisSpacing: 12,
                              ),
                          itemCount: _stagedFiles.length,
                          itemBuilder: (context, index) {
                            final file = _stagedFiles[index];
                            final isImg = _isImage(file.name);

                            return Stack(
                              clipBehavior: Clip.none,
                              children: [
                                // L'ANTEPRIMA
                                Container(
                                  width: double.infinity,
                                  height: double.infinity,
                                  decoration: BoxDecoration(
                                    color: Colors.grey.shade200,
                                    borderRadius: BorderRadius.circular(12),
                                    border: Border.all(
                                      color: Colors.grey.shade300,
                                    ),
                                  ),
                                  child: ClipRRect(
                                    borderRadius: BorderRadius.circular(12),
                                    child: isImg
                                        ? Image.file(
                                            File(file.path!),
                                            fit: BoxFit.cover,
                                          )
                                        : const Column(
                                            mainAxisAlignment:
                                                MainAxisAlignment.center,
                                            children: [
                                              Icon(
                                                Icons.picture_as_pdf,
                                                color: Colors.red,
                                                size: 36,
                                              ),
                                              SizedBox(height: 4),
                                              Text(
                                                "PDF",
                                                style: TextStyle(
                                                  fontSize: 10,
                                                  fontWeight: FontWeight.bold,
                                                ),
                                              ),
                                            ],
                                          ),
                                  ),
                                ),

                                // IL PULSANTE CESTINO (In alto a destra)
                                Positioned(
                                  top: -8,
                                  right: -8,
                                  child: GestureDetector(
                                    onTap: () {
                                      setState(() {
                                        _stagedFiles.removeAt(index);
                                      });
                                    },
                                    child: Container(
                                      padding: const EdgeInsets.all(4),
                                      decoration: const BoxDecoration(
                                        color: Colors.red,
                                        shape: BoxShape.circle,
                                      ),
                                      child: const Icon(
                                        Icons.close,
                                        color: Colors.white,
                                        size: 16,
                                      ),
                                    ),
                                  ),
                                ),
                              ],
                            );
                          },
                        ),
                ),

                // --- SEZIONE INVIA E CHIUDI ---
                SafeArea(
                  child: Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: SizedBox(
                      width: double.infinity,
                      height: 56,
                      child: ElevatedButton.icon(
                        // Il pulsante si accende SOLO se ci sono file nel carrello
                        onPressed: _stagedFiles.isEmpty || _isUploading
                            ? null
                            : _submitAllFiles,
                        icon: const Icon(Icons.cloud_upload),
                        label: Text(
                          "INVIA ${_stagedFiles.length} FILE E CHIUDI",
                          style: const TextStyle(
                            fontSize: 16,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                        style: ElevatedButton.styleFrom(
                          backgroundColor: Theme.of(
                            context,
                          ).colorScheme.primary,
                          foregroundColor: Theme.of(
                            context,
                          ).colorScheme.onPrimary,
                        ),
                      ),
                    ),
                  ),
                ),
              ],
            ),

            // --- OVERLAY DI CARICAMENTO (Impedisce tap multipli) ---
            if (_isUploading)
              Container(
                color: Colors.black.withValues(alpha: 0.5),
                child: const Center(
                  child: Card(
                    child: Padding(
                      padding: EdgeInsets.all(24.0),
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          CircularProgressIndicator(),
                          SizedBox(height: 16),
                          Text(
                            "Caricamento in corso...",
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
              ),
          ],
        ),
      ),
    );
  }

  // --- LOGICA FOTOCAMERA E LIBRERIA ---
  Future<void> _handleCamera() async {
    final picker = ImagePicker();
    final photo = await picker.pickImage(
      source: ImageSource.camera,
      imageQuality: 80,
    );
    if (photo != null) {
      final photoBytes = await photo.readAsBytes(); // Sicuro anche per Web!
      final photoSize = await photo.length();

      final platformFile = PlatformFile(
        name: photo.name,
        size: photoSize,
        path: photo.path,
        bytes: photoBytes, // I bytes ci salvano la vita su Supabase!
      );
      setState(() {
        _stagedFiles.add(platformFile); // Unifichiamo tutto in un dart:io File
      });
    }
  }

  Future<void> _handleFilePicker() async {
    // allowMultiple: true permette di pescare 5 foto dalla galleria in un colpo solo!
    final result = await FilePicker.pickFiles(allowMultiple: true);
    if (result != null) {
      setState(() {
        _stagedFiles.addAll(result.files);
      });
    }
  }

  // --- LOGICA DI INVIO AL BLoC ---
  void _submitAllFiles() {
    setState(() => _isUploading = true);

    // Diciamo al BLoC di caricare tutti i file.
    // Usiamo il tuo evento esistente per ogni file (il BLoC li metterà in coda)
    final bloc = context.read<OperationFilesBloc>();
    bloc.add(UploadOperationFilesEvent(pickedFiles: _stagedFiles));

    // N.B: Il Navigator.pop() viene chiamato dal BlocListener in alto quando lo stato diventa "success"!
  }
}