import 'dart:async';
import 'dart:io';
import 'dart:typed_data';

import 'package:camerawesome/camerawesome_plugin.dart';
import 'package:flutter/material.dart';
import 'package:google_mlkit_barcode_scanning/google_mlkit_barcode_scanning.dart';
import 'package:rxdart/rxdart.dart';
import 'ffi.dart';
import 'utils/mlkit_utils.dart';

void main() {
  runApp(const MyApp());
}

enum CuttleState {
  unitialized,
  receiving,
  received,
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Cuttle',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _barcodeScanner = BarcodeScanner(formats: [BarcodeFormat.qrCode]);
  final _rxTextController = BehaviorSubject<String>();
  late final Stream<String> _rxTextStream = _rxTextController.stream;
  final _scrollController = ScrollController();

  TxConfig? _txConfig;
  var _cuttleState = CuttleState.unitialized;
  final List<RaptorPacket> _rxData = [];
  String _rxText = '';

  @override
  void dispose() {
    _rxTextController.close();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CameraAwesomeBuilder.previewOnly(
        onImageForAnalysis: (img) => _processImageBarcode(img),
        imageAnalysisConfig: AnalysisConfig(
          androidOptions: const AndroidAnalysisOptions.nv21(
            width: 1024,
          ),
          maxFramesPerSecond: 30,
          autoStart: false,
        ),
        builder: (cameraModeState, previewSize, previewRect) {
          return _RxTextDisplayWidget(
            rxTextStream: _rxTextStream,
            scrollController: _scrollController,
            analysisController: cameraModeState.analysisController!,
          );
        },
      ),
    );
  }

  Future _processImageBarcode(AnalysisImage img) async {
    final inputImage = toInputImage(img as Nv21Image);

    try {
      var recognizedBarCodes = await _barcodeScanner.processImage(inputImage);
      for (Barcode barcode in recognizedBarCodes) {
        var bytes = barcode.rawBytes;
        if (bytes == null) {
          continue;
        }
        final Uint8List dbytes = bytes;
        switch (_cuttleState) {
          case CuttleState.unitialized:
            {
              var txconf = await api.getTxConfig(bytes: dbytes);
              if (txconf != null) {
                _txConfig = txconf;
                _cuttleState = CuttleState.receiving;
                final fname =
                    _txConfig!.filename ?? "large text on the command line";

                final desc = _txConfig!.description;
                final text = 'Receiving $fname, ${_txConfig!.len} bytes: $desc';
                _rxText = text;
                _rxTextController.add(text);
                continue;
              }
              // implicit else here; txconf was null
              var text = barcode.rawValue;
              if (text != null) {
                // it's not a txconfig, and it's not a raptor packet, so it must be a regular qr code
                _rxText = text;
                _rxTextController.add(text);
                _cuttleState = CuttleState.received;
              }
            }

          case CuttleState.receiving:
            {
              var txconf = await api.getTxConfig(bytes: dbytes);
              if (txconf != null || barcode.rawValue != null) {
                continue;
              }
              final packet = RaptorPacket(field0: dbytes);
              _rxData.add(packet);
              final content =
                  await api.decodePackets(packets: _rxData, txconf: _txConfig!);
              if (content != null) {
                _rxData.clear();
                _barcodeScanner.close();
                _cuttleState = CuttleState.received;
                _rxTextController.add("DONE RECEIVING $_rxText");
                final f = await _saveReceivedFile(_txConfig!.filename, content);
                _rxTextController.add("Saved content to $f");
                continue;
              }
              _rxTextController
                  .add("$_rxText -- ${_rxData.length} bytes so far");
            }

          case CuttleState.received:
            continue;
        }
      }
    } catch (error) {
      debugPrint("sending image resulted error $error");
    }
  }

  Future<String> _saveReceivedFile(String? filename, Uint8List bytes) async {
    final Directory downloadDir = Directory('/storage/emulated/0/Download');
    final String fname =
        filename ?? "cuttle_${DateTime.now().millisecondsSinceEpoch}.txt";
    final String path = "${downloadDir.path}/$fname";
    final file = await File(path).create();
    await file.writeAsBytes(bytes, flush: true);
    return path;
  }
}

class _RxTextDisplayWidget extends StatefulWidget {
  final Stream<String> rxTextStream;
  final ScrollController scrollController;

  final AnalysisController analysisController;

  const _RxTextDisplayWidget({
    // ignore: unused_element
    super.key,
    required this.rxTextStream,
    required this.scrollController,
    required this.analysisController,
  });

  @override
  State<_RxTextDisplayWidget> createState() => _RxTextDisplayWidgetState();
}

class _RxTextDisplayWidgetState extends State<_RxTextDisplayWidget> {
  @override
  Widget build(BuildContext context) {
    return Align(
      alignment: Alignment.bottomCenter,
      child: Container(
        decoration: BoxDecoration(
          color: Colors.tealAccent.withOpacity(0.7),
        ),
        child: Column(mainAxisSize: MainAxisSize.min, children: [
          Material(
            color: Colors.transparent,
            child: CheckboxListTile(
              value: widget.analysisController.enabled,
              onChanged: (newValue) async {
                if (widget.analysisController.enabled == true) {
                  await widget.analysisController.stop();
                } else {
                  await widget.analysisController.start();
                }
                setState(() {});
              },
              title: const Text(
                "Enable barcode scan",
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
            ),
          ),
          Container(
            height: 120,
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: SelectionArea(
                child: StreamBuilder<String>(
              stream: widget.rxTextStream,
              builder: (context, value) =>
                  !value.hasData ? const SizedBox.expand() : Text(value.data!),
            )),
          ),
        ]),
      ),
    );
  }
}