relatica/lib/screens/image_viewer_screen.dart

import 'dart:io';

import 'package:cached_network_image/cached_network_image.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter_file_dialog/flutter_file_dialog.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';

import '../globals.dart';
import '../models/media_attachment.dart';
import '../services/auth_service.dart';
import '../utils/snackbar_builder.dart';

class ImageViewerScreen extends StatefulWidget {
  final List<MediaAttachment> attachments;
  final int initialIndex;

  const ImageViewerScreen({
    super.key,
    required this.attachments,
    int this.initialIndex = 0,
  });

  @override
  State<ImageViewerScreen> createState() => _ImageViewerScreenState();
}

class _ImageViewerScreenState extends State<ImageViewerScreen> {
  var index = 0;

  @override
  void initState() {
    index = widget.initialIndex;
  }

  Future<void> saveImage(
    BuildContext context,
    MediaAttachment attachment,
  ) async {
    buildSnackbar(context, 'Downloading full image to save locally');
    final appsDir = await getApplicationDocumentsDirectory();
    final filename = p.basename(attachment.fullFileUri.path);
    final bytesResult = await getIt<AuthService>()
        .currentClient
        .value
        .getFileBytes(attachment.uri);
    if (bytesResult.isFailure && mounted) {
      buildSnackbar(context,
          'Error getting full size version of file: ${bytesResult.error}');
      return;
    }

    if (Platform.isAndroid || Platform.isIOS) {
      final params = SaveFileDialogParams(
        data: bytesResult.value,
        fileName: filename,
      );
      await FlutterFileDialog.saveFile(params: params);
    } else {
      final location = await FilePicker.platform.saveFile(
        dialogTitle: 'Save Image',
        fileName: filename,
        initialDirectory: appsDir.path,
      );
      if (location != null) {
        await File(location).writeAsBytes(bytesResult.value);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    print('Index: $index');
    final attachment = widget.attachments[index];
    final height = MediaQuery.of(context).size.height;
    return Scaffold(
      appBar: AppBar(
        actions: [
          IconButton(
              onPressed: () => saveImage(context, attachment),
              icon: const Icon(Icons.download))
        ],
      ),
      body: SafeArea(
        child: Stack(
          children: [
            GestureDetector(
              onHorizontalDragEnd: (details) {
                final velocity = details.primaryVelocity ?? 0.0;
                print('Velocity: $velocity');
                if (velocity > 0 && index > 0) {
                  setState(() {
                    index--;
                  });
                }

                if (velocity < 0 && index < widget.attachments.length - 1) {
                  setState(() {
                    index++;
                  });
                }
              },
              child: buildCoreViewer(attachment),
            ),
            if (index > 0)
              Positioned(
                top: height / 2,
                left: 0.0,
                child: buildButton(
                  Icon(Icons.keyboard_arrow_left),
                  onPressed: () {
                    setState(() {
                      index--;
                    });
                  },
                ),
              ),
            if (index < widget.attachments.length - 1)
              Positioned(
                top: height / 2,
                right: 0.0,
                child: buildButton(
                  Icon(Icons.keyboard_arrow_right),
                  onPressed: () {
                    setState(() {
                      index++;
                    });
                  },
                ),
              ),
          ],
        ),
      ),
    );
  }

  Widget buildCoreViewer(MediaAttachment attachment) {
    final width = MediaQuery.of(context).size.width;
    final height = MediaQuery.of(context).size.height;
    return Column(
      mainAxisAlignment: MainAxisAlignment.start,
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(
          width: width,
          height: 0.8 * height,
          child: InteractiveViewer(
            maxScale: 10.0,
            scaleFactor: 400,
            child: CachedNetworkImage(imageUrl: attachment.uri.toString()),
          ),
        ),
        Expanded(
          child: SingleChildScrollView(
            child: Padding(
              padding: const EdgeInsets.all(8.0),
              child: Text(attachment.description),
            ),
          ),
        ),
      ],
    );
  }

  Widget buildButton(Icon icon, {required Function() onPressed}) {
    return Center(
      child: Ink(
        decoration: ShapeDecoration(
          color: Theme.of(context).focusColor,
          shape: CircleBorder(),
        ),
        child: IconButton(
          icon: icon,
          color: Colors.white,
          onPressed: onPressed,
        ),
      ),
    );
  }
}