feat: implement web service

Signed-off-by: The one with the braid <info@braid.business>

lib/pkpass/models/barcode.dart

@@ -0,0 +1,89 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:barcode/barcode.dart';
+
+/// Information about a pass’s barcode.
+///
+/// Use with Flutter:
+///
+/// ```dart
+/// BarcodeWidget.fromBytes(
+///   barcode: Barcode.fromType(myPassBarcode.format),
+///   data: myPassBarcode.barcodeData,
+/// )
+/// ```
+///
+/// Please not the spec requires you to display the [altText] next to the
+/// barcode in case available.
+class PassBarcode {
+  /// the [Encoding] supported for [messageEncoding]. Can be expanded at runtime.
+  ///
+  /// Default values are
+  /// - iso-8859-1: [Latin1Codec]
+  /// - utf-8: [Utf8Codec]
+  static Map<String, Encoding> supportedCodecs = {
+    'iso-8859-1': Latin1Codec(),
+    'iso-8859': Latin1Codec(),
+    'iso8859': Latin1Codec(),
+    'utf-8': Utf8Codec(),
+    'utf8': Utf8Codec(),
+  };
+
+  static const _allowedFormats = {
+    'PKBarcodeFormatQR': BarcodeType.QrCode,
+    'PKBarcodeFormatPDF417': BarcodeType.PDF417,
+    'PKBarcodeFormatAztec': BarcodeType.Aztec,
+    'PKBarcodeFormatCode128': BarcodeType.Code128,
+  };
+
+  /// Barcode format. For the barcode dictionary, you can use only the
+  /// following values: PKBarcodeFormatQR, PKBarcodeFormatPDF417, or
+  /// PKBarcodeFormatAztec. For dictionaries in the barcodes array, you may
+  /// also use PKBarcodeFormatCode128.
+  ///
+  /// The spec defined keys are converted into the corresponding [BarcodeType]
+  /// representations.
+  final BarcodeType format;
+
+  /// Message or payload to be displayed as a barcode.
+  ///
+  /// Do not use directly, use the encoded [barcodeData] instead.
+  final String message;
+
+  /// Text encoding that is used to convert the message from the string
+  /// representation to a data representation to render the barcode.
+  ///
+  /// The value is typically iso-8859-1, but you may use another encoding that
+  /// is supported by your barcode scanning infrastructure.
+  ///
+  /// Only supported values by this packages are:
+  /// - iso-8859-1
+  /// - utf-8
+  ///
+  /// Custom codecs can be provided as [Codec] in [PassBarcode.supportedCodecs].
+  final Encoding messageEncoding;
+
+  /// Text displayed near the barcode. For example, a human-readable version
+  /// of the barcode data in case the barcode doesn’t scan.
+  final String? altText;
+
+  const PassBarcode({
+    required this.format,
+    required this.message,
+    required this.messageEncoding,
+    required this.altText,
+  });
+
+  factory PassBarcode.fromJson(Map<String, Object?> json) => PassBarcode(
+        format: _allowedFormats[json['format']]!,
+        message: json['message'] as String,
+        messageEncoding:
+            supportedCodecs[(json['messageEncoding'] as String).toLowerCase()]!,
+        altText: json['altText'] as String?,
+      );
+
+  /// Correctly encoded byte list to be displayed in the [barcode].
+  Uint8List get barcodeData =>
+      Uint8List.fromList(messageEncoding.encode(message));
+}