Fill in payments by scanning a QR code or picking one from photos

2026-09-20 02:00:52 +08:00
parent 399502cf72
commit c0903f4f02
8 changed files with 423 additions and 11 deletions
@@ -0,0 +1,135 @@
+import CoreImage
+import CoreImage.CIFilterBuiltins
+import Foundation
+import UIKit
+import Vision
+
+/// Renders a QR image (used by the UI and by the self-test, which round-trips
+/// an image through the reader).
+enum QRCodeImage {
+  static func make(_ text: String, scale: CGFloat = 10) -> UIImage? {
+    guard !text.isEmpty else { return nil }
+    let filter = CIFilter.qrCodeGenerator()
+    filter.message = Data(text.utf8)
+    filter.correctionLevel = "M"
+    guard let output = filter.outputImage else { return nil }
+    let scaled = output.transformed(by: CGAffineTransform(scaleX: scale, y: scale))
+    let context = CIContext()
+    guard let cgImage = context.createCGImage(scaled, from: scaled.extent) else { return nil }
+    return UIImage(cgImage: cgImage)
+  }
+}
+
+/// A payment request decoded from a QR code: the address plus whatever else the
+/// code carried.
+struct QRPayload {
+  var address: String
+  var amount: String?
+  var tag: UInt32?
+  var paymentId: String?
+  var memo: String?
+}
+
+enum QRCodeReader {
+  /// Reads the first QR code found in an image (used for photo-library import).
+  static func decodeText(in data: Data) -> String? {
+    guard let image = UIImage(data: data), let cgImage = image.cgImage else { return nil }
+    return decodeText(in: cgImage)
+  }
+
+  static func decodeText(in image: UIImage) -> String? {
+    guard let cgImage = image.cgImage else { return nil }
+    return decodeText(in: cgImage)
+  }
+
+  private static func decodeText(in cgImage: CGImage) -> String? {
+    if let text = decodeWithVision(cgImage) { return text }
+    // Vision's barcode detector does not work on the iOS simulator, so fall
+    // back to CoreImage, which does (and adds redundancy on device).
+    return decodeWithCoreImage(cgImage)
+  }
+
+  private static func decodeWithVision(_ cgImage: CGImage) -> String? {
+    let request = VNDetectBarcodesRequest()
+    request.symbologies = [.qr]
+    let handler = VNImageRequestHandler(cgImage: cgImage, orientation: .up)
+    try? handler.perform([request])
+    for observation in request.results ?? [] {
+      if let payload = observation.payloadStringValue, !payload.isEmpty {
+        return payload
+      }
+    }
+    return nil
+  }
+
+  private static func decodeWithCoreImage(_ cgImage: CGImage) -> String? {
+    let detector = CIDetector(ofType: CIDetectorTypeQRCode,
+                              context: nil,
+                              options: [CIDetectorAccuracy: CIDetectorAccuracyHigh])
+    let features = detector?.features(in: CIImage(cgImage: cgImage)) ?? []
+    for feature in features {
+      if let code = feature as? CIQRCodeFeature, let message = code.messageString, !message.isEmpty {
+        return message
+      }
+    }
+    return nil
+  }
+
+  /// Understands plain addresses as well as the payment URIs wallets emit:
+  /// `monero:` (tx_amount, tx_payment_id, tx_description) and `ripple:`
+  /// (amount, dt).
+  static func parse(_ raw: String) -> QRPayload? {
+    let text = raw.trimmingCharacters(in: .whitespacesAndNewlines)
+    guard !text.isEmpty else { return nil }
+
+    var body = text
+    var query: [String: String] = [:]
+
+    if let separator = text.firstIndex(of: "?") {
+      body = String(text[text.startIndex..<separator])
+      let queryText = String(text[text.index(after: separator)...])
+      for pair in queryText.split(separator: "&") {
+        let parts = pair.split(separator: "=", maxSplits: 1)
+        guard let key = parts.first else { continue }
+        let value = parts.count > 1 ? String(parts[1]) : ""
+        query[key.lowercased()] = value.removingPercentEncoding ?? value
+      }
+    }
+
+    let lowered = body.lowercased()
+    if let range = lowered.range(of: "monero:") {
+      body = String(body[range.upperBound...])
+    } else if let range = lowered.range(of: "ripple:") {
+      body = String(body[range.upperBound...])
+    }
+    while body.hasPrefix("/") { body.removeFirst() }
+
+    let address = body.trimmingCharacters(in: .whitespacesAndNewlines)
+    guard !address.isEmpty else { return nil }
+
+    var payload = QRPayload(address: address)
+    payload.amount = query["tx_amount"] ?? query["amount"]
+    payload.memo = query["tx_description"] ?? query["name"] ?? query["message"]
+    payload.paymentId = query["tx_payment_id"] ?? query["payment_id"] ?? query["pid"]
+    if let tag = query["dt"] ?? query["destination_tag"] ?? query["destinationtag"] {
+      payload.tag = UInt32(tag)
+    }
+    return payload
+  }
+}
+
+enum AddressFormat {
+  private static let moneroAlphabet = Set("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
+
+  /// Monero addresses are 95 characters (primary/subaddress) or 106
+  /// (integrated), all base58.
+  static func isMonero(_ address: String) -> Bool {
+    let text = address.trimmingCharacters(in: .whitespacesAndNewlines)
+    guard text.count == 95 || text.count == 106 else { return false }
+    return text.allSatisfy { moneroAlphabet.contains($0) }
+  }
+
+  static func isXRP(_ address: String) -> Bool {
+    XRPKey.isValidAddress(address.trimmingCharacters(in: .whitespacesAndNewlines))
+  }
+}