From bfaa26f4ca779e4568f954d2e111f1c66f10c809 Mon Sep 17 00:00:00 2001
From: Matthew <6657488+reez@users.noreply.github.com>
Date: Thu, 28 Sep 2023 11:11:42 -0500
Subject: [PATCH] view: add qrcodeview

---
 Sources/BitcoinUI/QRCodeView.swift | 79 ++++++++++++++++++++++++++++++
 Sources/BitcoinUI/Utilities.swift  | 12 +++++
 2 files changed, 91 insertions(+)
 create mode 100644 Sources/BitcoinUI/QRCodeView.swift

diff --git a/Sources/BitcoinUI/QRCodeView.swift b/Sources/BitcoinUI/QRCodeView.swift
new file mode 100644
index 0000000..80f9232
--- /dev/null
+++ b/Sources/BitcoinUI/QRCodeView.swift
@@ -0,0 +1,79 @@
+//
+//  QRCodeView.swift
+//
+//
+//  Created by Matthew Ramsden on 9/28/23.
+//
+
+import SwiftUI
+import CoreImage.CIFilterBuiltins
+
+enum QRCodeType {
+    case bitcoin(String)
+    case lightning(String)
+    
+    var qrString: String {
+        switch self {
+        case .bitcoin(let address):
+            return "bitcoin:\(address)"
+        case .lightning(let invoice):
+            return "lightning:\(invoice)"
+        }
+    }
+}
+
+struct QRCodeView: View {
+    @State private var viewState = CGSize.zero
+    let screenBounds = UIScreen.main.bounds
+    var qrCodeType: QRCodeType
+    
+    var body: some View {
+        Image(uiImage: generateQRCode(from: qrCodeType.qrString))
+            .interpolation(.none)
+            .resizable()
+            .scaledToFit()
+            .padding()
+            .applyFidgetEffect(viewState: $viewState)
+            .gesture(dragGesture())
+    }
+    
+    private func generateQRCode(from string: String) -> UIImage {
+        let context = CIContext()
+        let filter = CIFilter.qrCodeGenerator()
+        let data = Data(string.utf8)
+        filter.setValue(data, forKey: "inputMessage")
+
+        if let outputImage = filter.outputImage {
+            if let cgimg = context.createCGImage(outputImage, from: outputImage.extent) {
+                return UIImage(cgImage: cgimg)
+            }
+        }
+        return UIImage(systemName: "xmark.circle") ?? UIImage()
+    }
+    
+    private func dragGesture() -> some Gesture {
+        DragGesture()
+            .onChanged(handleDragChanged(_:))
+            .onEnded(handleDragEnded(_:))
+    }
+
+    private func handleDragChanged(_ value: DragGesture.Value) {
+        let translation = value.translation
+        let multiplier: CGFloat = 0.05
+        viewState.width = -translation.width * multiplier
+        viewState.height = -translation.height * multiplier
+    }
+
+    private func handleDragEnded(_ value: DragGesture.Value) {
+        withAnimation {
+            self.viewState = .zero
+        }
+    }
+}
+
+#Preview {
+    QRCodeView(qrCodeType: .bitcoin("bitcoinqrcode"))
+}
+#Preview {
+    QRCodeView(qrCodeType: .lightning("lightingqrcode"))
+}
diff --git a/Sources/BitcoinUI/Utilities.swift b/Sources/BitcoinUI/Utilities.swift
index 4ee99aa..23984e2 100644
--- a/Sources/BitcoinUI/Utilities.swift
+++ b/Sources/BitcoinUI/Utilities.swift
@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import SwiftUI
 
 extension CGFloat {
 
@@ -20,3 +21,14 @@ extension CGFloat {
     }
 
 }
+
+extension View {
+    func applyFidgetEffect(viewState: Binding<CGSize>) -> some View {
+        self
+            .offset(x: -viewState.wrappedValue.width, y: -viewState.wrappedValue.height)
+            .rotation3DEffect(
+                .degrees(viewState.wrappedValue.width),
+                axis: (x: 0, y: 1, z: 0)
+            )
+    }
+}