Convert SatsPrice to a Skip multiplatform app

Sources/SatsPrice/SatsViewModel.swift

@@ -0,0 +1,173 @@
+// This is free software: you can redistribute and/or modify it
+// under the terms of the GNU General Public License 3.0
+// as published by the Free Software Foundation https://fsf.org
+//
+//
+//  SatsViewModel.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/19/24.
+//
+
+import Foundation
+import SwiftUI
+
+class SatsViewModel: ObservableObject {
+    @Published var lastUpdated: Date = Date.now
+
+    @Published var btcToUsdStringInternal: String = ""
+    @Published var satsStringInternal: String = ""
+    @Published var btcStringInternal: String = ""
+    @Published var usdStringInternal: String = ""
+
+    var btcToUsdString: String {
+        get {
+            btcToUsdStringInternal
+        }
+        set {
+            btcToUsdStringInternal = newValue
+
+            if let btc, let btcToUsd {
+                usdStringInternal = (btc * btcToUsd).formatString()
+            } else {
+                usdStringInternal = ""
+            }
+        }
+    }
+
+    var satsString: String {
+        get {
+            satsStringInternal
+        }
+        set {
+            satsStringInternal = newValue
+
+            if let sats {
+#if !SKIP
+                let btc = sats / Decimal(100000000)
+#else
+                let btc = sats.divide(Decimal(100000000), 20, java.math.RoundingMode.DOWN)
+#endif
+                btcStringInternal = btc.formatString()
+                if let btcToUsd {
+                    usdStringInternal = (btc * btcToUsd).formatString()
+                } else {
+                    usdStringInternal = ""
+                }
+            } else {
+                btcStringInternal = ""
+                usdStringInternal = ""
+            }
+        }
+    }
+
+    var btcString: String {
+        get {
+            btcStringInternal
+        }
+        set {
+            btcStringInternal = newValue
+
+            if let btc {
+                let sats = btc * Decimal(100000000)
+                satsStringInternal = sats.formatString()
+
+                if let btcToUsd {
+                    usdStringInternal = (btc * btcToUsd).formatString()
+                } else {
+                    usdStringInternal = ""
+                }
+            } else {
+                satsStringInternal = ""
+                usdStringInternal = ""
+            }
+        }
+    }
+
+    var usdString: String {
+        get {
+            usdStringInternal
+        }
+        set {
+            usdStringInternal = newValue
+
+            if let usd {
+                if let btcToUsd {
+#if !SKIP
+                    let btc = usd / btcToUsd
+#else
+                    let btc = usd.divide(btcToUsd, 20, java.math.RoundingMode.DOWN)
+#endif
+                    btcStringInternal = btc.formatString()
+
+                    let sats = btc * Decimal(100000000)
+                    satsStringInternal = sats.formatString()
+                } else {
+                    satsStringInternal = ""
+                    usdStringInternal = ""
+                }
+            } else {
+                satsStringInternal = ""
+                usdStringInternal = ""
+            }
+        }
+    }
+
+    var btcToUsd: Decimal? {
+#if !SKIP
+        return Decimal(string: btcToUsdStringInternal)
+#else
+        do {
+            return Decimal(btcToUsdStringInternal)
+        } catch {
+            return nil
+        }
+#endif
+    }
+
+    var sats: Decimal? {
+#if !SKIP
+        return Decimal(string: satsStringInternal)
+#else
+        do {
+            return Decimal(satsStringInternal)
+        } catch {
+            return nil
+        }
+#endif
+    }
+
+    var btc: Decimal? {
+#if !SKIP
+        return Decimal(string: btcStringInternal)
+#else
+        do {
+            return Decimal(btcStringInternal)
+        } catch {
+            return nil
+        }
+#endif
+    }
+
+    var usd: Decimal? {
+#if !SKIP
+        return Decimal(string: usdStringInternal)
+#else
+        do {
+            return Decimal(usdStringInternal)
+        } catch {
+            return nil
+        }
+#endif
+    }
+}
+
+extension Decimal {
+    func formatString() -> String {
+#if !SKIP
+        return String(describing: self)
+#else
+        return stripTrailingZeros().toPlainString()
+#endif
+    }
+}