initial version

PortfolioJournal/Utilities/Extensions/Decimal+Extensions.swift

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+import Foundation
+
+extension Decimal {
+    // MARK: - Performance: Shared formatters (avoid creating on every call)
+    private static let percentFormatter: NumberFormatter = {
+        let formatter = NumberFormatter()
+        formatter.numberStyle = .percent
+        formatter.maximumFractionDigits = 2
+        formatter.multiplier = 1
+        return formatter
+    }()
+
+    private static let decimalFormatter: NumberFormatter = {
+        let formatter = NumberFormatter()
+        formatter.numberStyle = .decimal
+        formatter.maximumFractionDigits = 2
+        return formatter
+    }()
+
+    // MARK: - Performance: Cached currency symbol
+    private static var _cachedCurrencySymbol: String?
+    private static var currencySymbolCacheTime: Date?
+
+    private static var cachedCurrencySymbol: String {
+        // Refresh cache every 60 seconds to pick up settings changes
+        let now = Date()
+        if let cached = _cachedCurrencySymbol,
+           let cacheTime = currencySymbolCacheTime,
+           now.timeIntervalSince(cacheTime) < 60 {
+            return cached
+        }
+        let symbol = AppSettings.getOrCreate(in: CoreDataStack.shared.viewContext).currencySymbol
+        _cachedCurrencySymbol = symbol
+        currencySymbolCacheTime = now
+        return symbol
+    }
+
+    /// Call this when currency settings change to invalidate the cache
+    static func invalidateCurrencyCache() {
+        _cachedCurrencySymbol = nil
+        currencySymbolCacheTime = nil
+    }
+
+    // MARK: - Formatting
+
+    var currencyString: String {
+        CurrencyFormatter.format(self, style: .currency, maximumFractionDigits: 2)
+    }
+
+    var compactCurrencyString: String {
+        CurrencyFormatter.format(self, style: .currency, maximumFractionDigits: 0)
+    }
+
+    var shortCurrencyString: String {
+        let value = NSDecimalNumber(decimal: self).doubleValue
+        let symbol = Self.cachedCurrencySymbol
+
+        switch Swift.abs(value) {
+        case 1_000_000...:
+            return String(format: "%@%.1fM", symbol, value / 1_000_000)
+        case 1_000...:
+            return String(format: "%@%.1fK", symbol, value / 1_000)
+        default:
+            return compactCurrencyString
+        }
+    }
+
+    var percentageString: String {
+        Self.percentFormatter.string(from: self as NSDecimalNumber) ?? "0%"
+    }
+
+    var signedPercentageString: String {
+        let prefix = self >= 0 ? "+" : ""
+        return prefix + percentageString
+    }
+
+    var decimalString: String {
+        Self.decimalFormatter.string(from: self as NSDecimalNumber) ?? "0"
+    }
+
+    // MARK: - Conversions
+
+    var doubleValue: Double {
+        NSDecimalNumber(decimal: self).doubleValue
+    }
+
+    var intValue: Int {
+        NSDecimalNumber(decimal: self).intValue
+    }
+
+    // MARK: - Math Operations
+
+    var abs: Decimal {
+        self < 0 ? -self : self
+    }
+
+    func rounded(scale: Int = 2) -> Decimal {
+        var result = Decimal()
+        var mutableSelf = self
+        NSDecimalRound(&result, &mutableSelf, scale, .plain)
+        return result
+    }
+
+    // MARK: - Comparisons
+
+    var isPositive: Bool {
+        self > 0
+    }
+
+    var isNegative: Bool {
+        self < 0
+    }
+
+    var isZero: Bool {
+        self == 0
+    }
+
+    // MARK: - Static Helpers
+
+    static func from(_ double: Double) -> Decimal {
+        Decimal(double)
+    }
+
+    static func from(_ string: String) -> Decimal? {
+        let formatter = NumberFormatter()
+        formatter.numberStyle = .decimal
+        return formatter.number(from: string)?.decimalValue
+    }
+}
+
+// MARK: - NSDecimalNumber Extension
+
+extension NSDecimalNumber {
+    var currencyString: String {
+        decimalValue.currencyString
+    }
+
+    var compactCurrencyString: String {
+        decimalValue.compactCurrencyString
+    }
+}
+
+// MARK: - Optional Decimal
+
+extension Optional where Wrapped == Decimal {
+    var orZero: Decimal {
+        self ?? Decimal.zero
+    }
+
+    var currencyString: String {
+        (self ?? Decimal.zero).currencyString
+    }
+}