Parse hsv colors

Sources/LibMakeColors/Model/Scanner+ColorParser.swift

@@ -31,9 +31,58 @@ extension Scanner {
             return Color(white: arguments)
         }
 
+        if string("hsva") {
+            return readHSV(alpha: true)
+        }
+
+        if string("hsv") {
+            return readHSV(alpha: false)
+        }
+
         return nil
     }
 
+    private func readHSV(alpha readAlpha: Bool) -> Color? {
+        guard
+            string("("),
+            let hue = degrees(),
+            string(","),
+            let saturation = component(),
+            string(","),
+            let value = component()
+        else { return nil }
+
+        let alpha: UInt8
+
+        if readAlpha {
+            guard
+                string(","),
+                let value = component()
+            else { return nil }
+            alpha = value
+        } else {
+            alpha = 0xFF
+        }
+
+        guard string(")") else { return nil }
+
+        return Color(hue: hue, saturation: saturation, value: value, alpha: alpha)
+    }
+
+    func degrees() -> Int? {
+        guard let int = scanInt() else { return nil }
+
+        if string("%") {
+            guard 0...100 ~= int else { return nil }
+            return (360 * int) / 100
+        } else if string("°") || string("deg") {
+            return int
+        } else {
+            guard 0...0xFF ~= int else { return nil }
+            return (360 * int) / 0xFF
+        }
+    }
+
     func colorReference() -> String? {
         guard string("@") else { return nil }
         return name()

Tests/MakeColorsTests/ColorParserTest.swift

@@ -86,8 +86,38 @@ final class ColorParserTest: XCTestCase {
         XCTAssertTrue(scanner.isAtEnd)
     }
 
+    func testScanningDegreesAsByte() throws {
+        let scanner = Scanner(string: "128")
+        XCTAssertEqual(scanner.degrees(), 180)
+    }
+
+    func testScanningDegreesAsPercentage() throws {
+        let scanner = Scanner(string: "50%")
+        XCTAssertEqual(scanner.degrees(), 180)
+    }
+
+    func testScanningDegrees() throws {
+        let scanner = Scanner(string: "120°")
+        XCTAssertEqual(scanner.degrees(), 120)
+    }
+
+    func testScanningDegreesWithDegSuffix() throws {
+        let scanner = Scanner(string: "120 deg")
+        XCTAssertEqual(scanner.degrees(), 120)
+    }
+
+    func testScanningHSVColor() throws {
+        XCTAssertEqual(scanColor("hsv(60°, 255, 100%)"), Color(red: 0xFF, green: 0xFF, blue: 0))
+    }
+
+    func testScanningHSVAColor() throws {
+        XCTAssertEqual(scanColor("hsva(60°, 50%, 255, 99)"), Color(red: 0xFF, green: 0xFF, blue: 128, alpha: 99))
+    }
+
     private func scanColor(_ input: String) -> Color? {
         let scanner = Scanner(string: input)
-        return scanner.color()
+        let result = scanner.color()
+        XCTAssertTrue(result == nil || scanner.isAtEnd)
+        return result
     }
 }