import CoreImage
import CoreGraphics

// MARK: - SATURATION DETECTOR (Unlimited vs Revised)
class SaturationDetector {
    static func analyze(image: CGImage, orientation: CGImagePropertyOrientation = .up) -> Double {
        // Crop to center 50% to analyze artwork saturation, ignoring borders
        let ciImage = CIImage(cgImage: image).oriented(orientation)
        let width = ciImage.extent.width
        let height = ciImage.extent.height
        let cropRect = CGRect(x: width * 0.25, y: height * 0.25, width: width * 0.5, height: height * 0.5)

        let vector = CIVector(cgRect: cropRect)
        guard let filter = CIFilter(name: "CIAreaAverage", parameters: [kCIInputImageKey: ciImage, kCIInputExtentKey: vector]),
              let output = filter.outputImage else { return 0 }

        var bitmap = [UInt8](repeating: 0, count: 4)
        let context = SharedEngineResources.context
        context.render(output, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: .RGBA8, colorSpace: nil)

        // Simple Saturation approximation: (Max - Min) / Max
        let r = Double(bitmap[0]) / 255.0
        let g = Double(bitmap[1]) / 255.0
        let b = Double(bitmap[2]) / 255.0
        let maxC = max(r, max(g, b))
        let minC = min(r, min(g, b))

        return maxC == 0 ? 0 : (maxC - minC) / maxC
    }
}