import CoreImage
import CoreGraphics

// MARK: - BORDER DETECTOR
class BorderDetector {
    enum BorderColor { case black, white, gold, other }

    static func detect(image: CGImage, orientation: CGImagePropertyOrientation = .up) -> BorderColor {
        let context = SharedEngineResources.context
        let ciImage = CIImage(cgImage: image).oriented(orientation)
        let width = ciImage.extent.width
        let height = ciImage.extent.height

        // Crop a small strip from the left edge
        let cropRect = CGRect(x: CGFloat(width) * 0.02, y: CGFloat(height) * 0.4, width: CGFloat(width) * 0.05, height: CGFloat(height) * 0.2)
        let vector = CIVector(cgRect: cropRect)
        let filter = CIFilter(name: "CIAreaAverage", parameters: [kCIInputImageKey: ciImage, kCIInputExtentKey: vector])

        guard let output = filter?.outputImage else { return .other }
        var bitmap = [UInt8](repeating: 0, count: 4)
        context.render(output, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: .RGBA8, colorSpace: nil)

        let r = Int(bitmap[0])
        let g = Int(bitmap[1])
        let b = Int(bitmap[2])
        let brightness = (r + g + b) / 3

        // Gold/Yellow detection (World Champ Decks): High Red/Green, Low Blue
        if r > 140 && g > 120 && b < 100 && r > b + 40 { return .gold }

        if brightness < 60 { return .black }
        if brightness > 180 { return .white }
        return .other
    }
}