IFKaleidoscopeFilter.swift

import Foundation
import CoreImage
import UIKit

public final class IFKaleidoscopeFilter: IFFilterProtocol {
    public let id = "IFSKL01"
    public let name = "kaleidoscope"
    public let displayName = "Kaleidoscope"
    public let category = "Kaleidoscope"
    public let filterSet = "standard"
    public let order = 1

    public var amount: Float = 1.0 {
        didSet {
            amount = min(1.0, max(0.0, amount))
            // count: 2 (mirror) at low → 12 (mandala) at high
            let count = Int(2.0 + amount * 10.0)
            filter.setValue(count, forKey: "inputCount")
        }
    }

    private let filter: CIFilter
    private var context: CIContext { IFRenderContext.shared.ciContext }

    public init() {
        guard let filter = CIFilter(name: "CIKaleidoscope") else {
            fatalError("Failed to create CIKaleidoscope filter")
        }
        self.filter = filter
        filter.setValue(6, forKey: "inputCount")
        filter.setValue(0.0, forKey: kCIInputAngleKey)
    }

    public func apply(to image: CIImage) -> CIImage? {
        if amount == 0.0 { return image }
        let center = CIVector(x: image.extent.midX, y: image.extent.midY)
        filter.setValue(center, forKey: kCIInputCenterKey)
        filter.setValue(image, forKey: kCIInputImageKey)
        guard let outputImage = filter.outputImage else { return nil }
        return outputImage.cropped(to: image.extent)
    }

    public func generatePreview(from image: UIImage) -> UIImage {
        guard let ciImage = CIImage(image: image),
              let filteredImage = apply(to: ciImage),
              let cgImage = context.createCGImage(filteredImage, from: ciImage.extent) else {
            return image
        }
        return UIImage(cgImage: cgImage)
    }
}