import UIKit

final class RDEPUBSelectionLoupeView: UIView {

    private let imageView = UIImageView()

    private let magnification: CGFloat = 1.45

    private let captureSize = CGSize(width: 84, height: 84)

    override init(frame: CGRect) {
        super.init(frame: CGRect(origin: .zero, size: CGSize(width: 96, height: 96)))
        isUserInteractionEnabled = false
        backgroundColor = .clear
        layer.shadowColor = UIColor.black.cgColor
        layer.shadowOpacity = 0.18
        layer.shadowRadius = 10
        layer.shadowOffset = CGSize(width: 0, height: 5)

        imageView.frame = bounds
        imageView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        imageView.layer.cornerRadius = bounds.width / 2
        imageView.layer.cornerCurve = .continuous
        imageView.layer.borderWidth = 1.5
        imageView.layer.borderColor = UIColor(white: 0.82, alpha: 0.95).cgColor
        imageView.clipsToBounds = true
        addSubview(imageView)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func present(sourceView: UIView, focusPoint: CGPoint, hostBounds: CGRect, targetPoint: CGPoint) {
        imageView.image = snapshot(from: sourceView, focusPoint: focusPoint)

        let targetCenter = CGPoint(
            x: min(max(targetPoint.x, hostBounds.minX + bounds.width / 2), hostBounds.maxX - bounds.width / 2),
            y: min(
                max(hostBounds.minY + bounds.height / 2, targetPoint.y - 74),
                hostBounds.maxY - bounds.height / 2
            )
        )

        center = targetCenter
        if isHidden {
            alpha = 0
            transform = CGAffineTransform(scaleX: 0.92, y: 0.92)
            isHidden = false
            UIView.animate(withDuration: 0.12) {
                self.alpha = 1
                self.transform = .identity
            }
        }
    }

    func dismiss() {
        guard !isHidden else { return }
        isHidden = true
        alpha = 0
        imageView.image = nil
    }

    private func snapshot(from sourceView: UIView, focusPoint: CGPoint) -> UIImage {
        let renderer = UIGraphicsImageRenderer(size: captureSize)
        return renderer.image { context in
            let cgContext = context.cgContext
            cgContext.setFillColor(UIColor.systemBackground.cgColor)
            cgContext.fill(CGRect(origin: .zero, size: captureSize))
            cgContext.translateBy(
                x: captureSize.width / 2 - focusPoint.x * magnification,
                y: captureSize.height / 2 - focusPoint.y * magnification
            )
            cgContext.scaleBy(x: magnification, y: magnification)
            sourceView.layer.render(in: cgContext)
        }
    }
}