import UIKit

#if canImport(DTCoreText)
import DTCoreText

/// 基于 DTCoreText 的 Core Text 直接绘制视图
/// 将 DTCoreText 的排版结果直接绘制到 UIView 上，跳过 UITextView 的间接渲染。
final class RDEPUBTextPageRenderView: UIView {
    var layoutFrame: DTCoreTextLayoutFrame? {
        didSet {
            setNeedsDisplay()
        }
    }

    var drawOptions: DTCoreTextLayoutFrameDrawingOptions = DTCoreTextLayoutFrameDrawingOptions(rawValue: 1)! {
        didSet {
            setNeedsDisplay()
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        isOpaque = false
        contentMode = .redraw
    }

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

    override func draw(_ rect: CGRect) {
        guard let context = UIGraphicsGetCurrentContext(),
              let layoutFrame else { return }

        context.saveGState()
        layoutFrame.draw(in: context, options: drawOptions)
        context.restoreGState()
    }
}
#endif