import UIKit

public struct RDEPUBNavigatorLayoutContext: Equatable {

    public var containerSize: CGSize

    public var pagesPerScreen: Int

    public var safeAreaInsets: UIEdgeInsets

    public var userInterfaceIdiom: UIUserInterfaceIdiom

    public var reflowableContentInsets: UIEdgeInsets

    public init(
        containerSize: CGSize,
        pagesPerScreen: Int = 1,
        safeAreaInsets: UIEdgeInsets = .zero,
        userInterfaceIdiom: UIUserInterfaceIdiom = .phone,
        reflowableContentInsets: UIEdgeInsets = RDEPUBSafeArea.defaultReflowableContentInsets()
    ) {
        self.containerSize = containerSize
        self.pagesPerScreen = max(1, pagesPerScreen)
        self.safeAreaInsets = safeAreaInsets
        self.userInterfaceIdiom = userInterfaceIdiom
        self.reflowableContentInsets = reflowableContentInsets
    }

    public var viewportSize: CGSize {
        let width: CGFloat
        if pagesPerScreen > 1 {
            width = containerSize.width / CGFloat(pagesPerScreen)
        } else {
            width = containerSize.width
        }
        return CGSize(width: width, height: containerSize.height)
    }

    /// Content insets that account for safe area (Dynamic Island / notch) on iPhone.
    /// Uses the larger of safeAreaInsets and reflowableContentInsets for top/bottom
    /// to ensure content is never hidden under the Dynamic Island or home indicator.
    public var safeReflowableContentInsets: UIEdgeInsets {
        let top = max(safeAreaInsets.top, reflowableContentInsets.top)
        let bottom = max(safeAreaInsets.bottom, reflowableContentInsets.bottom)
        let left = max(safeAreaInsets.left, reflowableContentInsets.left)
        let right = max(safeAreaInsets.right, reflowableContentInsets.right)
        return UIEdgeInsets(top: top, left: left, bottom: bottom, right: right)
    }

    /// Fixed layout content insets that respect safe areas on all devices including iPhone.
    public var fixedContentInset: UIEdgeInsets {
        var insets = safeAreaInsets
        let horizontalInsets = max(insets.left, insets.right)
        insets.left = horizontalInsets
        insets.right = horizontalInsets
        return insets
    }
}