import UIKit

final class RDEPUBReaderEnvironment {

    weak var controller: RDEPUBReaderController?

    weak var readerView: RDReaderView?

    var displayEnvironment: any RDEPUBReaderDisplayEnvironment

    init(
        controller: RDEPUBReaderController,
        readerView: RDReaderView,
        displayEnvironment: any RDEPUBReaderDisplayEnvironment
    ) {
        self.controller = controller
        self.readerView = readerView
        self.displayEnvironment = displayEnvironment
    }

    func currentLayoutContext(configuration: RDEPUBReaderConfiguration) -> RDEPUBNavigatorLayoutContext {
        let containerSize = readerView?.bounds.size ?? .zero
        let viewSize = controller?.view.bounds.size ?? containerSize
        let resolvedSize = containerSize == .zero ? viewSize : containerSize
        return RDEPUBNavigatorLayoutContext(
            containerSize: resolvedSize,
            pagesPerScreen: readerView?.pagesPerScreen ?? 1,
            safeAreaInsets: controller?.view.safeAreaInsets ?? .zero,
            userInterfaceIdiom: controller?.traitCollection.userInterfaceIdiom ?? .phone,
            reflowableContentInsets: configuration.reflowableContentInsets
        )
    }

    func currentTextRenderStyle(configuration: RDEPUBReaderConfiguration) -> RDEPUBTextRenderStyle {
        let font = configuration.fontChoice.font(ofSize: configuration.fontSize)
        let lineSpacing = max(font.lineHeight * (configuration.lineHeightMultiple - 1), 4)
        return RDEPUBTextRenderStyle(
            font: font,
            lineSpacing: lineSpacing,
            textColor: configuration.theme.contentTextColor,
            backgroundColor: configuration.theme.contentBackgroundColor
        )
    }

    func currentTextLayoutConfig(
        configuration: RDEPUBReaderConfiguration,
        pageSize: CGSize
    ) -> RDEPUBTextLayoutConfig {
        RDEPUBTextLayoutConfig(
            frameWidth: max(pageSize.width, 1),
            frameHeight: max(pageSize.height, 1),
            edgeInsets: configuration.reflowableContentInsets,
            numberOfColumns: configuration.numberOfColumns,
            columnGap: configuration.columnGap,
            avoidOrphans: false,
            avoidWidows: false,
            avoidPageBreakInsideEnabled: true,
            hyphenation: true,
            imageMaxHeightRatio: 0.85,
            fallbackViewportSize: displayEnvironment.fallbackViewportSize
        )
    }

    var currentBrightness: CGFloat {
        get { displayEnvironment.currentBrightness }
        set { displayEnvironment.currentBrightness = newValue }
    }

    var fallbackViewportSize: CGSize {
        displayEnvironment.fallbackViewportSize
    }
}