import UIKit

public enum RDEPUBTextRenderingEngine: Equatable {

    case dtCoreText
}

public enum RDEPUBReaderFontChoice: String, Codable, CaseIterable, Equatable {

    case system

    case serif

    case rounded

    case monospaced

    public var displayName: String {
        switch self {
        case .system:
            return "系统"
        case .serif:
            return "宋体"
        case .rounded:
            return "圆体"
        case .monospaced:
            return "等宽"
        }
    }

    public func font(ofSize size: CGFloat) -> UIFont {
        switch self {
        case .system:
            return UIFont.systemFont(ofSize: size)
        case .serif:
            let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
                .withDesign(.serif) ?? UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
            return UIFont(descriptor: descriptor, size: size)
        case .rounded:
            let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
                .withDesign(.rounded) ?? UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
            return UIFont(descriptor: descriptor, size: size)
        case .monospaced:
            return UIFont.monospacedSystemFont(ofSize: size, weight: .regular)
        }
    }
}

public struct RDEPUBReaderConfiguration: Equatable {

    public var fontSize: CGFloat

    public var lineHeightMultiple: CGFloat

    public var fontChoice: RDEPUBReaderFontChoice

    public var numberOfColumns: Int

    public var columnGap: CGFloat

    public var displayType: RDReaderView.DisplayType

    public var landscapeDualPageEnabled: Bool

    public var showsTableOfContents: Bool

    public var allowsHighlights: Bool

    public var showsSettingsPanel: Bool

    public var reflowableContentInsets: UIEdgeInsets

    public var fixedContentInset: UIEdgeInsets

    public var theme: RDEPUBReaderTheme

    public var darkImageAdjustmentEnabled: Bool

    public var darkImageBlendRatio: CGFloat

    public var fixedLayoutFit: RDEPUBFixedLayoutFit

    public var fixedLayoutSpreadMode: RDEPUBFixedLayoutSpreadMode

    public var textRenderingEngine: RDEPUBTextRenderingEngine

    public var onDemandChapterWindowSize: Int

    public var metadataParsingConcurrency: Int

    public var jumpSessionPolicy: RDEPUBJumpSessionPolicy

    public var allowedExternalURLSchemes: Set<String>

    public var requiresExternalLinkConfirmation: Bool

    public var allowsInspectableWebViews: Bool

    public var enablesVerboseWebViewLogging: Bool

    public init(
        fontSize: CGFloat = 15,
        lineHeightMultiple: CGFloat = 1.6,
        fontChoice: RDEPUBReaderFontChoice = .system,
        numberOfColumns: Int = 1,
        columnGap: CGFloat = 20,
        displayType: RDReaderView.DisplayType = .pageCurl,
        landscapeDualPageEnabled: Bool = true,
        showsTableOfContents: Bool = true,
        allowsHighlights: Bool = true,
        showsSettingsPanel: Bool = true,
        reflowableContentInsets: UIEdgeInsets = UIEdgeInsets(top: 40, left: 16, bottom: 40, right: 16),
        fixedContentInset: UIEdgeInsets = .zero,
        theme: RDEPUBReaderTheme = .light,
        darkImageAdjustmentEnabled: Bool = true,
        darkImageBlendRatio: CGFloat = 0.15,
        fixedLayoutFit: RDEPUBFixedLayoutFit = .page,
        fixedLayoutSpreadMode: RDEPUBFixedLayoutSpreadMode = .automatic,
        textRenderingEngine: RDEPUBTextRenderingEngine = .dtCoreText,
        onDemandChapterWindowSize: Int = 3,
        metadataParsingConcurrency: Int = ProcessInfo.processInfo.activeProcessorCount,
        jumpSessionPolicy: RDEPUBJumpSessionPolicy = .default,
        allowedExternalURLSchemes: Set<String> = ["https"],
        requiresExternalLinkConfirmation: Bool = true,
        allowsInspectableWebViews: Bool = false,
        enablesVerboseWebViewLogging: Bool = false
    ) {
        self.fontSize = fontSize
        self.lineHeightMultiple = lineHeightMultiple
        self.fontChoice = fontChoice
        self.numberOfColumns = max(1, numberOfColumns)
        self.columnGap = max(0, columnGap)
        self.displayType = displayType
        self.landscapeDualPageEnabled = landscapeDualPageEnabled
        self.showsTableOfContents = showsTableOfContents
        self.allowsHighlights = allowsHighlights
        self.showsSettingsPanel = showsSettingsPanel
        self.reflowableContentInsets = reflowableContentInsets
        self.fixedContentInset = fixedContentInset
        self.theme = theme
        self.darkImageAdjustmentEnabled = darkImageAdjustmentEnabled
        self.darkImageBlendRatio = max(0, min(0.35, darkImageBlendRatio))
        self.fixedLayoutFit = fixedLayoutFit
        self.fixedLayoutSpreadMode = fixedLayoutSpreadMode
        self.textRenderingEngine = textRenderingEngine
        self.onDemandChapterWindowSize = Self.normalizedChapterWindowSize(onDemandChapterWindowSize)
        self.metadataParsingConcurrency = max(1, metadataParsingConcurrency)
        self.jumpSessionPolicy = jumpSessionPolicy
        self.allowedExternalURLSchemes = allowedExternalURLSchemes
        self.requiresExternalLinkConfirmation = requiresExternalLinkConfirmation
        self.allowsInspectableWebViews = allowsInspectableWebViews
        self.enablesVerboseWebViewLogging = enablesVerboseWebViewLogging
    }

    public static let `default` = RDEPUBReaderConfiguration()
}

extension RDEPUBReaderConfiguration {

    static func normalizedChapterWindowSize(_ size: Int) -> Int {
        let clamped = max(3, min(15, size))
        return clamped % 2 == 0 ? clamped + 1 : clamped
    }

    var chapterWindowRadius: Int {
        onDemandChapterWindowSize / 2
    }
}

extension RDEPUBReaderConfiguration {

    func makePreferences() -> RDEPUBPreferences {
        RDEPUBPreferences(
            fontSize: fontSize,
            lineHeightMultiple: lineHeightMultiple,
            reflowableContentInsets: reflowableContentInsets,
            fixedContentInset: fixedContentInset,
            numberOfColumns: numberOfColumns,
            columnGap: columnGap,
            themeBackgroundColor: theme.themeBackgroundColorCSS,
            themeTextColor: theme.themeTextColorCSS,
            fixedBackgroundColor: theme.themeBackgroundColorCSS,
            fixedLayoutFit: fixedLayoutFit,
            fixedLayoutSpreadMode: fixedLayoutSpreadMode
        )
    }
}