import UIKit

public struct RDEPUBTextRenderStyle {
    public var font: UIFont
    public var lineSpacing: CGFloat
    public var textColor: UIColor?
    public var backgroundColor: UIColor?

    public init(font: UIFont, lineSpacing: CGFloat, textColor: UIColor? = nil, backgroundColor: UIColor? = nil) {
        self.font = font
        self.lineSpacing = lineSpacing
        self.textColor = textColor
        self.backgroundColor = backgroundColor
    }
}

public struct RDEPUBRenderedChapterContent {
    public var attributedString: NSAttributedString
    public var fragmentOffsets: [String: Int]

    public init(attributedString: NSAttributedString, fragmentOffsets: [String: Int]) {
        self.attributedString = attributedString
        self.fragmentOffsets = fragmentOffsets
    }
}

public protocol RDEPUBTextRenderer {
    func renderChapter(
        html: String,
        baseURL: URL?,
        style: RDEPUBTextRenderStyle
    ) throws -> RDEPUBRenderedChapterContent
}

public enum RDEPUBTextRenderingError: LocalizedError {
    case htmlEncodingFailed
    case htmlImportFailed

    public var errorDescription: String? {
        switch self {
        case .htmlEncodingFailed:
            return "HTML 编码失败"
        case .htmlImportFailed:
            return "HTML 富文本导入失败"
        }
    }
}