import UIKit

public protocol RDEPUBReaderDisplayEnvironment: AnyObject {

    var currentBrightness: CGFloat { get set }

    var fallbackViewportSize: CGSize { get }
}

public final class RDEPUBUIScreenEnvironment: RDEPUBReaderDisplayEnvironment {
    public init() {}

    public var currentBrightness: CGFloat {
        get { CGFloat(UIScreen.main.brightness) }
        set { UIScreen.main.brightness = newValue }
    }

    public var fallbackViewportSize: CGSize {
        UIScreen.main.bounds.size
    }
}

public struct RDEPUBReaderDependencies {

    public var environment: any RDEPUBReaderDisplayEnvironment

    public var makeParser: () -> RDEPUBParser

    public var makePaginator: () -> RDEPUBPaginator

    public var makeTextBookBuilder: (RDEPUBTextRenderer, RDEPUBTextBookCache?, RDEPUBTextLayoutConfig) -> RDEPUBTextBookBuilder

    public var makePlainTextBookBuilder: (RDEPUBTextRenderer, RDEPUBTextLayoutConfig) -> RDPlainTextBookBuilder

    public var makeTextRenderer: (RDEPUBTextRenderingEngine) -> RDEPUBTextRenderer

    /// 自定义顶部工具栏工厂；nil 时使用内置 `RDEPUBReaderTopToolView`
    public var makeTopToolView: (() -> RDEPUBReaderTopToolViewProviding)?

    /// 自定义底部工具栏工厂；nil 时使用内置 `RDEPUBReaderBottomToolView`
    public var makeBottomToolView: (() -> RDEPUBReaderBottomToolViewProviding)?

    public init(
        environment: any RDEPUBReaderDisplayEnvironment,
        makeParser: @escaping () -> RDEPUBParser,
        makePaginator: @escaping () -> RDEPUBPaginator,
        makeTextBookBuilder: @escaping (RDEPUBTextRenderer, RDEPUBTextBookCache?, RDEPUBTextLayoutConfig) -> RDEPUBTextBookBuilder,
        makePlainTextBookBuilder: @escaping (RDEPUBTextRenderer, RDEPUBTextLayoutConfig) -> RDPlainTextBookBuilder,
        makeTextRenderer: @escaping (RDEPUBTextRenderingEngine) -> RDEPUBTextRenderer,
        makeTopToolView: (() -> RDEPUBReaderTopToolViewProviding)? = nil,
        makeBottomToolView: (() -> RDEPUBReaderBottomToolViewProviding)? = nil
    ) {
        self.environment = environment
        self.makeParser = makeParser
        self.makePaginator = makePaginator
        self.makeTextBookBuilder = makeTextBookBuilder
        self.makePlainTextBookBuilder = makePlainTextBookBuilder
        self.makeTextRenderer = makeTextRenderer
        self.makeTopToolView = makeTopToolView
        self.makeBottomToolView = makeBottomToolView
    }

    /// 构建带加密资源 provider 的默认依赖：
    /// 宿主实现 `RDEPUBResourceDataProvider` 后经此注入，即可打开单文件加密的 EPUB。
    /// - Parameter resourceDataProvider: 解密数据提供者；传 nil 等价于 `.live`
    public static func live(resourceDataProvider: RDEPUBResourceDataProvider?) -> RDEPUBReaderDependencies {
        var dependencies = RDEPUBReaderDependencies.live
        guard let resourceDataProvider else { return dependencies }
        dependencies.makeParser = {
            let parser = RDEPUBParser()
            parser.resourceDataProvider = resourceDataProvider
            return parser
        }
        return dependencies
    }

    public static var live: RDEPUBReaderDependencies {
        RDEPUBReaderDependencies(
            environment: RDEPUBUIScreenEnvironment(),
            makeParser: { RDEPUBParser() },
            makePaginator: { RDEPUBPaginator() },
            makeTextBookBuilder: { renderer, cache, layoutConfig in
                RDEPUBTextBookBuilder(renderer: renderer, cache: cache, layoutConfig: layoutConfig)
            },
            makePlainTextBookBuilder: { renderer, layoutConfig in
                RDPlainTextBookBuilder(renderer: renderer, layoutConfig: layoutConfig)
            },
            makeTextRenderer: { engine in
                switch engine {
                case .dtCoreText:
                    return RDEPUBDTCoreTextRenderer()
                }
            }
        )
    }
}