// RDEPUBReaderDependencies.swift
// EPUB 阅读器依赖注入配置，定义显示环境协议与核心组件工厂

import UIKit

/// 阅读器显示环境协议，抽象屏幕亮度和视口尺寸以支持测试和多平台适配
public protocol RDEPUBReaderDisplayEnvironment: AnyObject {
    /// 当前屏幕亮度，取值范围 0.0 ~ 1.0
    var currentBrightness: CGFloat { get set }
    /// 后备视口尺寸，用于无法获取实际视图尺寸时的布局计算
    var fallbackViewportSize: CGSize { get }
}

/// 基于 UIScreen 的默认显示环境实现，直接读写系统屏幕亮度
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
    }
}

/// EPUB 阅读器核心依赖容器，通过工厂闭包注入各组件以便替换和测试
public struct RDEPUBReaderDependencies {
    /// 显示环境实例
    public var environment: any RDEPUBReaderDisplayEnvironment
    /// EPUB 解析器工厂
    public var makeParser: () -> RDEPUBParser
    /// 分页器工厂
    public var makePaginator: () -> RDEPUBPaginator
    /// 富文本书籍构建器工厂
    public var makeTextBookBuilder: (RDEPUBTextRenderer, RDEPUBTextBookCache?, RDEPUBTextLayoutConfig) -> RDEPUBTextBookBuilder
    /// 纯文本书籍构建器工厂
    public var makePlainTextBookBuilder: (RDEPUBTextRenderer, RDEPUBTextLayoutConfig) -> RDPlainTextBookBuilder
    /// 文本渲染器工厂
    public var makeTextRenderer: (RDEPUBTextRenderingEngine) -> RDEPUBTextRenderer

    /// 初始化依赖容器
    /// - Parameters:
    ///   - environment: 显示环境实例
    ///   - makeParser: EPUB 解析器工厂闭包
    ///   - makePaginator: 分页器工厂闭包
    ///   - makeTextBookBuilder: 富文本书籍构建器工厂闭包
    ///   - makePlainTextBookBuilder: 纯文本书籍构建器工厂闭包
    ///   - makeTextRenderer: 文本渲染器工厂闭包
    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
    ) {
        self.environment = environment
        self.makeParser = makeParser
        self.makePaginator = makePaginator
        self.makeTextBookBuilder = makeTextBookBuilder
        self.makePlainTextBookBuilder = makePlainTextBookBuilder
        self.makeTextRenderer = makeTextRenderer
    }

    /// 默认生产环境依赖，使用系统屏幕环境和标准组件实现
    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()
                }
            }
        )
    }
}