import UIKit

/// EPUB 阅读器运行时总协调器。
/// 统一持有并分发给加载、分页、定位、搜索、工具栏、批注、视口监测等子协调器，
/// 作为阅读器控制器的门面（Facade），简化外部调用。
final class RDEPUBReaderRuntime {
    private unowned let context: RDEPUBReaderContext

    lazy var loadCoordinator = RDEPUBReaderLoadCoordinator(context: context)
    lazy var paginationCoordinator = RDEPUBReaderPaginationCoordinator(context: context)
    lazy var locationCoordinator = RDEPUBReaderLocationCoordinator(context: context)
    lazy var searchCoordinator = RDEPUBReaderSearchCoordinator(context: context)
    lazy var chromeCoordinator = RDEPUBReaderChromeCoordinator(context: context)
    lazy var annotationCoordinator = RDEPUBReaderAnnotationCoordinator(context: context)
    lazy var viewportMonitor = RDEPUBReaderViewportMonitor(context: context)

    init(context: RDEPUBReaderContext) {
        self.context = context
    }

    /// 创建顶部工具栏视图
    func makeTopToolView() -> RDEPUBReaderTopToolView {
        chromeCoordinator.makeTopToolView()
    }

    /// 创建底部工具栏视图
    func makeBottomToolView() -> RDEPUBReaderBottomToolView {
        chromeCoordinator.makeBottomToolView()
    }

    /// 若尚未加载则启动首次加载流程
    func startInitialLoadIfNeeded() {
        loadCoordinator.startInitialLoadIfNeeded()
    }

    /// 重新加载当前书籍，清空解析器、分页、批注等状态后从头初始化
    func reloadBook() {
        guard let readerView = context.readerView else { return }
        context.didStartInitialLoad = false
        context.parser = nil
        context.publication = nil
        context.clearActiveSnapshot()
        context.readingSession = nil
        context.textBook = nil
        context.activeBookmarks = []
        context.activeHighlights = []
        context.searchState = nil
        viewportMonitor.resetForReload()
        annotationCoordinator.updateCurrentSelection(nil)
        readerView.reloadData()
        startInitialLoadIfNeeded()
    }

    /// 跳转到指定阅读位置
    /// - Parameters:
    ///   - location: 目标位置
    ///   - animated: 是否动画过渡
    /// - Returns: 跳转是否成功
    func go(to location: RDEPUBLocation, animated: Bool = false) -> Bool {
        locationCoordinator.restoreReadingLocation(location, animated: animated)
    }

    /// 跳转到指定页码
    /// - Parameters:
    ///   - pageNumber: 目标页码（从 1 开始）
    ///   - animated: 是否动画过渡
    /// - Returns: 跳转是否成功
    @discardableResult
    func go(toPageNumber pageNumber: Int, animated: Bool = false) -> Bool {
        guard let controller = context.controller,
              let readerView = context.readerView,
              pageNumber > 0 else {
            return false
        }

        if context.textBook != nil {
            guard let location = controller.resolvedTextLocation(forPageNumber: pageNumber) else {
                return false
            }
            return locationCoordinator.restoreReadingLocation(location, animated: animated)
        }

        guard context.activePages.indices.contains(pageNumber - 1) else {
            return false
        }
        readerView.transitionToPage(pageNum: pageNumber - 1, animated: animated)
        if let location = locationCoordinator.currentVisibleLocation() {
            context.persist(location: location)
        }
        return true
    }

    /// 清除当前选区
    func clearSelection() {
        annotationCoordinator.updateCurrentSelection(nil)
    }

    func bookmark(withID id: String) -> RDEPUBBookmark? {
        annotationCoordinator.bookmark(withID: id)
    }

    func highlight(withID id: String) -> RDEPUBHighlight? {
        annotationCoordinator.highlight(withID: id)
    }

    @discardableResult
    func addHighlight(
        from selection: RDEPUBSelection? = nil,
        color: String = "#F8E16C",
        note: String? = nil
    ) -> RDEPUBHighlight? {
        annotationCoordinator.addHighlight(from: selection, color: color, note: note)
    }

    @discardableResult
    func addAnnotation(
        from selection: RDEPUBSelection? = nil,
        style: RDEPUBHighlightStyle,
        color: String = "#F8E16C",
        note: String? = nil
    ) -> RDEPUBHighlight? {
        annotationCoordinator.addAnnotation(from: selection, style: style, color: color, note: note)
    }

    @discardableResult
    func upsertHighlight(_ highlight: RDEPUBHighlight) -> RDEPUBHighlight? {
        annotationCoordinator.upsertHighlight(highlight)
    }

    @discardableResult
    func removeHighlight(id: String) -> RDEPUBHighlight? {
        annotationCoordinator.removeHighlight(id: id)
    }

    @discardableResult
    func updateHighlightNote(id: String, note: String?) -> RDEPUBHighlight? {
        annotationCoordinator.updateHighlightNote(id: id, note: note)
    }

    @discardableResult
    func go(toHighlightID id: String, animated: Bool = true) -> Bool {
        annotationCoordinator.go(toHighlightID: id, animated: animated)
    }

    func removeAllHighlights() {
        annotationCoordinator.removeAllHighlights()
    }

    @discardableResult
    func addBookmark(note: String? = nil) -> RDEPUBBookmark? {
        annotationCoordinator.addBookmark(note: note)
    }

    @discardableResult
    func toggleBookmark(note: String? = nil) -> RDEPUBBookmark? {
        annotationCoordinator.toggleBookmark(note: note)
    }

    @discardableResult
    func removeBookmark(id: String) -> RDEPUBBookmark? {
        annotationCoordinator.removeBookmark(id: id)
    }

    @discardableResult
    func go(toBookmarkID id: String, animated: Bool = true) -> Bool {
        annotationCoordinator.go(toBookmarkID: id, animated: animated)
    }

    func updateBookmarkChrome() {
        annotationCoordinator.updateBookmarkChrome()
    }

    func presentBookmarksManager() {
        annotationCoordinator.presentBookmarksManager()
    }

    func presentHighlightsManager() {
        annotationCoordinator.presentHighlightsManager()
    }

    func presentAnnotationCreation() {
        annotationCoordinator.presentAnnotationCreation()
    }

    func handleSelectionMenuAction(_ action: RDEPUBAnnotationMenuAction, selection: RDEPUBSelection?) {
        annotationCoordinator.handleSelectionMenuAction(action, selection: selection)
    }

    /// 按关键词搜索全文
    func search(keyword: String) {
        searchCoordinator.search(keyword: keyword)
    }

    /// 跳转到下一个搜索匹配项
    @discardableResult
    func searchNext() -> Bool {
        searchCoordinator.searchNext()
    }

    /// 跳转到上一个搜索匹配项
    @discardableResult
    func searchPrevious() -> Bool {
        searchCoordinator.searchPrevious()
    }

    /// 清除搜索状态
    func clearSearch() {
        searchCoordinator.clearSearch()
    }

    func searchPresentation(for page: EPUBPage) -> RDEPUBSearchPresentation? {
        searchCoordinator.searchPresentation(for: page)
    }

    /// 更新阅读器工具栏显示状态
    func updateReaderChrome() {
        chromeCoordinator.updateReaderChrome()
    }

    /// 弹出阅读设置面板
    func presentSettings() {
        chromeCoordinator.presentSettings()
    }

    /// 弹出目录面板
    func presentTableOfContents() {
        chromeCoordinator.presentTableOfContents()
    }

    /// 处理返回操作
    func handleBackAction() {
        chromeCoordinator.handleBackAction()
    }

    /// 启动 Publication 加载流程
    func loadPublication() {
        loadCoordinator.loadPublication()
    }

    /// 将已解析的 Publication 应用到控制器
    func applyParsedPublication(
        parser: RDEPUBParser,
        publication: RDEPUBPublication,
        bookIdentifier: String,
        restoreLocation: RDEPUBLocation?,
        bookmarks: [RDEPUBBookmark],
        highlights: [RDEPUBHighlight]
    ) {
        loadCoordinator.applyParsedPublication(
            parser: parser,
            publication: publication,
            bookIdentifier: bookIdentifier,
            restoreLocation: restoreLocation,
            bookmarks: bookmarks,
            highlights: highlights
        )
    }

    /// 对 Publication 执行分页计算
    func paginatePublication(restoreLocation: RDEPUBLocation?) {
        paginationCoordinator.paginatePublication(restoreLocation: restoreLocation)
    }

    /// 应用外部 TextBook 并恢复阅读位置
    func applyTextBook(_ textBook: RDEPUBTextBook, restoreLocation: RDEPUBLocation?) {
        paginationCoordinator.applyTextBook(textBook, restoreLocation: restoreLocation)
    }

    /// 应用分页快照并恢复阅读位置
    func applyPaginationSnapshot(
        _ snapshot: (pages: [EPUBPage], chapters: [EPUBChapterInfo]),
        restoreLocation: RDEPUBLocation?
    ) {
        paginationCoordinator.applyPaginationSnapshot(snapshot, restoreLocation: restoreLocation)
    }

    /// 完成分页流程并恢复阅读位置
    func finishPagination(restoreLocation: RDEPUBLocation?) {
        paginationCoordinator.finishPagination(restoreLocation: restoreLocation)
    }

    /// 重新分页并保持当前阅读位置不变
    func repaginatePreservingCurrentLocation() {
        paginationCoordinator.repaginatePreservingCurrentLocation()
    }

    /// 刷新当前可见内容，保持阅读位置不变
    func refreshVisibleContentPreservingLocation() {
        paginationCoordinator.refreshVisibleContentPreservingLocation()
    }

    /// 重建外部 TextBook 数据
    func rebuildExternalTextBook() {
        paginationCoordinator.rebuildExternalTextBook()
    }

    /// 恢复到指定阅读位置
    @discardableResult
    func restoreReadingLocation(_ location: RDEPUBLocation, animated: Bool = false) -> Bool {
        locationCoordinator.restoreReadingLocation(location, animated: animated)
    }

    /// 获取当前可见页面的阅读位置
    func currentVisibleLocation() -> RDEPUBLocation? {
        locationCoordinator.currentVisibleLocation()
    }

    /// 获取当前视口签名快照
    func currentViewportSignature() -> RDEPUBViewportSignature? {
        viewportMonitor.currentViewportSignature()
    }

    /// 视口变化时检查是否需要重新分页
    func handleViewportChangeIfNeeded(
        reason: RDEPUBViewportChangeReason,
        viewportSignature: RDEPUBViewportSignature? = nil
    ) {
        viewportMonitor.handleViewportChangeIfNeeded(reason: reason, viewportSignature: viewportSignature)
    }
}