import UIKit

/// EPUB 阅读器 Chrome 协调器：负责顶部/底部工具栏的创建、更新和交互处理。
///
/// 职责：
/// - 创建并配置顶部工具栏（返回、书签按钮）
/// - 创建并配置底部工具栏（目录、书签、高亮、设置按钮）
/// - 同步工具栏的主题和状态
/// - 弹出设置面板和目录面板
/// - 处理返回按钮的关闭逻辑
final class RDEPUBReaderChromeCoordinator {
    private unowned let context: RDEPUBReaderContext

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

    private var controller: RDEPUBReaderController? {
        context.controller
    }

    /// 创建顶部工具栏视图，绑定返回、搜索和书签切换回调。
    func makeTopToolView() -> RDEPUBReaderTopToolView {
        let toolView = RDEPUBReaderTopToolView()
        toolView.onBack = { [weak self] in
            self?.handleBackAction()
        }
        toolView.onSearch = { [weak self] in
            self?.toggleSearchBar()
        }
        toolView.onToggleBookmark = { [weak self] in
            _ = self?.context.runtime?.toggleBookmark()
        }
        return toolView
    }

    /// 创建底部工具栏视图，绑定目录、书签、高亮、设置等回调。
    func makeBottomToolView() -> RDEPUBReaderBottomToolView {
        let toolView = RDEPUBReaderBottomToolView()
        toolView.onShowTableOfContents = { [weak self] in
            self?.presentTableOfContents()
        }
        toolView.onShowBookmarks = { [weak self] in
            self?.context.runtime?.presentBookmarksManager()
        }
        toolView.onShowHighlights = { [weak self] in
            self?.context.runtime?.presentHighlightsManager()
        }
        toolView.onAddHighlight = { [weak self] in
            self?.context.runtime?.presentAnnotationCreation()
        }
        toolView.onShowSettings = { [weak self] in
            self?.presentSettings()
        }
        return toolView
    }

    /// 同步更新顶部和底部工具栏的主题、标题、按钮可用性等状态。
    func updateReaderChrome() {
        guard let controller else { return }
        controller.topToolView.apply(theme: controller.configuration.theme)
        controller.topToolView.setTitle(
            controller.title
                ?? controller.parser?.metadata.title
                ?? controller.epubURL.deletingPathExtension().lastPathComponent
        )
        controller.topToolView.setBookmarkEnabled(controller.currentBookIdentifier != nil)
        controller.bottomToolView.apply(theme: controller.configuration.theme)
        controller.bottomToolView.updateVisibility(
            showsTableOfContents: controller.configuration.showsTableOfContents,
            allowsHighlights: controller.configuration.allowsHighlights,
            showsSettingsPanel: controller.configuration.showsSettingsPanel
        )
        controller.bottomToolView.setBookmarksEnabled(!controller.activeBookmarks.isEmpty)
        controller.bottomToolView.setAddHighlightEnabled(
            controller.configuration.allowsHighlights && controller.currentSelection != nil
        )
        controller.bottomToolView.setHighlightsEnabled(
            controller.configuration.allowsHighlights && !controller.activeHighlights.isEmpty
        )
        controller.updateBookmarkChrome()
        updateSearchBar()
    }

    /// 弹出阅读设置面板（字号、字体、行距、分栏、主题、亮度等）。
    func presentSettings() {
        guard let controller else { return }
        guard controller.configuration.showsSettingsPanel else { return }
        let settingsController = RDEPUBReaderSettingsViewController(
            configuration: controller.configuration,
            brightness: controller.currentBrightness
        )
        settingsController.onBrightnessChange = { [weak controller] brightness in
            controller?.setScreenBrightness(brightness)
        }
        settingsController.onFontSizeChange = { [weak controller] fontSize in
            controller?.updateConfiguration { $0.fontSize = fontSize }
        }
        settingsController.onFontChoiceChange = { [weak controller] fontChoice in
            controller?.updateConfiguration { $0.fontChoice = fontChoice }
        }
        settingsController.onLineHeightChange = { [weak controller] lineHeightMultiple in
            controller?.updateConfiguration { $0.lineHeightMultiple = lineHeightMultiple }
        }
        settingsController.onColumnCountChange = { [weak controller] numberOfColumns in
            controller?.updateConfiguration { $0.numberOfColumns = numberOfColumns }
        }
        settingsController.onDisplayTypeChange = { [weak controller] displayType in
            controller?.updateConfiguration { $0.displayType = displayType }
        }
        settingsController.onThemeChange = { [weak controller] theme in
            controller?.updateConfiguration { $0.theme = theme }
        }

        let navigationController = UINavigationController(rootViewController: settingsController)
        navigationController.modalPresentationStyle = .pageSheet
        controller.present(navigationController, animated: true)
    }

    /// 弹出目录列表面板，支持点击跳转到指定章节。
    func presentTableOfContents() {
        guard let controller else { return }
        guard controller.configuration.showsTableOfContents else { return }
        let items = controller.flattenedTableOfContentsItems(
            from: controller.publication?.tableOfContents ?? [],
            includePageNumbers: false
        )
        guard !items.isEmpty else { return }

        let chapterController = RDEPUBReaderChapterListController(
            items: items,
            currentItem: controller.currentTableOfContentsItem,
            theme: controller.configuration.theme
        )
        chapterController.onSelectItem = { [weak controller] item in
            guard let controller else { return }
            chapterController.dismiss(animated: true) {
                _ = controller.go(toTableOfContentsItem: item, animated: true)
            }
        }

        let navigationController = UINavigationController(rootViewController: chapterController)
        navigationController.modalPresentationStyle = .pageSheet
        controller.present(navigationController, animated: true)
    }

    /// 切换搜索栏的显示/隐藏状态。
    func toggleSearchBar() {
        guard let controller else { return }
        if controller.isSearchBarVisible {
            controller.hideSearchBar()
        } else {
            controller.showSearchBar()
        }
    }

    /// 同步搜索栏的主题和匹配计数。
    func updateSearchBar() {
        guard let controller else { return }
        controller.searchBarView.apply(theme: controller.configuration.theme)
        if let searchState = controller.searchState {
            if let index = searchState.currentMatchIndex {
                controller.searchBarView.updateMatchCount(current: index + 1, total: searchState.matches.count)
            } else if searchState.matches.isEmpty {
                controller.searchBarView.showNoResults()
            }
        }
    }

    /// 处理返回按钮点击，自动判断 pop 或 dismiss 方式关闭阅读器。
    func handleBackAction() {
        guard let controller else { return }
        close(controller)
    }

    private func close(_ controller: UIViewController) {
        let target = closestDismissTarget(from: controller)
        if let navigationController = target.navigationController,
           navigationController.viewControllers.first !== target {
            navigationController.popViewController(animated: true)
            return
        }

        if let navigationController = target.navigationController,
           navigationController.presentingViewController != nil {
            navigationController.dismiss(animated: true)
            return
        }

        if target.presentingViewController != nil {
            target.dismiss(animated: true)
            return
        }

        controller.dismiss(animated: true)
    }

    private func closestDismissTarget(from controller: UIViewController) -> UIViewController {
        var candidate: UIViewController = controller
        var current = controller.parent
        while let parent = current {
            if let navigationController = parent.navigationController,
               navigationController.viewControllers.contains(parent) {
                return parent
            }
            if parent.presentingViewController != nil || parent.navigationController?.presentingViewController != nil {
                return parent
            }
            candidate = parent
            current = parent.parent
        }
        return candidate
    }
}