//
//  RDReaderView+ToolView.swift
//  ReadViewSDK
//
//  文件职责：工具栏管理扩展，处理工具栏的显示/隐藏动画、安装和布局约束。
//

import UIKit

/// 工具栏管理扩展：处理工具栏的显示/隐藏动画、安装、布局
extension RDReaderView {

    /// 点击屏幕中央区域，切换工具栏的显示/隐藏，带动画效果
    func tapCenter() {
        refreshToolViewsFromProviderIfNeeded()
        isShowToolView = !isShowToolView
        if isShowToolView {
            if let topToolView = topToolView {
                installToolViewIfNeeded(topToolView, position: .top)
                layoutIfNeeded()
                topToolView.transform = CGAffineTransform(translationX: 0, y: -topToolView.bounds.height)
                UIView.animate(withDuration: toolViewAnimationDuration) {
                    topToolView.transform = .identity
                }
            }

            if let bottomToolView = bottomToolView {
                installToolViewIfNeeded(bottomToolView, position: .bottom)
                layoutIfNeeded()
                bottomToolView.transform = CGAffineTransform(translationX: 0, y: bottomToolView.bounds.height)
                UIView.animate(withDuration: toolViewAnimationDuration) {
                    bottomToolView.transform = .identity
                }
            }

            collectionView.isUserInteractionEnabled = false
            pageViewController.view.isUserInteractionEnabled = false
        } else {
            if let topToolView = topToolView {
                UIView.animate(withDuration: toolViewAnimationDuration, animations: {
                    topToolView.transform = CGAffineTransform(translationX: 0, y: -topToolView.bounds.height)
                }) { _ in
                    topToolView.removeFromSuperview()
                }
            }

            if let bottomToolView = bottomToolView {
                UIView.animate(withDuration: toolViewAnimationDuration, animations: {
                    bottomToolView.transform = CGAffineTransform(translationX: 0, y: bottomToolView.bounds.height)
                }) { _ in
                    bottomToolView.removeFromSuperview()
                }
            }

            collectionView.isUserInteractionEnabled = true
            pageViewController.view.isUserInteractionEnabled = true
        }
        onToolViewVisibilityChanged?(isShowToolView)
    }

    /// 判断点击命中的视图是否在指定工具栏内，用于决定是否拦截点击事件
    func isHitView(_ hitView: UIView?, inside toolView: UIView, point: CGPoint) -> Bool {
        if toolView.frame.contains(point) {
            return true
        }

        guard let hitView else { return false }
        return hitView === toolView || hitView.isDescendant(of: toolView)
    }

    /// 工具栏位置枚举
    enum ToolViewPosition {
        /// 顶部工具栏（如标题栏、导航栏）
        case top
        /// 底部工具栏（如进度条、操作按钮）
        case bottom
    }

    /// 将工具栏安装到指定位置并设置布局约束，已安装则跳过
    func installToolViewIfNeeded(_ toolView: UIView, position: ToolViewPosition) {
        guard toolView.superview !== self else { return }

        toolView.removeFromSuperview()
        addSubview(toolView)
        toolView.translatesAutoresizingMaskIntoConstraints = false

        let heightConstraint: NSLayoutConstraint
        switch position {
        case .top:
            topToolViewHeightConstraint?.isActive = false
            heightConstraint = toolView.heightAnchor.constraint(equalToConstant: resolvedToolViewHeight(for: .top))
            topToolViewHeightConstraint = heightConstraint
            NSLayoutConstraint.activate([
                toolView.leadingAnchor.constraint(equalTo: leadingAnchor),
                toolView.trailingAnchor.constraint(equalTo: trailingAnchor),
                toolView.topAnchor.constraint(equalTo: topAnchor),
                heightConstraint
            ])
        case .bottom:
            bottomToolViewHeightConstraint?.isActive = false
            heightConstraint = toolView.heightAnchor.constraint(equalToConstant: resolvedToolViewHeight(for: .bottom))
            bottomToolViewHeightConstraint = heightConstraint
            NSLayoutConstraint.activate([
                toolView.leadingAnchor.constraint(equalTo: leadingAnchor),
                toolView.trailingAnchor.constraint(equalTo: trailingAnchor),
                toolView.bottomAnchor.constraint(equalTo: bottomAnchor),
                heightConstraint
            ])
        }
    }

    /// 更新顶部和底部工具栏的高度约束，通常在 safeAreaInsets 变化时调用
    func updateToolViewHeightConstraintsIfNeeded() {
        topToolViewHeightConstraint?.constant = resolvedToolViewHeight(for: .top)
        bottomToolViewHeightConstraint?.constant = resolvedToolViewHeight(for: .bottom)
    }

    private func resolvedToolViewHeight(for position: ToolViewPosition) -> CGFloat {
        let contentHeight: CGFloat = 52
        switch position {
        case .top:
            return safeAreaInsets.top + contentHeight
        case .bottom:
            return safeAreaInsets.bottom + contentHeight
        }
    }
}