Attractor/SBrowser/Browser View/BrowserView.swift

//
//  BrowserView.swift
//  SBrowser
//
//  Created by James Magahern on 7/21/20.
//

import Combine
import UIKit
import WebKit

class BrowserView: UIView
{
    let titlebarView = TitlebarView()
    
    var toolbarView: ToolbarView? {
        didSet { addSubview(toolbarView!) }
    }
    
    var webView: WKWebView? {
        didSet {
            if let toolbarView = toolbarView {
                insertSubview(webView!, belowSubview: toolbarView)
            } else {
                addSubview(webView!)
            }
        }
    }
    
    var keyboardWillShowObserver: AnyCancellable?
    var keyboardWillHideObserver: AnyCancellable?
    var keyboardLayoutOffset: CGFloat = 0 { didSet { setNeedsLayout() } }
    
    convenience init() {
        self.init(frame: .zero)
        
        addSubview(titlebarView)
        
        keyboardWillShowObserver = NotificationCenter.default.publisher(for: UIWindow.keyboardWillShowNotification).sink { notification in
            if let keyboardFrame = notification.userInfo?[UIWindow.keyboardFrameEndUserInfoKey] as? CGRect {
                self.keyboardLayoutOffset = self.bounds.height - keyboardFrame.minY
            }
        }
        
        keyboardWillHideObserver = NotificationCenter.default.publisher(for: UIWindow.keyboardWillHideNotification).sink { notification in
            if let keyboardFrame = notification.userInfo?[UIWindow.keyboardFrameEndUserInfoKey] as? CGRect {
                self.keyboardLayoutOffset = self.bounds.height - keyboardFrame.minY
            }
        }
    }
    
    override func layoutSubviews()
    {
        super.layoutSubviews()
        webView?.frame = bounds
        
        if let toolbarView = toolbarView {
            var toolbarSize = toolbarView.sizeThatFits(bounds.size)
            if keyboardLayoutOffset == 0 {
                toolbarSize.height += safeAreaInsets.bottom
            }
            
            toolbarView.bounds = CGRect(origin: .zero, size: toolbarSize)
            toolbarView.center = CGPoint(x: bounds.center.x, y: bounds.maxY - (toolbarView.bounds.height / 2) - keyboardLayoutOffset)
        }
        
        bringSubviewToFront(titlebarView)
        
        var titlebarHeight: CGFloat = 24.0
        titlebarHeight += safeAreaInsets.top
        
        titlebarView.frame = CGRect(origin: .zero, size: CGSize(width: bounds.width, height: titlebarHeight))
        
        // Fix web view content insets
        webView?.scrollView.automaticallyAdjustsScrollIndicatorInsets = false
        
        var webViewContentInset = UIEdgeInsets()
        webViewContentInset.top = titlebarView.frame.height
        webViewContentInset.bottom = toolbarView?.frame.height ?? 0
        webView?.scrollView.contentInset = webViewContentInset
        webView?.scrollView.scrollIndicatorInsets = webViewContentInset
    }
}