/*
 * Copyright (C) 2015 - 2017, Daniel Dahan and CosmicMind, Inc. <http://cosmicmind.com>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *	*	Redistributions of source code must retain the above copyright notice, this
 *		list of conditions and the following disclaimer.
 *
 *	*	Redistributions in binary form must reproduce the above copyright notice,
 *		this list of conditions and the following disclaimer in the documentation
 *		and/or other materials provided with the distribution.
 *
 *	*	Neither the name of CosmicMind nor the names of its
 *		contributors may be used to endorse or promote products derived from
 *		this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import UIKit

@objc(NavigationDrawerPosition)
public enum NavigationDrawerPosition: Int {
	case left
	case right
}

extension UIViewController {
	/**
     A convenience property that provides access to the NavigationDrawerController.
     This is the recommended method of accessing the NavigationDrawerController
     through child UIViewControllers.
     */
	public var navigationDrawerController: NavigationDrawerController? {
		return traverseViewControllerHierarchyForClassType()
	}
}

@objc(NavigationDrawerControllerDelegate)
public protocol NavigationDrawerControllerDelegate {
	/**
     An optional delegation method that is fired before the
     NavigationDrawerController opens.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, willOpen position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired after the
     NavigationDrawerController opened.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter position: The NavigationDrawerPosition.
     */
	@objc
    optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didOpen position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired before the
     NavigationDrawerController closes.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, willClose position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired after the
     NavigationDrawerController closed.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didClose position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired when the
     NavigationDrawerController pan gesture begins.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter didBeginPanAt point: A CGPoint.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didBeginPanAt point: CGPoint, position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired when the
     NavigationDrawerController pan gesture changes position.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter didChangePanAt point: A CGPoint.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didChangePanAt point: CGPoint, position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired when the
     NavigationDrawerController pan gesture ends.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter didEndPanAt point: A CGPoint.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didEndPanAt point: CGPoint, position: NavigationDrawerPosition)
	
	/**
     An optional delegation method that is fired when the
     NavigationDrawerController tap gesture executes.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter didTapAt point: A CGPoint.
     - Parameter position: The NavigationDrawerPosition.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, didTapAt point: CGPoint, position: NavigationDrawerPosition)

	/**
     An optional delegation method that is fired when the
     status bar is about to change display, isHidden or not.
     - Parameter navigationDrawerController: A NavigationDrawerController.
     - Parameter statusBar isHidden: A boolean.
     */
    @objc
	optional func navigationDrawerController(navigationDrawerController: NavigationDrawerController, statusBar isHidden: Bool)
}

@objc(NavigationDrawerController)
open class NavigationDrawerController: TransitionController {
	/**
     A CGFloat property that is used internally to track
     the original (x) position of the container view when panning.
     */
	fileprivate var originalX: CGFloat = 0
	
	/**
     A UIPanGestureRecognizer property internally used for the
     leftView pan gesture.
     */
	internal fileprivate(set) var leftPanGesture: UIPanGestureRecognizer?
	
    /**
     A UITapGestureRecognizer property internally used for the
     leftView tap gesture.
     */
    internal fileprivate(set) var leftTapGesture: UITapGestureRecognizer?
    
	/**
     A UIPanGestureRecognizer property internally used for the
     rightView pan gesture.
     */
	internal fileprivate(set) var rightPanGesture: UIPanGestureRecognizer?
	
	/**
     A UITapGestureRecognizer property internally used for the
     rightView tap gesture.
     */
	internal fileprivate(set) var rightTapGesture: UITapGestureRecognizer?
	
	/**
     A CGFloat property that accesses the leftView threshold of
     the NavigationDrawerController. When the panning gesture has
     ended, if the position is beyond the threshold,
     the leftView is opened, if it is below the threshold, the
     leftView is closed.
     */
	@IBInspectable
    open var leftThreshold: CGFloat = 64
	fileprivate var leftViewThreshold: CGFloat = 0
	
	/**
     A CGFloat property that accesses the rightView threshold of
     the NavigationDrawerController. When the panning gesture has
     ended, if the position is beyond the threshold,
     the rightView is closed, if it is below the threshold, the
     rightView is opened.
     */
	@IBInspectable
    open var rightThreshold: CGFloat = 64
	fileprivate var rightViewThreshold: CGFloat = 0
	
	/**
     A NavigationDrawerControllerDelegate property used to bind
     the delegation object.
     */
	open weak var delegate: NavigationDrawerControllerDelegate?
	
	/**
     A CGFloat property that sets the animation duration of the
     leftView when closing and opening. Defaults to 0.25.
     */
	@IBInspectable
    open var animationDuration: TimeInterval = 0.25
	
	/**
     A Boolean property that enables and disables the leftView from
     opening and closing. Defaults to true.
     */
	@IBInspectable
    open var isEnabled: Bool {
		get {
			return isLeftViewEnabled || isRightViewEnabled
		}
		set(value) {
			if nil != leftView {
				isLeftViewEnabled = value
			}
			if nil != rightView {
				isRightViewEnabled = value
			}
		}
	}
	
	/**
     A Boolean property that enables and disables the leftView from
     opening and closing. Defaults to true.
     */
	@IBInspectable
    open var isLeftViewEnabled = false {
		didSet {
			isLeftPanGestureEnabled = isLeftViewEnabled
			isLeftTapGestureEnabled = isLeftViewEnabled
		}
	}
	
	/// Enables the left pan gesture.
	@IBInspectable
    open var isLeftPanGestureEnabled = false {
		didSet {
			if isLeftPanGestureEnabled {
				prepareLeftPanGesture()
			} else {
				removeLeftPanGesture()
			}
		}
	}
	
	/// Enables the left tap gesture.
	@IBInspectable
    open var isLeftTapGestureEnabled = false {
		didSet {
			if isLeftTapGestureEnabled {
				prepareLeftTapGesture()
			} else {
				removeLeftTapGesture()
			}
		}
	}
	
	/**
     A Boolean property that enables and disables the rightView from
     opening and closing. Defaults to true.
     */
	@IBInspectable
    open var isRightViewEnabled = false {
		didSet {
			isRightPanGestureEnabled = isRightViewEnabled
			isRightTapGestureEnabled = isRightViewEnabled
		}
	}
	
	/// Enables the right pan gesture.
	@IBInspectable
    open var isRightPanGestureEnabled = false {
		didSet {
			if isRightPanGestureEnabled {
				prepareRightPanGesture()
			} else {
				removeRightPanGesture()
			}
		}
	}
	
	/// Enables the right tap gesture.
	@IBInspectable
    open var isRightTapGestureEnabled = false {
		didSet {
			if isRightTapGestureEnabled {
				prepareRightTapGesture()
			} else {
				removeRightTapGesture()
			}
		}
	}
	
	/**
     A Boolean property that triggers the status bar to be isHidden
     when the leftView is opened. Defaults to true.
     */
	@IBInspectable
    open var isHiddenStatusBarEnabled = true
	
	/**
     A DepthPreset property that is used to set the depth of the
     leftView when opened.
     */
    open var depthPreset = DepthPreset.depth1
	
	/**
     A UIView property that is used to hide and reveal the
     leftViewController. It is very rare that this property will
     need to be accessed externally.
     */
	open fileprivate(set) var leftView: UIView?
	
	/**
     A UIView property that is used to hide and reveal the
     rightViewController. It is very rare that this property will
     need to be accessed externally.
     */
	open fileprivate(set) var rightView: UIView?
	
	/// Indicates whether the leftView or rightView is opened.
	open var isOpened: Bool {
		return isLeftViewOpened || isRightViewOpened
	}
	
	/// indicates if the leftView is opened.
	open var isLeftViewOpened: Bool {
		guard let v = leftView else {
			return false
		}
		return v.x != -leftViewWidth
	}
	
	/// Indicates if the rightView is opened.
	open var isRightViewOpened: Bool {
		guard let v = rightView else {
			return false
		}
		return v.x != Screen.width
	}
	
	/**
     Content view controller to encompase the entire component. This is
     primarily used when the StatusBar is being isHidden. The alpha value of
     the rootViewController decreases, and shows the StatusBar. To avoid
     this, and to add a isHidden transition viewController for complex
     situations, the contentViewController was added.
     */
	open fileprivate(set) lazy var contentViewController = UIViewController()
	
	/**
     A UIViewController property that references the
     active left UIViewController.
     */
	open fileprivate(set) var leftViewController: UIViewController?
	
	/**
     A UIViewController property that references the
     active right UIViewController.
     */
	open fileprivate(set) var rightViewController: UIViewController?
	
	/**
     A CGFloat property to access the width that the leftView
     opens up to.
     */
	@IBInspectable
    open fileprivate(set) var leftViewWidth: CGFloat = 0
	
	/**
     A CGFloat property to access the width that the rightView
     opens up to.
     */
	@IBInspectable
    open fileprivate(set) var rightViewWidth: CGFloat = 0
	
	/**
     An initializer that initializes the object with a NSCoder object.
     - Parameter aDecoder: A NSCoder instance.
     */
	public required init?(coder aDecoder: NSCoder) {
		super.init(coder: aDecoder)
        prepare()
	}
	
	/**
     An initializer that initializes the object with an Optional nib and bundle.
     - Parameter nibNameOrNil: An Optional String for the nib.
     - Parameter bundle: An Optional NSBundle where the nib is located.
     */
	public override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
		super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        prepare()
	}
	
	/**
     An initializer for the NavigationDrawerController.
     - Parameter rootViewController: The main UIViewController.
     - Parameter leftViewController: An Optional left UIViewController.
     - Parameter rightViewController: An Optional right UIViewController.
     */
	public init(rootViewController: UIViewController, leftViewController: UIViewController? = nil, rightViewController: UIViewController? = nil) {
		super.init(rootViewController: rootViewController)
		self.leftViewController = leftViewController
		self.rightViewController = rightViewController
		prepare()
	}
	
    open override func transition(to viewController: UIViewController, completion: ((Bool) -> Void)? = nil) {
        super.transition(to: viewController) { [weak self, completion = completion] (result) in
            guard let s = self else {
                return
            }
            
            s.view.sendSubview(toBack: s.contentViewController.view)
            completion?(result)
        }
    }
    
	/// Layout subviews.
	open override func layoutSubviews() {
        super.layoutSubviews()
		toggleStatusBar()
        
        if let v = leftView {
			v.width = leftViewWidth
			v.height = view.bounds.height
			leftViewThreshold = leftViewWidth / 2
			if let vc = leftViewController {
				vc.view.width = leftViewWidth
				vc.view.height = v.bounds.height
                vc.view.center = CGPoint(x: leftViewWidth / 2, y: v.bounds.height / 2)
			}
		}
		
		if let v = rightView {
			v.width = rightViewWidth
			v.height = view.bounds.height
			rightViewThreshold = view.bounds.width - rightViewWidth / 2
			if let vc = rightViewController {
				vc.view.width = rightViewWidth
				vc.view.height = v.bounds.height
                vc.view.center = CGPoint(x: rightViewWidth / 2, y: v.bounds.height / 2)
			}
		}
        
        rootViewController.view.frame = container.bounds
	}
	
    open override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)
		// Ensures the view is isHidden.
        guard let v = rightView else {
            return
        }
        
        v.position.x = size.width + (isRightViewOpened ? -v.bounds.width : v.bounds.width) / 2
	}
    
    open override func prepare() {
        super.prepare()
        prepareContentViewController()
        prepareLeftView()
        prepareRightView()
    }
	
	/**
     A method that is used to set the width of the leftView when
     opened. This is the recommended method of setting the leftView
     width.
     - Parameter width: A CGFloat value to set as the new width.
     - Parameter isHidden: A Boolean value of whether the leftView
     should be isHidden after the width has been updated or not.
     - Parameter animated: A Boolean value that indicates to animate
     the leftView width change.
     */
	open func setLeftViewWidth(width: CGFloat, isHidden: Bool, animated: Bool, duration: TimeInterval = 0.5) {
        guard let v = leftView else {
            return
        }
        
        leftViewWidth = width
        
        var hide = isHidden
        
        if isRightViewOpened {
            hide = true
        }
        
        if animated {
            v.isShadowPathAutoSizing = false
            
            if hide {
                UIView.animate(withDuration: duration,
                    animations: { [weak self, v = v] in
                        guard let s = self else {
                            return
                        }
                        
                        v.bounds.size.width = width
                        v.position.x = -width / 2
                        s.rootViewController.view.alpha = 1
                    }) { [weak self, v = v] _ in
                        guard let s = self else {
                            return
                        }
                        
                        v.isShadowPathAutoSizing = true
                        s.layoutSubviews()
                        s.hideView(container: v)
                    }
            } else {
                UIView.animate(withDuration: duration,
                    animations: { [weak self, v = v] in
                        guard let s = self else {
                            return
                        }
                        
                        v.bounds.size.width = width
                        v.position.x = width / 2
                        s.rootViewController.view.alpha = 0.5
                    }) { [weak self, v = v] _ in
                        guard let s = self else {
                            return
                        }
                        
                        v.isShadowPathAutoSizing = true
                        s.layoutSubviews()
                        s.showView(container: v)
                    }
            }
        } else {
            v.bounds.size.width = width
            
            if hide {
                hideView(container: v)
                v.position.x = -v.bounds.width / 2
                rootViewController.view.alpha = 1
            } else {
                showView(container: v)
                v.position.x = width / 2
                rootViewController.view.alpha = 0.5
            }
            
            layoutSubviews()
        }
	}
	
	/**
     A method that is used to set the width of the rightView when
     opened. This is the recommended method of setting the rightView
     width.
     - Parameter width: A CGFloat value to set as the new width.
     - Parameter isHidden: A Boolean value of whether the rightView
     should be isHidden after the width has been updated or not.
     - Parameter animated: A Boolean value that indicates to animate
     the rightView width change.
     */
	open func setRightViewWidth(width: CGFloat, isHidden: Bool, animated: Bool, duration: TimeInterval = 0.5) {
        guard let v = rightView else {
            return
        }
        
        rightViewWidth = width
        
        var hide = isHidden
        
        if isLeftViewOpened {
            hide = true
        }
        
        if animated {
            v.isShadowPathAutoSizing = false
            
            if hide {
                UIView.animate(withDuration: duration,
                    animations: { [weak self, v = v] in
                        guard let s = self else {
                            return
                        }
                        
                        v.bounds.size.width = width
                        v.position.x = s.view.bounds.width + width / 2
                        s.rootViewController.view.alpha = 1
                    }) { [weak self, v = v] _ in
                        guard let s = self else {
                            return
                        }
                        
                        v.isShadowPathAutoSizing = true
                        s.layoutSubviews()
                        s.hideView(container: v)
                    }
            } else {
                UIView.animate(withDuration: duration,
                    animations: { [weak self, v = v] in
                        guard let s = self else {
                            return
                        }
                        
                        v.bounds.size.width = width
                        v.position.x = s.view.bounds.width - width / 2
                        s.rootViewController.view.alpha = 0.5
                    }) { [weak self, v = v] _ in
                        guard let s = self else {
                            return
                        }
                        
                        v.isShadowPathAutoSizing = true
                        s.layoutSubviews()
                        s.showView(container: v)
                    }
            }
        } else {
            v.bounds.size.width = width
            
            if hide {
                hideView(container: v)
                v.position.x = view.bounds.width + v.bounds.width / 2
                rootViewController.view.alpha = 1
            } else {
                showView(container: v)
                v.position.x = view.bounds.width - width / 2
                rootViewController.view.alpha = 0.5
            }
            
            layoutSubviews()
        }
	}
	
	/**
     A method that toggles the leftView opened if previously closed,
     or closed if previously opened.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func toggleLeftView(velocity: CGFloat = 0) {
		isLeftViewOpened ? closeLeftView(velocity: velocity) : openLeftView(velocity: velocity)
	}
	
	/**
     A method that toggles the rightView opened if previously closed,
     or closed if previously opened.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func toggleRightView(velocity: CGFloat = 0) {
		isRightViewOpened ? closeRightView(velocity: velocity) : openRightView(velocity: velocity)
	}
	
	/**
     A method that opens the leftView.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func openLeftView(velocity: CGFloat = 0) {
        guard isLeftViewEnabled else {
            return
        }
        
        guard let v = leftView else {
            return
        }
        
        hideStatusBar()
        showView(container: v)
        
        isUserInteractionEnabled = false
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, willOpen: .left)
        
        UIView.animate(withDuration: TimeInterval(0 == velocity ? animationDuration : fmax(0.1, fmin(1, Double(v.x / velocity)))),
            animations: { [weak self, v = v] in
                guard let s = self else {
                    return
                }
                
                v.position.x = v.bounds.width / 2
                s.rootViewController.view.alpha = 0.5
            }) { [weak self] _ in
                guard let s = self else {
                    return
                }
                
                s.delegate?.navigationDrawerController?(navigationDrawerController: s, didOpen: .left)
            }
	}
	
	/**
     A method that opens the rightView.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func openRightView(velocity: CGFloat = 0) {
        guard isRightViewEnabled else {
            return
        }
        
        guard let v = rightView else {
            return
        }
        
        hideStatusBar()
        showView(container: v)
        
        isUserInteractionEnabled = false
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, willOpen: .right)
        
        UIView.animate(withDuration: TimeInterval(0 == velocity ? animationDuration : fmax(0.1, fmin(1, Double(v.x / velocity)))),
            animations: { [weak self, v = v] in
                guard let s = self else {
                    return
                }
                
                v.position.x = s.view.bounds.width - v.bounds.width / 2
                s.rootViewController.view.alpha = 0.5
            }) { [weak self] _ in
                guard let s = self else {
                    return
                }
                
                s.delegate?.navigationDrawerController?(navigationDrawerController: s, didOpen: .right)
            }
	}
	
	/**
     A method that closes the leftView.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func closeLeftView(velocity: CGFloat = 0) {
        guard isLeftViewEnabled else {
            return
        }
        
        guard let v = leftView else {
            return
        }
        
        isUserInteractionEnabled = true
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, willClose: .left)
        
        UIView.animate(withDuration: TimeInterval(0 == velocity ? animationDuration : fmax(0.1, fmin(1, Double(v.x / velocity)))),
            animations: { [weak self, v = v] in
                guard let s = self else {
                    return
                }
                
                v.position.x = -v.bounds.width / 2
                s.rootViewController.view.alpha = 1
            }) { [weak self, v = v] _ in
                guard let s = self else {
                    return
                }
                
                s.hideView(container: v)
                s.toggleStatusBar()
                
                s.delegate?.navigationDrawerController?(navigationDrawerController: s, didClose: .left)
            }
	}
	
	/**
     A method that closes the rightView.
     - Parameter velocity: A CGFloat value that sets the
     velocity of the user interaction when animating the
     leftView. Defaults to 0.
     */
	open func closeRightView(velocity: CGFloat = 0) {
        guard isRightViewEnabled else {
            return
        }
        
        guard let v = rightView else {
            return
        }
        
        isUserInteractionEnabled = true
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, willClose: .right)
        
        UIView.animate(withDuration: TimeInterval(0 == velocity ? animationDuration : fmax(0.1, fmin(1, Double(v.x / velocity)))),
            animations: { [weak self, v = v] in
                guard let s = self else {
                    return
                }
                
                v.position.x = s.view.bounds.width + v.bounds.width / 2
                s.rootViewController.view.alpha = 1
            }) { [weak self, v = v] _ in
                guard let s = self else {
                    return
                }
                
                s.hideView(container: v)
                s.toggleStatusBar()
                
                s.delegate?.navigationDrawerController?(navigationDrawerController: s, didClose: .right)
            }
	}
	
	/// A method that removes the passed in pan and leftView tap gesture recognizers.
	fileprivate func removeLeftViewGestures() {
		removeLeftPanGesture()
		removeLeftTapGesture()
	}
	
	/// Removes the left pan gesture.
	fileprivate func removeLeftPanGesture() {
        guard let v = leftPanGesture else {
            return
        }
        
        view.removeGestureRecognizer(v)
        leftPanGesture = nil
	}
	
	/// Removes the left tap gesture.
	fileprivate func removeLeftTapGesture() {
        guard let v = leftTapGesture else {
            return
        }
        
        view.removeGestureRecognizer(v)
        leftTapGesture = nil
	}
	
	/// A method that removes the passed in pan and rightView tap gesture recognizers.
	fileprivate func removeRightViewGestures() {
		removeRightPanGesture()
		removeRightTapGesture()
		
	}
	
	/// Removes the right pan gesture.
	fileprivate func removeRightPanGesture() {
        guard let v = rightPanGesture else {
            return
        }
        
        view.removeGestureRecognizer(v)
        rightPanGesture = nil
	}
	
	/// Removes the right tap gesture.
	fileprivate func removeRightTapGesture() {
        guard let v = rightTapGesture else {
            return
        }
        
        view.removeGestureRecognizer(v)
        rightTapGesture = nil
	}
	
	/// Shows the statusBar.
	fileprivate func showStatusBar() {
        DispatchQueue.main.async { [weak self] in
            guard let s = self else {
                return
            }
            
            guard let v = Application.keyWindow else {
                return
            }
            
            v.windowLevel = UIWindowLevelNormal
            
            s.delegate?.navigationDrawerController?(navigationDrawerController: s, statusBar: false)
        }
	}
	
	/// Hides the statusBar.
	fileprivate func hideStatusBar() {
        guard isHiddenStatusBarEnabled else {
            return
        }
        
        DispatchQueue.main.async { [weak self] in
            guard let s = self else {
                return
            }
            
            guard let v = Application.keyWindow else {
                return
            }
            
            v.windowLevel = UIWindowLevelStatusBar + 1
            
            s.delegate?.navigationDrawerController?(navigationDrawerController: s, statusBar: true)
        }
	}
	
	/// Toggles the statusBar
	fileprivate func toggleStatusBar() {
		if isOpened {
			hideStatusBar()
		} else {
			showStatusBar()
		}
	}
	
	/**
     A method that determines whether the passed point is
     contained within the bounds of the leftViewThreshold
     and height of the NavigationDrawerController view frame
     property.
     - Parameter point: A CGPoint to test against.
     - Returns: A Boolean of the result, true if yes, false
     otherwise.
     */
	fileprivate func isPointContainedWithinLeftThreshold(point: CGPoint) -> Bool {
		return point.x <= leftThreshold
	}
	
	/**
     A method that determines whether the passed point is
     contained within the bounds of the rightViewThreshold
     and height of the NavigationDrawerController view frame
     property.
     - Parameter point: A CGPoint to test against.
     - Returns: A Boolean of the result, true if yes, false
     otherwise.
     */
	fileprivate func isPointContainedWithinRighThreshold(point: CGPoint) -> Bool {
		return point.x >= view.bounds.width - rightThreshold
	}
	
	/**
     A method that determines whether the passed in point is
     contained within the bounds of the passed in container view.
     - Parameter container: A UIView that sets the bounds to test
     against.
     - Parameter point: A CGPoint to test whether or not it is
     within the bounds of the container parameter.
     - Returns: A Boolean of the result, true if yes, false
     otherwise.
     */
	fileprivate func isPointContainedWithinView(container: UIView, point: CGPoint) -> Bool {
		return container.bounds.contains(point)
	}
	
	/**
     A method that shows a view.
     - Parameter container: A container view.
     */
	fileprivate func showView(container: UIView) {
		container.depthPreset = depthPreset
		container.isHidden = false
	}
	
	/**
     A method that hides a view.
     - Parameter container: A container view.
     */
	fileprivate func hideView(container: UIView) {
		container.depthPreset = .none
		container.isHidden = true
	}
}

extension NavigationDrawerController {
    /// Prepares the contentViewController.
    fileprivate func prepareContentViewController() {
        contentViewController.view.backgroundColor = .black
        prepare(viewController: contentViewController, in: view)
        view.sendSubview(toBack: contentViewController.view)
    }
    
    /// A method that prepares the leftViewController.
    fileprivate func prepareLeftViewController() {
        guard let v = leftView else {
            return
        }
        
        prepare(viewController: leftViewController, in: v)
    }
    
    /// A method that prepares the rightViewController.
    fileprivate func prepareRightViewController() {
        guard let v = rightView else {
            return
        }
        
        prepare(viewController: rightViewController, in: v)
    }
    
    /// A method that prepares the leftView.
    fileprivate func prepareLeftView() {
        guard nil != leftViewController else {
            return
        }
        
        isLeftViewEnabled = true
        
        leftViewWidth = .phone == Device.userInterfaceIdiom ? 280 : 320
        leftView = UIView()
        leftView!.frame = CGRect(x: 0, y: 0, width: leftViewWidth, height: view.bounds.height)
        leftView!.backgroundColor = nil
        view.addSubview(leftView!)
        
        leftView!.isHidden = true
        leftView!.position.x = -leftViewWidth / 2
        leftView!.zPosition = 2000
        prepareLeftViewController()
    }
    
    /// A method that prepares the leftView.
    fileprivate func prepareRightView() {
        guard nil != rightViewController else {
            return
        }
        
        isRightViewEnabled = true
        
        rightViewWidth = .phone == Device.userInterfaceIdiom ? 280 : 320
        rightView = UIView()
        rightView!.frame = CGRect(x: view.bounds.width, y: 0, width: rightViewWidth, height: view.bounds.height)
        rightView!.backgroundColor = nil
        view.addSubview(rightView!)
        
        rightView!.isHidden = true
        rightView!.position.x = view.bounds.width + rightViewWidth / 2
        rightView!.zPosition = 2000
        prepareRightViewController()
    }
    
    /// Prepare the left pan gesture.
    fileprivate func prepareLeftPanGesture() {
        guard nil == leftPanGesture else {
            return
        }
        
        leftPanGesture = UIPanGestureRecognizer(target: self, action: #selector(handleLeftViewPanGesture(recognizer:)))
        leftPanGesture!.delegate = self
        view.addGestureRecognizer(leftPanGesture!)
    }
    
    /// Prepare the left tap gesture.
    fileprivate func prepareLeftTapGesture() {
        guard nil == leftTapGesture else {
            return
        }
        
        leftTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleLeftViewTapGesture(recognizer:)))
        leftTapGesture!.delegate = self
        leftTapGesture!.cancelsTouchesInView = false
        view.addGestureRecognizer(leftTapGesture!)
    }
    
    /// Prepares the right pan gesture.
    fileprivate func prepareRightPanGesture() {
        guard nil == rightPanGesture else {
            return
        }
        
        rightPanGesture = UIPanGestureRecognizer(target: self, action: #selector(handleRightViewPanGesture(recognizer:)))
        rightPanGesture!.delegate = self
        view.addGestureRecognizer(rightPanGesture!)
    }
    
    /// Prepares the right tap gesture.
    fileprivate func prepareRightTapGesture() {
        guard nil == rightTapGesture else {
            return
        }
        
        rightTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleRightViewTapGesture(recognizer:)))
        rightTapGesture!.delegate = self
        rightTapGesture!.cancelsTouchesInView = false
        view.addGestureRecognizer(rightTapGesture!)
    }
}

extension NavigationDrawerController: UIGestureRecognizerDelegate {
    /**
     Detects the gesture recognizer being used.
     - Parameter gestureRecognizer: A UIGestureRecognizer to detect.
     - Parameter touch: The UITouch event.
     - Returns: A Boolean of whether to continue the gesture or not.
     */
    @objc
    open func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        if !isRightViewOpened && gestureRecognizer == leftPanGesture && (isLeftViewOpened || isPointContainedWithinLeftThreshold(point: touch.location(in: view))) {
            return true
        }
        
        if !isLeftViewOpened && gestureRecognizer == rightPanGesture && (isRightViewOpened || isPointContainedWithinRighThreshold(point: touch.location(in: view))) {
            return true
        }
        
        if isLeftViewOpened && gestureRecognizer == leftTapGesture {
            return true
        }
        
        if isRightViewOpened && gestureRecognizer == rightTapGesture {
            return true
        }
        
        return false
    }
    
    /**
     A method that is fired when the pan gesture is recognized
     for the leftView.
     - Parameter recognizer: A UIPanGestureRecognizer that is
     passed to the handler when recognized.
     */
    @objc
    fileprivate func handleLeftViewPanGesture(recognizer: UIPanGestureRecognizer) {
        guard isLeftViewEnabled && (isLeftViewOpened || !isRightViewOpened && isPointContainedWithinLeftThreshold(point: recognizer.location(in: view))) else {
            return
        }
        
        guard let v = leftView else {
            return
        }
        
        let point = recognizer.location(in: view)
        
        // Animate the panel.
        switch recognizer.state {
        case .began:
            originalX = v.position.x
            showView(container: v)
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didBeginPanAt: point, position: .left)
        case .changed:
            let w = v.bounds.width
            let translationX = recognizer.translation(in: v).x
            
            v.position.x = originalX + translationX > (w / 2) ? (w / 2) : originalX + translationX
            
            let a = 1 - v.position.x / v.bounds.width
            rootViewController.view.alpha = 0.5 < a && v.position.x <= v.bounds.width / 2 ? a : 0.5
            
            if translationX >= leftThreshold {
                hideStatusBar()
            }
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didChangePanAt: point, position: .left)
        case .ended, .cancelled, .failed:
            let p = recognizer.velocity(in: recognizer.view)
            let x = p.x >= 500 || p.x <= -500 ? p.x : 0
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didEndPanAt: point, position: .left)
            
            if v.x <= -leftViewWidth + leftViewThreshold || x < -500 {
                closeLeftView(velocity: x)
            } else {
                openLeftView(velocity: x)
            }
        case .possible:break
        }
    }
    
    /**
     A method that is fired when the pan gesture is recognized
     for the rightView.
     - Parameter recognizer: A UIPanGestureRecognizer that is
     passed to the handler when recognized.
     */
    @objc
    fileprivate func handleRightViewPanGesture(recognizer: UIPanGestureRecognizer) {
        guard isRightViewEnabled && (isRightViewOpened || !isLeftViewOpened && isPointContainedWithinRighThreshold(point: recognizer.location(in: view))) else {
            return
        }
        
        guard let v = rightView else {
            return
        }
        
        let point = recognizer.location(in: view)
        
        // Animate the panel.
        switch recognizer.state {
        case .began:
            originalX = v.position.x
            showView(container: v)
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didBeginPanAt: point, position: .right)
        case .changed:
            let w = v.bounds.width
            let translationX = recognizer.translation(in: v).x
            
            v.position.x = originalX + translationX < view.bounds.width - (w / 2) ? view.bounds.width - (w / 2) : originalX + translationX
            
            let a = 1 - (view.bounds.width - v.position.x) / v.bounds.width
            rootViewController.view.alpha = 0.5 < a && v.position.x >= v.bounds.width / 2 ? a : 0.5
            
            if translationX <= -rightThreshold {
                hideStatusBar()
            }
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didChangePanAt: point, position: .right)
        case .ended, .cancelled, .failed:
            let p = recognizer.velocity(in: recognizer.view)
            let x = p.x >= 1000 || p.x <= -1000 ? p.x : 0
            
            delegate?.navigationDrawerController?(navigationDrawerController: self, didEndPanAt: point, position: .right)
            
            if v.x >= rightViewThreshold || x > 1000 {
                closeRightView(velocity: x)
            } else {
                openRightView(velocity: x)
            }
        case .possible:break
        }
    }
    
    /**
     A method that is fired when the tap gesture is recognized
     for the leftView.
     - Parameter recognizer: A UITapGestureRecognizer that is
     passed to the handler when recognized.
     */
    @objc
    fileprivate func handleLeftViewTapGesture(recognizer: UITapGestureRecognizer) {
        guard isLeftViewOpened else {
            return
        }
        
        guard let v = leftView else {
            return
        }
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, didTapAt: recognizer.location(in: view), position: .left)
        
        guard isLeftViewEnabled && isLeftViewOpened && !isPointContainedWithinView(container: v, point: recognizer.location(in: v)) else {
            return
        }
        
        closeLeftView()
    }
    
    /**
     A method that is fired when the tap gesture is recognized
     for the rightView.
     - Parameter recognizer: A UITapGestureRecognizer that is
     passed to the handler when recognized.
     */
    @objc
    fileprivate func handleRightViewTapGesture(recognizer: UITapGestureRecognizer) {
        guard isRightViewOpened else {
            return
        }
        
        guard let v = rightView else {
            return
        }
        
        delegate?.navigationDrawerController?(navigationDrawerController: self, didTapAt: recognizer.location(in: view), position: .right)
        
        guard isRightViewEnabled && isRightViewOpened && !isPointContainedWithinView(container: v, point: recognizer.location(in: v)) else {
            return
        }
        
        closeRightView()
    }
}
