/*
 * Copyright (C) 2015 - 2016, Daniel Dahan and CosmicMind, Inc. <http://cosmicmind.io>.
 * 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

private var TextFieldContext: UInt8 = 0

@objc(TextFieldDelegate)
public protocol TextFieldDelegate: UITextFieldDelegate {
    /**
     A delegation method that is executed when the textField changed.
     - Parameter textField: A UITextField.
     - Parameter didChange text: An optional String.
     */
    @objc
    optional func textField(textField: UITextField, didChange text: String?)

    /**
     A delegation method that is executed when the textField will clear.
     - Parameter textField: A UITextField.
     - Parameter willClear text: An optional String.
     */
    @objc
    optional func textField(textField: UITextField, willClear text: String?)
    
    /**
     A delegation method that is executed when the textField is cleared.
     - Parameter textField: A UITextField.
     - Parameter didClear text: An optional String.
     */
    @objc
    optional func textField(textField: UITextField, didClear text: String?)
}

open class TextField: UITextField {
    /// Will layout the view.
    open var willLayout: Bool {
        return 0 < width && 0 < height && nil != superview
    }
    
    /// Default size when using AutoLayout.
    open override var intrinsicContentSize: CGSize {
        return CGSize(width: width, height: 32)
    }
    
    /// A Boolean that indicates if the placeholder label is animated.
    @IBInspectable
    open var isPlaceholderAnimated = true
    
    /// A Boolean that indicates if the TextField is in an animating state.
	open internal(set) var isAnimating = false
	
    open override var leftView: UIView? {
        didSet {
            prepareLeftView()
            layoutSubviews()
        }
    }
    
    /// A boolean indicating whether the text is empty.
    open var isEmpty: Bool {
        return true == text?.isEmpty
    }
    
    /// The leftView width value.
    open var leftViewWidth: CGFloat {
        guard nil != leftView else {
            return 0
        }
        
        return leftViewOffset + height
    }
    
    /// The leftView width value.
    open var leftViewOffset: CGFloat = 16
    
    /// Divider normal height.
    @IBInspectable
    open var dividerNormalHeight: CGFloat = 1
    
    
	/// Divider active height.
	@IBInspectable
    open var dividerActiveHeight: CGFloat = 2
	
	/// Divider normal color.
	@IBInspectable
    open var dividerNormalColor = Color.darkText.dividers {
        didSet {
            guard !isEditing else {
                return
            }
            
            dividerColor = dividerNormalColor
        }
    }
	
	/// Divider active color.
	@IBInspectable
    open var dividerActiveColor = Color.blue.base {
		didSet {
            guard isEditing else {
                return
            }
            
            dividerColor = dividerActiveColor
		}
	}
	
	/// The placeholderLabel font value.
	@IBInspectable
    open override var font: UIFont? {
		didSet {
			placeholderLabel.font = font
		}
	}
 
	/// TextField's text property observer.
	@IBInspectable
    open override var text: String? {
		didSet {
            guard isEmpty else {
                return
            }
            
            guard !isFirstResponder else {
                return
            }
            
			placeholderEditingDidEndAnimation()
		}
	}
	
	/// The placeholderLabel text value.
	@IBInspectable
    open override var placeholder: String? {
		get {
			return placeholderLabel.text
		}
		set(value) {
			placeholderLabel.text = value
		}
	}
	
	/// The placeholder UILabel.
	@IBInspectable
    open private(set) lazy var placeholderLabel = UILabel()
	
	/// Placeholder normal text
	@IBInspectable
    open var placeholderNormalColor = Color.darkText.others {
		didSet {
            updatePlaceholderLabelColor()
		}
	}
	
	/// Placeholder active text
	@IBInspectable
    open var placeholderActiveColor = Color.blue.base {
		didSet {
            tintColor = placeholderActiveColor
            updatePlaceholderLabelColor()
		}
	}
	
	/// This property adds a padding to placeholder y position animation
	@IBInspectable
    open var placeholderVerticalOffset: CGFloat = 0
	
	/// The detailLabel UILabel that is displayed.
	@IBInspectable
    open private(set) lazy var detailLabel = UILabel()
	
	/// The detailLabel text value.
	@IBInspectable
    open var detail: String? {
		get {
			return detailLabel.text
		}
		set(value) {
			detailLabel.text = value
		}
	}
	
	/// Detail text
	@IBInspectable
    open var detailColor = Color.darkText.others {
		didSet {
            updateDetailLabelColor()
		}
	}
    
	/// Vertical distance for the detailLabel from the divider.
	@IBInspectable
    open var detailVerticalOffset: CGFloat = 8 {
		didSet {
			layoutDetailLabel()
		}
	}
	
	/// Handles the textAlignment of the placeholderLabel.
	open override var textAlignment: NSTextAlignment {
		get {
			return super.textAlignment
		}
		set(value) {
			super.textAlignment = value
			placeholderLabel.textAlignment = value
			detailLabel.textAlignment = value
		}
	}
	
    /// A reference to the clearIconButton.
    open private(set) var clearIconButton: IconButton?
    
	/// Enables the clearIconButton.
	@IBInspectable
    open var isClearIconButtonEnabled: Bool {
		get {
			return nil != clearIconButton
		}
		set(value) {
            guard value else {
                clearIconButton?.removeTarget(self, action: #selector(handleClearIconButton), for: .touchUpInside)
                clearIconButton = nil
                return
            }
            
            guard nil == clearIconButton else {
                return
            }
            
            clearIconButton = IconButton(image: Icon.cm.clear, tintColor: placeholderNormalColor)
            clearIconButton!.contentEdgeInsetsPreset = .none
            clearIconButton!.pulseAnimation = .none
            clearButtonMode = .never
            rightViewMode = .whileEditing
            rightView = clearIconButton
            isClearIconButtonAutoHandled = isClearIconButtonAutoHandled ? true : false
            
            layoutSubviews()
		}
	}
	
	/// Enables the automatic handling of the clearIconButton.
	@IBInspectable
    open var isClearIconButtonAutoHandled = true {
		didSet {
			clearIconButton?.removeTarget(self, action: #selector(handleClearIconButton), for: .touchUpInside)
			
            guard isClearIconButtonAutoHandled else {
                return
			}
            
            clearIconButton?.addTarget(self, action: #selector(handleClearIconButton), for: .touchUpInside)
		}
	}
    
    /// A reference to the visibilityIconButton.
    open private(set) var visibilityIconButton: IconButton?
	
	/// Enables the visibilityIconButton.
	@IBInspectable
    open var isVisibilityIconButtonEnabled: Bool {
		get {
			return nil != visibilityIconButton
		}
		set(value) {
            guard value else {
                visibilityIconButton?.removeTarget(self, action: #selector(handleVisibilityIconButton), for: .touchUpInside)
                visibilityIconButton = nil
                return
            }
            
            guard nil == visibilityIconButton else {
                return
            }
            
            visibilityIconButton = IconButton(image: Icon.visibility, tintColor: placeholderNormalColor.withAlphaComponent(isSecureTextEntry ? 0.38 : 0.54))
            visibilityIconButton!.contentEdgeInsetsPreset = .none
            visibilityIconButton!.pulseAnimation = .none
            isSecureTextEntry = true
            clearButtonMode = .never
            rightViewMode = .whileEditing
            rightView = visibilityIconButton
            isVisibilityIconButtonAutoHandled = isVisibilityIconButtonAutoHandled ? true : false
            
            layoutSubviews()
		}
	}
	
	/// Enables the automatic handling of the visibilityIconButton.
	@IBInspectable
    open var isVisibilityIconButtonAutoHandled: Bool = true {
		didSet {
			visibilityIconButton?.removeTarget(self, action: #selector(handleVisibilityIconButton), for: .touchUpInside)
			
            guard isVisibilityIconButtonAutoHandled else {
                return
			}
            
            visibilityIconButton?.addTarget(self, action: #selector(handleVisibilityIconButton), for: .touchUpInside)
		}
	}
	
    open override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        guard "placeholderLabel.text" != keyPath else {
            updatePlaceholderLabelColor()
            return
        }
        
        guard "detailLabel.text" != keyPath else {
            updateDetailLabelColor()
            return
        }
        
        super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
    }
    
    deinit {
        removeObserver(self, forKeyPath: "placeholderLabel.text")
        removeObserver(self, forKeyPath: "detailLabel.text")
    }
    
	/**
     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 a CGRect object.
     If AutoLayout is used, it is better to initilize the instance
     using the init() initializer.
     - Parameter frame: A CGRect instance.
     */
	public override init(frame: CGRect) {
		super.init(frame: frame)
		prepare()
	}
	
	/// A convenience initializer.
	public convenience init() {
		self.init(frame: .zero)
	}
	
	open override func layoutSubviews() {
		super.layoutSubviews()
        reload()
	}
	
	open override func layoutSublayers(of layer: CALayer) {
		super.layoutSublayers(of: layer)
        guard self.layer == layer else {
            return
        }
        
        layoutShape()
	}
	
	/// Handles the text editing did begin state.
    @objc
	open func handleEditingDidBegin() {
        placeholderEditingDidBeginAnimation()
        dividerEditingDidBeginAnimation()
        
	}
    
    // Live updates the textField text.
    @objc
    internal func handleEditingChanged(textField: UITextField) {
        (delegate as? TextFieldDelegate)?.textField?(textField: self, didChange: textField.text)
    }
	
	/// Handles the text editing did end state.
	@objc
    open func handleEditingDidEnd() {
        placeholderEditingDidEndAnimation()
        dividerEditingDidEndAnimation()
	}
	
	/// Handles the clearIconButton TouchUpInside event.
	@objc
    open func handleClearIconButton() {
        guard nil == delegate?.textFieldShouldClear || true == delegate?.textFieldShouldClear?(self) else {
            return
        }
        
        let t = text
		
        (delegate as? TextFieldDelegate)?.textField?(textField: self, willClear: t)
        
        text = nil
        
        (delegate as? TextFieldDelegate)?.textField?(textField: self, didClear: t)
	}
	
	/// Handles the visibilityIconButton TouchUpInside event.
    @objc
	open func handleVisibilityIconButton() {
		isSecureTextEntry = !isSecureTextEntry
		
        if !isSecureTextEntry {
			super.font = nil
			font = placeholderLabel.font
		}
		
        visibilityIconButton?.tintColor = visibilityIconButton?.tintColor.withAlphaComponent(isSecureTextEntry ? 0.38 : 0.54)
	}
    
	/**
     Prepares the view instance when intialized. When subclassing,
     it is recommended to override the prepare method
     to initialize property values and other setup operations.
     The super.prepare method should always be called immediately
     when subclassing.
     */
	open func prepare() {
		clipsToBounds = false
		borderStyle = .none
		backgroundColor = nil
		contentScaleFactor = Device.scale
		prepareDivider()
		preparePlaceholderLabel()
		prepareDetailLabel()
		prepareTargetHandlers()
        prepareTextAlignment()
	}
    
	/// Ensures that the components are sized correctly.
	open func reload() {
        guard willLayout else {
            return
        }
        
        guard !isAnimating else {
            return
        }
        
        layoutPlaceholderLabel()
        layoutDetailLabel()
        layoutButton(button: clearIconButton)
        layoutButton(button: visibilityIconButton)
        layoutDivider()
        layoutLeftView()
    }
	
	/// Layout the placeholderLabel.
	open func layoutPlaceholderLabel() {
        let w = leftViewWidth
        let h = 0 == height ? intrinsicContentSize.height : height
        
        guard isEditing || !isEmpty || !isPlaceholderAnimated else {
            placeholderLabel.frame = CGRect(x: w, y: 0, width: width - w, height: h)
            return
        }
        
        placeholderLabel.transform = CGAffineTransform.identity
        placeholderLabel.frame = CGRect(x: w, y: 0, width: width - w, height: h)
        placeholderLabel.transform = CGAffineTransform(scaleX: 0.75, y: 0.75)
        
        switch textAlignment {
        case .left, .natural:
            placeholderLabel.x = w
        case .right:
            placeholderLabel.x = width - placeholderLabel.width
        default:break
        }
        
        placeholderLabel.y = -placeholderLabel.height + placeholderVerticalOffset
	}
	
	/// Layout the detailLabel.
	open func layoutDetailLabel() {
        let c = divider.contentEdgeInsets
        detailLabel.sizeToFit()
        detailLabel.x = c.left
        detailLabel.y = height + detailVerticalOffset
        detailLabel.width = width - c.left - c.right
	}
	
	/// Layout the a button.
    open func layoutButton(button: UIButton?) {
        guard 0 < width && 0 < height else {
            return
        }
        
        button?.frame = CGRect(x: width - height, y: 0, width: height, height: height)
	}
    
    /// Layout the divider.
    open func layoutDivider() {
        divider.reload()
    }
    
    /// Layout the leftView.
    open func layoutLeftView() {
        guard let v = leftView else {
            return
        }
        
        let w = leftViewWidth
        v.frame = CGRect(x: 0, y: 0, width: w, height: height)
        divider.contentEdgeInsets.left = w
    }
	
	/// The animation for the divider when editing begins.
	open func dividerEditingDidBeginAnimation() {
		dividerThickness = dividerActiveHeight
		dividerColor = dividerActiveColor
    }
	
	/// The animation for the divider when editing ends.
	open func dividerEditingDidEndAnimation() {
		dividerThickness = dividerNormalHeight
		dividerColor = dividerNormalColor
	}
	
	/// The animation for the placeholder when editing begins.
	open func placeholderEditingDidBeginAnimation() {
        guard isPlaceholderAnimated else {
            return
        }
        
        guard isEmpty && !isAnimating else {
            return
        }
        
        isAnimating = true
        UIView.animate(withDuration: 0.15, animations: { [weak self] in
            guard let s = self else {
                return
            }
            
            s.placeholderLabel.transform = CGAffineTransform(scaleX: 0.75, y: 0.75)
            
            switch s.textAlignment {
            case .left, .natural:
                s.placeholderLabel.x = s.leftViewWidth
            case .right:
                s.placeholderLabel.x = s.width - s.placeholderLabel.width
            default:break
            }
            
            s.placeholderLabel.y = -s.placeholderLabel.height + s.placeholderVerticalOffset
        }) { [weak self] _ in
            self?.isAnimating = false
        }
	}
	
	/// The animation for the placeholder when editing ends.
	open func placeholderEditingDidEndAnimation() {
        guard isPlaceholderAnimated else {
            return
        }
        
        guard isEmpty && !isAnimating else {
            return
        }
        
        isAnimating = true
        UIView.animate(withDuration: 0.15, animations: { [weak self] in
            guard let s = self else {
                return
            }
            
            s.placeholderLabel.transform = CGAffineTransform.identity
            s.placeholderLabel.x = s.leftViewWidth
            s.placeholderLabel.y = 0
            s.placeholderLabel.textColor = s.placeholderNormalColor
        }) { [weak self] _ in
            self?.isAnimating = false
        }
	}
	
	/// Prepares the divider.
	private func prepareDivider() {
        dividerColor = dividerNormalColor
	}
	
	/// Prepares the placeholderLabel.
	private func preparePlaceholderLabel() {
        font = RobotoFont.regular(with: 16)
        placeholderNormalColor = Color.darkText.others
        addSubview(placeholderLabel)
        addObserver(self, forKeyPath: "placeholderLabel.text", options: [], context: &TextFieldContext)
	}
	
	/// Prepares the detailLabel.
	private func prepareDetailLabel() {
        detailLabel.font = RobotoFont.regular(with: 12)
        detailLabel.numberOfLines = 0
		detailColor = Color.darkText.others
		addSubview(detailLabel)
        addObserver(self, forKeyPath: "detailLabel.text", options: [], context: &TextFieldContext)
	}
    
    /// Prepares the leftView.
    private func prepareLeftView() {
        leftView?.contentMode = .left
    }
	
	/// Prepares the target handlers.
	private func prepareTargetHandlers() {
		addTarget(self, action: #selector(handleEditingDidBegin), for: .editingDidBegin)
        addTarget(self, action: #selector(handleEditingChanged), for: .editingChanged)
		addTarget(self, action: #selector(handleEditingDidEnd), for: .editingDidEnd)
	}
    
    /// Prepares the textAlignment.
    private func prepareTextAlignment() {
        textAlignment = .rightToLeft == UIApplication.shared.userInterfaceLayoutDirection ? .right : .left
    }
    
    /// Updates the placeholderLabel attributedText.
    private func updatePlaceholderLabelColor() {
        guard let v = placeholder else {
            return
        }
        
        placeholderLabel.attributedText = NSAttributedString(string: v, attributes: [NSForegroundColorAttributeName: isEditing ? placeholderActiveColor : placeholderNormalColor])
    }
    
    /// Updates the detailLabel attributedText.
    private func updateDetailLabelColor() {
        guard let v = detail else {
            return
        }
        
        detailLabel.attributedText = NSAttributedString(string: v, attributes: [NSForegroundColorAttributeName: detailColor])
    }
}
