/*
 * 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
import Motion

@objc(CollectionViewCell)
open class CollectionViewCell: UICollectionViewCell, Pulseable, PulseableLayer {
  /**
   A CAShapeLayer used to manage elements that would be affected by
   the clipToBounds property of the backing layer. For example, this
   allows the dropshadow effect on the backing layer, while clipping
   the image to a desired shape within the visualLayer.
   */
  open let visualLayer = CAShapeLayer()
  
  /// A Pulse reference.
  internal var pulse: Pulse!
  
  /// A reference to the pulse layer.
  internal var pulseLayer: CALayer? {
    return pulse.pulseLayer
  }
  
  /// PulseAnimation value.
  open var pulseAnimation: PulseAnimation {
    get {
      return pulse.animation
    }
    set(value) {
      pulse.animation = value
    }
  }
  
  /// PulseAnimation color.
  @IBInspectable
  open var pulseColor: UIColor {
    get {
      return pulse.color
    }
    set(value) {
      pulse.color = value
    }
  }
  
  /// Pulse opacity.
  @IBInspectable
  open var pulseOpacity: CGFloat {
    get {
      return pulse.opacity
    }
    set(value) {
      pulse.opacity = value
    }
  }
  
  /**
   A property that manages an image for the visualLayer's contents
   property. Images should not be set to the backing layer's contents
   property to avoid conflicts when using clipsToBounds.
   */
  @IBInspectable
  open var image: UIImage? {
    didSet {
      visualLayer.contents = image?.cgImage
    }
  }
  
  /**
   Allows a relative subrectangle within the range of 0 to 1 to be
   specified for the visualLayer's contents property. This allows
   much greater flexibility than the contentsGravity property in
   terms of how the image is cropped and stretched.
   */
  @IBInspectable
  open var contentsRect: CGRect {
    get {
      return visualLayer.contentsRect
    }
    set(value) {
      visualLayer.contentsRect = value
    }
  }
  
  /**
   A CGRect that defines a stretchable region inside the visualLayer
   with a fixed border around the edge.
   */
  @IBInspectable
  open var contentsCenter: CGRect {
    get {
      return visualLayer.contentsCenter
    }
    set(value) {
      visualLayer.contentsCenter = value
    }
  }
  
  /**
   A floating point value that defines a ratio between the pixel
   dimensions of the visualLayer's contents property and the size
   of the view. By default, this value is set to the Screen.scale.
   */
  @IBInspectable
  open var contentsScale: CGFloat {
    get {
      return visualLayer.contentsScale
    }
    set(value) {
      visualLayer.contentsScale = value
    }
  }
  
  /// A Preset for the contentsGravity property.
  public var contentsGravityPreset: Gravity {
    didSet {
      contentsGravity = GravityToValue(gravity: contentsGravityPreset)
    }
  }
  
  /// Determines how content should be aligned within the visualLayer's bounds.
  @IBInspectable
  open var contentsGravity: String {
    get {
      return visualLayer.contentsGravity
    }
    set(value) {
      visualLayer.contentsGravity = value
    }
  }
  
  /// A property that accesses the backing layer's background
  @IBInspectable
  open override var backgroundColor: UIColor? {
    didSet {
      layer.backgroundColor = backgroundColor?.cgColor
    }
  }
  
  /**
   An initializer that initializes the object with a NSCoder object.
   - Parameter aDecoder: A NSCoder instance.
   */
  public required init?(coder aDecoder: NSCoder) {
    contentsGravityPreset = .resizeAspectFill
    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) {
    contentsGravityPreset = .resizeAspectFill
    super.init(frame: frame)
    prepare()
  }
  
  /// A convenience initializer.
  public convenience init() {
    self.init(frame: .zero)
  }
  
  open override func layoutSubviews() {
    super.layoutSubviews()
    layoutShape()
    layoutVisualLayer()
    layoutShadowPath()
  }
  
  /**
   Triggers the pulse animation.
   - Parameter point: A Optional point to pulse from, otherwise pulses
   from the center.
   */
  open func pulse(point: CGPoint? = nil) {
    pulse.expand(point: point ?? center)
    Motion.delay(0.35) { [weak self] in
      self?.pulse.contract()
    }
  }
  
  /**
   A delegation method that is executed when the view has began a
   touch event.
   - Parameter touches: A set of UITouch objects.
   - Parameter event: A UIEvent object.
   */
  open override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesBegan(touches, with: event)
    pulse.expand(point: layer.convert(touches.first!.location(in: self), from: layer))
  }
  
  /**
   A delegation method that is executed when the view touch event has
   ended.
   - Parameter touches: A set of UITouch objects.
   - Parameter event: A UIEvent object.
   */
  open override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesEnded(touches, with: event)
    pulse.contract()
  }
  
  /**
   A delegation method that is executed when the view touch event has
   been cancelled.
   - Parameter touches: A set of UITouch objects.
   - Parameter event: A UIEvent object.
   */
  open override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesCancelled(touches, with: event)
    pulse.contract()
  }
  
  /**
   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() {
    backgroundColor = .white
    contentScaleFactor = Screen.scale
    
    prepareVisualLayer()
    preparePulse()
  }
}

extension CollectionViewCell {
  /// Prepares the pulse motion.
  fileprivate func preparePulse() {
    pulse = Pulse(pulseView: self, pulseLayer: visualLayer)
  }
  
  /// Prepares the visualLayer property.
  fileprivate func prepareVisualLayer() {
    visualLayer.zPosition = 0
    visualLayer.masksToBounds = true
    layer.addSublayer(visualLayer)
  }
}

extension CollectionViewCell {
  /// Manages the layout for the visualLayer property.
  fileprivate func layoutVisualLayer() {
    visualLayer.frame = bounds
    visualLayer.cornerRadius = layer.cornerRadius
  }
}
