Added DialogView

Sources/iOS/DialogView.swift

+/*
+ * Copyright (C) 2018, Daniel Dahan and CosmicMind, Inc. <http://cosmicmind.com>.
+ * All rights reserved.
+ *
+ * Original Inspiration & Author
+ * Copyright (C) 2018 Orkhan Alikhanov <orkhan.alikhanov@gmail.com>
+ *
+ * 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 class DialogScrollView: UIScrollView {
+  /// A weak reference to DialogView.
+  weak var dialogView: DialogView?
+  
+  override func layoutSubviews() {
+    super.layoutSubviews()
+    dialogView?.layoutDividers()
+  }
+}
+
+open class DialogView: View, Themeable {
+  /// A container view for title area.
+  public let titleArea = UIView()
+  
+  /// A container view for button area.
+  public let buttonArea = UIView()
+  
+  /// A container view for content area.
+  public let contentArea = UIView()
+  
+  /// A scroll view containing contentArea.
+  public let scrollView: UIScrollView = DialogScrollView()
+  
+  /// A UILabel.
+  public let titleLabel = UILabel()
+  
+  /// A UILabel.
+  public let detailsLabel = UILabel()
+  
+  /// A Button.
+  public let neutralButton = FlatButton()
+  
+  /// A Button.
+  public let positiveButton = FlatButton()
+  
+  /// A Button.
+  public let negativeButton = FlatButton()
+  
+  /// Maximum size of the dialog.
+  open var maxSize = CGSize(width: 200, height: 300) {
+    didSet {
+      invalidateIntrinsicContentSize()
+    }
+  }
+  
+  open override func prepare() {
+    super.prepare()
+    
+    depthPreset = .depth5
+    cornerRadiusPreset = .cornerRadius2
+    prepareTitleArea()
+    prepareTitleLabel()
+    prepareScrollView()
+    prepareContentArea()
+    prepareDetailsLabel()
+    prepareButtonArea()
+    prepareButtons()
+    applyCurrentTheme()
+  }
+  
+  open override var intrinsicContentSize: CGSize {
+    return sizeThatFits(maxSize)
+  }
+  
+  open override func sizeThatFits(_ size: CGSize) -> CGSize {
+    var w: CGFloat = 0
+    func setW(_ newW: CGFloat) {
+      w = max(w, newW)
+      w = min(w, size.width)
+    }
+    
+    setW(titleAreaSizeThatFits(width: size.width).width)
+    setW(buttonAreaSizeThatFits(width: size.width).width)
+    setW(contentAreaSizeThatFits(width: size.width).width)
+    
+    var h: CGFloat = 0
+    h += titleAreaSizeThatFits(width: w).height
+    h += buttonAreaSizeThatFits(width: w).height
+    h += contentAreaSizeThatFits(width: w).height
+    h = min(h, size.height)
+    
+    return CGSize(width: w, height: h)
+  }
+  
+  open override func layoutSubviews() {
+    super.layoutSubviews()
+    
+    layoutTitleArea()
+    layoutButtonArea()
+    layoutContentArea()
+    layoutScrollView()
+    layoutDividers()
+    
+    /// Position button area after having correct sizes.
+    buttonArea.frame.origin.y = scrollView.frame.maxY
+  }
+  
+  /**
+   Calculates the size for title area that best fits the specified width.
+   - Parameter width: A CGFloat.
+   - Returns: Calculated CGSize.
+   */
+  open func titleAreaSizeThatFits(width: CGFloat) -> CGSize {
+    guard !titleLabel.isEmpty else {
+      return .zero
+    }
+    
+    let insets = Constants.titleArea.insets
+    var size = titleLabel.sizeThatFits(CGSize(width: width - insets.left - insets.right, height: .greatestFiniteMagnitude))
+    size.width += insets.left + insets.right
+    size.height += insets.top + insets.bottom
+    return size
+  }
+  
+  /**
+   Calculates the size for button area that best fits the specified width.
+   - Parameter width: A CGFloat.
+   - Returns: Calculated CGSize.
+   */
+  open func buttonAreaSizeThatFits(width: CGFloat) -> CGSize {
+    guard !nonHiddenButtons.isEmpty else {
+      return .zero
+    }
+    
+    let isStacked = requiredButtonAreaWidth > width
+    let buttonsHeight = Constants.button.height * CGFloat(isStacked ? nonHiddenButtons.count : 1)
+    let buttonsInterim = isStacked ? CGFloat(nonHiddenButtons.count - 1) * Constants.button.interimStacked : 0
+    let insets = isStacked ? Constants.buttonArea.insetsStacked : Constants.buttonArea.insets
+    let h = buttonsInterim + buttonsHeight + insets.bottom + insets.top
+    let w = min(width, isStacked ? requiredButtonAreaWidthForStacked : requiredButtonAreaWidth)
+    return CGSize(width: w, height: h)
+  }
+  
+  /**
+   Calculates the size for content area that best fits the specified width.
+   - Parameter width: A CGFloat.
+   - Returns: Calculated CGSize.
+   */
+  open func contentAreaSizeThatFits(width: CGFloat) -> CGSize {
+    guard !detailsLabel.isEmpty else {
+      return .zero
+    }
+    
+    let insets = titleLabel.isEmpty ? Constants.contentArea.insetsNoTitle : Constants.contentArea.insets
+    var size = detailsLabel.sizeThatFits(CGSize(width: width - insets.left - insets.right, height: .greatestFiniteMagnitude))
+    size.width += insets.left + insets.right
+    size.height += insets.top + insets.bottom
+    return size
+  }
+  
+  /**
+   Applies the given theme.
+   - Parameter theme: A Theme.
+   */
+  open func apply(theme: Theme) {
+    backgroundColor = theme.surface
+    titleLabel.textColor = theme.onSurface.withAlphaComponent(0.87)
+    detailsLabel.textColor = theme.onSurface.withAlphaComponent(0.60)
+    
+    titleArea.dividerColor = theme.onSurface.withAlphaComponent(0.12)
+    buttonArea.dividerColor = theme.onSurface.withAlphaComponent(0.12)
+  }
+}
+
+private extension DialogView {
+  /// Prepares titleArea.
+  func prepareTitleArea() {
+    addSubview(titleArea)
+    titleArea.dividerColor = Color.darkText.dividers
+    titleArea.dividerThickness = 1
+    titleArea.dividerAlignment = .bottom
+  }
+  
+  /// Prepares titleTitle.
+  func prepareTitleLabel() {
+    titleArea.addSubview(titleLabel)
+    titleLabel.font = RobotoFont.bold(with: 20)
+    titleLabel.textColor = Color.darkText.primary
+    titleLabel.numberOfLines = 0
+  }
+  
+  /// Prepares buttonArea.
+  func prepareButtonArea() {
+    addSubview(buttonArea)
+    buttonArea.dividerColor = Color.darkText.dividers
+    buttonArea.dividerThickness = 1
+    buttonArea.dividerAlignment = .top
+  }
+  
+  /// Prepares buttons.
+  func prepareButtons() {
+    [positiveButton, negativeButton, neutralButton].forEach {
+      buttonArea.addSubview($0)
+      $0.titleLabel?.font = RobotoFont.medium(with: 14)
+      $0.contentEdgeInsets = Constants.button.insets
+      $0.cornerRadiusPreset = .cornerRadius1
+    }
+  }
+  
+  /// Prepares scrollView.
+  func prepareScrollView() {
+    (scrollView as! DialogScrollView).dialogView = self
+    addSubview(scrollView)
+  }
+  
+  /// Prepares contentArea.
+  func prepareContentArea() {
+    scrollView.addSubview(contentArea)
+  }
+
+  /// Prepares detailsLabel.
+  func prepareDetailsLabel() {
+    contentArea.addSubview(detailsLabel)
+    detailsLabel.numberOfLines = 0
+    detailsLabel.textColor = Color.darkText.secondary
+  }
+}
+
+private extension DialogView {
+  /// Layout the titleArea.
+  func layoutTitleArea() {
+    let size = CGSize(width: frame.width, height: titleAreaSizeThatFits(width: frame.width).height)
+    titleArea.frame.size = size
+    
+    guard !titleLabel.isEmpty else {
+      return
+    }
+    
+    let rect = CGRect(origin: .zero, size: size)
+    titleLabel.frame = rect.inset(by: Constants.titleArea.insets)
+  }
+  
+  /// Layout the buttonArea.
+  func layoutButtonArea() {
+    let width = frame.width
+    buttonArea.frame.size.width = width
+    buttonArea.frame.size.height = buttonAreaSizeThatFits(width: width).height
+    
+    let buttons = nonHiddenButtons
+    guard !buttons.isEmpty else {
+      return
+    }
+    
+    let isStacked = requiredButtonAreaWidth > width
+    if isStacked {
+      let insets = Constants.buttonArea.insetsStacked
+      buttons.forEach {
+        let w = min($0.optimalWidth, width - insets.left - insets.right)
+        $0.frame.size = CGSize(width: w, height: Constants.button.height)
+        $0.frame.origin.x = width - insets.right - w
+      }
+      
+      positiveButton.frame.origin.y = insets.top
+      let belowPositive = positiveButton.isHidden ? insets.top : positiveButton.frame.maxY + Constants.button.interimStacked
+      negativeButton.frame.origin.y = belowPositive
+      neutralButton.frame.origin.y = negativeButton.isHidden ? belowPositive : negativeButton.frame.maxY + Constants.button.interimStacked
+    } else {
+      let insets = Constants.buttonArea.insets
+      buttons.forEach {
+        $0.frame.size = CGSize(width: $0.optimalWidth, height: Constants.button.height)
+        $0.frame.origin.y = insets.top
+      }
+      
+      neutralButton.frame.origin.x = insets.left
+      positiveButton.frame.origin.x = width - insets.right - positiveButton.frame.width
+      
+      let maxX = positiveButton.isHidden ? width - insets.right : positiveButton.frame.minX - Constants.button.interim
+      negativeButton.frame.origin.x = maxX - negativeButton.frame.width
+    }
+  }
+  
+  /// Layout the contentArea.
+  func layoutContentArea() {
+    let size = CGSize(width: frame.width, height: contentAreaSizeThatFits(width: frame.width).height)
+    contentArea.frame.size = size
+    guard !detailsLabel.isEmpty else {
+      return
+    }
+    
+    let rect = CGRect(origin: .zero, size: size)
+    let insets = titleArea.frame.height == 0 ? Constants.contentArea.insetsNoTitle : Constants.contentArea.insets
+    detailsLabel.frame = rect.inset(by: insets)
+  }
+  
+  /// Layout the scrollView.
+  func layoutScrollView() {
+    let h = titleArea.frame.height + buttonArea.frame.height
+    let allowed = min(frame.height - h, contentArea.frame.height)
+    
+    scrollView.frame.size = CGSize(width: frame.width, height: max(allowed, 0))
+    scrollView.frame.origin.y = titleArea.frame.maxY
+    
+    scrollView.contentSize = contentArea.frame.size
+  }
+  
+  /**
+   Layout the dividers.
+   This method is also called (by scrollView) when scrolling happens
+  */
+  func layoutDividers() {
+    let isScrollable = contentArea.frame.height > scrollView.frame.height
+    
+    titleArea.isDividerHidden = titleArea.frame.height == 0 || !isScrollable || scrollView.isAtTop
+    buttonArea.isDividerHidden =  buttonArea.frame.height == 0 || !isScrollable || scrollView.isAtBottom
+    
+    titleArea.layoutDivider()
+    buttonArea.layoutDivider()
+  }
+}
+
+private extension DialogView {
+  /// Required width to fit content of buttonArea.
+  var requiredButtonAreaWidth: CGFloat {
+    let buttons = nonHiddenButtons
+    guard !buttons.isEmpty else {
+      return 0
+    }
+    
+    let buttonsWidth: CGFloat = buttons.reduce(0) { $0 + $1.optimalWidth }
+    let additional: CGFloat = neutralButton.isHidden ? 0 : 8 // additional spacing for neutral button
+    let insets = Constants.buttonArea.insets
+    return buttonsWidth + insets.left + insets.right + CGFloat((buttons.count - 1)) * Constants.button.interim + additional
+  }
+  
+  /// Required width to fit statcked content of buttonArea.
+  var requiredButtonAreaWidthForStacked: CGFloat {
+    let insets = Constants.buttonArea.insetsStacked
+    return insets.left + insets.right + nonHiddenButtons.reduce(0) {
+      max($0, $1.optimalWidth)
+    }
+  }
+  
+  /// Non-hidden buttons within buttonArea.
+  var nonHiddenButtons: [Button] {
+    positiveButton.isHidden = positiveButton.title(for: .normal)?.isEmpty ?? true
+    negativeButton.isHidden = negativeButton.title(for: .normal)?.isEmpty ?? true
+    neutralButton.isHidden = neutralButton.title(for: .normal)?.isEmpty ?? true
+    return [positiveButton, negativeButton, neutralButton].filter { !$0.isHidden }
+  }
+}
+
+private extension UIScrollView {
+  /// Checks if scroll view is at the top.
+  var isAtTop: Bool {
+    return contentOffset.y <= 0
+  }
+  
+  /// Checks if scroll view is at the bottom.
+  var isAtBottom: Bool {
+    /// -1 is used to get rid of precision errors
+    /// make divider appear even when scroll is at the bottom.
+    return contentOffset.y >= (contentSize.height - frame.height - 1)
+  }
+}
+
+private extension Button {
+  /// Optimal width for dialog button.
+  var optimalWidth: CGFloat {
+    let size = CGSize(width: .greatestFiniteMagnitude, height: Constants.button.height)
+    return max(Constants.button.minWidth, sizeThatFits(size).width)
+  }
+}
+
+private extension UILabel {
+  /// Checks if label is empty.
+  var isEmpty: Bool {
+    let empty = text?.isEmpty ?? true
+    isHidden = empty
+    return empty
+  }
+}
+
+private struct Constants {
+  struct titleArea {
+    static let insets = UIEdgeInsets(top: 24, left: 24, bottom: 20, right: 24)
+  }
+  
+  struct contentArea {
+    static let insets = UIEdgeInsets(top: 0, left: 24, bottom: 24, right: 24)
+    static let insetsNoTitle = UIEdgeInsets(top: 20, left: 24, bottom: 24, right: 24)
+  }
+  
+  struct buttonArea {
+    static let insets = UIEdgeInsets(top: 8, left: 8, bottom: 8, right: 8)
+    static let insetsStacked = UIEdgeInsets(top: 6, left: 8, bottom: 14, right: 8)
+  }
+  
+  struct button {
+    static let insets = UIEdgeInsets(top: 0, left: 8, bottom: 0, right: 8)
+    static let minWidth: CGFloat = 64
+    static let height: CGFloat = 36
+    static let interimStacked: CGFloat = 12
+    static let interim: CGFloat = 8
+  }
+}