vChewing-macOS/Packages/Sindresorhus_Preferences/Source/Preferences/PreferencesTabViewController.swift

// (c) 2018 and onwards Sindre Sorhus (MIT License).
// ====================
// This code is released under the MIT license (SPDX-License-Identifier: MIT)

import Cocoa

final class PreferencesTabViewController: NSViewController, PreferencesStyleControllerDelegate {
  private var activeTab: Int?
  private var preferencePanes = [PreferencePane]()
  private var style: Preferences.Style?
  internal var preferencePanesCount: Int { preferencePanes.count }
  private var preferencesStyleController: PreferencesStyleController!
  private var isKeepingWindowCentered: Bool { preferencesStyleController.isKeepingWindowCentered }

  private var toolbarItemIdentifiers: [NSToolbarItem.Identifier] {
    preferencesStyleController?.toolbarItemIdentifiers() ?? []
  }

  var window: NSWindow! { view.window }

  var isAnimated = true

  var activeViewController: NSViewController? {
    guard let activeTab = activeTab else {
      return nil
    }

    return preferencePanes[activeTab]
  }

  override func loadView() {
    let newView = NSVisualEffectView()
    newView.material = NSVisualEffectView.Material.sidebar
    newView.blendingMode = NSVisualEffectView.BlendingMode.behindWindow
    newView.state = NSVisualEffectView.State.active
    view = newView
    view.translatesAutoresizingMaskIntoConstraints = false
  }

  func configure(preferencePanes: [PreferencePane], style: Preferences.Style) {
    self.preferencePanes = preferencePanes
    self.style = style
    children = preferencePanes

    let toolbar = NSToolbar(identifier: "PreferencesToolbar")
    toolbar.allowsUserCustomization = false
    toolbar.displayMode = .iconAndLabel
    toolbar.showsBaselineSeparator = true
    toolbar.delegate = self

    switch style {
      case .segmentedControl:
        preferencesStyleController = SegmentedControlStyleViewController(preferencePanes: preferencePanes)
      case .toolbarItems:
        preferencesStyleController = ToolbarItemStyleViewController(
          preferencePanes: preferencePanes,
          toolbar: toolbar,
          centerToolbarItems: false
        )
    }
    preferencesStyleController.delegate = self

    // Called last so that `preferencesStyleController` can be asked for items.
    window.toolbar = toolbar
  }

  func activateTab(preferencePane: PreferencePane, animated: Bool) {
    activateTab(preferenceIdentifier: preferencePane.preferencePaneIdentifier, animated: animated)
  }

  func activateTab(preferenceIdentifier: Preferences.PaneIdentifier, animated: Bool) {
    guard let index = (preferencePanes.firstIndex { $0.preferencePaneIdentifier == preferenceIdentifier }) else {
      return activateTab(index: 0, animated: animated)
    }

    activateTab(index: index, animated: animated)
  }

  func activateTab(index: Int, animated: Bool) {
    defer {
      activeTab = index
      preferencesStyleController.selectTab(index: index)
      updateWindowTitle(tabIndex: index)
    }

    if activeTab == nil {
      immediatelyDisplayTab(index: index)
    } else {
      guard index != activeTab else {
        return
      }

      animateTabTransition(index: index, animated: animated)
    }
  }

  func restoreInitialTab() {
    if activeTab == nil {
      activateTab(index: 0, animated: false)
    }
  }

  private func updateWindowTitle(tabIndex _: Int) {
    window.title = {
      //			if preferencePanes.count > 1 {
      //				return preferencePanes[tabIndex].preferencePaneTitle
      //			} else {
      //				let preferences = Localization[.preferences]
      //				let appName = Bundle.main.appName
      //				return "\(appName) \(preferences)"
      //			}
      var preferencesTitleName = NSLocalizedString("vChewing Preferences…", comment: "")
      preferencesTitleName.removeLast()
      return preferencesTitleName
    }()
  }

  /// Cached constraints that pin `childViewController` views to the content view.
  private var activeChildViewConstraints = [NSLayoutConstraint]()

  private func immediatelyDisplayTab(index: Int) {
    let toViewController = preferencePanes[index]
    view.addSubview(toViewController.view)
    activeChildViewConstraints = toViewController.view.constrainToSuperviewBounds()
    setWindowFrame(for: toViewController, animated: false)
  }

  private func animateTabTransition(index: Int, animated: Bool) {
    guard let activeTab = activeTab else {
      assertionFailure(
        "animateTabTransition called before a tab was displayed; transition only works from one tab to another")
      immediatelyDisplayTab(index: index)
      return
    }

    let fromViewController = preferencePanes[activeTab]
    let toViewController = preferencePanes[index]

    // View controller animations only work on macOS 10.14 and newer.
    let options: NSViewController.TransitionOptions
    if #available(macOS 10.14, *) {
      options = animated && isAnimated ? [.slideUp] : []
    } else {
      options = []
    }

    view.removeConstraints(activeChildViewConstraints)

    transition(
      from: fromViewController,
      to: toViewController,
      options: options
    ) { [self] in
      activeChildViewConstraints = toViewController.view.constrainToSuperviewBounds()
    }
  }

  override func transition(
    from fromViewController: NSViewController,
    to toViewController: NSViewController,
    options: NSViewController.TransitionOptions = [],
    completionHandler completion: (() -> Void)? = nil
  ) {
    let isAnimated =
      options
      .intersection([
        .crossfade,
        .slideUp,
        .slideDown,
        .slideForward,
        .slideBackward,
        .slideLeft,
        .slideRight,
      ])
      .isEmpty == false

    if isAnimated {
      NSAnimationContext.runAnimationGroup(
        { context in
          context.allowsImplicitAnimation = true
          context.duration = 0.25
          context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
          setWindowFrame(for: toViewController, animated: true)

          super.transition(
            from: fromViewController,
            to: toViewController,
            options: options,
            completionHandler: completion
          )
        }, completionHandler: nil
      )
    } else {
      super.transition(
        from: fromViewController,
        to: toViewController,
        options: options,
        completionHandler: completion
      )
    }
  }

  private func setWindowFrame(for viewController: NSViewController, animated: Bool = false) {
    guard let window = window else {
      preconditionFailure()
    }

    let contentSize = viewController.view.fittingSize

    let newWindowSize = window.frameRect(forContentRect: CGRect(origin: .zero, size: contentSize)).size
    var frame = window.frame
    frame.origin.y += frame.height - newWindowSize.height
    frame.size = newWindowSize

    if isKeepingWindowCentered {
      let horizontalDiff = (window.frame.width - newWindowSize.width) / 2
      frame.origin.x += horizontalDiff
    }

    let animatableWindow = animated ? window.animator() : window
    animatableWindow.setFrame(frame, display: false)
  }
}

extension PreferencesTabViewController: NSToolbarDelegate {
  func toolbarDefaultItemIdentifiers(_: NSToolbar) -> [NSToolbarItem.Identifier] {
    toolbarItemIdentifiers
  }

  func toolbarAllowedItemIdentifiers(_: NSToolbar) -> [NSToolbarItem.Identifier] {
    toolbarItemIdentifiers
  }

  func toolbarSelectableItemIdentifiers(_: NSToolbar) -> [NSToolbarItem.Identifier] {
    style == .segmentedControl ? [] : toolbarItemIdentifiers
  }

  public func toolbar(
    _: NSToolbar,
    itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier,
    willBeInsertedIntoToolbar _: Bool
  ) -> NSToolbarItem? {
    if itemIdentifier == .flexibleSpace {
      return nil
    }

    return preferencesStyleController.toolbarItem(
      preferenceIdentifier: Preferences.PaneIdentifier(fromToolbarItemIdentifier: itemIdentifier))
  }
}