TabTrayCell.swift

// Copyright 2021 The Brave Authors. All rights reserved.
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

import Foundation
import Shared
import UIKit
import DesignSystem
import Favicon

class TabCell: UICollectionViewCell {

  struct UX {
    static let cornerRadius = 6.0
    static let defaultBorderWidth = 1.0 / UIScreen.main.scale
    static let textBoxHeight = 32.0
    static let faviconSize = 20.0
  }

  static let identifier = "TabCellIdentifier"
  static let borderWidth = 3.0

  let backgroundHolder = UIView()
  let screenshotView = UIImageView()
  let titleBackgroundView = GradientView(
    colors: [UIColor(white: 1.0, alpha: 0.98), UIColor(white: 1.0, alpha: 0.9), UIColor(white: 1.0, alpha: 0.0)],
    positions: [0, 0.5, 1],
    startPoint: .zero,
    endPoint: CGPoint(x: 0, y: 1)
  )
  let titleLabel: UILabel
  let favicon: UIImageView = UIImageView().then {
    $0.contentMode = .scaleAspectFit
  }
  let closeButton: UIButton

  var animator: SwipeAnimator!

  // Changes depending on whether we're full-screen or not.
  var margin = 0.0

  var closedTab: ((Tab) -> Void)?
  weak var tab: Tab?

  func configure(with tab: Tab) {
    self.tab = tab
    tab.onScreenshotUpdated = { [weak self, weak tab] in
      guard let self = self, let tab = tab else { return }
      
      if !tab.displayTitle.isEmpty {
        self.accessibilityLabel = tab.displayTitle
      }
      
      self.titleLabel.text = tab.displayTitle
      self.favicon.image = tab.displayFavicon?.image ?? Favicon.defaultImage
      self.screenshotView.image = tab.screenshot
    }

    titleLabel.text = tab.displayTitle
    favicon.image = tab.displayFavicon?.image ?? Favicon.defaultImage

    if !tab.displayTitle.isEmpty {
      accessibilityLabel = tab.displayTitle
    } else {
      if let url = tab.url {
        accessibilityLabel = InternalURL(url)?.aboutComponent ?? ""
      } else {
        accessibilityLabel = ""
      }
    }
    isAccessibilityElement = true
    accessibilityHint = Strings.tabTrayCellCloseAccessibilityHint

    favicon.image = nil
    favicon.cancelFaviconLoad()

    // Tab may not be restored and so may not include a tab URL yet...
    if let displayFavicon = tab.displayFavicon {
      favicon.image = displayFavicon.image ?? Favicon.defaultImage
    } else if let url = tab.url, !url.isLocal, !InternalURL.isValid(url: url) {
      favicon.loadFavicon(for: url, isPrivateBrowsing: tab.isPrivate)
    } else {
      favicon.image = Favicon.defaultImage
    }

    screenshotView.image = tab.screenshot
  }

  override init(frame: CGRect) {
    self.backgroundHolder.backgroundColor = .white
    self.backgroundHolder.layer.cornerRadius = UX.cornerRadius
    self.backgroundHolder.layer.cornerCurve = .continuous
    self.backgroundHolder.clipsToBounds = true

    self.screenshotView.contentMode = .scaleAspectFill
    self.screenshotView.clipsToBounds = true
    self.screenshotView.isUserInteractionEnabled = false
    self.screenshotView.backgroundColor = .braveBackground

    self.favicon.backgroundColor = .clear
    self.favicon.layer.cornerRadius = 2.0
    self.favicon.layer.cornerCurve = .continuous
    self.favicon.layer.masksToBounds = true

    self.titleLabel = UILabel()
    self.titleLabel.isUserInteractionEnabled = false
    self.titleLabel.numberOfLines = 1
    self.titleLabel.font = DynamicFontHelper.defaultHelper.DefaultSmallFontBold
    self.titleLabel.textColor = .black
    self.titleLabel.backgroundColor = .clear

    self.closeButton = UIButton()
    self.closeButton.setImage(UIImage(named: "tab_close", in: .module, compatibleWith: nil)!, for: [])
    self.closeButton.imageView?.contentMode = .scaleAspectFit
    self.closeButton.contentMode = .center
    self.closeButton.imageEdgeInsets = UIEdgeInsets(equalInset: 7)

    super.init(frame: frame)

    animator = SwipeAnimator(animatingView: self)
    animator.delegate = self
    self.closeButton.addTarget(self, action: #selector(close), for: .touchUpInside)

    layer.borderWidth = UX.defaultBorderWidth
    layer.borderColor = UIColor.braveSeparator.resolvedColor(with: traitCollection).cgColor
    layer.cornerRadius = UX.cornerRadius
    layer.cornerCurve = .continuous

    contentView.addSubview(backgroundHolder)
    backgroundHolder.addSubview(self.screenshotView)
    backgroundHolder.addSubview(self.titleBackgroundView)

    titleBackgroundView.addSubview(self.closeButton)
    titleBackgroundView.addSubview(self.titleLabel)
    titleBackgroundView.addSubview(self.favicon)

    self.accessibilityCustomActions = [
      UIAccessibilityCustomAction(name: Strings.tabAccessibilityCloseActionLabel, target: self.animator, selector: #selector(SwipeAnimator.closeWithoutGesture))
    ]
  }

  func setTabSelected(_ tab: Tab) {
    layer.shadowColor = UIColor.braveInfoBorder.resolvedColor(with: traitCollection).cgColor
    layer.shadowOpacity = 1
    layer.shadowRadius = 0  // A 0 radius creates a solid border instead of a gradient blur
    layer.masksToBounds = false
    // create a frame that is "BorderWidth" size bigger than the cell
    layer.shadowOffset = CGSize(width: -TabCell.borderWidth, height: -TabCell.borderWidth)
    let shadowPath = CGRect(width: layer.frame.width + (TabCell.borderWidth * 2), height: layer.frame.height + (TabCell.borderWidth * 2))
    layer.shadowPath = UIBezierPath(roundedRect: shadowPath, cornerRadius: UX.cornerRadius + TabCell.borderWidth).cgPath
    layer.borderWidth = 0.0
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }

  override func layoutSubviews() {
    super.layoutSubviews()

    backgroundHolder.frame = CGRect(x: margin, y: margin, width: frame.width, height: frame.height)
    screenshotView.frame = CGRect(size: backgroundHolder.frame.size)

    titleBackgroundView.snp.makeConstraints { make in
      make.top.left.right.equalTo(backgroundHolder)
      make.height.equalTo(UX.textBoxHeight + 15.0)
    }

    favicon.snp.makeConstraints { make in
      make.leading.equalTo(titleBackgroundView).offset(6)
      make.top.equalTo((UX.textBoxHeight - UX.faviconSize) / 2)
      make.size.equalTo(UX.faviconSize)
    }

    titleLabel.snp.makeConstraints { make in
      make.leading.equalTo(favicon.snp.trailing).offset(6)
      make.trailing.equalTo(closeButton.snp.leading).offset(-6)
      make.centerY.equalTo(favicon)
    }

    closeButton.snp.makeConstraints { make in
      make.size.equalTo(32)
      make.trailing.equalTo(titleBackgroundView)
      make.centerY.equalTo(favicon)
    }

    let shadowPath = CGRect(width: layer.frame.width + (TabCell.borderWidth * 2), height: layer.frame.height + (TabCell.borderWidth * 2))
    layer.shadowPath = UIBezierPath(roundedRect: shadowPath, cornerRadius: UX.cornerRadius + TabCell.borderWidth).cgPath
  }

  override func prepareForReuse() {
    // Reset any close animations.
    backgroundHolder.transform = .identity
    backgroundHolder.alpha = 1
    titleLabel.font = DynamicFontHelper.defaultHelper.DefaultSmallFontBold
    layer.shadowOffset = .zero
    layer.shadowPath = nil
    layer.shadowOpacity = 0
    layer.borderWidth = UX.defaultBorderWidth
  }

  override func accessibilityScroll(_ direction: UIAccessibilityScrollDirection) -> Bool {
    var right: Bool
    switch direction {
    case .left:
      right = false
    case .right:
      right = true
    default:
      return false
    }
    animator.close(right: right)
    return true
  }

  @objc
  func close() {
    if let tab = tab {
      closedTab?(tab)
    }
  }

  override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)

    // cgcolor does not dynamically update
    traitCollection.performAsCurrent {
      layer.shadowColor = UIColor.braveInfoBorder.cgColor
      layer.borderColor = UIColor.braveSeparator.cgColor
    }
  }
}

extension TabCell: SwipeAnimatorDelegate {
  func swipeAnimator(_ animator: SwipeAnimator, viewWillExitContainerBounds: UIView) {
    if let tab = tab {
      closedTab?(tab)
    }
  }
}