Typed UITableViewCell/UICollectionViewCell registration and dequeuing

Reusable.swift

//
//  Reusable.swift
//  Reusable
//
//  Copyright (c) <2018>, Gabriel O'Flaherty-Chan
//  All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are met:
//  1. Redistributions of source code must retain the above copyright
//  notice, this list of conditions and the following disclaimer.
//  2. 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.
//  3. All advertising materials mentioning features or use of this software
//  must display the following acknowledgement:
//  This product includes software developed by skysent.
//  4. Neither the name of the skysent 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 skysent ''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 skysent 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

public protocol Reusable {
}

extension UICollectionReusableView: Reusable {
}

extension UITableViewCell: Reusable {
}

extension UICollectionView {
  public typealias Cell = UICollectionReusableView

  public enum CellType {
    case cell, header, footer

    var kind: String? {
      switch self {
      case .header:
        return UICollectionView.elementKindSectionHeader
      case .footer:
        return UICollectionView.elementKindSectionFooter
      default:
        return nil
      }
    }
  }

  public func register(_ type: CellType, _ cellClass: Cell.Type) {
    let identifier = String(describing: cellClass)
    switch type {
    case .cell:
      if let nib = cellClass.nib {
        register(nib, forCellWithReuseIdentifier: identifier)
      } else {
        register(cellClass, forCellWithReuseIdentifier: identifier)
      }
    default:
      let kind = type.kind!
      if let nib = cellClass.nib {
        register(nib, forSupplementaryViewOfKind: kind, withReuseIdentifier: identifier)
      } else {
        register(cellClass, forSupplementaryViewOfKind: kind, withReuseIdentifier: identifier)
      }
    }
  }

  public func dequeue<T>(_ type: CellType = .cell, for indexPath: IndexPath) -> T? where T: Reusable {
    let identifier = String(describing: T.self)
    switch type {
    case .cell:
      return dequeueReusableCell(withReuseIdentifier: identifier, for: indexPath) as? T
    default:
      return dequeueReusableSupplementaryView(ofKind: type.kind!, withReuseIdentifier: identifier, for: indexPath) as? T
    }
  }
}

public protocol ReusableHeader {
}

extension UITableViewHeaderFooterView: ReusableHeader {
}

extension UITableView {
  public typealias Cell = UITableViewCell

  public func registerHeader(_ cellClass: UITableViewHeaderFooterView.Type) {
    let identifier = String(describing: cellClass)
    if let nib = cellClass.nib {
      register(nib, forHeaderFooterViewReuseIdentifier: identifier)
    } else {
      register(cellClass, forHeaderFooterViewReuseIdentifier: identifier)
    }
  }

  public func register(_ types: Cell.Type...) {
    types.forEach { cellClass in
      let identifier = String(describing: cellClass)
      if let nib = cellClass.nib {
        register(nib, forCellReuseIdentifier: identifier)
      } else {
        register(cellClass, forCellReuseIdentifier: identifier)
      }
    }
  }

  public func dequeueReusableCell<T>(for indexPath: IndexPath) -> T? where T: Reusable {
    return dequeueReusableCell(withIdentifier: String(describing: T.self), for: indexPath) as? T
  }

  public func dequeueReusableCell<T: Reusable>(for indexPath: IndexPath, type: T.Type) -> T? {
    return dequeueReusableCell(withIdentifier: String(describing: type), for: indexPath) as? T
  }

  public func dequeueHeader<T: ReusableHeader>() -> T? {
    return dequeueReusableHeaderFooterView(withIdentifier: String(describing: T.self)) as? T
  }
}