//
//  Differentiable.swift
//  CoreStore
//
//  Copyright © 2018 John Rommel Estropia
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

import Foundation


// MARK: - Differentiable

@usableFromInline
internal protocol Differentiable {

    associatedtype DifferenceIdentifier: Hashable

    var differenceIdentifier: DifferenceIdentifier { get }

    func isContentEqual(to source: Self) -> Bool
}

extension Differentiable where Self: AnyObject {

    // MARK: Internal
    
    internal var differenceIdentifier: ObjectIdentifier {
    
        return .init(self)
    }
}


// MARK: - DifferentiableSection

@usableFromInline
internal protocol DifferentiableSection: Differentiable {
    
    associatedtype Collection: Swift.Collection where Collection.Element: Differentiable
    
    var elements: Collection { get }

    init<S: Sequence>(source: Self, elements: S) where S.Element == Collection.Element
}