Adapter Pattern

AdapterPattern.swift

import UIKit

// MARK: - Base Protocol

typealias Result = ((Bool) -> Void)
typealias Err = ((Error?) -> Void)

protocol Share {
    func post(image: UIImage?, text: String?, result: Result, error: Err?)
}

// MARK: - Share Helpers

class FacebookShareHelper: Share {
    func post(image: UIImage?, text: String?, result: Result, error: Err?) {
        /// .. sharing instructions
        print("successful - shared: \(text)")
        result(true)
    }
}

class TwitterShareHelper: Share {
    func post(image: UIImage?, text: String?, result: Result, error: Err?) {
        /// .. sharing instructions
        print("successful - shared: \(text)")
        result(true)
    }
}

class InstagramShareHelper {
    func share(image: UIImage?) -> Bool {
        /// .. sharing instructions
        print("successful - shared")
        return true
    }
}

// MARK: - Adapter

class InstagramShareAdapter: Share {
    private let instance = InstagramShareHelper()
    
    func post(image: UIImage?, text: String?, result: Result, error: Err?) {
        let success = instance.share(image: image)
        result(success)
    }
}

// MARK: - Base Class

enum Platform {
    case facebook
    case twitter
    case instagram
    case whatsapp
    
    var platformName: String {
        switch self {
        case .facebook: return "Facebook"
        case .twitter: return "Twitter"
        case .instagram: return "Instagram"
        case .whatsapp: return "Whatsapp"
        }
    }
}

// MARK: - Implementation

class ShareHelper {
    private let services: [Platform: Share] = [
        .facebook: FacebookShareHelper(),
        .twitter: TwitterShareHelper(),
        .instagram: InstagramShareAdapter(), // Implemented by Adapter Pattern Class
        .whatsapp: WhatsappShareHelper(), // Implemented by Extension
    ]
    
    func share(image: UIImage?, message: String?, platform: Platform) {
        guard let service = services[platform] else {
            return
        }
        
        service.post(image: image, text: message) { (result) in
            print("Success: \(result) platform: \(platform.platformName)")
        } error: { (err) in
            print("error occured: \(err?.localizedDescription)")
        }
    }
}

// MARK: - Instance

let helper = ShareHelper()

helper.share(image: nil, message: "Burak", platform: .instagram)
helper.share(image: nil, message: "Furkan", platform: .twitter)
helper.share(image: nil, message: "Asilturk", platform: .facebook)

// MARK: - Adapter Extension

class WhatsappShareHelper {
    func share(text: String?, image: UIImage?, userId: Int) -> Bool {
        /// .. sharing instructions
        print("successful - shared: \(text)")
        return true
    }
}

extension WhatsappShareHelper: Share {
    var defaultUserId: Int { 0 }
    
    func post(image: UIImage?, text: String?, result: (Bool) -> Void, error: Err?) {
        let success = self.share(text: text, image: image, userId: defaultUserId)
        result(success)
    }
}

helper.share(image: nil, message: "Much more pretty.", platform: .whatsapp)