Simple data store API for Swift applications.

Domain.swift

//
//  Domain.swift
//  Inspired by Eve
//
//  Created by Jason Jobe on 11/26/16.
//  Copyright © 2016 Jason Jobe. All rights reserved.
//  https://gist.github.com/wildthink/b911a5b8e0d7dc6ef190fd8fe4f7a2ee
//

import Foundation


public struct DomainType: ExpressibleByStringLiteral, CustomStringConvertible {

    public var name: String
    public var plural_name: String { return "\(name)s" }
    public var description: String { return "Type:\(name)" }

    public init(unicodeScalarLiteral value: String) {
        self.init(stringLiteral: value)
    }

    public init(extendedGraphemeClusterLiteral value: String) {
        self.init(stringLiteral: value)
    }

    public init(stringLiteral value: String) {
        name = value
    }
    
}

public enum ChangeType { case insert, update, delete }

public protocol Domain {

    func recall (type: DomainType, with context: Any?, where test: Any?, result: ([Any]?) -> Void)

    func bind <T> (type: T.Type, graph: Any, update: (ChangeType, [T]) -> Void)
    func commit <T: Any> (change: ChangeType, with: Any?, _ objects: [T])

    var name: String? { get }
}

extension Domain {
    
    public var name: String? { return nil }

    public func recall (type: DomainType, result: ([Any]?) -> Void)
    {
        return self.recall (type: type, with: nil, where: nil, result: result)
    }
    public func recall (type: DomainType, with context: Any?, result: ([Any]) -> Void)
    {
        self.recall (type: type, with: context, where: nil, result: result)
    }
    public func recall  (type: DomainType, with context: Any?, where test: Any?, result: ([Any]) -> Void)
    {
        Swift.print ("WARNING:", #function, "NOT IMPLEMENTED")
    }

    public func bind <T> (type: T.Type, graph: Any, update: (ChangeType, [T]) -> Void) {
        Swift.print ("WARNING:", #function, "NOT IMPLEMENTED")
    }
  
    public func commit <T: Any> (change: ChangeType = .update, _ objects: [T]) {
        self.commit(change: change, with: nil, objects)
    }
    public func commit <T: Any> (change: ChangeType, with context: Any?, _ objects: [T]) {
        Swift.print ("WARNING:", #function, "NOT IMPLEMENTED")
    }
}

#if os(iOS)
    import UIKit.UIResponder
    public typealias Responder = UIResponder
    public typealias Application = UIApplication
    public typealias ApplicationDelegate = UIApplicationDelegate
#else
    import AppKit.NSResponder
    public typealias Responder = NSResponder
    public typealias Application = NSApplication
    public typealias ApplicationDelegate = NSApplicationDelegate
#endif

public extension NSObjectProtocol where Self: Responder
{
    public var domain: Domain?
    {
        var next: Responder? = self
        
        while next != nil {
            if next is Domain { return next as? Domain }
            next = next?.next
        }
        return self is ApplicationDelegate
            ? nil : Application.shared.delegate as? Domain
    }

    public func domain (named: String) -> Domain?
    {
        var next: Responder? = self
        
        while next != nil {
            if let domain = next as? Domain, domain.name == named  { return domain }
            next = next?.next
        }
        return self is ApplicationDelegate
            ? nil : Application.shared.delegate as? Domain
    }

}