Tusker/Tusker/Preferences/Preference.swift

//  Preference.swift
//  Tusker
//
//  Created by Shadowfacts on 6/13/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import SwiftUI

@propertyWrapper
struct Preference<Value>: BindingConvertible {
    let path: WritableKeyPath<Preferences, Value>
    let binding: Binding<Value>
    
    init(_ path: WritableKeyPath<Preferences, Value>) {
        self.path = path
        self.binding = Binding(get: {
            return Preferences.shared[keyPath: path]
        }, set: { (newValue) in
            Preferences.shared[keyPath: path] = newValue
        })
    }
    
    var wrappedValue: Value {
        get {
            return Preferences.shared[keyPath: path]
        }
        set {
            Preferences.shared[keyPath: path] = newValue
        }
    }
}

@propertyWrapper
struct MappedPreference<Value, PrefValue>: BindingConvertible {
    let path: WritableKeyPath<Preferences, PrefValue>
    let fromPref: (PrefValue) -> Value
    let toPref: (Value) -> PrefValue
    let binding: Binding<Value>
    
    init(_ path: WritableKeyPath<Preferences, PrefValue>, fromPref: @escaping (PrefValue) -> Value, toPref: @escaping (Value) -> PrefValue) {
        self.path = path
        self.fromPref = fromPref
        self.toPref = toPref
        self.binding = Binding(get: {
            return fromPref(Preferences.shared[keyPath: path])
        }, set: { (newValue) in
            Preferences.shared[keyPath: path] = toPref(newValue)
        })
    }
    
    var wrappedValue: Value {
        get {
            return fromPref(Preferences.shared[keyPath: path])
        }
        set {
            Preferences.shared[keyPath: path] = toPref(newValue)
        }
    }
}