AIO ObservableUserDefault PropertyWrapper

ObservableUserDefault.swift

//
//  UserDefaultWrapper.swift
//  Code Drawer
//
//  Created by Jinyu Meng on 2023/7/23.
//

import Combine
import SwiftUI

@propertyWrapper
public struct ObservableUserDefault<T: Sendable> {
    private let get: () -> T
    private let set: (T) -> Void
    
    public var wrappedValue: T {
        get {
            get()
        }
        nonmutating set {
            set(newValue)
        }
    }
    
    public init(wrappedValue value: T, key: String, container: UserDefaults = .standard) {
        
        get = {
            return container.object(forKey: key) as? T ?? value
        }
        set = { newValue in
            container.set(newValue, forKey: key)
        }
    }
    
    public init(wrappedValue value: T, key: String, container: UserDefaults = .standard) where T: RawRepresentable {
        get = {
            if let rawValue = container.object(forKey: key) as? T.RawValue {
                return T(rawValue: rawValue) ?? value
            } else {
                return value
            }
        }
        set = { newValue in
            container.set(newValue.rawValue, forKey: key)
        }
    }
    
    public init(wrappedValue value: T, key: String, container: UserDefaults = .standard) where T: Codable {
        get = {
            let decoder = JSONDecoder()
            if let data = container.data(forKey: key) {
                return (try? decoder.decode(T.self, from: data)) ?? value
            } else {
                return value
            }
        }
        set = { newValue in
            let encoder = JSONEncoder()
            if let data = try? encoder.encode(newValue) {
                container.set(data, forKey: key)
            } else {
                container.removeObject(forKey: key)
            }
        }
    }
    
    public init(wrappedValue value: T, key: String, container: UserDefaults = .standard) where T: Codable & RawRepresentable {
        get = {
            let decoder = JSONDecoder()
            if let data = container.data(forKey: key) {
                return (try? decoder.decode(T.self, from: data)) ?? value
            } else {
                return value
            }
        }
        set = { newValue in
            let encoder = JSONEncoder()
            if let data = try? encoder.encode(newValue) {
                container.set(data, forKey: key)
            } else {
                container.removeObject(forKey: key)
            }
        }
    }
    
    @MainActor
    public static subscript<EnclosingSelf: AnyObject> (
        _enclosingInstance object: EnclosingSelf,
        wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, T>,
        storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, ObservableUserDefault<T>>
    ) -> T {
        get {
            return object[keyPath: storageKeyPath].wrappedValue
        }
        set {
            if let object = object as? any ObservableObject {
                DispatchQueue.main.async {
                    (object.objectWillChange as? ObservableObjectPublisher)?.send()
                }
            }
            object[keyPath: storageKeyPath].wrappedValue = newValue
        }
    }
}