// Created by Gil Birman on 1/11/20.

import SwiftUI

/// Inject a Cloe Store into a SwiftUI view

///

/// Example usage:

///

/// struct MyView: View {

/// var index: Int

///

/// // Define your derived state

/// struct MyDerivedState: Equatable {

/// var age: Int

/// var name: String

/// }

///

/// // Inject your store

/// @EnvironmentObject var store: AppStore

///

/// // Connect to the store

/// var body: some View {

/// Connect(store: store, selector: selector, content: body)

/// }

///

/// // Setup a state selector

/// private func selector(_ state: AppState) -> MyDerivedState {

/// .init(age: state.age, name: state.names[index])

/// }

///

/// // Render something using the selected state

/// private func body(_ state: MyDerivedState) -> some View {

/// Text("Hello \(state.name)!")

/// }

/// }

@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)

public struct Connect<State, SubState: Equatable, Content: View>: View {

// MARK: Public

public var store: Store<State>

public var selector: StateSelector<State, SubState>

public var content: (SubState) -> Content

public init(

store: Store<State>,

selector: @escaping StateSelector<State, SubState>,

content: @escaping (SubState) -> Content)

{

self.store = store

self.selector = selector

self.content = content

}

public var body: some View {

Group {

(state ?? selector(store.state)).map(content)

}.onReceive(store.uniqueSubStatePublisher(selector)) { state in

self.state = state

}

}

// MARK: Private

@SwiftUI.State private var state: SubState?

}