Composable messages

Chatto/sources/Chat Items/ChatItemProtocolDefinitions.swift

@@ -77,6 +77,10 @@ public protocol ChatItemPresenterBuilderProtocol {
     var presenterType: ChatItemPresenterProtocol.Type { get }
 }
 
+public protocol ChatItemPresenterBuilderCollectionViewConfigurable {
+    func configure(with collectionView: UICollectionView)
+}
+
 // MARK: - Updatable Chat Items
 
 public protocol ContentEquatableChatItemProtocol: ChatItemProtocol {

Chatto/sources/ChatController/Collaborators/ChatItemPresenterFactory.swift

@@ -30,10 +30,16 @@ public protocol ChatItemPresenterFactoryProtocol {
 }
 
 public final class ChatItemPresenterFactory: ChatItemPresenterFactoryProtocol {
-    let presenterBuildersByType: [ChatItemType: [ChatItemPresenterBuilderProtocol]]
 
-    public init(presenterBuildersByType: [ChatItemType: [ChatItemPresenterBuilderProtocol]]) {
+    public typealias PresenterBuildersByType = [ChatItemType: [ChatItemPresenterBuilderProtocol]]
+
+    private let presenterBuildersByType: PresenterBuildersByType
+    private let fallbackItemPresenterFactory: ChatItemPresenterFactoryProtocol
+
+    public init(presenterBuildersByType: PresenterBuildersByType,
+                fallbackItemPresenterFactory: ChatItemPresenterFactoryProtocol = DummyItemPresenterFactory()) {
         self.presenterBuildersByType = presenterBuildersByType
+        self.fallbackItemPresenterFactory = fallbackItemPresenterFactory
     }
 
     public func createChatItemPresenter(_ chatItem: ChatItemProtocol) -> ChatItemPresenterProtocol {
@@ -42,13 +48,30 @@ public final class ChatItemPresenterFactory: ChatItemPresenterFactoryProtocol {
                 return builder.createPresenterWithChatItem(chatItem)
             }
         }
-        return DummyChatItemPresenter()
+        return self.fallbackItemPresenterFactory.createChatItemPresenter(chatItem)
     }
 
     public func configure(withCollectionView collectionView: UICollectionView) {
         for presenterBuilder in self.presenterBuildersByType.flatMap({ $0.1 }) {
-            presenterBuilder.presenterType.registerCells(collectionView)
+            if let configurablePresenterBuilder = presenterBuilder as? ChatItemPresenterBuilderCollectionViewConfigurable {
+                configurablePresenterBuilder.configure(with: collectionView)
+            } else {
+                presenterBuilder.presenterType.registerCells(collectionView)
+            }
         }
+        self.fallbackItemPresenterFactory.configure(withCollectionView: collectionView)
+    }
+}
+
+public final class DummyItemPresenterFactory: ChatItemPresenterFactoryProtocol {
+
+    public init() {}
+
+    public func createChatItemPresenter(_ chatItem: ChatItemProtocol) -> ChatItemPresenterProtocol {
+        DummyChatItemPresenter()
+    }
+
+    public func configure(withCollectionView collectionView: UICollectionView) {
         DummyChatItemPresenter.registerCells(collectionView)
     }
 }

ChattoAdditions/sources/Chat Items/Composable/BaseViewComposition.swift

@@ -0,0 +1,5 @@
+
+public protocol BaseViewComposition {
+    associatedtype View
+}
+

ChattoAdditions/sources/Chat Items/Composable/Binder.swift

@@ -0,0 +1,73 @@
+
+// MARK: - Protocols
+
+public protocol BinderProtocol {
+    typealias Key = AnyBindingKey
+    typealias Subviews = IndexedSubviews<Key>
+    typealias ViewModels = [Key: Any]
+
+    func bind(subviews: Subviews, viewModels: ViewModels) throws
+}
+
+public protocol BinderRegistryProtocol {
+    mutating func register<Binding: ViewModelBinding, Key: BindingKeyProtocol>(
+        binding: Binding,
+        for key: Key
+    ) where Binding.View == Key.View, Binding.ViewModel == Key.ViewModel
+}
+
+// MARK: - Implementation
+
+public struct Binder: BinderProtocol, BinderRegistryProtocol {
+
+    // MARK: - Type declarations
+
+    public enum Error: Swift.Error {
+        case keysMismatch
+        case noView(key: String)
+        case noViewModel(key: String)
+    }
+
+    // MARK: - Private properties
+
+    private var bindings: [AnyBindingKey: AnyViewModelBinding] = [:]
+
+    // MARK: - Instantiation
+
+    public init() {}
+
+    // MARK: - BinderRegistryProtocol
+
+    public mutating func register<Binding: ViewModelBinding, Key: BindingKeyProtocol>(binding: Binding, for key: Key)
+        where Binding.View == Key.View, Binding.ViewModel == Key.ViewModel {
+        self.bindings[.init(key)] = AnyViewModelBinding(binding)
+    }
+
+    // MARK: - BinderProtocol
+
+    public func bind(subviews: Subviews, viewModels: ViewModels) throws {
+        try self.checkKeys(subviews: subviews, viewModels: viewModels)
+
+        for (key, binding) in self.bindings {
+            guard let view = subviews.subviews[key] else {
+                throw Error.noView(key: key.description)
+            }
+            guard let viewModel = viewModels[key] else {
+                throw Error.noViewModel(key: key.description)
+            }
+            try binding.bind(view: view, to: viewModel)
+        }
+    }
+
+    // MARK: - Private
+
+    private func checkKeys(subviews: Subviews, viewModels: ViewModels) throws {
+        let bindingKeys = Set(bindings.keys)
+        let subviewsKeys = Set(subviews.subviews.keys)
+        let viewModelsKeys = Set(viewModels.keys)
+        guard bindingKeys == subviewsKeys && subviewsKeys == viewModelsKeys else {
+            throw Error.keysMismatch
+        }
+    }
+}
+

ChattoAdditions/sources/Chat Items/Composable/BindingKey.swift

@@ -0,0 +1,64 @@
+
+import Foundation
+
+// MARK: - Protocol
+
+public protocol BindingKeyProtocol: Hashable, CustomStringConvertible {
+    associatedtype View
+    associatedtype ViewModel
+    associatedtype LayoutProvider: LayoutProviderProtocol
+    var uuid: UUID { get }
+}
+
+// MARK: - Implementation
+
+public struct BindingKey<View, ViewModel, LayoutProvider: LayoutProviderProtocol>: BindingKeyProtocol {
+    public let uuid = UUID()
+    public var description: String { "BindingKey<\(View.self),\(ViewModel.self),\(LayoutProvider.self)>" }
+}
+
+// MARK: - Type erasure
+
+public struct AnyBindingKey: Hashable, CustomStringConvertible {
+
+    let uuid: UUID
+
+    // MARK: - Private properties
+
+    private let viewType: Any.Type
+    private let viewModelType: Any.Type
+    private let layoutProviderType: Any.Type
+    private let _description: () -> String
+
+    // MARK: - Instantiation
+
+    public init<Base: BindingKeyProtocol>(_ base: Base) {
+        self.viewType = Base.View.self
+        self.viewModelType = Base.ViewModel.self
+        self.layoutProviderType = Base.LayoutProvider.self
+        self.uuid = base.uuid
+        self._description = { base.description }
+    }
+
+    // MARK: - Hashable
+
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(self.uuid)
+        hasher.combine(ObjectIdentifier(self.viewType))
+        hasher.combine(ObjectIdentifier(self.viewModelType))
+        hasher.combine(ObjectIdentifier(self.layoutProviderType))
+    }
+
+    // MARK: - Equatable
+
+    public static func == (lhs: AnyBindingKey, rhs: AnyBindingKey) -> Bool {
+        return lhs.viewType == rhs.viewType
+            && lhs.viewModelType == rhs.viewModelType
+            && lhs.layoutProviderType == rhs.layoutProviderType
+            && lhs.uuid == rhs.uuid
+    }
+
+    // MARK: - CustomStringConvertible
+
+    public var description: String { self._description() }
+}

ChattoAdditions/sources/Chat Items/Composable/ChatItemCell.swift

@@ -0,0 +1,47 @@
+//
+// The MIT License (MIT)
+//
+// Copyright (c) 2015-present Badoo Trading Limited.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+import UIKit
+
+public final class ChatItemCell: UICollectionViewCell {
+
+    public var indexed: AnyIndexedSubviews? {
+        didSet {
+            guard oldValue == nil else { return }
+            guard let subviews = self.indexed else { fatalError() }
+            self.setup(subviews: subviews)
+        }
+    }
+
+    private func setup(subviews: AnyIndexedSubviews) {
+        let subview = subviews.root
+        subview.translatesAutoresizingMaskIntoConstraints = false
+        self.contentView.addSubview(subview)
+        NSLayoutConstraint.activate([
+            subview.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor),
+            subview.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor),
+            subview.topAnchor.constraint(equalTo: self.contentView.topAnchor),
+            subview.bottomAnchor.constraint(equalTo: self.contentView.bottomAnchor)
+        ])
+    }
+}

ChattoAdditions/sources/Chat Items/Composable/ChatItemContentView.swift

@@ -0,0 +1,21 @@
+
+public protocol ChatItemContentView: AnyObject {
+    associatedtype ViewModel
+    func subscribe(for viewModel: ViewModel)
+}
+
+// MARK: - Automatic binding
+
+private struct ChatItemContentViewModelBinding<View: ChatItemContentView>: ViewModelBinding {
+    func bind(view: View, to viewModel: View.ViewModel) {
+        view.subscribe(for: viewModel)
+    }
+}
+
+public extension Binder {
+    mutating func registerBinding<Key: BindingKeyProtocol>(for key: Key) where Key.View: ChatItemContentView, Key.ViewModel == Key.View.ViewModel {
+        self.register(binding: ChatItemContentViewModelBinding(), for: key)
+    }
+}
+
+

ChattoAdditions/sources/Chat Items/Composable/ChatItemLifecycleViewModel.swift

@@ -0,0 +1,26 @@
+//
+// The MIT License (MIT)
+//
+// Copyright (c) 2015-present Badoo Trading Limited.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+public protocol ChatItemLifecycleViewModel {
+    func willShow()
+}