Fix #1934 - Hook reaction pickers into the system's recently used keyboard emojis (#3453)

ElementX/Sources/Services/Emojis/EmojiProviderProtocol.swift

@@ -0,0 +1,42 @@
+//
+// Copyright 2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+//
+
+import Foundation
+
+struct EmojiItem: Equatable, Identifiable {
+    var id: String {
+        label
+    }
+
+    let label: String
+    let unicode: String
+    let keywords: [String]
+    let shortcodes: [String]
+}
+
+struct EmojiCategory: Equatable, Identifiable {
+    static let frequentlyUsedCategoryIdentifier = "io.element.elementx.frequently_used"
+    
+    let id: String
+    let emojis: [EmojiItem]
+}
+
+enum EmojiProviderState {
+    case notLoaded
+    case inProgress(Task<[EmojiCategory], Never>)
+    case loaded([EmojiCategory])
+}
+
+@MainActor
+protocol EmojiProviderProtocol {
+    var state: EmojiProviderState { get }
+    
+    func categories(searchString: String?) async -> [EmojiCategory]
+    
+    func frequentlyUsedSystemEmojis() -> [String]
+    func markEmojiAsFrequentlyUsed(_ emoji: String)
+}