新增景区排队管理功能

suixinkan/Features/ScenicQueue/Services/ScenicQueueSocketClient.swift

@@ -0,0 +1,73 @@
+//
+//  ScenicQueueSocketClient.swift
+//  suixinkan
+//
+
+import Foundation
+
+/// 排队 WebSocket 客户端，订阅打卡点队列刷新与叫号事件。
+final class ScenicQueueSocketClient {
+    var onMessage: ((ScenicQueueSocketMessage) -> Void)?
+
+    private let environment: APIEnvironment
+    private let session: URLSession
+    private let decoder = JSONDecoder()
+    private var task: URLSessionWebSocketTask?
+    private var connectedSpotId: Int64?
+
+    init(environment: APIEnvironment = .current, session: URLSession = .shared) {
+        self.environment = environment
+        self.session = session
+    }
+
+    /// 建立连接并订阅指定打卡点。
+    func connect(socketToken: String, scenicId: Int64, scenicSpotId: Int64) {
+        guard !socketToken.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return }
+        disconnect()
+        connectedSpotId = scenicSpotId
+        let webSocketTask = session.webSocketTask(with: environment.webSocketURL)
+        task = webSocketTask
+        webSocketTask.resume()
+        sendSubscribePayloads(scenicSpotId: scenicSpotId)
+        receiveLoop()
+    }
+
+    /// 断开连接。
+    func disconnect() {
+        task?.cancel(with: .normalClosure, reason: nil)
+        task = nil
+        connectedSpotId = nil
+    }
+
+    private func sendSubscribePayloads(scenicSpotId: Int64) {
+        [
+            #"{"type":306,"params":{"scenic_spot_id":\#(scenicSpotId)}}"#,
+            #"{"type":307,"params":{"scenic_spot_id":\#(scenicSpotId)}}"#,
+        ].forEach { payload in
+            task?.send(.string(payload)) { _ in }
+        }
+    }
+
+    private func receiveLoop() {
+        task?.receive { [weak self] result in
+            guard let self else { return }
+            switch result {
+            case .success(let message):
+                if case .string(let text) = message {
+                    self.handle(text)
+                }
+                self.receiveLoop()
+            case .failure:
+                self.task = nil
+            }
+        }
+    }
+
+    private func handle(_ text: String) {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard trimmed.hasPrefix("{"), let data = trimmed.data(using: .utf8) else { return }
+        guard let message = try? decoder.decode(ScenicQueueSocketMessage.self, from: data) else { return }
+        guard message.isQueueEvent else { return }
+        onMessage?(message)
+    }
+}