RemoteInspector.swift

RemoteInspector.swift

import Foundation

public class RemoteInspector {
    private struct UpdateMessage<T: Encodable>: Encodable {
        let type = "update"
        var id: String
        var data: T
    }

    private struct LogMessage: Encodable {
        let type = "log"
        var message: String
        var level: String
        var attributesJSON: String?
    }

    public static let shared = RemoteInspector()

    static func connect(url: URL) -> URLSessionWebSocketTask {
        let urlSession = URLSession(configuration: .default)

        return urlSession.webSocketTask(with: url)
    }

    var webSocketTask: URLSessionWebSocketTask?

    var url: URL?

    public var isConnected: Bool {
        return webSocketTask?.state == .running
    }

    public func connect(url: URL) -> Bool {
        #if !DEBUG
            return false
        #else
            self.url = url

            webSocketTask = Self.connect(url: url)

            if let webSocketTask = webSocketTask {
                logger.infoMessage("Starting remote inspector session at \(url.absoluteString)")

                webSocketTask.resume()

                return true
            }

            return false
        #endif
    }

    func reconnect() -> Bool {
        guard let webSocketTask = webSocketTask else {
            return false
        }

        webSocketTask.cancel(with: .goingAway, reason: nil)

        if let url = url {
            return connect(url: url)
        }

        return false
    }

    public func disconnect() {
        guard let webSocketTask = webSocketTask else {
            return
        }

        webSocketTask.cancel(with: .goingAway, reason: nil)
        self.webSocketTask = nil
    }

    public func send(_ id: String, _ value: Encodable) {
        guard let webSocketTask = webSocketTask else {
            return
        }

        do {
            let encoder = JSONEncoder()

            let jsonData = try encoder.encode(UpdateMessage(id: id, data: AnyEncodable(value: value)))
            let message = URLSessionWebSocketTask.Message.data(jsonData)

            webSocketTask.send(message) { error in
                if let error = error {
                    _ = self.reconnect()

                    logger.errorMessage("\(error)")
                }
            }
        } catch {
            // Blegh
        }
    }

    func log(_ message: String, logLevel: String, attributes: [String: Any]? = nil) {
        guard let webSocketTask = webSocketTask else {
            return
        }

        let encoder = JSONEncoder()
        var attributesJSON: Data?

        if let attributes = attributes {
            attributesJSON = try? JSONSerialization.data(withJSONObject: attributes, options: [])
        }

        guard let jsonData: Data = {
            do {
                if let attributesJSON = attributesJSON {
                    return try encoder.encode(
                        LogMessage(
                            message: message,
                            level: logLevel.description,
                            attributesJSON: String(data: attributesJSON, encoding: .utf8)
                        )
                    )
                } else {
                    return try encoder.encode(
                        LogMessage(
                            message: message,
                            level: logLevel.description,
                            attributesJSON: nil
                        )
                    )
                }
            } catch {
                return nil
            }
        }() else {
            return
        }

        let message = URLSessionWebSocketTask.Message.data(jsonData)

        webSocketTask.send(message) { error in
            if let error = error {
                _ = self.reconnect()

                logger.errorMessage("\(error)")
            }
        }
    }
}