import Foundation

public class NetworkLogger {
    public static let shared = NetworkLogger()

    public func startLogging() {
        let notificationCenter = NotificationCenter.default

        notificationCenter.addObserver(
            self,
            selector: #selector(logRequestInfo),
            name: Notification.Name.Task.DidResume,
            object: nil
        )

        notificationCenter.addObserver(
            self,
            selector: #selector(logRequestInfo),
            name: Notification.Name.Task.DidComplete,
            object: nil
        )
    }

    @objc private func logRequestInfo(_ notification: Notification) {
        guard let userInfo = notification.userInfo,
            let task = userInfo[Notification.Key.Task] as? URLSessionTask,
            let request = task.originalRequest,
            let httpMethod = request.httpMethod
            else { return }
        let requestPath = [request.url?.path, request.url?.query].compactMap { $0 }.joined(separator: "?")

        if let response = task.response as? HTTPURLResponse {
            let message = components(
                httpMethod: httpMethod,
                requestPath: requestPath,
                data: userInfo[Notification.Key.ResponseData] as? Data,
                statusCode: response.statusCode
                )
            print("Finished network request: \(message)")
        } else if let error = task.error {
            let message = components(
                httpMethod: httpMethod,
                requestPath: requestPath,
                data: userInfo[Notification.Key.ResponseData] as? Data
            )
            print("Finished network request: \(message) with errors: \(error)")
        } else {
            let message = components(
                httpMethod: httpMethod,
                requestPath: requestPath,
                data: task.originalRequest?.httpBody
            )
            print("Started network request: \(message)")
        }
    }
    func components(httpMethod: String, requestPath: String, data: Data?, statusCode: Int? = nil) -> String {
        return [
            "AF request",
            "<\(httpMethod)",
            statusCode?.description,
            "\(requestPath)>",
            json(from: data)
            ]
            .compactMap { $0 }
            .joined(separator: " ")
    }

    func json(from data: Data?) -> String? {
        let emptyArray = "[]"
        let emptyDictionary = "{}"
        let converted: String
        if let data = data {
            converted = String(data: data, encoding: .utf8) ?? emptyDictionary
        } else {
            converted = emptyDictionary
        }
        if [emptyDictionary, emptyArray].contains(converted) {
            return "HTTPBody: \(converted);"
        } else {
            return "HTTPBody:\n" + converted
        }
    }
}