DeviceDriver.swift

//
//  DeviceDriver.swift
//  spt
//
//  Created by Diogo Andre de Assumpcao on 22/10/18.

import RealmSwift // Realm Mobile Database. Used instead of CoreData.
import Alamofire // HTTP networking library written in Swift.

class DeviceDriver {
    
    let device: Device
    var timeout: Int
    let configuration = URLSessionConfiguration.ephemeral
    var sessionManager = Alamofire.SessionManager()
    var base_url: String
    var default_headers: HTTPHeaders = ["Content-Type": "text/plain"]
    
    init(_ device: Device) {
        self.device = device
        self.timeout = device.timeout
        self.base_url = "https://\(device.ipv4):\(device.port)/admin/exec"
        setSessionManager()
        addAuthHeaders()
    }
    
    func setSessionManager() {
        // This will disable certificate check. Not a great idea in production.
        let serverTrustPolicies: [String: ServerTrustPolicy] = [
            "\(self.device.ipv4)": .disableEvaluation
        ]

        self.sessionManager = SessionManager(
            configuration: self.configuration,
            serverTrustPolicyManager: ServerTrustPolicyManager(policies: serverTrustPolicies)
        )
        
    }
    
    //  Add authentication headers
    func addAuthHeaders() {
        if let authorizationHeader = Request.authorizationHeader(user: device.username, password: device.password) {
            default_headers[authorizationHeader.key] = authorizationHeader.value
        }
    }
    
    //  Test connection to device
    func isAlive(_ completionHandler: @escaping (DataResponse<String>) -> Void) {
        let url = "\(self.base_url)/show+version"
        self.sessionManager.request(url, headers: self.default_headers)
            .validate(statusCode: 200..<300)
            .validate(contentType: ["text/plain"])
            .responseString { response in
                completionHandler(response)
        }
    }
    
    //  Send request to device
    func sendRequest(endpoint: String = "", _ completionHandler: @escaping (DataResponse<String>) -> Void) {
        let url = "\(self.base_url)/\(endpoint)"
        
        let _ = self.sessionManager.request(url, headers: self.default_headers)
            .validate(statusCode: 200..<300)
            .validate(contentType: ["text/plain"])
            .responseString { response in
               completionHandler(response)
        }
    }
}