LeStorage/LeStorage/Services.swift

//
//  Services.swift
//  LeStorage
//
//  Created by Laurent Morvillier on 02/02/2024.
//

import Foundation
import UIKit

public enum HTTPMethod: String, CaseIterable, Codable {
    case get = "GET"
    case post = "POST"
    case put = "PUT"
    case delete = "DELETE"
}

struct ServiceCall {
    var path: String
    var method: HTTPMethod
    var requiresToken: Bool
}

let createAccountCall: ServiceCall = ServiceCall(
    path: "users/", method: .post, requiresToken: false)
let requestTokenCall: ServiceCall = ServiceCall(
    path: "token-auth/", method: .post, requiresToken: false)
let logoutCall: ServiceCall = ServiceCall(
    path: "api-token-logout/", method: .post, requiresToken: true)
let getUserCall: ServiceCall = ServiceCall(
    path: "user-by-token/", method: .get, requiresToken: true)
let changePasswordCall: ServiceCall = ServiceCall(
    path: "change-password/", method: .put, requiresToken: true)
let postDeviceTokenCall: ServiceCall = ServiceCall(
    path: "device-token/", method: .post, requiresToken: true)
let getUserDataAccessCallContent: ServiceCall = ServiceCall(
    path: "data-access-content/", method: .get, requiresToken: true)
let userAgentsCall: ServiceCall = ServiceCall(
    path: "user-agents/", method: .get, requiresToken: true)

/// A class used to send HTTP request to the django server
public class Services {

    fileprivate let storeCenter: StoreCenter
    
    /// The base API URL to send requests
    fileprivate(set) var baseURL: String

    public init(storeCenter: StoreCenter, url: String) {
        self.storeCenter = storeCenter
        self.baseURL = url
    }
    
    static let storeIdURLParameter = "store_id"
    
    // MARK: - Base

    /// Runs a request using a configuration object
    /// - Parameters:
    ///   - serviceConf: A instance of ServiceConf
    ///   - apiCallId: an optional id referencing an ApiCall
    fileprivate func _runRequest<U: Decodable>(serviceCall: ServiceCall)
        async throws -> U {
        let request = try self._baseRequest(call: serviceCall)
        return try await _runRequest(request)
    }

    /// Runs a request using a configuration object
    /// - Parameters:
    ///   - serviceConf: A instance of ServiceConf
    ///   - payload: a codable value stored in the body of the request
    ///   - apiCallId: an optional id referencing an ApiCall
    fileprivate func _runRequest<T: Encodable, U: Decodable>(serviceCall: ServiceCall, payload: T)
        async throws -> U {
        var request = try self._baseRequest(call: serviceCall)
        request.httpBody = try JSON.encoder.encode(payload)
        return try await _runRequest(request)
    }

    /// Runs a request using a traditional URLRequest
    /// - Parameters:
    ///   - request: the URLRequest to run
    ///   - apiCallId: the id of the ApiCall to delete in case of success, or to schedule for a rerun in case of failure
    fileprivate func _runGetApiCallRequest<T: SyncedStorable>(
        _ request: URLRequest, apiCall: ApiCall<T>
    ) async throws -> Data {
        let debugURL = request.url?.absoluteString ?? ""
//        print("Run \(request.httpMethod ?? "") \(debugURL)")
        let task: (Data, URLResponse) = try await URLSession.shared.data(for: request)
//        print("\(apiCall.method.rawValue) \(String(describing: T.self)) => \(String(data: task.0, encoding: .utf8) ?? "")")

        if let response = task.1 as? HTTPURLResponse {
            let statusCode = response.statusCode
            switch statusCode {
            case 200..<300: // success
                try await self.storeCenter.deleteApiCallById(type: T.self, id: apiCall.id)
            default:  // error
                print("\(debugURL) ended, status code = \(statusCode)")
                Logger.log(
                    "Failed Run \(request.httpMethod ?? "") \(request.url?.absoluteString ?? "")")
                let errorString: String = String(data: task.0, encoding: .utf8) ?? ""
                var errorMessage = ErrorMessage(error: errorString, domain: "")

                if let message = self.errorMessageFromResponse(data: task.0) {
                    errorMessage = message
                }

                try await self.storeCenter.rescheduleApiCalls(type: T.self)
                self.storeCenter.logFailedAPICall(
                    apiCall.id, request: request, collectionName: T.resourceName(),
                    error: errorMessage.message)

                throw ServiceError.responseError(response: errorMessage.error)
            }
        } else {
            let message: String = "Unexpected and unmanaged URL Response \(task.1)"
            self.storeCenter.log(message: message)
            Logger.w(message)
        }

        return task.0 //try self._decode(data: task.0)
        
    }

    fileprivate func _decode<V: Decodable>(data: Data) throws -> V {
        if !(V.self is Empty?.Type || V.self is Empty.Type) {
            return try JSON.decoder.decode(V.self, from: data)
        } else {
            return try JSON.decoder.decode(V.self, from: "{}".data(using: .utf8)!)
        }
    }
    
    /// Runs a request using a traditional URLRequest
    /// - Parameters:
    ///   - request: the URLRequest to run
    ///   - apiCallId: the id of the ApiCall to delete in case of success, or to schedule for a rerun in case of failure
    fileprivate func _runRequest<V: Decodable>(_ request: URLRequest) async throws -> V {
        let debugURL = request.url?.absoluteString ?? ""
//        print("Run \(request.httpMethod ?? "") \(debugURL)")
        let task: (Data, URLResponse) = try await URLSession.shared.data(for: request)
//        print("\(request.httpMethod ?? "") \(debugURL) => \(String(data: task.0, encoding: .utf8) ?? "")")

        if let response = task.1 as? HTTPURLResponse {
            let statusCode = response.statusCode
            switch statusCode {
            case 200..<300:  // success
                break
            default:  // error
                print("\(debugURL) ended, status code = \(statusCode)")
                Logger.log(
                    "Failed Run \(request.httpMethod ?? "") \(request.url?.absoluteString ?? "")")
                let errorString: String = String(data: task.0, encoding: .utf8) ?? ""
                var errorMessage = ErrorMessage(error: errorString, domain: "")
                if let message = self.errorMessageFromResponse(data: task.0) {
                    errorMessage = message
                }
                throw ServiceError.responseError(response: errorMessage.error)
            }
        } else {
            let message: String = "Unexpected and unmanaged URL Response \(task.1)"
            self.storeCenter.log(message: message)
            Logger.w(message)
        }
        return try self._decode(data: task.0)
    }

    /// Returns if the token is required for a request
    /// - Parameters:
    ///   - type: the type of the request resource
    ///   - method: the HTTP method of the request
    fileprivate func _isTokenRequired<T: SyncedStorable>(type: T.Type, method: HTTPMethod) -> Bool {
        let methods = T.tokenExemptedMethods()
        if methods.contains(method) {
            return false
        } else {
            return true
        }
    }

    /// Returns a GET request for the resource
    /// - Parameters:
    ///   - type: the type of the request resource
    fileprivate func _getRequest<T: SyncedStorable>(type: T.Type, identifier: String?)
        throws
        -> URLRequest
    {
        let requiresToken = self._isTokenRequired(type: T.self, method: .get)
        return try self._baseRequest(
            servicePath: T.path(), method: .get, requiresToken: requiresToken,
            identifier: identifier)
    }

    /// Returns the base URLRequest for a ServiceConf instance
    /// - Parameters:
    ///   - conf: a ServiceConf instance
    fileprivate func _baseRequest(call: ServiceCall, getArguments: [String: String]? = nil) throws -> URLRequest {
        return try self._baseRequest(
            servicePath: call.path, method: call.method, requiresToken: call.requiresToken, getArguments: getArguments)
    }

//
//        /// Returns a POST request for the resource
//        /// - Parameters:
//        ///   - type: the type of the request resource
//        fileprivate func _postRequest<T: Storable>(type: T.Type) throws -> URLRequest {
//            let requiresToken = self._isTokenRequired(type: T.self, method: .post)
//            return try self._baseRequest(servicePath: T.path(), method: .post, requiresToken: requiresToken)
//        }
//        
//        /// Returns a PUT request for the resource
//        /// - Parameters:
//        ///   - type: the type of the request resource
//        fileprivate func _putRequest<T: Storable>(type: T.Type, id: String) throws -> URLRequest {
//            let requiresToken = self._isTokenRequired(type: T.self, method: .put)
//            return try self._baseRequest(servicePath: T.path(id: id), method: .put, requiresToken: requiresToken)
//        }
//        
//        /// Returns a DELETE request for the resource
//        /// - Parameters:
//        ///   - type: the type of the request resource
//        fileprivate func _deleteRequest<T: Storable>(type: T.Type, id: String) throws -> URLRequest {
//            let requiresToken = self._isTokenRequired(type: T.self, method: .delete)
//            return try self._baseRequest(servicePath: T.path(id: id), method: .delete, requiresToken: requiresToken)
//        }
    
    /// Returns the base URLRequest for a ServiceConf instance
    /// - Parameters:
    ///   - conf: a ServiceConf instance
    fileprivate func _baseRequest(call: ServiceCall) throws -> URLRequest {
        return try self._baseRequest(servicePath: call.path, method: call.method, requiresToken: call.requiresToken)
    }
    
    /// Returns a base request for a path and method
    /// - Parameters:
    ///   - servicePath: the path to add to the API base URL
    ///   - method: the HTTP method to execute
    ///   - requiresToken: An optional boolean to indicate if the token is required
    ///   - identifier: an optional StoreIdentifier that allows to filter GET requests with the StoreIdentifier values
    public func _baseRequest(
        servicePath: String, method: HTTPMethod, requiresToken: Bool? = nil,
        identifier: String? = nil, getArguments: [String : String]? = nil
    ) throws -> URLRequest {
        var urlString = baseURL + servicePath
        var arguments: [String : String] = getArguments ?? [:]
        if let identifier {
            arguments[Services.storeIdURLParameter] = identifier
        }
        
        urlString.append(arguments.toQueryString())
        
        guard let url = URL(string: urlString) else {
            throw ServiceError.urlCreationError(url: urlString)
        }
        var request = URLRequest(url: url)
        request.httpMethod = method.rawValue
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addAppVersion()
        if !(requiresToken == false) {
            let token = try self.storeCenter.token()
            request.addValue("Token \(token)", forHTTPHeaderField: "Authorization")
        }
        return request
    }

    // MARK: - Synchronization

    /// Runs a request using a traditional URLRequest
    /// - Parameters:
    ///   - request: the URLRequest to run
    ///   - apiCallId: the id of the ApiCall to delete in case of success, or to schedule for a rerun in case of failure
    fileprivate func _runSyncPostRequest<T: SyncedStorable>(
        _ request: URLRequest, type: T.Type) async throws -> [OperationResult<T>] {
        let debugURL = request.url?.absoluteString ?? ""
        //        print("Run \(request.httpMethod ?? "") \(debugURL)")
        let task: (Data, URLResponse) = try await URLSession.shared.data(for: request)
        //        print("sync POST \(String(describing: T.self)) => \(String(data: task.0, encoding: .utf8) ?? "")")
        
        var rescheduleApiCalls: Bool = false
        var results: [OperationResult<T>] = []
        
        if let response = task.1 as? HTTPURLResponse {
            let statusCode = response.statusCode
            switch statusCode {
            case 200..<300: // success
                
                let decoded: BatchResponse<T> = try self._decode(data: task.0)
                results = decoded.results
                
                for result in decoded.results {
                    
                    switch result.status {
                    case 200..<300:
                        break
                    default:
                        if let message = result.message {
                            let type = String(describing: T.self)
                            print("*** \(type) - \(result.data?.stringId ?? ""): \(result.status) > \(message)")
                        }
                        rescheduleApiCalls = true
                        break
                    }
                }
                
            default: // error
                print("\(String(describing: T.self))> \(debugURL) ended, status code = \(statusCode)")
                Logger.log(
                    "Failed Run \(request.httpMethod ?? "") \(request.url?.absoluteString ?? "")")
                let errorString: String = String(data: task.0, encoding: .utf8) ?? ""
                var errorMessage = ErrorMessage(error: errorString, domain: "")
                
                if let message = self.errorMessageFromResponse(data: task.0) {
                    errorMessage = message
                }
                try await self.storeCenter.rescheduleApiCalls(type: T.self)
                
                //                self.storeCenter.logFailedAPICall(
                //                    apiCall.id, request: request, collectionName: T.resourceName(),
                //                    error: errorMessage.message)
                
                throw ServiceError.responseError(response: errorMessage.error)
            }
        } else {
            let message: String = "Unexpected and unmanaged URL Response \(task.1)"
            self.storeCenter.log(message: message)
            Logger.w(message)
        }
        
        if rescheduleApiCalls {
            try? await self.storeCenter.rescheduleApiCalls(type: T.self)
        }
        
        return results
    }

    /// Returns the URLRequest for an ApiCall
    /// - Parameters:
    ///  - apiCall: An ApiCall instance to configure the returned request
    fileprivate func _syncGetRequest<T: SyncedStorable>(from apiCall: ApiCall<T>) throws -> URLRequest {
        
        var urlString = "\(baseURL)\(T.resourceName())/" // baseURL + T.resourceName() // "data/"
        if let urlParameters = apiCall.formattedURLParameters() {
            urlString.append(urlParameters)
        }
        
        guard let url = URL(string: urlString) else {
            throw ServiceError.urlCreationError(url: urlString)
        }
        
        var request = URLRequest(url: url)
        request.httpMethod = HTTPMethod.get.rawValue
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addAppVersion()
        
        if self._isTokenRequired(type: T.self, method: apiCall.method), self.storeCenter.isAuthenticated {
            let token = try self.storeCenter.token()
            request.addValue("Token \(token)", forHTTPHeaderField: "Authorization")
        }
        
        return request
    }

    
    //    /// Executes a PUT request
//    public func put<T: Storable>(_ instance: T) async throws -> T {
//        var postRequest = try self._putRequest(type: T.self, id: instance.stringId)
//        postRequest.httpBody = try jsonEncoder.encode(instance)
//        return try await self._runRequest(postRequest)
//    }
//    
//    public func delete<T: Storable>(_ instance: T) async throws -> T {
//        let deleteRequest = try self._deleteRequest(type: T.self, id: instance.stringId)
//        return try await self._runRequest(deleteRequest)
//    }
//    
//    /// Executes an ApiCall
//    func runApiCall<T: Storable, V: Decodable>(_ apiCall: ApiCall<T>) async throws -> V {
//        let request = try self._request(from: apiCall)
//        print("HTTP \(request.httpMethod ?? "") : id = \(apiCall.dataId)")
//        return try await self._runRequest(request, apiCall: apiCall)
//>>>>>>> main
//    }
    
    /// Returns the URLRequest for an ApiCall
    /// - Parameters:
    ///  - apiCall: An ApiCall instance to configure the returned request
    fileprivate func _syncPostRequest<T: SyncedStorable>(from apiCalls: [ApiCall<T>]) throws -> URLRequest {

        let urlString = "\(baseURL)\(GetSyncData.resourceName())/"

        guard let url = URL(string: urlString) else {
            throw ServiceError.urlCreationError(url: urlString)
        }
        
        var request = URLRequest(url: url)
        request.httpMethod = HTTPMethod.post.rawValue
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        let token = try self.storeCenter.token()
        request.addValue("Token \(token)", forHTTPHeaderField: "Authorization")
        request.addAppVersion()

        let modelName = String(describing: T.self)
        let operations = apiCalls.map { apiCall in
            
            return Operation(apiCallId: apiCall.id,
                             operation: apiCall.method.rawValue,
                             modelName: modelName,
                             data: apiCall.data,
                             storeId: apiCall.data?.getStoreId())
        }
        
//        let posts = apiCalls.filter({ $0.method == .post })
//        for post in posts {
//            print("POST \(T.resourceName()): id = \(post.dataId ?? "")")
//        }
        
        let payload = SyncPayload(operations: operations,
                                  deviceId: self.storeCenter.deviceId())
        request.httpBody = try JSON.encoder.encode(payload)
        
        return request
    }
    
//    /// Starts a request to retrieve the synchronization updates
//    /// - Parameters:
//    ///  - since: The date from which updates are retrieved
//    func synchronizeLastUpdates(since: Date?) async throws {
//        let request = try self._getSyncLogRequest(since: since)
//        if let data = try await self._runRequest(request) {
//            await self.storeCenter.synchronizeContent(data)
//        }
//    }

    /// Returns the URLRequest for an ApiCall
    /// - Parameters:
    ///  - since: The date from which updates are retrieved
    fileprivate func _getSyncLogRequest(since: Date?) throws -> URLRequest {

        let formattedDate = ISO8601DateFormatter().string(from: since ?? Date.distantPast)
        let encodedDate =
            formattedDate.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) ?? ""
        let encodedDateWithPlus = encodedDate.replacingOccurrences(of: "+", with: "%2B")
        let urlString = baseURL + "\(GetSyncData.resourceName())/?last_update=\(encodedDateWithPlus)"
        Logger.log("urlString = \(urlString)")
        
        guard let url = URL(string: urlString) else {
            throw ServiceError.urlCreationError(url: urlString)
        }

        var request = URLRequest(url: url)
        request.httpMethod = HTTPMethod.get.rawValue
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")

        let token = try self.storeCenter.token()
        request.addValue("Token \(token)", forHTTPHeaderField: "Authorization")

        return request
    }

    /// Runs the a sync request and forwards the response to the StoreCenter for processing
    /// - Parameters:
    ///  - request: The synchronization request
    fileprivate func _runRequest(_ request: URLRequest) async throws -> Data? {
        let debugURL = request.url?.absoluteString ?? ""

//        print("Run \(request.httpMethod ?? "") \(debugURL)")
        let task: (Data, URLResponse) = try await URLSession.shared.data(for: request)
//        print("\(request.httpMethod ?? "") \(debugURL) => \(String(data: task.0, encoding: .utf8) ?? "")")

        if let response = task.1 as? HTTPURLResponse {
            let statusCode = response.statusCode
            switch statusCode {
            case 200..<300:  // success
                return task.0
//                success(task.0)
            default:  // error
                print("\(debugURL) ended, status code = \(statusCode)")
                Logger.log(
                    "Failed Run \(request.httpMethod ?? "") \(request.url?.absoluteString ?? "")")
                let errorString: String = String(data: task.0, encoding: .utf8) ?? ""
                var errorMessage = ErrorMessage(error: errorString, domain: "")
                if let message = self.errorMessageFromResponse(data: task.0) {
                    errorMessage = message
                }
                throw ServiceError.responseError(response: errorMessage.error)
            }
        } else {
            let message: String = "Unexpected and unmanaged URL Response \(task.1)"
            self.storeCenter.log(message: message)
            Logger.w(message)
        }
        return nil
    }

    // MARK: - Services

    /// Executes a GET request
    public func get<T: SyncedStorable>(identifier: String? = nil) async throws -> [T] {
        let getRequest = try _getRequest(type: T.self, identifier: identifier)
        return try await self._runRequest(getRequest)
    }

    /// Executes a POST request on the generated DRF services corresponding to T
    public func rawPost<T: Storable>(_ instance: T) async throws -> T {
        var postRequest = try self._postRequest(type: T.self)
        postRequest.httpBody = try JSON.encoder.encode(instance)
        return try await self._runRequest(postRequest)
    }
    
    /// Executes a PUT request on the generated DRF services corresponding to T
    public func rawPut<T: Storable>(_ instance: T) async throws -> T {
        var postRequest = try self._putRequest(type: T.self, id: instance.stringId)
        postRequest.httpBody = try JSON.encoder.encode(instance)
        return try await self._runRequest(postRequest)
    }
    
    /// Executes a DELETE request on the generated DRF services corresponding to T
    public func rawDelete<T: Storable>(_ instance: T) async throws -> T {
        let deleteRequest = try self._deleteRequest(type: T.self, id: instance.stringId)
        return try await self._runRequest(deleteRequest)
    }
    
    /// Executes an ApiCall
    func runGetApiCall<T: SyncedStorable>(_ apiCall: ApiCall<T>) async throws -> Data {
        let request = try self._syncGetRequest(from: apiCall)
        return try await self._runGetApiCallRequest(request, apiCall: apiCall)
    }

    /// Executes an ApiCall
    func runApiCalls<T: SyncedStorable>(_ apiCalls: [ApiCall<T>]) async throws -> [OperationResult<T>] {
        let request = try self._syncPostRequest(from: apiCalls)
        return try await self._runSyncPostRequest(request, type: T.self)
    }

    /// Returns the URLRequest for an ApiCall
    /// - Parameters:
    ///  - apiCall: An ApiCall instance to configure the returned request
    fileprivate func _request<T: SyncedStorable>(from apiCall: ApiCall<T>) throws -> URLRequest {
        let url = try self._url(from: apiCall)
        var request = URLRequest(url: url)
        request.httpMethod = apiCall.method.rawValue
        request.httpBody = try apiCall.data?.jsonData()
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addAppVersion()
        if self._isTokenRequired(type: T.self, method: apiCall.method) {
            do {
                let token = try self.storeCenter.token()
                request.setValue("Token \(token)", forHTTPHeaderField: "Authorization")
            } catch {
                Logger.log("missing token")
            }
        }

        return request
    }

    /// Returns the URL corresponding to the ApiCall
    /// - Parameters:
    ///  - apiCall: an instance of ApiCall to build to URL
    fileprivate func _url<T: Storable>(from apiCall: ApiCall<T>) throws -> URL {
        var stringURL: String = self.baseURL
        stringURL += apiCall.urlExtension()
        
        if let url = URL(string: stringURL) {
            return url
        } else {
            throw ServiceError.urlCreationError(url: stringURL)
        }
    }
    
    // MARK: - Others
    
    public func getUserAgents() async throws -> [ShortUser] {
        return try await self._runRequest(serviceCall: userAgentsCall)
    }

    // MARK: - Authentication

    /// Creates an account
    /// - Parameters:
    ///  - user: A user instance to send to the server
    public func createAccount<U: UserPasswordBase, V: UserBase>(user: U) async throws -> V {
        return try await _runRequest(serviceCall: createAccountCall, payload: user)
    }

    /// Requests a token for a username and password
    /// - Parameters:
    ///  - username: the account's username
    ///  - password: the account's password
    public func requestToken(username: String, password: String) async throws -> String {
        var postRequest = try self._baseRequest(call: requestTokenCall)
        let deviceId = self.storeCenter.deviceId()
        
        let deviceModel = await UIDevice.current.deviceModel()
        
        let credentials = Credentials(username: username, password: password, deviceId: deviceId, deviceModel: deviceModel)
        postRequest.httpBody = try JSON.encoder.encode(credentials)
        let response: AuthResponse = try await self._runRequest(postRequest)
        try self.storeCenter.storeToken(username: username, token: response.token)
        return response.token
    }

    /// A login method that actually requests a token from the server, and stores the appropriate data for later usage
    /// - Parameters:
    ///  - username: the account's username
    ///  - password: the account's password
    public func login<U: UserBase>(username: String, password: String) async throws -> U {
        
        _ = try await requestToken(username: username, password: password)
        let postRequest = try self._baseRequest(call: getUserCall)
        let loggingDate = Date() // ideally we want the date of the latest retrieved object when loading collection objects
        let user: U = try await self._runRequest(postRequest)
        self.storeCenter.userDidLogIn(user: user, at: loggingDate)
        return user
    }

    /// A login method that actually requests a token from the server, and stores the appropriate data for later usage
    /// - Parameters:
    ///  - username: the account's username
    ///  - password: the account's password
    public func logout() async throws {
        let deviceId: String = self.storeCenter.deviceId()
        let _: Empty = try await self._runRequest(
            serviceCall: logoutCall, payload: Logout(deviceId: deviceId))
    }

    /// A login method that actually requests a token from the server, and stores the appropriate data for later usage
    /// - Parameters:
    ///  - username: the account's username
    ///  - password: the account's password
    public func postDeviceToken(deviceToken: Data) async throws {
        let tokenString = deviceToken.map { String(format: "%02x", $0) }.joined()
        let token = DeviceToken(value: tokenString)
        //        Logger.log("Send device token = \(tokenString)")
        let _: Empty = try await self._runRequest(serviceCall: postDeviceTokenCall, payload: token)
    }
    
    /// Returns the list of DataAccess
    func getUserDataAccessContent() async throws {
        let request = try self._baseRequest(call: getUserDataAccessCallContent)
        if let data = try await self._runRequest(request) {
            await self.storeCenter.userDataAccessRetrieved(data)
        }
    }

    /// A method that sends a request to change a user's password
    /// - Parameters:
    ///  - oldPassword: the account's old password
    ///  - password1: the account's new password
    ///  - password2: a repeat of the new password
    public func changePassword(oldPassword: String, password1: String, password2: String)
        async throws
    {

        guard let username = self.storeCenter.userName else {
            throw ServiceError.missingUserName
        }

        struct ChangePasswordParams: Codable {
            var old_password: String
            var new_password1: String
            var new_password2: String
        }

        let params = ChangePasswordParams(
            old_password: oldPassword, new_password1: password1, new_password2: password2)
        let response: Token = try await self._runRequest(
            serviceCall: changePasswordCall, payload: params)

        try self.storeCenter.storeToken(username: username, token: response.token)
    }

    /// The method send a request to reset the user's password
    /// - Parameters:
    ///  - email: the email of the user
    public func forgotPassword(email: String) async throws {
        var postRequest = try self._baseRequest(servicePath: "dj-rest-auth/password/reset/", method: .post, requiresToken: false)
        postRequest.httpBody = try JSON.encoder.encode(Email(email: email))
        let response: Email = try await self._runRequest(postRequest)
        Logger.log("response = \(response)")
    }

    /// A login method that actually requests a token from the server, and stores the appropriate data for later usage
    /// - Parameters:
    ///  - username: the account's username
    ///  - password: the account's password
    public func deleteAccount() async throws {
        guard let userId = self.storeCenter.userId else {
            throw StoreError.missingUserId
        }
        let path = "users/\(userId)/"
        let deleteAccount = ServiceCall(path: path, method: .delete, requiresToken: true)

        let request = try self._baseRequest(call: deleteAccount)
        let _: Empty = try await self._runRequest(request)
    }

    /// Parse a json data and tries to extract its error message
    /// - Parameters:
    ///  - data: some JSON data
    fileprivate func errorMessageFromResponse(data: Data) -> ErrorMessage? {
        do {
            if let jsonObject = try JSONSerialization.jsonObject(with: data, options: [])
                as? [String: Any]
            {
                if let tuple = jsonObject.first {
                    var error = ""
                    if let stringsArray = tuple.value as? [String], let first = stringsArray.first {
                        error = first
                    } else if let string = tuple.value as? String {
                        error = string
                    }
                    return ErrorMessage(error: error, domain: tuple.key)
                }
            }
        } catch {
            Logger.log("Failed to parse JSON: \(error.localizedDescription)")
        }
        return nil
    }

    // MARK: - Convenience method for tests
    
    /// Executes a POST request
    public func post<T: SyncedStorable>(_ instance: T) async throws -> T? {
        let apiCall: ApiCall<T> = ApiCall(method: .post, data: instance)
        let results: [OperationResult<T>] = try await self.runApiCalls([apiCall])
        return results.first?.data
    }
    
    /// Executes a PUT request
    public func put<T: SyncedStorable>(_ instance: T) async throws -> T? {
        let apiCall: ApiCall<T> = ApiCall(method: .put, data: instance)
        let results: [OperationResult<T>] = try await self.runApiCalls([apiCall])
        return results.first?.data
    }
    
    public func delete<T: SyncedStorable>(_ instance: T) async throws -> T? {
        let apiCall: ApiCall<T> = ApiCall(method: .delete, data: instance)
        let results: [OperationResult<T>] = try await self.runApiCalls([apiCall])
        return results.first?.data
    }
    
    /// Returns a POST request for the resource
    /// - Parameters:
    ///   - type: the type of the request resource
    fileprivate func _postRequest<T: Storable>(type: T.Type) throws -> URLRequest {
        return try self._baseRequest(servicePath: T.path(), method: .post, requiresToken: true)
    }
    
    /// Returns a PUT request for the resource
    /// - Parameters:
    ///   - type: the type of the request resource
    fileprivate func _putRequest<T: Storable>(type: T.Type, id: String) throws -> URLRequest {
        return try self._baseRequest(servicePath: T.path(id: id), method: .put, requiresToken: true)
    }
    
    /// Returns a DELETE request for the resource
    /// - Parameters:
    ///   - type: the type of the request resource
    fileprivate func _deleteRequest<T: Storable>(type: T.Type, id: String) throws -> URLRequest {
        return try self._baseRequest(servicePath: T.path(id: id), method: .delete, requiresToken: true)
    }
    
}

struct SyncPayload<T: Encodable>: Encodable {
    var operations: [Operation<T>]
    var deviceId: String?
}

struct Operation<T: Encodable>: Encodable {
    var apiCallId: String
    var operation: String
    var modelName: String
    var data: T
    var storeId: String?
}

struct BatchResponse<T: Decodable>: Decodable {
    var results: [OperationResult<T>]
}

public struct OperationResult<T: Decodable>: Decodable {
    var apiCallId: String
    public var status: Int
    var data: T?
    public var message: String?
}

struct ErrorMessage {
    let error: String
    let domain: String

    var message: String {
        return "\(self.error) (\(self.domain))"
    }
}

struct AuthResponse: Codable {
    let token: String
}
struct Credentials: Codable {
    var username: String
    var password: String
    var deviceId: String
    var deviceModel: String?
}
struct Token: Codable {
    var token: String
}
struct Email: Codable {
    var email: String
}
struct Empty: Codable {

}
struct Logout: Codable {
    var deviceId: String
}
struct DeviceToken: Codable {
    var value: String
}

public protocol UserBase: Codable {
    var id: String { get }
    var username: String { get }
    var email: String { get }

    func uuid() throws -> UUID
}

public protocol UserPasswordBase: UserBase {
    var password: String { get }
}
public struct ShortUser: Codable, Identifiable, Equatable {
    public var id: String
    public var firstName: String
    public var lastName: String
}

fileprivate extension URLRequest {
    
    mutating func addAppVersion() {
        let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String ?? "Unknown"
        let build = Bundle.main.infoDictionary?["CFBundleVersion"] as? String ?? "Unknown"
        let appVersion = "\(version) (\(build))"
        self.setValue(appVersion, forHTTPHeaderField: "App-Version")
    }
    
}