From d00607d55e899ae45e721514ea8a19772c8877de Mon Sep 17 00:00:00 2001
From: ThibaultBee <37510686+ThibaultBee@users.noreply.github.com>
Date: Tue, 28 Nov 2023 12:08:09 +0100
Subject: [PATCH] wip(client): add support for background upload

---
 .../xcshareddata/swiftpm/Package.resolved     |   9 --
 Sources/APIs.swift                            |   2 +
 Sources/APIs/VideosAPI.swift                  |   6 +-
 Sources/FileHelper.swift                      |  29 +++++
 Sources/URLSessionImplementations.swift       | 114 ++++++++++++++----
 5 files changed, 126 insertions(+), 34 deletions(-)
 create mode 100644 Sources/FileHelper.swift

diff --git a/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved b/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
index 969e0eb..a6aeb70 100644
--- a/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
+++ b/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -1,14 +1,5 @@
 {
   "pins" : [
-    {
-      "identity" : "alamofire",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/Alamofire/Alamofire",
-      "state" : {
-        "revision" : "d120af1e8638c7da36c8481fd61a66c0c08dc4fc",
-        "version" : "5.4.4"
-      }
-    },
     {
       "identity" : "anycodable",
       "kind" : "remoteSourceControl",
diff --git a/Sources/APIs.swift b/Sources/APIs.swift
index c2dbff2..e63c6cf 100644
--- a/Sources/APIs.swift
+++ b/Sources/APIs.swift
@@ -14,6 +14,7 @@ public class ApiVideoClient {
     internal static var requestBuilderFactory: RequestBuilderFactory = URLSessionRequestBuilderFactory()
     public static var apiResponseQueue: DispatchQueue = .main
     public static var timeout: TimeInterval = 60
+    public static var backgroundIdentifier: String = "video.api.upload.background"
     internal static var customHeaders:[String: String] {
         var headers = defaultHeaders
         if let apiKey = apiKey {
@@ -135,4 +136,5 @@ open class RequestBuilder<T> {
 public protocol RequestBuilderFactory {
     func getNonDecodableBuilder<T>() -> RequestBuilder<T>.Type
     func getBuilder<T: Decodable>() -> RequestBuilder<T>.Type
+    func getBackgroundBuilder<T: Decodable>() -> RequestBuilder<T>.Type
 }
diff --git a/Sources/APIs/VideosAPI.swift b/Sources/APIs/VideosAPI.swift
index 5bcd506..76e77d6 100644
--- a/Sources/APIs/VideosAPI.swift
+++ b/Sources/APIs/VideosAPI.swift
@@ -190,7 +190,7 @@ The latter allows you to split a video source into X chunks and send those chunk
 
         let localVariableHeaderParameters = APIHelper.rejectNilHeaders(localVariableNillableHeaders)
 
-        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBuilder()
+        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBackgroundBuilder()
 
         return localVariableRequestBuilder.init(method: "POST", URLString: (localVariableUrlComponents?.string ?? localVariableURLString), parameters: localVariableParameters, headers: localVariableHeaderParameters, onProgressReady: onProgressReady)
     }
@@ -248,7 +248,7 @@ The latter allows you to split a video source into X chunks and send those chunk
 
         let localVariableHeaderParameters = APIHelper.rejectNilHeaders(localVariableNillableHeaders)
 
-        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBuilder()
+        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBackgroundBuilder()
 
         return localVariableRequestBuilder.init(method: "POST", URLString: (localVariableUrlComponents?.string ?? localVariableURLString), parameters: localVariableParameters, headers: localVariableHeaderParameters, onProgressReady: onProgressReady)
     }
@@ -395,7 +395,7 @@ The latter allows you to split a video source into X chunks and send those chunk
 
         let localVariableHeaderParameters = APIHelper.rejectNilHeaders(localVariableNillableHeaders)
 
-        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBuilder()
+        let localVariableRequestBuilder: RequestBuilder<Video>.Type = ApiVideoClient.requestBuilderFactory.getBackgroundBuilder()
 
         return localVariableRequestBuilder.init(method: "POST", URLString: (localVariableUrlComponents?.string ?? localVariableURLString), parameters: localVariableParameters, headers: localVariableHeaderParameters, onProgressReady: onProgressReady)
     }
diff --git a/Sources/FileHelper.swift b/Sources/FileHelper.swift
new file mode 100644
index 0000000..d0d2302
--- /dev/null
+++ b/Sources/FileHelper.swift
@@ -0,0 +1,29 @@
+// APIHelper.swift
+//
+// Generated by openapi-generator
+// https://openapi-generator.tech
+//
+
+import Foundation
+
+public struct FileHelper {
+    /**
+    This function will copy a video file to a temporary location so that it remains accessbile for further handling such as an upload to S3.
+    - Parameter url: This is the url of the media item.
+    - Returns: Return a new URL for the local copy of the vidoe file.
+    */
+   static func createTemporaryURLfrom(_ url: URL) -> URL {
+       /// Create the temporary directory.
+       let temporaryDirectoryURL = URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true)
+       /// create a temporary file for us to copy the video to.
+       let temporaryFileURL = temporaryDirectoryURL.appendingPathComponent(url.lastPathComponent)
+       /// Attempt the copy.
+       do {
+           try FileManager().copyItem(at: url.absoluteURL, to: temporaryFileURL)
+       } catch {
+           fatalError("There was an error copying the video file to the temporary location.")
+       }
+
+       return temporaryFileURL
+   }
+}
diff --git a/Sources/URLSessionImplementations.swift b/Sources/URLSessionImplementations.swift
index aaf42d3..8f68b59 100644
--- a/Sources/URLSessionImplementations.swift
+++ b/Sources/URLSessionImplementations.swift
@@ -9,6 +9,12 @@ import Foundation
 import MobileCoreServices
 #endif
 
+public protocol URLSessionProtocol {
+    func dataTask(with request: URLRequest, completionHandler: @escaping @Sendable (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask
+}
+
+extension URLSession: URLSessionProtocol {}
+
 class URLSessionRequestBuilderFactory: RequestBuilderFactory {
     func getNonDecodableBuilder<T>() -> RequestBuilder<T>.Type {
         return URLSessionRequestBuilder<T>.self
@@ -17,6 +23,10 @@ class URLSessionRequestBuilderFactory: RequestBuilderFactory {
     func getBuilder<T: Decodable>() -> RequestBuilder<T>.Type {
         return URLSessionDecodableRequestBuilder<T>.self
     }
+
+    func getBackgroundBuilder<T: Decodable>() -> RequestBuilder<T>.Type {
+        return URLSessionBackgroundUploadRequestBuilder<T>.self
+    }
 }
 
 public typealias ApiVideoClientChallengeHandler = ((URLSession, URLSessionTask, URLAuthenticationChallenge) -> (URLSession.AuthChallengeDisposition, URLCredential?))
@@ -62,7 +72,7 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      May be overridden by a subclass if you want to control the URLSession
      configuration.
      */
-    open func createURLSession() -> URLSession {
+    open func createURLSession() -> URLSessionProtocol {
         return defaultURLSession
     }
 
@@ -81,7 +91,7 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
      May be overridden by a subclass if you want to control the URLRequest
      configuration (e.g. to override the cache policy).
      */
-    open func createURLRequest(urlSession: URLSession, method: HTTPMethod, encoding: ParameterEncoding, headers: [String: String]) throws -> URLRequest {
+    open func createURLRequest(urlSession: URLSessionProtocol, method: HTTPMethod, encoding: ParameterEncoding, headers: [String: String]) throws -> URLRequest {
 
         guard let url = URL(string: URLString) else {
             throw DownloadException.requestMissingURL
@@ -144,26 +154,9 @@ open class URLSessionRequestBuilder<T>: RequestBuilder<T> {
              }
 
             let dataTask = urlSession.dataTask(with: request) { data, response, error in
-
-                if let taskCompletionShouldRetry = self.taskCompletionShouldRetry {
-
-                    taskCompletionShouldRetry(data, response, error) { shouldRetry in
-
-                        if shouldRetry {
-                            cleanupRequest()
-                            self.execute(apiResponseQueue, completion)
-                        } else {
-                            apiResponseQueue.async {
-                                self.processRequestResponse(urlRequest: request, data: data, response: response, error: error, completion: completion)
-                                cleanupRequest()
-                            }
-                        }
-                    }
-                } else {
-                    apiResponseQueue.async {
-                        self.processRequestResponse(urlRequest: request, data: data, response: response, error: error, completion: completion)
-                        cleanupRequest()
-                    }
+                apiResponseQueue.async {
+                    self.processRequestResponse(urlRequest: request, data: data, response: response, error: error, completion: completion)
+                    cleanupRequest()
                 }
             }
 
@@ -372,6 +365,68 @@ open class URLSessionDecodableRequestBuilder<T: Decodable>: URLSessionRequestBui
     }
 }
 
+class BackgroundUploadTaskURLSession<T>: NSObject, URLSessionProtocol {
+    private let file: URL
+    private let sessionDelegate = BackgroundUploadSessionDelegate()
+
+    private lazy var urlSession = URLSession(configuration: .background(withIdentifier: ApiVideoClient.backgroundIdentifier), delegate: sessionDelegate, delegateQueue: nil)
+ 
+    init(_ file: URL) {
+        self.file = FileHelper.createTemporaryURLfrom(file)
+    }
+
+    func dataTask(with request: URLRequest, completionHandler: @escaping @Sendable (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask {
+        sessionDelegate.completionHandler = completionHandler
+        return urlSession.uploadTask(with: request, fromFile: file)
+    }
+}
+
+open class URLSessionBackgroundUploadRequestBuilder<T: Decodable>: URLSessionDecodableRequestBuilder<T> {
+    private var completion: ((Result<Response<T>, ErrorResponse>) -> Void)? = nil
+
+    override open func createURLSession() -> URLSessionProtocol {
+        guard let parameters = parameters else { fatalError("No parameters found") }
+
+        // Find file URL
+        var file: URL? = nil
+        for (_, value) in parameters {
+            if let fileURL = value as? URL {
+                file = fileURL
+                break
+            }
+        }
+        guard let fileURL = file else {
+            fatalError("No file URL found")
+        }
+        return BackgroundUploadTaskURLSession<T>(fileURL)
+    }
+
+    /**
+     May be overridden by a subclass if you want to control the URLRequest
+     configuration (e.g. to override the cache policy).
+     */
+    override open func createURLRequest(urlSession: URLSessionProtocol, method: HTTPMethod, encoding: ParameterEncoding, headers: [String: String]) throws -> URLRequest {
+
+        guard let url = URL(string: URLString) else {
+            throw DownloadException.requestMissingURL
+        }
+
+        var originalRequest = URLRequest(url: url)
+        originalRequest.timeoutInterval = ApiVideoClient.timeout
+        originalRequest.httpMethod = method.rawValue
+
+        headers.forEach { key, value in
+            originalRequest.setValue(value, forHTTPHeaderField: key)
+        }
+
+        buildHeaders().forEach { key, value in
+            originalRequest.setValue(value, forHTTPHeaderField: key)
+        }
+
+        return originalRequest
+    }
+}
+
 private class SessionDelegate: NSObject, URLSessionTaskDelegate {
     func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
 
@@ -397,6 +452,21 @@ private class SessionDelegate: NSObject, URLSessionTaskDelegate {
     }
 }
 
+private class BackgroundUploadSessionDelegate: SessionDelegate, URLSessionDataDelegate {
+    var completionHandler: ((Data?, URLResponse?, Error?) -> Void)? = nil
+
+    func urlSession(_ session: URLSession, task: URLSessionTask, didBecomeInvalidWithError error: Error?) {
+        guard let error = error else {
+            return
+        }
+        completionHandler?(nil, task.response, error)
+    }
+
+    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
+        completionHandler?(data, dataTask.response, nil)
+    }
+}
+
 public enum HTTPMethod: String {
     case options = "OPTIONS"
     case get = "GET"