Unify share API

.gitignore

@@ -3,3 +3,4 @@
 /Packages
 /*.xcodeproj
 xcuserdata/
+.swiftpm/

Package.swift

@@ -6,23 +6,11 @@ import PackageDescription
 let package = Package(
     name: "Share",
     products: [
-        // Products define the executables and libraries produced by a package, and make them visible to other packages.
-        .library(
-            name: "Share",
-            targets: ["Share"]),
-    ],
-    dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        // .package(url: /* package url */, from: "1.0.0"),
+        .library(name: "Share", targets: ["Share"]),
     ],
+    dependencies: [ ],
     targets: [
-        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
-        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
-        .target(
-            name: "Share",
-            dependencies: []),
-        .testTarget(
-            name: "ShareTests",
-            dependencies: ["Share"]),
+        .target(name: "Share", dependencies: []),
+        .testTarget(name: "ShareTests", dependencies: ["Share"]),
     ]
 )

Sources/Share/Share.swift

@@ -1,3 +1,51 @@
-struct Share {
-    var text = "Hello, World!"
+#if os(macOS)
+import Cocoa
+#elseif os(iOS)
+import UIKit
+#endif
+
+public protocol Sharable {
+    var shareItems: [Any] { get }
+}
+
+public protocol ShareDelegate {
+    func didChange(status: Share.Service.Status)
+}
+
+public struct Share { }
+
+extension Share {
+    #if os(macOS)
+    public typealias Service = NSSharingService
+    #elseif os(iOS)
+    public typealias Service = UIActivity.ActivityType
+    #endif
+}
+
+extension Share.Service {
+    public enum Status {
+        case willShare([Any], via: Share.Service)
+        case didShare([Any], via: Share.Service)
+        case error(Share.Service.Status.Error, sharing:[Any])
+    }
+}
+
+extension Share.Service.Status {
+    public enum Error {
+        case cancelled(Share.Service?)
+        case other(Swift.Error, with: Share.Service?)
+
+        var service: Share.Service? {
+            switch self {
+                case .cancelled(let service): return service
+                case .other(_, with: let service): return service
+            }
+        }
+    }
+}
+
+extension Sharable {
+    public func shareSheet(delegate: ShareDelegate? = nil) -> Share.Sheet {
+        return Share.Sheet(for: self, delegate: delegate)
+    }
 }

Sources/Share/Sheet.swift

@@ -0,0 +1,85 @@
+#if os(macOS)
+import Cocoa
+
+extension Share {
+    public class Sheet: NSSharingServicePicker, NSSharingServicePickerDelegate, NSSharingServiceDelegate {
+        let sharable: Sharable
+        let serviceDelegate: ShareDelegate?
+
+        private override init(items: [Any]) { fatalError("This is private") }
+
+        public init(for sharable: Sharable, delegate: ShareDelegate? = nil) {
+            self.sharable = sharable
+            serviceDelegate = delegate
+            super.init(items: sharable.shareItems)
+        }
+
+        // MARK:- NSSharingServicePickerDelegate
+        public func sharingServicePicker(_ sharingServicePicker: NSSharingServicePicker, didChoose service: NSSharingService?) {
+            guard service == nil
+                else { return }
+
+            serviceDelegate?.didChange(status: .error(.cancelled(service), sharing: sharable.shareItems))
+        }
+
+        public func sharingServicePicker(_ sharingServicePicker: NSSharingServicePicker, delegateFor sharingService: NSSharingService) -> NSSharingServiceDelegate? {
+            return self
+        }
+
+        // MARK:- NSSharingServiceDelegate
+
+        public func sharingService(_ sharingService: NSSharingService, willShareItems items: [Any]) {
+            serviceDelegate?.didChange(status: .willShare(items, via: sharingService))
+        }
+
+        public func sharingService(_ sharingService: NSSharingService, didShareItems items: [Any]) {
+            serviceDelegate?.didChange(status: .didShare(items, via: sharingService))
+        }
+
+        public func sharingService(_ sharingService: NSSharingService, didFailToShareItems items: [Any], error: Error) {
+            serviceDelegate?.didChange(status: .error(.other(error, with: sharingService), sharing: items))
+        }
+    }
+}
+#endif
+
+#if os(iOS)
+import UIKit
+
+extension Share {
+    public class Sheet: UIActivityViewController {
+        let sharable: Sharable
+        let serviceDelegate: ShareDelegate?
+
+        public init(for sharable: Sharable, delegate: ShareDelegate? = nil) {
+            self.sharable = sharable
+            serviceDelegate = delegate
+
+            super.init(activityItems: sharable.shareItems, applicationActivities: nil)
+
+            completionWithItemsHandler = {(activityType: UIActivity.ActivityType?, completed: Bool, returnedItems:[Any]?, error: Error?) in
+                guard let service = activityType
+                    else { self.report(error: .cancelled(activityType)); return }
+
+                if let error = error {
+                    self.report(error: .other(error, with: service)); return
+                }
+
+                if !completed {
+                    self.report(.willShare(sharable.shareItems, via: service))
+                } else {
+                    self.report(.didShare(sharable.shareItems, via: service))
+                }
+            }
+        }
+
+        private func report(_ status: Share.Service.Status) {
+            serviceDelegate?.didChange(status: status)
+        }
+
+        private func report(error: Share.Service.Status.Error) {
+            serviceDelegate?.didChange(status: .error(error, sharing: sharable.shareItems))
+        }
+    }
+}
+#endif