Improve update UI error details

Sources/Update/UpdateViewModel.swift

@@ -5,9 +5,14 @@ import Sparkle
 
 class UpdateViewModel: ObservableObject {
     @Published var state: UpdateState = .idle
+    @Published var overrideState: UpdateState?
+
+    var effectiveState: UpdateState {
+        overrideState ?? state
+    }
 
     var text: String {
-        switch state {
+        switch effectiveState {
         case .idle:
             return ""
         case .permissionRequest:
@@ -33,12 +38,12 @@ class UpdateViewModel: ObservableObject {
         case .notFound:
             return "No Updates Available"
         case .error(let err):
-            return err.error.localizedDescription
+            return Self.userFacingErrorTitle(for: err.error)
         }
     }
 
     var maxWidthText: String {
-        switch state {
+        switch effectiveState {
         case .downloading:
             return "Downloading: 100%"
         case .extracting:
@@ -49,7 +54,7 @@ class UpdateViewModel: ObservableObject {
     }
 
     var iconName: String? {
-        switch state {
+        switch effectiveState {
         case .idle:
             return nil
         case .permissionRequest:
@@ -72,7 +77,7 @@ class UpdateViewModel: ObservableObject {
     }
 
     var description: String {
-        switch state {
+        switch effectiveState {
         case .idle:
             return ""
         case .permissionRequest:
@@ -89,13 +94,13 @@ class UpdateViewModel: ObservableObject {
             return install.isAutoUpdate ? "Restart to Complete Update" : "Installing update and preparing to restart"
         case .notFound:
             return "You are running the latest version"
-        case .error:
-            return "An error occurred during the update process"
+        case .error(let err):
+            return Self.userFacingErrorMessage(for: err.error)
         }
     }
 
     var badge: String? {
-        switch state {
+        switch effectiveState {
         case .updateAvailable(let update):
             let version = update.appcastItem.displayVersionString
             return version.isEmpty ? nil : version
@@ -113,7 +118,7 @@ class UpdateViewModel: ObservableObject {
     }
 
     var iconColor: Color {
-        switch state {
+        switch effectiveState {
         case .idle:
             return .secondary
         case .permissionRequest:
@@ -132,7 +137,7 @@ class UpdateViewModel: ObservableObject {
     }
 
     var backgroundColor: Color {
-        switch state {
+        switch effectiveState {
         case .permissionRequest:
             return Color(nsColor: NSColor.systemBlue.blended(withFraction: 0.3, of: .black) ?? .systemBlue)
         case .updateAvailable:
@@ -147,7 +152,7 @@ class UpdateViewModel: ObservableObject {
     }
 
     var foregroundColor: Color {
-        switch state {
+        switch effectiveState {
         case .permissionRequest:
             return .white
         case .updateAvailable:
@@ -160,6 +165,165 @@ class UpdateViewModel: ObservableObject {
             return .primary
         }
     }
+
+    static func userFacingErrorTitle(for error: Swift.Error) -> String {
+        let nsError = error as NSError
+        if let networkError = networkError(from: nsError) {
+            switch networkError.code {
+            case NSURLErrorNotConnectedToInternet:
+                return "No Internet Connection"
+            case NSURLErrorTimedOut:
+                return "Update Timed Out"
+            case NSURLErrorCannotFindHost:
+                return "Server Not Found"
+            case NSURLErrorCannotConnectToHost:
+                return "Server Unreachable"
+            case NSURLErrorNetworkConnectionLost:
+                return "Connection Lost"
+            case NSURLErrorSecureConnectionFailed,
+                 NSURLErrorServerCertificateUntrusted,
+                 NSURLErrorServerCertificateHasBadDate,
+                 NSURLErrorServerCertificateHasUnknownRoot,
+                 NSURLErrorServerCertificateNotYetValid:
+                return "Secure Connection Failed"
+            default:
+                break
+            }
+        }
+        if nsError.domain == SUSparkleErrorDomain {
+            switch nsError.code {
+            case 2001:
+                return "Couldn't Download Update"
+            case 1000, 1002:
+                return "Update Feed Error"
+            case 4:
+                return "Invalid Update Feed"
+            case 3:
+                return "Insecure Update Feed"
+            case 1, 2, 3001, 3002:
+                return "Update Signature Error"
+            case 1003, 1005:
+                return "App Location Issue"
+            default:
+                break
+            }
+        }
+        return "Update Failed"
+    }
+
+    static func userFacingErrorMessage(for error: Swift.Error) -> String {
+        let nsError = error as NSError
+        if let networkError = networkError(from: nsError) {
+            switch networkError.code {
+            case NSURLErrorNotConnectedToInternet:
+                return "cmux can’t reach the update server. Check your internet connection and try again."
+            case NSURLErrorTimedOut:
+                return "The update server took too long to respond. Try again in a moment."
+            case NSURLErrorCannotFindHost:
+                return "The update server can’t be found. Check your connection or try again later."
+            case NSURLErrorCannotConnectToHost:
+                return "cmux couldn’t connect to the update server. Check your connection or try again later."
+            case NSURLErrorNetworkConnectionLost:
+                return "The network connection was lost while checking for updates. Try again."
+            case NSURLErrorSecureConnectionFailed,
+                 NSURLErrorServerCertificateUntrusted,
+                 NSURLErrorServerCertificateHasBadDate,
+                 NSURLErrorServerCertificateHasUnknownRoot,
+                 NSURLErrorServerCertificateNotYetValid:
+                return "A secure connection to the update server couldn’t be established. Try again later."
+            default:
+                break
+            }
+        }
+        if nsError.domain == SUSparkleErrorDomain {
+            switch nsError.code {
+            case 2001:
+                return "cmux couldn’t download the update feed. Check your connection and try again."
+            case 1000, 1002:
+                return "The update feed could not be read. Please try again later."
+            case 4:
+                return "The update feed URL is invalid. Please contact support."
+            case 3:
+                return "The update feed is insecure. Please contact support."
+            case 1, 2, 3001, 3002:
+                return "The update’s signature could not be verified. Please try again later."
+            case 1003, 1005:
+                return "Move cmux into Applications and relaunch to enable updates."
+            default:
+                break
+            }
+        }
+        return nsError.localizedDescription
+    }
+
+    static func errorDetails(for error: Swift.Error, technicalDetails: String?, feedURLString: String?) -> String {
+        let nsError = error as NSError
+        var lines: [String] = []
+        lines.append("Message: \(nsError.localizedDescription)")
+        lines.append("Domain: \(nsError.domain)")
+        if nsError.domain == SUSparkleErrorDomain,
+           let sparkleName = sparkleErrorCodeName(for: nsError.code) {
+            lines.append("Code: \(sparkleName) (\(nsError.code))")
+        } else {
+            lines.append("Code: \(nsError.code)")
+        }
+
+        if let url = nsError.userInfo[NSURLErrorFailingURLErrorKey] as? URL {
+            lines.append("URL: \(url.absoluteString)")
+        } else if let urlString = nsError.userInfo[NSURLErrorFailingURLStringErrorKey] as? String {
+            lines.append("URL: \(urlString)")
+        }
+
+        if let failure = nsError.userInfo[NSLocalizedFailureReasonErrorKey] as? String,
+           !failure.isEmpty {
+            lines.append("Failure: \(failure)")
+        }
+        if let recovery = nsError.userInfo[NSLocalizedRecoverySuggestionErrorKey] as? String,
+           !recovery.isEmpty {
+            lines.append("Recovery: \(recovery)")
+        }
+
+        if let feedURLString, !feedURLString.isEmpty {
+            lines.append("Feed: \(feedURLString)")
+        }
+
+        if let technicalDetails, !technicalDetails.isEmpty {
+            lines.append("Debug: \(technicalDetails)")
+        }
+
+        lines.append("Log: \(UpdateLogStore.shared.logPath())")
+        return lines.joined(separator: "\n")
+    }
+
+    private static func networkError(from error: NSError) -> NSError? {
+        if error.domain == NSURLErrorDomain {
+            return error
+        }
+        if let underlying = error.userInfo[NSUnderlyingErrorKey] as? NSError,
+           underlying.domain == NSURLErrorDomain {
+            return underlying
+        }
+        return nil
+    }
+
+    private static func sparkleErrorCodeName(for code: Int) -> String? {
+        switch code {
+        case 1: return "SUNoPublicDSAFoundError"
+        case 2: return "SUInsufficientSigningError"
+        case 3: return "SUInsecureFeedURLError"
+        case 4: return "SUInvalidFeedURLError"
+        case 1000: return "SUAppcastParseError"
+        case 1001: return "SUNoUpdateError"
+        case 1002: return "SUAppcastError"
+        case 1003: return "SURunningFromDiskImageError"
+        case 1005: return "SURunningTranslocated"
+        case 2001: return "SUDownloadError"
+        case 3001: return "SUSignatureError"
+        case 3002: return "SUValidationError"
+        default:
+            return nil
+        }
+    }
 }
 
 enum UpdateState: Equatable {
@@ -325,6 +489,20 @@ enum UpdateState: Equatable {
         let error: any Swift.Error
         let retry: () -> Void
         let dismiss: () -> Void
+        let technicalDetails: String?
+        let feedURLString: String?
+
+        init(error: any Swift.Error,
+             retry: @escaping () -> Void,
+             dismiss: @escaping () -> Void,
+             technicalDetails: String? = nil,
+             feedURLString: String? = nil) {
+            self.error = error
+            self.retry = retry
+            self.dismiss = dismiss
+            self.technicalDetails = technicalDetails
+            self.feedURLString = feedURLString
+        }
     }
 
     struct Downloading {