feat(voting): derive keys through the platform wallet; rework node selection

DashWallet.xcodeproj/project.pbxproj

@@ -1916,6 +1916,8 @@
 		E503EDEA94E656CAE70E5A11 /* UsernameRequestStatusScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED4CB35186918CCBD2FFC49F /* UsernameRequestStatusScreen.swift */; };
 		D19A81C4F6103AC513D737AA /* UsernameRequestStatusScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED4CB35186918CCBD2FFC49F /* UsernameRequestStatusScreen.swift */; };
 		63C3BBEF4EE77A6F02144B2D /* BulkVoteSheet.swift in Sources */ = {isa = PBXBuildFile; fileRef = C3E5E523355F3EEC5CDEB00A /* BulkVoteSheet.swift */; };
+		A1B2C3D40002VOTINGNODESEL /* VotingNodeSelectionSheet.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B2C3D40001VOTINGNODESEL /* VotingNodeSelectionSheet.swift */; };
+		A1B2C3D40003VOTINGNODESEL /* VotingNodeSelectionSheet.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B2C3D40001VOTINGNODESEL /* VotingNodeSelectionSheet.swift */; };
 		25B84141680B6A9F225C995C /* BulkVoteSheet.swift in Sources */ = {isa = PBXBuildFile; fileRef = C3E5E523355F3EEC5CDEB00A /* BulkVoteSheet.swift */; };
 		7062FCF792F292D84A0B819B /* VoteHistoryDAO.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0AFB72236D79932EAE7A38E2 /* VoteHistoryDAO.swift */; };
 		553696A24F315D361BC86231 /* VoteHistoryDAO.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0AFB72236D79932EAE7A38E2 /* VoteHistoryDAO.swift */; };
@@ -3642,6 +3644,7 @@
 		FF2C19E8480582798A0155E4 /* CastVoteSheet.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = CastVoteSheet.swift; sourceTree = "<group>"; };
 		ED4CB35186918CCBD2FFC49F /* UsernameRequestStatusScreen.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = UsernameRequestStatusScreen.swift; sourceTree = "<group>"; };
 		C3E5E523355F3EEC5CDEB00A /* BulkVoteSheet.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = BulkVoteSheet.swift; sourceTree = "<group>"; };
+		A1B2C3D40001VOTINGNODESEL /* VotingNodeSelectionSheet.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = VotingNodeSelectionSheet.swift; sourceTree = "<group>"; };
 		0AFB72236D79932EAE7A38E2 /* VoteHistoryDAO.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = VoteHistoryDAO.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -6722,6 +6725,7 @@
 			isa = PBXGroup;
 			children = (
 				C3E5E523355F3EEC5CDEB00A /* BulkVoteSheet.swift */,
+				A1B2C3D40001VOTINGNODESEL /* VotingNodeSelectionSheet.swift */,
 				33DEAFAEEDCA07D0A331911B /* UsernameVotingScreen.swift */,
 				6BA141C505AF0AE495DCAA37 /* ContestDetailScreen.swift */,
 				FF2C19E8480582798A0155E4 /* CastVoteSheet.swift */,
@@ -9403,6 +9407,7 @@
 			files = (
 				553696A24F315D361BC86231 /* VoteHistoryDAO.swift in Sources */,
 				25B84141680B6A9F225C995C /* BulkVoteSheet.swift in Sources */,
+				A1B2C3D40003VOTINGNODESEL /* VotingNodeSelectionSheet.swift in Sources */,
 				D19A81C4F6103AC513D737AA /* UsernameRequestStatusScreen.swift in Sources */,
 				6181C570B638E07D8B369CDB /* VotingViewModel.swift in Sources */,
 				AD24D88215A4E51186112B34 /* CastVoteSheet.swift in Sources */,
@@ -10272,6 +10277,7 @@
 			files = (
 				7062FCF792F292D84A0B819B /* VoteHistoryDAO.swift in Sources */,
 				63C3BBEF4EE77A6F02144B2D /* BulkVoteSheet.swift in Sources */,
+				A1B2C3D40002VOTINGNODESEL /* VotingNodeSelectionSheet.swift in Sources */,
 				E503EDEA94E656CAE70E5A11 /* UsernameRequestStatusScreen.swift in Sources */,
 				1FED991A9D2D236582CE3C99 /* CastVoteSheet.swift in Sources */,
 				D0C564276BD8B9770F0E0499 /* ContestDetailScreen.swift in Sources */,

DashWallet/Sources/Infrastructure/SwiftDashSDK/Voting/MasternodeVoteCaster.swift

@@ -129,7 +129,6 @@ final class MasternodeVoteCaster {
         case authenticationCancelled
         case noNodesSelected
         case contestClosed(String)
-        case choiceNotBulkable
         case sdkUnavailable
 
         var errorDescription: String? {
@@ -144,10 +143,6 @@ final class MasternodeVoteCaster {
                 return String(format: NSLocalizedString(
                     "Voting on “%@” has already closed. Refresh to see the result.",
                     comment: "Voting"), label)
-            case .choiceNotBulkable:
-                return NSLocalizedString(
-                    "Approving a specific request can only be done one username at a time.",
-                    comment: "Voting")
             case .sdkUnavailable:
                 return NSLocalizedString(
                     "Dash Platform is not connected yet. Wait for syncing to finish and try again.",
@@ -267,20 +262,21 @@ final class MasternodeVoteCaster {
     /// becomes a report with every node failed rather than aborting the run,
     /// so one stale row cannot discard the rest of the batch.
     ///
-    /// - Note: Only ``VoteChoice/abstain`` and ``VoteChoice/lock`` generalize
-    ///   across contests. `towards` names a specific contender, and the
-    ///   legacy "vote for whoever submitted first" rule is not reproducible
-    ///   here: contender submission time lives inside the serialized `domain`
-    ///   document, which the FFI returns as opaque hex.
+    /// - Note: Each entry carries its own choice. `abstain` and `lock`
+    ///   generalize across contests, but "award it to the only requester"
+    ///   names a different contender identity per contest, so the caller
+    ///   resolves that and passes the result per label. This function does not
+    ///   decide who a contest's contenders are.
     func castBulk(
-        choice: VoteChoice,
-        onNormalizedLabels labels: [String],
-        with nodes: [VoterNode]
+        _ work: [(label: String, choice: VoteChoice, nodes: [VoterNode])]
     ) async throws -> [VoteCastReport] {
-        guard !nodes.isEmpty else { throw CastError.noNodesSelected }
-        guard !labels.isEmpty else { return [] }
-        if case .towards = choice {
-            throw CastError.choiceNotBulkable
+        // Nothing to do is not the same as nothing selected. An empty batch
+        // means every selected contest was already fully voted or dropped, and
+        // reporting "select a masternode" for that sends the user to fix a
+        // selection that is fine.
+        guard !work.isEmpty else { return [] }
+        guard work.contains(where: { !$0.nodes.isEmpty }) else {
+            throw CastError.noNodesSelected
         }
         guard let sdk = SwiftDashSDKHost.shared.sdk else { throw CastError.sdkUnavailable }
 
@@ -295,9 +291,9 @@ final class MasternodeVoteCaster {
         }
 
         var reports: [VoteCastReport] = []
-        reports.reserveCapacity(labels.count)
+        reports.reserveCapacity(work.count)
 
-        for label in labels {
+        for (label, choice, nodes) in work {
             // "The check failed" and "the poll is closed" are different
             // outcomes: collapsing them would tell the user a live contest had
             // already resolved whenever the network hiccupped.

DashWallet/Sources/Infrastructure/SwiftDashSDK/Voting/MasternodeVoterRegistry.swift

@@ -124,8 +124,18 @@ final class MasternodeVoterRegistry {
 
         let nodes = eligible
             .compactMap { masternode -> (PlatformMasternode, UInt32)? in
-                guard let address = masternode.votingAddress,
-                      let index = indexByAddress[address] else { return nil }
+                guard let address = masternode.votingAddress else {
+                    Self.logger.info(
+                        "🗳️ VOTING :: skipping a node with no published voting address")
+                    return nil
+                }
+                guard let index = indexByAddress[address] else {
+                    Self.logger.info(
+                        "🗳️ VOTING :: a registered voting address is not in this wallet's pool — not votable: \(address, privacy: .private)")
+                    return nil
+                }
+                Self.logger.info(
+                    "🗳️ VOTING :: matched a registered voting address at pool index \(index, privacy: .public): \(address, privacy: .private)")
                 return (masternode, index)
             }
             .sorted { $0.0.orderIndex < $1.0.orderIndex }
@@ -160,8 +170,19 @@ final class MasternodeVoterRegistry {
             Self.logger.error("🗳️ VOTING :: no provider-voting deriver available")
             return nil
         }
-        guard let wif = deriver.wif(at: node.votingKeyIndex),
-              let key = WIFParser.parseWIF(wif) else {
+
+        // The index came from joining the node's registered address against
+        // the live pool; the key is resolved Rust-side from the running wallet
+        // (platform#4338), which cross-checks it against the account xpub
+        // before returning. So a key that does not match this node's registered
+        // voting address cannot reach the signer — Platform would only be able
+        // to report that as "no voter identity exists", which is
+        // indistinguishable from a node that was never registered.
+        Self.logger.info(
+            "🗳️ VOTING :: signing with the key at pool index \(node.votingKeyIndex, privacy: .public) for \(deriver.address(at: node.votingKeyIndex) ?? "unknown address", privacy: .private)")
+
+        guard let hex = deriver.privateKeyHex(at: node.votingKeyIndex),
+              let key = Data(hex: hex) else {
             Self.logger.error(
                 "🗳️ VOTING :: failed to derive voting key at index \(node.votingKeyIndex, privacy: .public)")
             return nil

DashWallet/Sources/Models/Voting/VotingPrefs.swift

@@ -18,7 +18,7 @@
 import Foundation
 
 private let kVotingEnabled = "votingEnabledKey"
-private let kVoteWithAllNodes = "voteWithAllNodesKey"
+private let kVotingNodeSelection = "votingNodeSelectionKey"
 
 // MARK: - VotingPrefs
 
@@ -28,12 +28,8 @@ class VotingPrefs {
     public static let shared: VotingPrefs = .init()
 
     init() {
-        // Voting one node at a time is the default on purpose: casting every
-        // node's vote in one action publicly links those masternodes to each
-        // other, which is a privacy loss the user cannot undo afterwards.
         UserDefaults.standard.register(defaults: [
             kVotingEnabled: true,
-            kVoteWithAllNodes: false,
         ])
     }
 
@@ -49,15 +45,27 @@ class VotingPrefs {
         }
     }
 
-    /// `false` (default) casts one masternode's vote per tap; `true` casts
-    /// with every votable node at once.
+    /// proTxHashes of the masternodes the user last voted with, so the next
+    /// contest opens with the same nodes ticked.
     ///
-    /// Voting all at once broadcasts several `MasternodeVote` transitions for
-    /// the same poll in quick succession, which lets an observer group those
-    /// nodes as one operator. One at a time keeps that correlation the user's
-    /// choice rather than a side effect of the default.
-    var voteWithAllNodes: Bool {
-        get { UserDefaults.standard.bool(forKey: kVoteWithAllNodes) }
-        set { UserDefaults.standard.set(newValue, forKey: kVoteWithAllNodes) }
+    /// Empty means "never chosen": callers fall back to a single node rather
+    /// than every node. That default is deliberate — casting with every node
+    /// at once broadcasts several `MasternodeVote` transitions for the same
+    /// poll in quick succession, which lets an observer group those nodes as
+    /// one operator. Linking them stays something the user opts into and
+    /// cannot be an accident of the first vote.
+    ///
+    /// Local only: this is a UI convenience, never consulted to decide what a
+    /// node is permitted to do.
+    var votingNodeSelection: Set<Data> {
+        get {
+            let stored = UserDefaults.standard.array(forKey: kVotingNodeSelection) as? [String] ?? []
+            return Set(stored.compactMap { Data(base64Encoded: $0) })
+        }
+        set {
+            UserDefaults.standard.set(
+                newValue.map { $0.base64EncodedString() }.sorted(),
+                forKey: kVotingNodeSelection)
+        }
     }
 }