Improve SeedShamirShareOptionsView handling when adding/finalizing

Author: alvroble

src/seedsigner/models/seed_storage.py

@@ -161,8 +161,34 @@ def discard_pending_shamir_share_set(self):
         self._pending_shamir_share_set = []
         self._pending_shamir_num_words = None
 
+    def get_pending_shamir_threshold(self) -> int | None:
+        """Return threshold based on the first parsed share."""
+        if not self._pending_shamir_share_set:
+            return None
+
+        try:
+            from embit import slip39
+            first_share = " ".join(self._pending_shamir_share_set[0])
+            share = slip39.Share.parse(first_share)
+        except Exception:
+            return None
+
+        return share.group_threshold
+
+
+    def can_finalize_pending_shamir_share_set(self, passphrase: str = "") -> bool:
+        """Return True if the current share set can reconstruct a Shamir seed."""
+        if not self._pending_shamir_share_set:
+            return False
+        
+        try:
+            ShamirSeed(self._pending_shamir_share_set, passphrase)
+        except InvalidSeedException:
+            return False
+
+        return True
+
     def convert_pending_shamir_share_set_to_pending_seed(self, passphrase: str = '', finalize: bool = True):
-        share_set_formatted = [" ".join(share) for share in self._pending_shamir_share_set]
         self.pending_seed = ShamirSeed(self._pending_shamir_share_set, passphrase)
         self.pending_seed.set_passphrase(passphrase)
         if finalize:

src/seedsigner/views/seed_views.py

@@ -9,11 +9,11 @@
 
 from seedsigner.gui.components import FontAwesomeIconConstants, SeedSignerIconConstants
 from seedsigner.gui.screens import (RET_CODE__BACK_BUTTON, ButtonListScreen,
-    WarningScreen, DireWarningScreen, seed_screens)
+    WarningScreen, DireWarningScreen, LargeIconStatusScreen, seed_screens)
 from seedsigner.gui.screens.screen import ButtonOption
 from seedsigner.models.encode_qr import CompactSeedQrEncoder, GenericStaticQrEncoder, SeedQrEncoder, SpecterXPubQrEncoder, StaticXpubQrEncoder, UrXpubQrEncoder
 from seedsigner.models.qr_type import QRType
-from seedsigner.models.seed import Seed, ShamirSeed
+from seedsigner.models.seed import Seed, ShamirSeed, InvalidSeedException
 from seedsigner.models.settings import Settings, SettingsConstants
 from seedsigner.models.settings_definition import SettingsDefinition
 from seedsigner.models.threads import BaseThread, ThreadsafeCounter
@@ -2446,29 +2446,55 @@ def run(self):
 
             # Add the completed share
             self.controller.storage.add_pending_shamir_share()
-            return Destination(SeedShamirShareOptionsView)
+            can_finalize = self.controller.storage.can_finalize_pending_shamir_share_set()
+            share_threshold = self.controller.storage.get_pending_shamir_threshold()
+            share_count = self.controller.storage.pending_shamir_share_set_length
+            return Destination(
+                    SeedShamirShareOptionsView,
+                    view_args={
+                        "can_finalize": can_finalize,
+                        "share_threshold": share_threshold,
+                        "share_count": share_count
+                    }
+                )
 
 
 
 class SeedShamirShareOptionsView(View):
     # TRANSLATOR_NOTE: These options apply to SLIP-39 Shamir shares (add another share or finalize share set).
     ADD_SHARE = ButtonOption("Add another share")
     FINALIZE = ButtonOption("Finalize")
-    # TRANSLATOR_NOTE: "Shares" here means SLIP-39 Shamir secret shares.
-    toast_error_message: str = _("Need more shares to reconstruct seed")
-                
+
+    def __init__(self, can_finalize, share_threshold, share_count):
+        super().__init__()
+        self.can_finalize = can_finalize
+        self.share_threshold = share_threshold
+        self.share_count = share_count
+        self.shares_remaining = share_threshold - share_count
+
 
     def run(self):
-        button_data = [self.ADD_SHARE, self.FINALIZE]
+        button_data = []
+        if self.can_finalize:
+            button_data.append(self.FINALIZE)
+        else:
+            button_data.append(self.ADD_SHARE)
 
-        share_count = self.controller.storage.pending_shamir_share_set_length
         # TRANSLATOR_NOTE: "Shares" here means SLIP-39 Shamir's secret shares.
-        title = _("Shares Added: {}").format(share_count)
+        title = _("Share Added")
+        text = None
+        if self.share_threshold is not None and self.shares_remaining is not None:
+            if self.shares_remaining > 0:
+                # TRANSLATOR_NOTE: Indicates how many more SLIP-39 shares must be collected.
+                text = _("Shares entered: {}\nShares remaining: {}").format(self.share_count, self.shares_remaining)
+            else:
+                text = _("Required shares collected.\nReady to finalize.")
 
         selected_menu_num = self.run_screen(
-            ButtonListScreen,
+            LargeIconStatusScreen,
             title=title,
             button_data=button_data,
+            text=text,
         )
 
         if selected_menu_num == RET_CODE__BACK_BUTTON:
@@ -2478,16 +2504,19 @@ def run(self):
             return Destination(SeedShamirShareMnemonicEntryView)
 
         elif button_data[selected_menu_num] == self.FINALIZE:
-            # Try to finalize with current shares
-            from seedsigner.models.seed import InvalidSeedException
             try:
                 self.controller.storage.convert_pending_shamir_share_set_to_pending_seed(finalize=False)
-                return Destination(SeedShamirShareFinalizeView)
             except InvalidSeedException:
-                # If seed does not reconstruct, more shares are needed
-                from seedsigner.gui.toast import ErrorToast
-                self.controller.activate_toast(ErrorToast(self.toast_error_message))
-                return Destination(SeedShamirShareOptionsView)
+                logger.exception("Pending Shamir share set unexpectedly failed to reconstruct despite eligibility.")
+                return Destination(
+                        SeedShamirShareOptionsView,
+                        view_args={
+                            "can_finalize": self.can_finalize,
+                            "share_threshold": self.share_threshold,
+                            "share_count": self.share_count
+                        }
+                    )
+            return Destination(SeedShamirShareFinalizeView)
 
 
 
@@ -2523,7 +2552,17 @@ def run(self):
                 return Destination(MainMenuView)
 
             else:
-                return Destination(SeedShamirShareOptionsView)
+                can_finalize = self.controller.storage.can_finalize_pending_shamir_share_set()
+                share_threshold = self.controller.storage.get_pending_shamir_threshold()
+                share_count = self.controller.storage.pending_shamir_share_set_length
+                return Destination(
+                        SeedShamirShareOptionsView,
+                        view_args={
+                            "can_finalize": can_finalize,
+                            "share_threshold": share_threshold,
+                            "share_count": share_count
+                        }
+                    )
 
 
 

tests/screenshot_generator/generator.py

@@ -370,8 +370,8 @@ def PSBTOpReturnView_raw_hex_data_cb_before():
                 ScreenshotConfig(seed_views.SeedShamirShareStartView),
                 ScreenshotConfig(seed_views.SeedShamirShareImportSelectWordCount),
                 ScreenshotConfig(seed_views.SeedShamirShareMnemonicEntryView),
-                ScreenshotConfig(seed_views.SeedShamirShareOptionsView),
-                ScreenshotConfig(seed_views.SeedShamirShareOptionsView, screenshot_name='SeedShamirShareOptionsView_ErrorToast', toast_thread=ErrorToast(seed_views.SeedShamirShareOptionsView.toast_error_message, activation_delay=0, duration=0)),
+                ScreenshotConfig(seed_views.SeedShamirShareOptionsView, dict(can_finalize=False, share_threshold=3, share_count=2), screenshot_name="SeedShamirShareOptionsView_AddShare"),
+                ScreenshotConfig(seed_views.SeedShamirShareOptionsView, dict(can_finalize=True, share_threshold=3, share_count=3), screenshot_name="SeedShamirShareOptionsView_Finalize"),
                 ScreenshotConfig(seed_views.SeedShamirShareFinalizeView),
                 ScreenshotConfig(seed_views.SeedShamirShareInvalidView),
             ],