BL-16690 Honor a collection's minimum Bloom version, upgrading in place

DistFiles/localization/en/Bloom.xlf

@@ -314,6 +314,28 @@
         <source xml:lang="en">There was a problem while saving. Please return to the previous page and make sure it looks correct.</source>
         <note>ID: Browser.ProblemSaving</note>
       </trans-unit>
+      <trans-unit id="Collection.CollectionRequiresNewerVersion" translate="no">
+        <source xml:lang="en">The collection "{0}" requires Bloom {1} or greater. You are running Bloom {2}.</source>
+        <note>ID: Collection.CollectionRequiresNewerVersion</note>
+        <note>{0} is the name of the collection, {1} is the version it requires, {2} is the version of Bloom that is running.</note>
+      </trans-unit>
+      <trans-unit id="Collection.NewerVersionNeededHeader" sil:dynamic="true" translate="no">
+        <source xml:lang="en">This collection needs a newer version of Bloom.</source>
+        <note>ID: Collection.NewerVersionNeededHeader</note>
+      </trans-unit>
+      <trans-unit id="Collection.NothingNewerAvailable" translate="no">
+        <source xml:lang="en">This collection needs Bloom {0}, but you already have the newest Bloom available to you.</source>
+        <note>ID: Collection.NothingNewerAvailable</note>
+        <note>{0} is the version the collection requires.</note>
+      </trans-unit>
+      <trans-unit id="Collection.OpenDifferentCollection" translate="no">
+        <source xml:lang="en">Open a Different Collection</source>
+        <note>ID: Collection.OpenDifferentCollection</note>
+      </trans-unit>
+      <trans-unit id="Collection.UpgradeBloom" translate="no">
+        <source xml:lang="en">Upgrade Bloom</source>
+        <note>ID: Collection.UpgradeBloom</note>
+      </trans-unit>
       <trans-unit id="CollectionSettingsDialog.AboutBloomSubscriptions">
         <source xml:lang="en">About Bloom Subscriptions</source>
         <note>ID: CollectionSettingsDialog.AboutBloomSubscriptions</note>

src/BloomExe/ApplicationContainer.cs

@@ -70,7 +70,12 @@ public ApplicationContainer()
                 // containers, which is what we want for all the application singletons.
                 .SingleInstance()
                 .Where(t =>
-                    new[] { typeof(CommonApi), typeof(NewCollectionWizardApi) }.Contains(t)
+                    new[]
+                    {
+                        typeof(CommonApi),
+                        typeof(NewCollectionWizardApi),
+                        typeof(ProgressDialogApi),
+                    }.Contains(t)
                 );
 
             _container = builder.Build();
@@ -87,6 +92,17 @@ public ApplicationContainer()
             var server = _container.Resolve<BloomServer>();
             _container.Resolve<CommonApi>().RegisterWithApiHandler(server.ApiHandler);
             _container.Resolve<NewCollectionWizardApi>().RegisterWithApiHandler(server.ApiHandler);
+            // A progress dialog has to be possible before any collection is open: the "this
+            // collection needs a newer Bloom" dialog upgrades Bloom right there, and the dialog it
+            // shows while doing so talks over these endpoints. This belongs here rather than in
+            // ProjectContext (where it used to be) because all of ProgressDialogApi's handlers are
+            // static and know nothing about a project -- and because it can only be registered
+            // ONCE: RegisterEndpointHandler does a Dictionary.Add, which throws on a duplicate
+            // key, and application-level registrations are deliberately not cleared between
+            // collections, so a second registration would never go away.
+            _container
+                .Resolve<ProgressDialogApi>()
+                .RegisterWithApiHandler(server.ApiHandler);
             server.ApiHandler.RecordApplicationLevelHandlers();
         }
 

src/BloomExe/Collection/CollectionSettings.cs

@@ -72,6 +72,20 @@ public class CollectionSettings
         // if this is null, relevant code uses the default, so we don't have to initialize it here
         public string BadgeQrCodeLabel;
 
+        /// <summary>
+        /// The oldest version of Bloom that is allowed to open this collection, e.g. "6.5".
+        /// Empty means any version may open it. At this point there is no UI for setting this;
+        /// it has to be added by editing the .bloomCollection file by hand. See BL-16690.
+        /// The gate that actually enforces it is MinimumBloomVersionCheck.
+        /// </summary>
+        public string MinimumBloomVersion = "";
+
+        /// <summary>
+        /// The name of the element in the .bloomCollection file that holds MinimumBloomVersion.
+        /// MinimumBloomVersionCheck reads it without loading the whole CollectionSettings.
+        /// </summary>
+        public const string kMinimumBloomVersionElementName = "MinimumBloomVersion";
+
         public static readonly Dictionary<string, string> CssNumberStylesToCultureOrDigits =
             new Dictionary<string, string>()
             {
@@ -419,6 +433,10 @@ public void Save()
             xml.Add(BulkPublishBloomPubSettings.ToXElement());
             xml.Add(new XElement("ShowBlorgLanguageQrCode", ShowBlorgLanguageQrCode));
             xml.Add(new XElement("BadgeQrCodeLabel", BadgeQrCodeLabel));
+            // Only write this if it is actually in use. Save() builds the file from scratch, so if we
+            // didn't write it back, the first save after someone hand-added it would silently lose it.
+            if (!string.IsNullOrWhiteSpace(MinimumBloomVersion))
+                xml.Add(new XElement(kMinimumBloomVersionElementName, MinimumBloomVersion));
             RobustIO.SaveXElement(xml, SettingsFilePath);
 
             // Color palette settings are stored in a separate Json file
@@ -705,6 +723,7 @@ public void Load()
 
                 ShowBlorgLanguageQrCode = ReadBoolean(xml, "ShowBlorgLanguageQrCode", true);
                 BadgeQrCodeLabel = ReadString(xml, "BadgeQrCodeLabel", "");
+                MinimumBloomVersion = ReadString(xml, kMinimumBloomVersionElementName, "");
 
                 LoadDictionary(xml, "Palette", ColorPalettes);
             }