Determine required files from custom HTML

CHDataManagement/Generator/Results/PageGenerationResults.swift

@@ -94,6 +94,10 @@ final class PageGenerationResults: ObservableObject {
     @Published
     private(set) var unsavedOutputFiles: [String: Set<ItemReference>] = [:]
 
+    /// The files that need to be present in the output folder
+    @Published
+    private(set) var requiredOutputFiles: [String: Set<String>] = [:]
+
     private(set) var pageIsEmpty: Bool
 
     private(set) var redirect: (originalUrl: String, newUrl: String)?
@@ -120,6 +124,7 @@ final class PageGenerationResults: ObservableObject {
         invalidBlocks = []
         warnings = []
         unsavedOutputFiles = [:]
+        requiredOutputFiles = [:]
         pageIsEmpty = false
         redirect = nil
     }
@@ -151,6 +156,7 @@ final class PageGenerationResults: ObservableObject {
             self.invalidBlocks = []
             self.warnings = []
             self.unsavedOutputFiles = [:]
+            self.requiredOutputFiles = [:]
             self.pageIsEmpty = false
             self.redirect = nil
         }
@@ -258,6 +264,11 @@ final class PageGenerationResults: ObservableObject {
         onMain { self.requiredIcons.formUnion(icons) }
     }
 
+    func requiredOutput(_ path: String, source: String) {
+        onMain { self.requiredOutputFiles[path, default: []].insert(source) }
+        delegate.requiredOutputFile(path)
+    }
+
     func linked(to page: Page) {
         onMain { self.linkedPages.insert(page) }
     }