Populate render context for footnote references.

src/intermediate/footnote_reference.rs

@@ -5,6 +5,7 @@ use super::registry::Registry;
 #[derive(Debug)]
 pub(crate) struct IFootnoteReference {
     footnote_id: usize,
+    duplicate_offset: usize,
 }
 
 impl IFootnoteReference {
@@ -13,6 +14,33 @@ impl IFootnoteReference {
         original: &'intermediate organic::types::FootnoteReference<'parse>,
     ) -> Result<IFootnoteReference, CustomError> {
         let footnote_id = registry.get_footnote_reference_id(original.label, &original.definition);
-        Ok(IFootnoteReference { footnote_id })
+        Ok(IFootnoteReference {
+            footnote_id,
+            duplicate_offset: 0, // TODO
+        })
+    }
+
+    pub(crate) fn get_display_label(&self) -> String {
+        format!("{}", self.footnote_id + 1)
+    }
+
+    /// Get an ID to refer to this footnote reference.
+    ///
+    /// This ID could, for example, be used for the id attribute in HTML for the reference anchor tag.
+    pub(crate) fn get_reference_id(&self) -> String {
+        if self.duplicate_offset == 0 {
+            format!("fnr.{}", self.get_display_label())
+        } else {
+            // Org-mode makes all duplicates use "100" but I figure there is no harm in giving each a unique ID.
+            let append = 100 + self.duplicate_offset;
+            format!("fnr.{}.{}", self.get_display_label(), append)
+        }
+    }
+
+    /// Get an ID to refer to the footnote definition this footnote reference references.
+    ///
+    /// This ID could, for example, be used for the id attribute in HTML for the definition anchor tag.
+    pub(crate) fn get_definition_id(&self) -> String {
+        format!("fn.{}", self.get_display_label())
     }
 }