Assign the reference counts.

src/intermediate/footnote_reference.rs

@@ -10,11 +10,11 @@ pub(crate) struct IFootnoteReference {
 }
 
 intermediate!(IFootnoteReference, FootnoteReference, original, registry, {
-    let footnote_id =
+    let (footnote_id, reference_count) =
         get_footnote_reference_id(registry, original.label, &original.definition).await?;
     Ok(IFootnoteReference {
         footnote_id,
-        duplicate_offset: 0, // TODO
+        duplicate_offset: reference_count,
     })
 });
 
@@ -31,7 +31,7 @@ impl IFootnoteReference {
             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;
+            let append = 100 + self.duplicate_offset - 1;
             format!("fnr.{}.{}", self.get_display_label(), append)
         }
     }

src/intermediate/registry.rs

@@ -13,6 +13,7 @@ pub(crate) struct Registry<'orig, 'parse> {
     id_counter: IdCounter,
     targets: HashMap<&'parse str, String>,
     footnote_ids: Vec<(Option<&'parse str>, Vec<IAstNode>)>,
+    footnote_reference_counts: HashMap<&'parse str, usize>,
     on_deck_footnote_ids: HashMap<&'parse str, &'orig Vec<Element<'parse>>>,
 }
 
@@ -22,6 +23,7 @@ impl<'orig, 'parse> Registry<'orig, 'parse> {
             id_counter: 0,
             targets: HashMap::new(),
             footnote_ids: Vec::new(),
+            footnote_reference_counts: HashMap::new(),
             on_deck_footnote_ids: HashMap::new(),
         }
     }
@@ -48,7 +50,7 @@ pub(crate) async fn get_footnote_reference_id<'orig, 'parse>(
     registry: RefRegistry<'orig, 'parse>,
     label: Option<&'parse str>,
     definition: &'orig Vec<Object<'parse>>,
-) -> Result<usize, CustomError> {
+) -> Result<(usize, usize), CustomError> {
     if let None = label {
         // If it has no label then it must always get a new ID.
         let contents = convert_reference_contents(registry.clone(), definition).await?;
@@ -57,12 +59,21 @@ pub(crate) async fn get_footnote_reference_id<'orig, 'parse>(
             registry.footnote_ids.push((None, contents));
             registry.footnote_ids.len() - 1
         };
-        return Ok(pos);
+        return Ok((pos, 0));
     }
 
-    if let Some(label) = label {
+    let reference_count = if let Some(label) = label {
         promote_footnote_definition(registry.clone(), label).await?;
-    }
+        let mut registry = registry.lock().unwrap();
+        let reference_count = registry
+            .footnote_reference_counts
+            .entry(label)
+            .and_modify(|count| *count += 1)
+            .or_insert(0);
+        *reference_count
+    } else {
+        0
+    };
 
     let existing_index = registry
         .lock()
@@ -80,7 +91,7 @@ pub(crate) async fn get_footnote_reference_id<'orig, 'parse>(
                 .expect("If-statement proves this to be Some.");
             entry.1 = contents;
         }
-        Ok(existing_id)
+        Ok((existing_id, reference_count))
     } else {
         let existing_id = {
             let mut registry = registry.lock().unwrap();
@@ -96,7 +107,7 @@ pub(crate) async fn get_footnote_reference_id<'orig, 'parse>(
                 .expect("If-statement proves this to be Some.");
             entry.1 = contents;
         }
-        Ok(existing_id)
+        Ok((existing_id, reference_count))
     }
 }