fix: preserve table width remainders

Author: Bortlesboat

src/cortex-core/src/markdown/table/tests.rs

@@ -151,6 +151,29 @@ mod tests {
         assert!(table.column_widths[1] >= 20);
     }
 
+    #[test]
+    fn test_column_width_distribution_preserves_available_space() {
+        let mut builder = TableBuilder::new();
+        builder.start_header();
+        builder.add_cell("A A A".to_string());
+        builder.add_cell("B B B".to_string());
+        builder.add_cell("C C C".to_string());
+        builder.end_header();
+
+        builder.start_row();
+        builder.add_cell("aa bb cc".to_string());
+        builder.add_cell("dd ee ff".to_string());
+        builder.add_cell("gg hh ii".to_string());
+        builder.end_row();
+
+        let mut table = builder.build();
+        let max_width = 21;
+        table.calculate_column_widths(max_width);
+
+        // Three columns have 4 border chars and 6 padding chars, leaving 11 content chars.
+        assert_eq!(table.column_widths.iter().sum::<usize>(), 11);
+    }
+
     #[test]
     fn test_missing_cells_in_rows() {
         let mut builder = TableBuilder::new();

src/cortex-core/src/markdown/table/types.rs

@@ -209,11 +209,35 @@ impl Table {
             self.column_widths = min_widths.clone();
 
             if pref_extra > 0 {
+                let mut allocated_total = 0;
+                let mut remainders = Vec::with_capacity(num_cols);
+
                 for i in 0..num_cols {
                     let col_extra = pref_widths[i].saturating_sub(min_widths[i]);
-                    let allocated =
-                        (col_extra as f64 / pref_extra as f64 * extra_space as f64) as usize;
+                    let weighted_extra = col_extra * extra_space;
+                    let allocated = weighted_extra / pref_extra;
+                    let remainder = weighted_extra % pref_extra;
+
                     self.column_widths[i] += allocated;
+                    allocated_total += allocated;
+
+                    if allocated < col_extra {
+                        remainders.push((i, remainder));
+                    }
+                }
+
+                let mut remaining = extra_space.saturating_sub(allocated_total);
+                remainders.sort_by(|a, b| b.1.cmp(&a.1).then_with(|| a.0.cmp(&b.0)));
+
+                for (i, _) in remainders {
+                    if remaining == 0 {
+                        break;
+                    }
+
+                    if self.column_widths[i] < pref_widths[i] {
+                        self.column_widths[i] += 1;
+                        remaining -= 1;
+                    }
                 }
             }
         } else {