Fix: Bug: names may be shortened unnecessarily

The code calculating the width of a row to use vs the width of the
terminal wasn't quite right.

If we had 2 long filepaths one at the top of the dir tree and one at the
bottom the old code would shorten both equally. This doesn't make sense
as the one at the shallowest part of the tree would have used less
screen real estate and so should show a longer part of the filepath.

src/display.rs

@@ -128,20 +128,21 @@ pub fn draw_it(
     } else {
         5 // Under normal usage we need 5 chars to display the size of a directory
     };
+
     assert!(
-        terminal_width > 9 + num_chars_needed_on_left_most,
+        terminal_width > num_chars_needed_on_left_most + 2,
         "Not enough terminal width"
     );
 
-    let terminal_width = terminal_width - 9 - num_chars_needed_on_left_most;
+    let t = terminal_width - num_chars_needed_on_left_most - 2;
     let num_indent_chars = 3;
     let longest_string_length =
-        find_longest_dir_name(&root_node, num_indent_chars, terminal_width, !use_full_path);
+        find_longest_dir_name(&root_node, num_indent_chars, t, !use_full_path);
 
-    let max_bar_length = if no_percents || longest_string_length >= terminal_width as usize {
+    let max_bar_length = if no_percents || longest_string_length + 7 >= t as usize {
         0
     } else {
-        terminal_width as usize - longest_string_length
+        t as usize - longest_string_length - 7
     };
 
     let first_size_bar = repeat(BLOCKS[0]).take(max_bar_length).collect::<String>();
@@ -264,23 +265,31 @@ fn pad_or_trim_filename(node: &DisplayNode, indent: &str, display_data: &Display
     let indent_and_name = format!("{} {}", indent, name);
     let width = UnicodeWidthStr::width(&*indent_and_name);
 
-    assert!(display_data.longest_string_length >= width);
+    assert!(
+        display_data.longest_string_length >= width,
+        "Terminal width not wide enough to draw directory tree"
+    );
 
     // Add spaces after the filename so we can draw the % used bar chart.
     let name_and_padding = name
         + " "
-            .repeat(display_data.longest_string_length - width)
+            .repeat((display_data.longest_string_length) - (width))
             .as_str();
 
-    maybe_trim_filename(name_and_padding, display_data)
+    name_and_padding
 }
 
-fn maybe_trim_filename(name_in: String, display_data: &DisplayData) -> String {
-    if UnicodeWidthStr::width(&*name_in) > display_data.longest_string_length {
-        let name = name_in
-            .chars()
-            .take(display_data.longest_string_length - 2)
-            .collect::<String>();
+fn maybe_trim_filename(name_in: String, indent: &str, display_data: &DisplayData) -> String {
+    let indent_length = UnicodeWidthStr::width(indent);
+    assert!(
+        display_data.longest_string_length >= indent_length + 2,
+        "Terminal width not wide enough to draw directory tree"
+    );
+
+    // println!("{} : {} : {}", UnicodeWidthStr::width(&*name_in) ,display_data.longest_string_length, indent_length);
+    let max_size = display_data.longest_string_length - indent_length;
+    if UnicodeWidthStr::width(&*name_in) > max_size {
+        let name = name_in.chars().take(max_size - 2).collect::<String>();
         name + ".."
     } else {
         name_in
@@ -313,7 +322,7 @@ fn get_name_percent(
         (percents, name_and_padding)
     } else {
         let n = get_printable_name(&node.name, display_data.short_paths);
-        let name = maybe_trim_filename(n, display_data);
+        let name = maybe_trim_filename(n, indent, display_data);
         ("".into(), name)
     }
 }
@@ -406,7 +415,7 @@ mod tests {
             indent,
             percent_bar,
             is_biggest,
-            &get_fake_display_data(6),
+            &get_fake_display_data(20),
         );
         assert_eq!(s, " 4.0K ┌─┴ short");
     }
@@ -427,7 +436,7 @@ mod tests {
         let s = format_string(&n, indent, percent_bar, is_biggest, &dd);
         assert_eq!(
             s,
-            " 4.0K ┌─┴ very_long_name_longer_than_the_eighty_character_limit_very_lon.."
+            " 4.0K ┌─┴ very_long_name_longer_than_the_eighty_character_limit_very_.."
         );
     }