Only add parameter indices if they are missing

This change also makes the code handle strings where some parameters
have indices and some don't. The ones that don't are assigned indices
sequentially starting from the last specified index plus one, or one if
there aren't any.

1 files changed, 33 insertions, 2 deletions

diff --git a/android/translations-converter/src/android/string_value.rs b/android/translations-converter/src/android/string_value.rs
index 9207dad6ed..47c12265e7 100644
--- a/android/translations-converter/src/android/string_value.rs
+++ b/android/translations-converter/src/android/string_value.rs
@@ -1,3 +1,5 @@
+use lazy_static::lazy_static;
+use regex::Regex;
 use serde::{Deserialize, Serialize};
 use std::{
     fmt::{self, Display, Formatter},
@@ -11,7 +13,10 @@ pub struct StringValue(String);
 impl StringValue {
     /// Create a `StringValue` from an unescaped string.
     ///
-    /// The string will be properly escaped, and all parameters will have indices added to them.
+    /// The string will be properly escaped, and all parameters will have indices added to them if
+    /// they don't have any. Indices are assigned sequentially starting from the previously
+    /// specified index plus one, or starting from one if there aren't any previously specified
+    /// indices.
     pub fn from_unescaped(string: &str) -> Self {
         let value_with_parameters = htmlize::escape_text(string)
             .replace(r"\", r"\\")
@@ -41,11 +46,37 @@ impl StringValue {
     /// would update the string so that all parameters have indices: `Things are %1$d, %3$s and
     /// %4$s`.
     fn ensure_parameters_are_indexed(original: String) -> String {
+        lazy_static! {
+            static ref PARAMETER_INDEX: Regex = Regex::new(r"^(\d+)\$").unwrap();
+        }
+
         let mut parts = original.split("%");
         let mut output = parts.next().unwrap().to_owned();
+        let mut offset = 1;
 
         for (index, part) in parts.enumerate() {
-            output.push_str(&format!("%{}$", index + 1));
+            let index = index as isize;
+
+            if let Some(captures) = PARAMETER_INDEX.captures(part) {
+                // String already has a parameter index
+                let specified_index: isize = captures
+                    .get(1)
+                    .expect("Regex has at least one capture group")
+                    .as_str()
+                    .parse()
+                    .expect("First capture group should match an integer");
+
+                // Update offset so that next parameters without index receive sequential values
+                // starting after the specified index
+                offset = specified_index - index;
+
+                // Restore '%' removed during the split
+                output.push('%');
+            } else {
+                // String doesn't have a parameter index, so it is added
+                output.push_str(&format!("%{}$", index + offset));
+            }
+
             output.push_str(part);
         }