refactor(evaluation): fix yet another evaluation bug by refactoring

src/game/mod.rs

@@ -126,34 +126,60 @@ impl<'wl, WL: WordList> Game<'wl, WL> {
 
     /// Generates an [Evaluation] for a given solution and guess.
     pub(crate) fn evaluate(solution: WordData, guess: &Word) -> Evaluation {
-        let mut evaluation = Vec::new();
+        let solution = solution.0;
+        let mut evaluation: Vec<(char, Status)> = vec![('!', Status::None); solution.len()];
         let mut status: Status;
-        let mut buf = solution.0.clone();
+        let mut buf: Vec<char> = solution.chars().collect();
 
-        for ((idx, c_guess), c_sol) in guess.chars().enumerate().zip(solution.0.chars()) {
+        #[cfg(debug_assertions)]
+        let buflen = solution.len();
+        #[cfg(debug_assertions)]
+        {
+            assert_eq!(buflen, buf.len());
+            assert_eq!(buflen, evaluation.len());
+        }
+
+        // first the correct solutions
+        for ((idx, c_guess), c_sol) in guess.chars().enumerate().zip(solution.chars()) {
             if c_guess == c_sol {
                 status = Status::Matched;
-                buf.replace_range(idx..idx + 1, "_");
+                buf[idx] = '!';
-            } else if buf.contains(c_guess)
+                evaluation[idx] = (c_guess, status);
-                && buf
-                    .char_indices()
-                    .filter(|c| c.1 == c_guess)
-                    .filter(|c| {
-                        guess
-                            .chars()
-                            .nth(c.0)
-                            .expect("the evaluations are somehow different lengths")
-                            == c.1
-                    })
-                    .count()
-                    == 0
-            {
-                status = Status::Exists;
-                buf = buf.replacen(c_guess, "_", 1);
-            } else {
-                status = Status::None
             }
-            evaluation.push((c_guess, status));
+        }
+
+        #[cfg(debug_assertions)]
+        {
+            assert_eq!(buflen, buf.len());
+            assert_eq!(buflen, evaluation.len());
+        }
+
+        // then check if the char exists, but was not guessed to be at the correct position
+        //
+        // We split this up, because finding the "exists" chars at the same time as the "correct"
+        // chars causes bugs
+        for ((idx, c_guess), c_sol) in guess.chars().enumerate().zip(solution.chars()) {
+            if c_guess == c_sol {
+                continue;
+            } else if buf.contains(&c_guess) {
+                status = Status::Exists;
+                // replace that char in the buffer to signal that is has been paired with the
+                // current char
+                let idx_of_a_match = buf
+                    .iter()
+                    .position(|c| *c == c_guess)
+                    .expect("did not find a character in a string even though we know it exists");
+                buf[idx_of_a_match] = '!';
+            } else {
+                status = Status::None;
+            }
+            evaluation[idx] = (c_guess, status);
+        }
+
+        #[cfg(debug_assertions)]
+        {
+            assert_eq!(buflen, buf.len());
+            assert_eq!(buflen, evaluation.len());
         }
         evaluation.into()
     }

tests/game.rs

@@ -47,11 +47,12 @@ fn test_eval_simple() -> anyhow::Result<()> {
 }
 
 #[test]
-fn test_eval_reoccuring_char() -> anyhow::Result<()> {
+fn test_eval_reoccuring_char0() -> anyhow::Result<()> {
     let wl = wordlist();
     let builder = game::Game::builder(&wl)
         .solution(Some(wl.get_word(&Word::from("nines")).unwrap()))
         .precompute(false);
+    info!("solution=nines");
 
     let mut game = builder.build()?;
     let guess = Word::from("pines");
@@ -110,3 +111,25 @@ fn test_eval_reoccuring_char() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn test_eval_reoccuring_char1() -> anyhow::Result<()> {
+    let wl = wordlist();
+    let builder = game::Game::builder(&wl)
+        .solution(Some(wl.get_word(&Word::from("fatty")).unwrap()))
+        .precompute(false);
+    info!("solution=fatty");
+
+    let mut game = builder.build()?;
+    let guess = Word::from("state");
+    game.guess(&guess, None)?;
+    let correct = Evaluation::build(&guess, "xffcx")?;
+    info!(
+        "{} =? {}",
+        *game.last_response().unwrap().evaluation(),
+        correct
+    );
+    assert_eq!(*game.last_response().unwrap().evaluation(), correct);
+
+    Ok(())
+}