fix(dict): Fix should match typo's case

Fixes #10

src/dict.rs

@@ -2,6 +2,8 @@ use std::borrow::Cow;
 
 use unicase::UniCase;
 
+use crate::tokens::Case;
+
 #[derive(Default)]
 pub struct Dictionary {}
 
@@ -18,7 +20,8 @@ impl Dictionary {
     }
 
     pub fn correct_word<'s, 'w>(&'s self, word: crate::tokens::Word<'w>) -> Option<Cow<'s, str>> {
-        map_lookup(&crate::dict_codegen::WORD_DICTIONARY, word.token()).map(|s| s.into())
+        map_lookup(&crate::dict_codegen::WORD_DICTIONARY, word.token())
+            .map(|s| case_correct(s, word.case()))
     }
 }
 
@@ -37,3 +40,45 @@ fn map_lookup(
         map.get(&UniCase(key)).cloned()
     }
 }
+
+fn case_correct(correction: &str, case: Case) -> Cow<'_, str> {
+    match case {
+        Case::Lower | Case::None => correction.into(),
+        Case::Title => {
+            let mut title = String::with_capacity(correction.as_bytes().len());
+            let mut char_indices = correction.char_indices();
+            if let Some((_, c)) = char_indices.next() {
+                title.extend(c.to_uppercase());
+                if let Some((i, _)) = char_indices.next() {
+                    title.push_str(&correction[i..]);
+                }
+            }
+            title.into()
+        }
+        Case::Scream => correction
+            .chars()
+            .flat_map(|c| c.to_uppercase())
+            .collect::<String>()
+            .into(),
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_case_correct() {
+        let cases = [
+            ("foo", Case::Lower, "foo"),
+            ("foo", Case::None, "foo"),
+            ("foo", Case::Title, "Foo"),
+            ("foo", Case::Scream, "FOO"),
+            ("fOo", Case::None, "fOo"),
+        ];
+        for (correction, case, expected) in cases.iter() {
+            let actual = case_correct(correction, *case);
+            assert_eq!(*expected, actual);
+        }
+    }
+}