From 4fb87c85771bd7bf89e7c8d5e2d18bd743f35ef0 Mon Sep 17 00:00:00 2001
From: Juxhin Dyrmishi Brigjaj <juxhinbox@gmail.com>
Date: Sun, 6 Oct 2024 18:05:28 +0200
Subject: [PATCH] feat(permute): add support for character insertion between
 two vowels

---
 README.md                | 25 ---------------------
 twistrs/src/permutate.rs | 48 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 26 deletions(-)

diff --git a/README.md b/README.md
index 70867a3..a1d868a 100644
--- a/README.md
+++ b/README.md
@@ -67,31 +67,6 @@ async fn main() {
 - Exceptionally fast end-to-end results
 - Core library allowing easy extensions (i.e. CLI, API & streams)
 
-#### Permutation Modes
-
-- [x] Addition
-- [x] Bit Squatting
-- [x] Homoglyph
-- [x] Hyphenation
-- [x] Insertion
-- [x] Omission
-- [x] Repetition
-- [x] Replacement
-- [x] Sub-domain
-- [x] Transposition
-- [x] Vowel-swap
-- [x] Dictionary
-- [x] TLD addition
-
-#### Domain Enrichment Features
-
-- [x] DNS lookup
-- [x] MX parsing
-- [ ] SMTP Banner
-- [x] HTTP Banner
-- [x] GeoIP Lookup (Cached)
-- [x] WhoIs Lookup
-
 #### Miscellaneous
 - [x] [Blog post](https://blog.digital-horror.com/twistrs)
 - [x] [HaveIBeenSquatted](https://haveibeensquatted.com/) 
diff --git a/twistrs/src/permutate.rs b/twistrs/src/permutate.rs
index bdeeb44..1fed030 100644
--- a/twistrs/src/permutate.rs
+++ b/twistrs/src/permutate.rs
@@ -64,6 +64,7 @@ pub enum PermutationKind {
     Subdomain,
     Transposition,
     VowelSwap,
+    DoubleVowelInsertion,
     Keyword,
     Tld,
     Homoglyph,
@@ -148,6 +149,7 @@ impl Domain {
             .chain(self.subdomain())
             .chain(self.transposition())
             .chain(self.vowel_swap())
+            .chain(self.double_vowel_insertion())
             .chain(self.keyword())
             .chain(self.tld())
             .chain(self.homoglyph()?))
@@ -496,7 +498,7 @@ impl Domain {
             .chars()
             .enumerate()
             .filter_map(move |(i, c)| {
-                if VOWELS.contains(&c) {
+                if VOWELS.contains(&c.to_ascii_lowercase()) {
                     Some(VOWELS.iter().filter_map(move |vowel| {
                         let permutation =
                             format!("{}{}{}", &self.fqdn[..i], vowel, &self.fqdn[i + 1..]);
@@ -519,6 +521,37 @@ impl Domain {
             .flatten()
     }
 
+    /// Permutation method that inserts every lowercase ascii character between
+    /// two vowels.
+    pub fn double_vowel_insertion(&self) -> impl Iterator<Item = Permutation> + '_ {
+        self.fqdn
+            .chars()
+            .enumerate()
+            .tuple_windows()
+            .filter_map(move |((i1, c1), (i2, c2))| {
+                if VOWELS.contains(&c1.to_ascii_lowercase())
+                    && VOWELS.contains(&c2.to_ascii_lowercase())
+                {
+                    Some(ASCII_LOWER.iter().filter_map(move |inserted| {
+                        let permutation =
+                            format!("{}{inserted}{}", &self.fqdn[..=i1], &self.fqdn[i2..]);
+
+                        if let Ok(domain) = Domain::new(permutation.as_str()) {
+                            Some(Permutation {
+                                domain,
+                                kind: PermutationKind::DoubleVowelInsertion,
+                            })
+                        } else {
+                            None
+                        }
+                    }))
+                } else {
+                    None
+                }
+            })
+            .flatten()
+    }
+
     /// Permutation mode that appends and prepends common keywords to the
     /// domain in the following order:
     ///
@@ -770,4 +803,17 @@ mod tests {
             assert!(!permutations.is_empty());
         }
     }
+
+    #[test]
+    fn test_domains_double_vowel_insertion() {
+        let domain = Domain::new("exampleiveus.com").unwrap();
+        let expected = Domain::new("exampleivesus.com").unwrap();
+
+        let results: Vec<Permutation> = domain
+            .double_vowel_insertion()
+            .filter(|p| p.domain.fqdn == expected.fqdn)
+            .collect();
+
+        assert_eq!(results.len(), 1);
+    }
 }