Implement `build_alias`

Copy of the functionality in W. Caleb McDaniel's Bash script implemented
in Rust:

    echo "${MESSAGE}" | grep ^"From: " | sed s/[\,\"\']//g | awk '{$1=""; if (NF == 3) {print "alias" $0;} else if (NF == 2) {print "alias" $0 $0;} else if (NF > 3) {print "alias", tolower($(NF-1))"-"tolower($2) $0;}}'

Doesn't currently include the [,"'] filtering.

Added a couple of new test cases to cover other address formats.

Not sure if I should use `if..else if` here or a `match`. I feel like I
should return an empty string at the end if we can't build an alias
line.

2 files changed, 31 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index 92ea8e1..2a0a471 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,7 +8,27 @@ fn handle_alias(s: &str) {
 }
 
 fn build_alias(s: &str) -> String {
-    String::from("String")
+    // Replace , ' " with nothing
+
+    let mut split: Vec<&str> = s.split_whitespace().collect();
+
+    // Remove "From: "
+    split.remove(0);
+
+    let mut alias_line = String::from("alias ");
+
+    if split.len() == 1 {
+        alias_line.push_str(&format!("{} ", split[0].to_lowercase()));
+        alias_line.push_str(&split.join(" "))
+    } else if split.len() == 2 {
+        alias_line.push_str(&format!("{} ", split[0].to_lowercase()));
+        alias_line.push_str(&split.join(" "));
+    } else if split.len() > 2 {
+        alias_line.push_str(&format!("{}-{} ", split[split.len() - 2], split[0]).to_lowercase());
+        alias_line.push_str(&split.join(" "));
+    }
+
+    alias_line
 }
 
 fn main() {
diff --git a/src/tests.rs b/src/tests.rs
index 20bbcc5..eff385a 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -3,6 +3,16 @@ use super::build_alias;
 #[test]
 fn test_build_alias() {
     assert_eq!(
+        "alias producer@765pro.ductions producer@765pro.ductions",
+        build_alias("From: producer@765pro.ductions")
+    );
+
+    assert_eq!(
+        "alias decim Decim <decim@quindecim.jp>",
+        build_alias("From: Decim <decim@quindecim.jp>")
+    );
+
+    assert_eq!(
         "alias farnsworth-hubert Hubert Farnsworth <professor@planetexpress.com>",
         build_alias("From: Hubert Farnsworth <professor@planetexpress.com>")
     );