1 files changed, 47 insertions, 1 deletions
diff --git a/src/main.rs b/src/main.rs
index f743256..450b01b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,13 +1,59 @@
 #![warn(rust_2018_idioms)]
 
+use std::env;
+use std::process;
+
+use getopts::Options;
 use git2::Repository;
 
 use git_todo::Todos;
 
 
 fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let mut opts = Options::new();
+
+    let matches = match opts.parse(&args[1..]) {
+        Ok(m) => m,
+        Err(e) => {
+            eprintln!("TODO {}", e);
+            process::exit(exitcode::NOINPUT);
+        },
+    };
+
     let repo = Repository::open(".").unwrap();
 
     let todos = Todos { repo: &repo };
-    todos.write_since(todos.master_tree().unwrap(), &mut std::io::stdout()).unwrap();
+
+    let tree = if matches.free.is_empty() {
+        match todos.master_tree() {
+            Ok(t) => t,
+            Err(e) => {
+                eprintln!("TODO {}", e);
+                process::exit(exitcode::USAGE);
+            },
+        }
+    } else {
+        // TODO: error if more than one ref given
+        let refname = &matches.free[0];
+
+        let oid = match repo.refname_to_id(&refname) {
+            Ok(oid) => oid,
+            Err(e) => {
+                eprintln!("TODO {}", e);
+                process::exit(exitcode::USAGE);
+            },
+        };
+
+        match repo.find_tree(oid) {
+            Ok(t) => t,
+            Err(e) => {
+                eprintln!("TODO {}", e);
+                process::exit(exitcode::USAGE);
+            },
+        }
+    };
+
+    todos.write_since(tree, &mut std::io::stdout()).unwrap();
 }