From 0afdcc4aa9d55db40cb045f11600956866945946 Mon Sep 17 00:00:00 2001
From: Sebastian Kuzminsky <seb@highlab.com>
Date: Sat, 5 Jul 2025 10:30:07 -0600
Subject: [PATCH] WIP git::create_orphan_branch()

---
 Cargo.toml |  1 +
 src/git.rs | 73 ++++++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 64 insertions(+), 10 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index c017ff3..03db057 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 anyhow = "1.0.95"
 clap = { version = "4.5.26", features = ["derive"] }
+mktemp = "0.5.1"
 serde = { version = "1.0.217", features = ["derive"] }
 thiserror = "2.0.11"
 toml = "0.8.19"
diff --git a/src/git.rs b/src/git.rs
index 3ca250f..adfb147 100644
--- a/src/git.rs
+++ b/src/git.rs
@@ -1,3 +1,5 @@
+use std::io::Write;
+
 #[derive(Debug, thiserror::Error)]
 pub enum GitError {
     #[error(transparent)]
@@ -34,16 +36,62 @@ pub fn remove_worktree(worktree_dir: &std::path::Path) -> Result<(), GitError> {
     Ok(())
 }
 
-pub fn create_orphan_branch(branch: &str) {
-    // git checkout --orphan orphan-branch
-    // git rm -rf .
-    // git clean -fdx .
-    //
-    // echo "hello world" > test-file
-    // git add test-file
-    // git commit -m 'first commit, again'
-    //
-    // git checkout dev
+pub fn create_orphan_branch(branch: &str) -> Result<(), GitError> {
+    let tmp_worktree = mktemp::Temp::new_path();
+    let tmp_worktree_pathbuf = tmp_worktree.to_path_buf();
+    let Some(tmp_worktree_dir) = tmp_worktree_pathbuf.as_path().to_str() else {
+        return Err(GitError::Oops);
+    };
+
+    let result = std::process::Command::new("git")
+        .args([
+            "worktree",
+            "add",
+            "--orphan",
+            "-b",
+            branch,
+            tmp_worktree_dir,
+        ])
+        .output()?;
+    if !result.status.success() {
+        println!("stdout: {}", std::str::from_utf8(&result.stdout).unwrap());
+        println!("stderr: {}", std::str::from_utf8(&result.stderr).unwrap());
+        return Err(GitError::Oops);
+    }
+
+    let mut readme_filename = tmp_worktree_pathbuf.clone();
+    readme_filename.push("README.md");
+    println!("readme_filename: {:?}", readme_filename);
+    println!("tmp_worktree_pathbuf: {:?}", tmp_worktree_pathbuf);
+    let mut readme = std::fs::File::create(readme_filename)?;
+    write!(
+        readme,
+        "This branch is used by entomologist to track issues."
+    )?;
+
+    let result = std::process::Command::new("git")
+        .args(["add", "README.md"])
+        .current_dir(tmp_worktree_dir)
+        .output()?;
+    if !result.status.success() {
+        println!("stdout: {}", std::str::from_utf8(&result.stdout).unwrap());
+        println!("stderr: {}", std::str::from_utf8(&result.stderr).unwrap());
+        return Err(GitError::Oops);
+    }
+
+    let result = std::process::Command::new("git")
+        .args(["commit", "-m", "create entomologist issue branch"])
+        .current_dir(tmp_worktree_dir)
+        .output()?;
+    if !result.status.success() {
+        println!("stdout: {}", std::str::from_utf8(&result.stdout).unwrap());
+        println!("stderr: {}", std::str::from_utf8(&result.stderr).unwrap());
+        return Err(GitError::Oops);
+    }
+
+    // git worktree prune
+
+    Ok(())
 }
 
 #[cfg(test)]
@@ -56,4 +104,9 @@ mod tests {
         checkout_branch_in_worktree("main", worktree_dir).unwrap();
         remove_worktree(worktree_dir).unwrap();
     }
+
+    #[test]
+    fn test_create_orphan_branch() {
+        create_orphan_branch("bloppers").unwrap();
+    }
 }