1 files changed, 113 insertions, 0 deletions
diff --git a/src/repo/git/mod.rs b/src/repo/git/mod.rs
new file mode 100644
index 0000000..7370ee8
--- /dev/null
+++ b/src/repo/git/mod.rs
@@ -0,0 +1,113 @@
+use super::{LocalRepoState, Repo, RepoError};
+
+use anyhow::Context;
+use gix::{
+    bstr::BString,
+    refs::{
+        transaction::{LogChange, PreviousValue, RefEdit},
+        FullName,
+    },
+    remote, Id, ObjectId, Remote,
+};
+
+mod checkout;
+mod fetch;
+
+impl Repo {
+    #[tracing::instrument(level = "debug")]
+    pub fn is_clean(&self) -> Result<LocalRepoState, RepoError> {
+        let repo = self.repo()?;
+
+        if let Some(state) = repo.state() {
+            Ok(LocalRepoState::InProgress(state))
+        } else {
+            let head = repo.head().unwrap();
+
+            if head.is_detached() {
+                return Ok(LocalRepoState::DetachedHead);
+            }
+
+            if head.is_unborn() {
+                return Ok(LocalRepoState::UnbornHead);
+            }
+
+            Ok(LocalRepoState::Clean)
+        }
+    }
+
+    pub fn default_remote(&self) -> Result<Remote, RepoError> {
+        Ok(self
+            .repo()?
+            .find_default_remote(gix::remote::Direction::Fetch)
+            .ok_or(RepoError::NoRemoteFound)?
+            .context("fetch: failed to find default remote")?)
+    }
+
+    pub fn default_branch(&self) -> Result<BString, RepoError> {
+        let repo = self.repo()?;
+        let remote = self.default_remote()?;
+        let remote_name = remote.name().context("remote does not have name")?;
+
+        let origin_ref = repo
+            .find_reference(&format!("remotes/{}/HEAD", remote_name.as_bstr()))
+            .context("the remotes HEAD references does not exist")?;
+
+        if let Some(origin_ref) = origin_ref.target().try_name() {
+            Ok(origin_ref.shorten().to_owned())
+        } else {
+            Err(RepoError::NoDefaultBranch)
+        }
+    }
+
+    pub fn refedit(target: ObjectId, name: &str, message: &str) -> RefEdit {
+        RefEdit {
+            change: gix::refs::transaction::Change::Update {
+                log: LogChange {
+                    mode: gix::refs::transaction::RefLog::AndReference,
+                    force_create_reflog: false,
+                    message: message.into(),
+                },
+                expected: PreviousValue::Any,
+                new: gix::refs::Target::Peeled(target),
+            },
+            name: FullName::try_from(name).unwrap(),
+            deref: true,
+        }
+    }
+
+    pub fn update_default_branch_ref(
+        &self,
+        remote: remote::Name,
+        head: Id,
+    ) -> Result<(), RepoError> {
+        let default_branch = self.default_branch()?;
+        let repo = self.repo()?;
+
+        repo.edit_reference(Repo::refedit(
+            head.into(),
+            &format!("heads/{}", default_branch),
+            &format!("checkout: {}/HEAD with gtree", remote.as_bstr()),
+        ))
+        .context("checkout: failed to edit ref")?;
+
+        Ok(())
+    }
+
+    pub fn default_remote_head(&self) -> Result<(remote::Name, Id), RepoError> {
+        let repo = self.repo()?;
+
+        let remote = repo
+            .find_fetch_remote(None)
+            .context("could not find remote to fetch")?;
+        let remote = remote.name().context("remote does not have name")?;
+
+        let head_ref = repo
+            .find_reference(&format!("remotes/{}/HEAD", remote.as_bstr()))
+            .context("the remotes HEAD references does not exist")?;
+        let head = head_ref
+            .into_fully_peeled_id()
+            .context("failed to peel ref")?;
+
+        Ok((remote.to_owned(), head.to_owned()))
+    }
+}