@@ -6,7 +6,8 @@
  All git data (objects, refs, packs) is stored via a pluggable storage backend.
  """
  alias ExGitObjectstore.{Object, ObjectResolver, Repo, Ref}
  alias ExGitObjectstore.{Object, ObjectResolver, Repo, Ref, Walk}
  alias ExGitObjectstore.Object.{Blob, Commit, Tree}
  @type sha :: String.t()
  @type ref_name :: String.t()
@@ -112,5 +113,96 @@
  @spec delete_tag(Repo.t(), String.t()) :: :ok | {:error, term()}
  def delete_tag(%Repo{} = repo, name) do
    Ref.delete(repo, "refs/tags/#{name}")
  end
  @doc """
  Get a commit by SHA or ref.
  """
  @spec commit(Repo.t(), sha() | ref_name()) :: {:ok, {sha(), Commit.t()}} | {:error, term()}
  def commit(%Repo{} = repo, ref_or_sha) do
    with {:ok, sha} <- resolve(repo, ref_or_sha),
         {:ok, %Commit{} = commit} <- cat_object(repo, sha) do
      {:ok, {sha, commit}}
    end
  end
  @doc """
  Get the commit log starting from a ref or SHA.
  ## Options
    * `:max_count` — maximum number of commits (default: all)
    * `:skip` — skip N commits (default: 0)
  """
  @spec log(Repo.t(), sha() | ref_name(), keyword()) ::
          {:ok, [{sha(), Commit.t()}]} | {:error, term()}
  def log(%Repo{} = repo, ref_or_sha, opts \\ []) do
    with {:ok, sha} <- resolve(repo, ref_or_sha) do
      Walk.log(repo, sha, opts)
    end
  end
  @doc """
  Get a tree listing at a given path for a ref or SHA.
  Path "/" returns the root tree.
  """
  @spec tree(Repo.t(), sha() | ref_name(), String.t()) ::
          {:ok, Tree.t()} | {:error, term()}
  def tree(%Repo{} = repo, ref_or_sha, path \\ "/") do
    with {:ok, sha} <- resolve(repo, ref_or_sha),
         {:ok, %Commit{} = commit} <- cat_object(repo, sha),
         {:ok, %Tree{} = root_tree} <- cat_object(repo, commit.tree) do
      if path == "/" or path == "" do
        {:ok, root_tree}
      else
        walk_tree_path(repo, root_tree, String.split(path, "/", trim: true))
      end
    end
  end
  @doc """
  Get blob content by SHA.
  """
  @spec blob(Repo.t(), sha()) :: {:ok, binary()} | {:error, term()}
  def blob(%Repo{} = repo, sha) do
    case cat_object(repo, sha) do
      {:ok, %Blob{content: content}} -> {:ok, content}
      {:ok, _other} -> {:error, :not_a_blob}
      {:error, _} = err -> err
    end
  end
  @doc """
  Get the size of a blob by SHA without reading full content.
  Currently reads the full blob — could be optimized with pack header parsing.
  """
  @spec blob_size(Repo.t(), sha()) :: {:ok, non_neg_integer()} | {:error, term()}
  def blob_size(%Repo{} = repo, sha) do
    case blob(repo, sha) do
      {:ok, content} -> {:ok, byte_size(content)}
      {:error, _} = err -> err
    end
  end
  # Walk into nested tree directories by path components
  defp walk_tree_path(_repo, tree, []), do: {:ok, tree}
  defp walk_tree_path(repo, %Tree{entries: entries}, [component | rest]) do
    case Enum.find(entries, &(&1.name == component)) do
      nil ->
        {:error, {:path_not_found, component}}
      %{mode: "40000", sha: sha} ->
        case cat_object(repo, sha) do
          {:ok, %Tree{} = subtree} -> walk_tree_path(repo, subtree, rest)
          {:error, _} = err -> err
        end
      %{sha: sha} when rest == [] ->
        # Leaf entry — return the blob/tree
        cat_object(repo, sha)
      _ ->
        {:error, {:not_a_directory, component}}
    end
  end
end