git_client.rb

# frozen_string_literal: true

require "git"

module Importmap
  module Update
    # Git operations the executor needs: creating/resetting a branch from
    # base, committing changes, and pushing. Every method delegates to an
    # injected Git::Base repo object (or a Minitest::Mock in tests) so the
    # class does no orchestration — that's the executor's job.
    class GitClient
      def initialize(repo:, author_name:, author_email:)
        @repo = repo
        @author_name = author_name
        @author_email = author_email
      end

      # Resets the working tree to base and creates/switches to `branch`.
      # If `branch` already exists locally it is checked out and hard-reset
      # to origin/base, mirroring `git checkout -B branch origin/base`.
      # This is destructive of local state by design — the action runs in
      # CI where there is no uncommitted work to save.
      def checkout_fresh_branch(branch:, base:)
        @repo.fetch("origin", ref: base)
        begin
          @repo.checkout(branch)
        rescue Git::Error
          # Branch does not exist yet — create it at origin/base and stop.
          @repo.checkout(branch, new_branch: true, start_point: "origin/#{base}")
          return nil
        end
        # Branch existed; reset it to origin/base from a clean state.
        @repo.reset_hard("origin/#{base}")
        nil
      end

      # Stages the importmap and vendored JS files and commits them.
      # Returns true iff a commit was actually created; false when
      # bin/importmap pin was a no-op and there is nothing to commit.
      def commit_changes(message:)
        @repo.add(["config/importmap.rb", "vendor/javascript"])
        @repo.commit(message, author: "#{@author_name} <#{@author_email}>")
        true
      rescue Git::FailedError => e
        return false if e.result.stderr.to_s.include?("nothing to commit")
        raise
      end

      def push(branch:, force: false)
        @repo.push("origin", branch, force: force)
        nil
      end
    end
  end
end