"""Helper class for Git repo operations."""

import sys
import os

PARENT_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__), '../ReleaseAutomation'))
sys.path.insert(0, PARENT_DIR)

import subprocess
from git import Repo, Actor
from github import GithubException
from release_config import ReleaseConfig

def get_local_repo():
    root_dir = subprocess.check_output(['git', 'rev-parse', '--show-toplevel'],
                                       universal_newlines=True, stderr=subprocess.STDOUT).strip()
    return Repo(root_dir)


def get_latest_git_revision(branch_name):
    """Gets the latest commit SHA for a given branch using git rev-parse."""
    try:
        subprocess.run(
            ['git', 'fetch', 'origin'],
            capture_output=True,
            text=True,
            check=True
        )
        remote_branch_name = f'origin/{branch_name}'
        # Executes the git command: git rev-parse <remote_branch_name>
        result = subprocess.run(
            ['git', 'rev-parse', remote_branch_name],
            capture_output=True,
            text=True,
            check=True
        )
        return result.stdout.strip()

    except FileNotFoundError as exc:
        raise Exception("Git command not found. Please ensure Git is installed and available in your PATH.") from exc
    except subprocess.CalledProcessError as e:
        raise Exception(f"Failed to get the latest revision for branch '{branch_name}'.") from e

def create_release_branch(config: ReleaseConfig):
    """
    Creates a new branch with the specified name, performs specified action, commits the current changes and pushes it to the repo.
    Note that command_to_run_on_release_branch (within the Config) should be a single command that will be executed using subprocess.run. For multiple commands consider using a Python script file.
    """

    try:
        if config.github_manager.is_branch_present(config.release_branch_name):
            raise Exception(f"Branch '{config.release_branch_name}' already exists.")

        repo = get_local_repo()

        new_branch = repo.create_head(config.release_branch_name, repo.head.commit)
        new_branch.checkout()

        if config.command_to_run_on_release_branch:
            print(f"\nExecuting command on branch '{config.release_branch_name}': {config.command_to_run_on_release_branch.__name__}")
            config.command_to_run_on_release_branch(config.manifest_path, config.changelog_path, config.validation_exceptions_path, config.package_version)

        repo.git.add(config.changelog_path)
        repo.git.add(config.manifest_path)
        repo.git.add(config.validation_exceptions_path)

        author = Actor(config.commiter_name, config.commiter_email)
        committer = Actor(config.commiter_name, config.commiter_email)

        repo.index.commit(config.release_commit_message, author=author, committer=committer, skip_hooks=True)
        repo.git.push("origin", config.release_branch_name)

        print(f"Successfully created, updated and pushed new branch: {config.release_branch_name}")

    except GithubException as e:
        raise GithubException(f"An error occurred with the GitHub API: {e.status}", data=e.data) from e
    except Exception as e:
        raise Exception(f"An unexpected error occurred: {e}") from e