import argparse
import subprocess
import sys

# push origin HEAD:refs/for/main
# HEAD: The target branch
# origin: The target repository (not a fork!)
# HEAD: The local branch containing the changes you are proposing
TARGET_REMOTE_REPOSITORY = "origin"
DEFAULT_TARGET_BRANCH = "main"


def run_git_command(command: list) -> tuple[int, str, str]:
    """Run a git command and return exit code, stdout, and stderr."""
    try:
        result = subprocess.run(command, capture_output=True, text=True, check=False)
        return result.returncode, result.stdout.strip(), result.stderr.strip()
    except Exception as e:
        return 1, "", str(e)


def get_latest_commit_info() -> tuple[str, str]:
    """Get the title and body of the latest commit."""
    exit_code, commit_msg, error = run_git_command(
        ["git", "log", "-1", "--pretty=format:%B"]
    )

    if exit_code != 0:
        print(f"Error getting commit info: {error}")
        sys.exit(1)

    lines = commit_msg.strip().split("\n")
    title = lines[0].strip() if lines else ""

    body_lines = []
    for line in lines[1:]:
        if body_lines or line.strip():
            body_lines.append(line)

    body = "\n".join(body_lines).strip()

    return title, body


def create_agit_push(
    remote: str = "origin",
    branch: str = "main",
    topic: str | None = None,
    title: str | None = None,
    description: str | None = None,
    force_push: bool = False,
    local_branch: str = "HEAD",
) -> None:
    if topic is None or title is None:
        commit_title, _ = get_latest_commit_info()

        if topic is None:
            topic = commit_title
        if title is None:
            title = commit_title

    refspec = f"{local_branch}:refs/for/{branch}"
    push_cmd = ["git", "push", remote, refspec]

    push_cmd.extend(["-o", f"topic={topic}"])

    if title:
        push_cmd.extend(["-o", f"title={title}"])

    if description:
        escaped_desc = description.replace('"', '\\"')
        push_cmd.extend(["-o", f"description={escaped_desc}"])

    if force_push:
        push_cmd.extend(["-o", "force-push"])

    if description:
        print(
            f"  Description: {description[:50]}..."
            if len(description) > 50
            else f"  Description: {description}"
        )
    print()

    exit_code, stdout, stderr = run_git_command(push_cmd)

    if stdout:
        print(stdout)
    if stderr:
        print(stderr, file=sys.stderr)

    if exit_code != 0:
        print("\nPush failed!")
        sys.exit(exit_code)
    else:
        print("\nPush successful!")


def cmd_create(args: argparse.Namespace) -> None:
    """Handle the create subcommand."""
    create_agit_push(
        remote=args.remote,
        branch=args.branch,
        topic=args.topic,
        title=args.title,
        description=args.description,
        force_push=args.force,
        local_branch=args.local_branch,
    )


def create_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        prog="agit",
        description="AGit utility for creating and pulling PRs",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=f"""
The defaults that are assumed are:
TARGET_REMOTE_REPOSITORY = {TARGET_REMOTE_REPOSITORY}
DEFAULT_TARGET_BRANCH = {DEFAULT_TARGET_BRANCH}

Examples:
  $ agit create
  Will create an AGit Pr with the latest commit message title as it's topic.

  $ agit create --topic "my-feature"
  Set a custom topic.

  $ agit create --force
  Force push to a certain topic
        """,
    )

    subparsers = parser.add_subparsers(dest="subcommand", help="Commands")

    create_parser = subparsers.add_parser(
        "create",
        aliases=["c"],
        help="Create an AGit PR",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  $ agit create
  Will create an AGit Pr with the latest commit message title as it's topic.

  $ agit create --topic "my-feature"
  Set a custom topic.

  $ agit create --force
  Force push to a certain topic
        """,
    )

    create_parser.add_argument(
        "-r",
        "--remote",
        default=TARGET_REMOTE_REPOSITORY,
        help=f"Git remote to push to (default: {TARGET_REMOTE_REPOSITORY})",
    )

    create_parser.add_argument(
        "-b",
        "--branch",
        default=DEFAULT_TARGET_BRANCH,
        help=f"Target branch for the PR (default: {DEFAULT_TARGET_BRANCH})",
    )

    create_parser.add_argument(
        "-l",
        "--local-branch",
        default="HEAD",
        help="Local branch to push (default: HEAD)",
    )

    create_parser.add_argument(
        "-t", "--topic", help="Set PR topic (default: last commit title)"
    )

    create_parser.add_argument(
        "--title", help="Set the PR title (default: last commit title)"
    )

    create_parser.add_argument(
        "--description", help="Override the PR description (default: commit body)"
    )

    create_parser.add_argument(
        "-f", "--force", action="store_true", help="Force push the changes"
    )

    create_parser.set_defaults(func=cmd_create)
    return parser


def main() -> None:
    parser = create_parser()
    args = parser.parse_args()
    if args.subcommand is None:
        parser.print_help()
        sys.exit(0)
    args.func(args)


if __name__ == "__main__":
    main()