import os
import platform
import subprocess
import venv
from typing import Dict, Optional

from letta.log import get_logger
from letta.schemas.sandbox_config import LocalSandboxConfig

logger = get_logger(__name__)


def find_python_executable(local_configs: LocalSandboxConfig) -> str:
    """
    Determines the Python executable path based on sandbox configuration and platform.
    Resolves any '~' (tilde) paths to absolute paths.

    Returns:
        str: Full path to the Python binary.
    """
    sandbox_dir = os.path.expanduser(local_configs.sandbox_dir)  # Expand tilde

    if not local_configs.use_venv:
        return "python.exe" if platform.system().lower().startswith("win") else "python3"

    venv_path = os.path.join(sandbox_dir, local_configs.venv_name)
    python_exec = (
        os.path.join(venv_path, "Scripts", "python.exe")
        if platform.system().startswith("Win")
        else os.path.join(venv_path, "bin", "python3")
    )

    if not os.path.isfile(python_exec):
        raise FileNotFoundError(f"Python executable not found: {python_exec}. Ensure the virtual environment exists.")

    return python_exec


def run_subprocess(command: list, env: Optional[Dict[str, str]] = None, fail_msg: str = "Command failed"):
    """
    Helper to execute a subprocess with logging and error handling.

    Args:
        command (list): The command to run as a list of arguments.
        env (dict, optional): The environment variables to use for the process.
        fail_msg (str): The error message to log in case of failure.

    Raises:
        RuntimeError: If the subprocess execution fails.
    """
    logger.info(f"Running command: {' '.join(command)}")
    try:
        result = subprocess.run(command, check=True, capture_output=True, text=True, env=env)
        logger.info(f"Command successful. Output:\n{result.stdout}")
        return result.stdout
    except subprocess.CalledProcessError as e:
        logger.error(f"{fail_msg}\nSTDOUT:\n{e.stdout}\nSTDERR:\n{e.stderr}")
        raise RuntimeError(f"{fail_msg}: {e.stderr.strip()}") from e


def ensure_pip_is_up_to_date(python_exec: str, env: Optional[Dict[str, str]] = None):
    """
    Ensures pip, setuptools, and wheel are up to date before installing any other dependencies.

    Args:
        python_exec (str): Path to the Python executable to use.
        env (dict, optional): Environment variables to pass to subprocess.
    """
    run_subprocess(
        [python_exec, "-m", "pip", "install", "--upgrade", "pip", "setuptools", "wheel"],
        env=env,
        fail_msg="Failed to upgrade pip, setuptools, and wheel.",
    )


def install_pip_requirements_for_sandbox(
    local_configs: LocalSandboxConfig,
    upgrade: bool = True,
    user_install_if_no_venv: bool = False,
    env: Optional[Dict[str, str]] = None,
):
    """
    Installs the specified pip requirements inside the correct environment (venv or system).
    """
    if not local_configs.pip_requirements:
        logger.debug("No pip requirements specified; skipping installation.")
        return

    sandbox_dir = os.path.expanduser(local_configs.sandbox_dir)  # Expand tilde
    local_configs.sandbox_dir = sandbox_dir  # Update the object to store the absolute path

    python_exec = find_python_executable(local_configs)

    # If using a virtual environment, upgrade pip before installing dependencies.
    if local_configs.use_venv:
        ensure_pip_is_up_to_date(python_exec, env=env)

    # Construct package list
    packages = [f"{req.name}=={req.version}" if req.version else req.name for req in local_configs.pip_requirements]

    # Construct pip install command
    pip_cmd = [python_exec, "-m", "pip", "install"]
    if upgrade:
        pip_cmd.append("--upgrade")
    pip_cmd += packages

    if user_install_if_no_venv and not local_configs.use_venv:
        pip_cmd.append("--user")

    run_subprocess(pip_cmd, env=env, fail_msg=f"Failed to install packages: {', '.join(packages)}")


def create_venv_for_local_sandbox(sandbox_dir_path: str, venv_path: str, env: Dict[str, str], force_recreate: bool):
    """
    Creates a virtual environment for the sandbox. If force_recreate is True, deletes and recreates the venv.

    Args:
        sandbox_dir_path (str): Path to the sandbox directory.
        venv_path (str): Path to the virtual environment directory.
        env (dict): Environment variables to use.
        force_recreate (bool): If True, delete and recreate the virtual environment.
    """
    sandbox_dir_path = os.path.expanduser(sandbox_dir_path)
    venv_path = os.path.expanduser(venv_path)

    # If venv exists and force_recreate is True, delete it
    if force_recreate and os.path.isdir(venv_path):
        logger.warning(f"Force recreating virtual environment at: {venv_path}")
        import shutil

        shutil.rmtree(venv_path)

    # Create venv if it does not exist
    if not os.path.isdir(venv_path):
        logger.info(f"Creating new virtual environment at {venv_path}")
        venv.create(venv_path, with_pip=True)

    pip_path = os.path.join(venv_path, "bin", "pip")
    try:
        # Step 2: Upgrade pip
        logger.info("Upgrading pip in the virtual environment...")
        subprocess.run([pip_path, "install", "--upgrade", "pip"], env=env, check=True)

        # Step 3: Install packages from requirements.txt if available
        requirements_txt_path = os.path.join(sandbox_dir_path, "requirements.txt")
        if os.path.isfile(requirements_txt_path):
            logger.info(f"Installing packages from requirements file: {requirements_txt_path}")
            subprocess.run([pip_path, "install", "-r", requirements_txt_path], env=env, check=True)
            logger.info("Successfully installed packages from requirements.txt")
        else:
            logger.warning("No requirements.txt file found. Skipping package installation.")

    except subprocess.CalledProcessError as e:
        logger.error(f"Error while setting up the virtual environment: {e}")
        raise RuntimeError(f"Failed to set up the virtual environment: {e}")