import os
import sys
import logging
from logging.handlers import RotatingFileHandler
import shutil
import pathlib
import urllib.request
import subprocess
import zipfile
import venv
from pathlib import Path

# ==============================
# Configuration constants
# ==============================
ROOT_DIR = Path(__file__).parent.resolve()
LIBS_DIR = ROOT_DIR / "libs"
LOGS_DIR = ROOT_DIR / "logs"
APP_MAIN = LIBS_DIR / "app" / "main.py"
APP_ZIP = LIBS_DIR / "app.zip"
DEFAULT_REPOSITORY = "https://n0sys.duckdns.org/downloads/libs"
ARGS_LIST = ["updateApp=False", "updateLibs=True", "repack=True"]

# ==============================
# Logger setup
# ==============================
def setup_logger() -> logging.Logger:
    """Configure application logger with console and rotating file handlers."""
    logger = logging.getLogger("start")
    logger.setLevel(logging.DEBUG)

    LOGS_DIR.mkdir(parents=True, exist_ok=True)

    # Log format
    formatter = logging.Formatter(
        fmt="%(asctime)s | %(levelname)-8s | %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S"
    )

    # Console handler
    console_handler = logging.StreamHandler()
    console_handler.setLevel(logging.INFO)
    console_handler.setFormatter(formatter)
    logger.addHandler(console_handler)

    # File handler
    file_handler = RotatingFileHandler(LOGS_DIR / "start.log", maxBytes=5_000_000, backupCount=3, encoding="utf-8")
    file_handler.setLevel(logging.DEBUG)
    file_handler.setFormatter(formatter)
    logger.addHandler(file_handler)

    return logger

logger = setup_logger()

# ==============================
# Functions
# ==============================
def start_app():
    """Entry point for the launcher"""
    logger.info("--------- START ---------")
    logger.debug(f"Root path: {ROOT_DIR}")

    LIBS_DIR.mkdir(parents=True, exist_ok=True)

    # TODO: remove in production
    # update_libs()

    create_venv()
    ensure_app()

    # Import after app is available
    from libs.app.common.process import new_python_process
    from libs.app.common.args import read_kargs, kargs_to_array

    args = kargs_to_array()
    pid = new_python_process(APP_MAIN, str(get_venv_python()), args=args, wait=True, new_console=True)
    logger.info(f"Main process running. PID {pid} - Args: {args}")
    logger.info("--------- END ---------")


def get_venv_python():
    """Return the path to the venv's Python executable in a cross-platform way"""
    if os.name == "nt":
        return ROOT_DIR / ".venv" / "Scripts" / "python.exe"
    else:
        return ROOT_DIR / ".venv" / "bin" / "python"

def update_libs():
    """Development only: repack local libs"""
    if ("updateApp=True" in ARGS_LIST or "updateLibs=True" in ARGS_LIST) and "repack=True" in ARGS_LIST:
        update_version_script = r"C:\Workspace\utils\updateLibsVersion.py"
        try:
            subprocess.run(
                [str(get_venv_python()), update_version_script],
                cwd=ROOT_DIR,
                creationflags=subprocess.CREATE_NEW_CONSOLE,
                check=True,
            )
        except subprocess.CalledProcessError as e:
            logger.error(f"Error running update libs: {e}")

def ensure_app():
    """Download, extract and install requirements of the application if not already present"""
    if APP_MAIN.exists():
        logger.debug("App already present, skipping download.")
        return
    
    url = f"{DEFAULT_REPOSITORY}/app/app.zip"
    logger.info(f"Downloading app from {url} ...")
    try:
        urllib.request.urlretrieve(url, APP_ZIP)
    except Exception as e:
        logger.exception(f"Failed to download app")
        raise

    logger.info(f"Extracting {APP_ZIP}...")
    with zipfile.ZipFile(APP_ZIP, 'r') as zip_ref:
        zip_ref.extractall(LIBS_DIR)

    logger.info(f"Installing app requirements ...")
    python_exec = str(get_venv_python())
    requirements_path = os.path.join(ROOT_DIR, "libs/app/requirements.txt")
    subprocess.check_call([python_exec, "-m", "pip", "install", "-r", requirements_path])


def create_venv():
    """Ensure a local virtual environment exists."""
    venv_dir = os.path.join(ROOT_DIR, ".venv")
    if not os.path.exists(venv_dir):
        logger.debug(f"Creating python venv: {venv_dir}")
        venv.create(venv_dir, with_pip=True)

# ==============================
# Main
# ==============================
if __name__ == "__main__":
    try:
        start_app()
    except Exception:
        logger.exception("Error starting application")
        sys.exit(1)