import importlib
import subprocess
from qgis.PyQt.QtWidgets import QMessageBox
from qgis.PyQt.QtCore import QSettings
from concurrent.futures import ThreadPoolExecutor


def check_and_install_libraries(filename):
    """Check and install required third-party Python libraries."""
    settings = QSettings()
    # Read the list of required libraries from the file
    required_libraries = read_libraries_from_file(filename)

    # Check if the list of required libraries is stored
    cached_libraries = settings.value("cached_libraries", [])

    # If no cached libraries exist or libraries have changed, perform a full check
    if not cached_libraries or cached_libraries != required_libraries:
        missing_packages = check_missing_libraries(required_libraries)

    # if settings.value("libraries_installed", False, type=bool):
    #     return  # Skip the check if libraries are already installed
    # required_libraries = read_libraries_from_file(filename)
    # # Collect missing libraries in parallel
    # missing_packages = check_missing_libraries(required_libraries)

    # If there are missing packages, prompt the user to install them
    if missing_packages:
        message = "The following Python packages are required to use the plugin:\n\n"
        message += "\n".join(missing_packages)
        message += "\n\nWould you like to install them now? After installation, please restart QGIS."

        # Display the message box to the user
        reply = QMessageBox.question(
            None,
            "Missing Dependencies",
            message,
            QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
            QMessageBox.StandardButton.No,
        )
        if reply == QMessageBox.StandardButton.Yes:
            # Install the missing packages
            install_libraries(missing_packages)
            # settings.setValue("libraries_installed", True)  # Mark libraries as installed
            settings.setValue(
                "cached_libraries", required_libraries
            )  # Cache the list of installed libraries

        elif reply == QMessageBox.StandardButton.No:
            # Close the current dialog or window when the user clicks "No"
            return  # Stop installation if user declines
    else:
        # settings.setValue("libraries_installed", True)  # Mark libraries as installed if none are missing
        settings.setValue("cached_libraries", required_libraries)


def check_missing_libraries(libraries):
    """Function to install missing libraries using pip."""
    missing_packages = []

    # Use ThreadPoolExecutor for parallel checking
    with ThreadPoolExecutor() as executor:
        results = executor.map(check_library, libraries)

    for library, missing in results:
        if missing:
            missing_packages.append(library)

    return missing_packages


def check_library(library_info):
    """Check if a library is installed, return (library, is_missing)."""
    library, module = library_info
    try:
        importlib.import_module(module)
        return (library, False)  # Library is installed
    except ImportError:
        return (library, True)  # Library is missing


def install_libraries(libraries):
    """Install missing libraries using pip."""

    try:
        print(f"Installing missing libraries: {libraries}")
        subprocess.check_call(["python3", "-m", "pip", "install"] + libraries)
        print("Libraries installed successfully.")
    except subprocess.CalledProcessError as e:
        print(f"Error installing missing libraries: {e}")


def read_libraries_from_file(filename):
    """Read the list of libraries and their import paths from a text file."""
    libraries = []
    with open(filename, "r") as file:
        for line in file:
            if line.strip():  # Skip empty lines
                # Each line is in the format: library_name:module_name
                library, module = line.strip().split(":")
                libraries.append((library, module))
    return libraries
