from typing import List, Union, Optional
import os
import requests
import re
import time
import shutil
import subprocess
import pandas as pd
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options
from bs4 import BeautifulSoup
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import chromedriver_autoinstaller


class PatentDownloader:
    url = "https://patents.google.com"

    def __init__(self, verbose: bool = False):
        """
        Parameters
        ----------
        verbose : bool
            Print additional debug information.
        """
        self.verbose = verbose
        self.chrome_path = self.install_chrome()

    def install_chrome(self) -> str:
        """
        Download and install Google Chrome dynamically.
        Returns
        -------
        str: Path to the Chrome binary.
        """
        chrome_path = "/usr/bin/google-chrome"

        if not shutil.which("google-chrome"):
            print("Downloading and installing Google Chrome...")
            subprocess.run(
                "wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb -O chrome.deb",
                shell=True,
                check=True,
            )
            subprocess.run(
                "apt-get update && apt-get install -y ./chrome.deb",
                shell=True,
                check=True,
            )
            os.remove("chrome.deb")

        if not shutil.which("google-chrome"):
            raise ValueError("Google Chrome installation failed!")
        return chrome_path

    def download(self, patent: Union[str, List[str]], output_path: str = "./",
                 waiting_time: int = 10, remove_kind_codes: Optional[List[str]] = None) -> None:
        """
        Download patent document(s) as PDF.
        """
        if isinstance(patent, list) or os.path.isfile(patent):
            self.get_pdfs(patent, output_path, waiting_time, remove_kind_codes)
        else:
            self.get_pdf(patent, output_path, waiting_time, remove_kind_codes)

    def get_pdf(self, patent: str, output_path: str = "./", waiting_time: int = 10,
                remove_kind_codes: Optional[List[str]] = None) -> None:
        """
        Download a single patent PDF.
        """
        if remove_kind_codes:
            for kind_code in remove_kind_codes:
                patent = re.sub(kind_code + "$", "", patent)

        # Automatically install ChromeDriver
        chromedriver_autoinstaller.install()

        # Set up Chrome options
        chrome_options = Options()
        chrome_options.binary_location = self.chrome_path
        chrome_options.add_argument("--headless")
        chrome_options.add_argument("--no-sandbox")
        chrome_options.add_argument("--disable-dev-shm-usage")

        # Initialize Selenium WebDriver
        service = Service()
        driver = webdriver.Chrome(service=service, options=chrome_options)
        pdf_link = None  # Ensure pdf_link is defined

        try:
            driver.get(self.url)

            # Wait for the search input field and interact with it
            print("Waiting for the search input field...")
            search_input_xpath = "//input[@aria-label='Search patents']"
            WebDriverWait(driver, 20).until(
                EC.presence_of_element_located((By.XPATH, search_input_xpath))
            )
            element = driver.find_element(By.XPATH, search_input_xpath)
            print("Search input field located.")

            element.send_keys(patent)
            element.send_keys(Keys.RETURN)

            # Wait for search results to load
            print("Waiting for search results to load...")
            WebDriverWait(driver, 20).until(
                EC.presence_of_element_located((By.TAG_NAME, "body"))
            )
            time.sleep(waiting_time)

            # Parse HTML and get the PDF link
            soup = BeautifulSoup(driver.page_source, "html.parser")
            pdf_link = self.get_pdf_link(soup, patent)
        except Exception as e:
            print(f"Error occurred: {e}")
        finally:
            driver.quit()

        # Download the PDF
        if pdf_link:
            validate_directory(output_path)
            pdf_content = requests.get(pdf_link).content
            with open(os.path.join(output_path, f"{patent}.pdf"), "wb") as file:
                file.write(pdf_content)
            print(f">>> Patent {patent} successfully downloaded <<<")
        else:
            print(f"Error: PDF link for patent {patent} not found!")

    def get_pdfs(self, patents: Union[List[str], str], output_path: str = "./",
                 waiting_time: int = 10, remove_kind_codes: Optional[List[str]] = None) -> None:
        """
        Download multiple patent PDFs from a list or file.
        """
        if isinstance(patents, str):
            if patents.lower().endswith('csv'):
                df_patents = pd.read_csv(patents)
                patents = df_patents['patent_number'].to_list()
            elif patents.lower().endswith('txt'):
                with open(patents, 'r') as txt_file:
                    patents = txt_file.read().splitlines()
            else:
                raise NotImplementedError(f'Unsupported file type: {patents}')

        for i, patent in enumerate(patents):
            print(len(patents) - i, "patent(s) remaining.")
            self.get_pdf(patent, output_path, waiting_time, remove_kind_codes)

    @staticmethod
    def get_pdf_link(soup: BeautifulSoup, patent: str) -> Optional[str]:
        """
        Extract the PDF link from parsed HTML.
        """
        pdf_links = [link['href'] for link in soup.find_all('a', href=True) if link['href'].lower().endswith("pdf")]
        for link in pdf_links:
            if patent.lower() in link.lower():
                return link
        return None


def validate_directory(directory: str) -> None:
    """
    Ensure the output directory exists.
    """
    if not os.path.exists(directory):
        os.makedirs(directory)