import os
import time
import random
import requests
from urllib.parse import urljoin
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from webdriver_manager.chrome import ChromeDriverManager
from bs4 import BeautifulSoup

# Configuration
BASE_URL = "https://openi.nlm.nih.gov"
SEARCH_URL = "https://openi.nlm.nih.gov/gridquery?it=xg&m=1&n=100&q=pneumonia%20x%20ray"
DATA_DIR = "xray_images"
DELAY_RANGE = (1, 3)
HEADERS = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36",
    "Referer": BASE_URL
}


def setup_driver():
    """Configure Chrome with advanced anti-detection settings"""
    chrome_options = Options()
    chrome_options.add_argument("--headless=new")
    chrome_options.add_argument("--disable-blink-features=AutomationControlled")
    chrome_options.add_experimental_option("excludeSwitches", ["enable-automation"])
    chrome_options.add_experimental_option("useAutomationExtension", False)
    chrome_options.add_argument("--window-size=1920,1080")

    # Random user agent rotation
    user_agents = [
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36",
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36"
    ]
    chrome_options.add_argument(f"user-agent={random.choice(user_agents)}")

    service = Service(ChromeDriverManager().install())
    driver = webdriver.Chrome(service=service, options=chrome_options)

    # Mask WebDriver parameters
    driver.execute_cdp_cmd("Page.addScriptToEvaluateOnNewDocument", {
        "source": """
        Object.defineProperty(navigator, 'webdriver', {get: () => undefined});
        window.navigator.chrome = {runtime: {}};
        """
    })

    return driver


def load_full_page(driver):
    """Ensure all content is loaded with multiple scroll attempts"""
    print("Loading full page content...")
    for _ in range(3):
        driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
        time.sleep(random.uniform(2, 4))
        driver.execute_script("window.scrollTo(0, 0);")
        time.sleep(random.uniform(1, 2))


def extract_image_urls(driver):
    """Multi-strategy URL extraction with fallbacks"""
    print("Extracting image URLs...")
    soup = BeautifulSoup(driver.page_source, "html.parser")
    urls = []

    # Strategy 1: Direct image sources
    for img in soup.select('img[src*="/imgs/"]'):
        src = img.get('src', '')
        if src.endswith('.png'):
            urls.append(urljoin(BASE_URL, src))

    # Strategy 2: Angular data attributes (fallback)
    if not urls:
        for div in soup.select('div[data-ng-init*="img"]'):
            init_str = div.get('data-ng-init', '')
            if 'img:' in init_str:
                img_id = init_str.split("'")[3]
                urls.append(f"{BASE_URL}/imgs/collections/{img_id}.png")

    # Strategy 3: JavaScript-rendered content
    if not urls:
        script_tags = soup.find_all('script', type='text/javascript')
        for script in script_tags:
            if 'img:' in script.text:
                lines = script.text.split('\n')
                for line in lines:
                    if 'img:' in line:
                        img_id = line.split("'")[3]
                        urls.append(f"{BASE_URL}/imgs/collections/{img_id}.png")

    return list(set(urls))


def verify_download(url):
    """Validate image URLs before downloading"""
    try:
        head_response = requests.head(url, headers=HEADERS, timeout=10)
        if head_response.status_code == 200:
            return True
        print(f"Invalid URL: {url} (Status: {head_response.status_code})")
        return False
    except Exception as e:
        print(f"URL verification failed: {url} - {str(e)}")
        return False


def download_images(url_list):
    """Batch download with progress tracking"""
    os.makedirs(DATA_DIR, exist_ok=True)
    success_count = 0

    for idx, url in enumerate(url_list, 1):
        print(f"Processing {idx}/{len(url_list)}")

        if not verify_download(url):
            continue

        try:
            filename = url.split('/')[-1]
            filepath = os.path.join(DATA_DIR, filename)

            if os.path.exists(filepath):
                print(f"Skipping existing: {filename}")
                success_count += 1
                continue

            response = requests.get(url, headers=HEADERS, stream=True, timeout=30)
            response.raise_for_status()

            # Validate image content
            if response.headers['Content-Type'] not in ['image/png', 'image/jpeg']:
                raise ValueError("Invalid content type")

            with open(filepath, 'wb') as f:
                for chunk in response.iter_content(chunk_size=8192):
                    if chunk:  # Filter out keep-alive chunks
                        f.write(chunk)

            print(f"Downloaded: {filename}")
            success_count += 1

        except Exception as e:
            print(f"Download failed: {url} - {str(e)}")

        time.sleep(random.uniform(*DELAY_RANGE))

    return success_count


def main():
    driver = setup_driver()

    try:
        # Initial page load
        print("Navigating to search page...")
        driver.get(SEARCH_URL)

        # Wait for core content
        WebDriverWait(driver, 20).until(
            EC.presence_of_element_located((By.CSS_SELECTOR, "body"))
        )

        # Force full page load
        load_full_page(driver)

        # Extract URLs using multiple strategies
        image_urls = extract_image_urls(driver)

        if not image_urls:
            print("No URLs found - saving debug files...")
            with open("debug_page.html", "w", encoding="utf-8") as f:
                f.write(driver.page_source)
            driver.save_screenshot("debug_screenshot.png")
            return

        print(f"Found {len(image_urls)} potential image URLs")

        # Download images
        success = download_images(image_urls)
        print(f"\nDownload complete! Successfully saved {success}/{len(image_urls)} images")

    finally:
        driver.quit()


if __name__ == "__main__":
    main()