from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.chrome.options import Options
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

import os
import sys
import time
import argparse


# parse args
parser = argparse.ArgumentParser(description = "Facebook scraper")
parser.add_argument("URL", help = 'URL of the facebook page / profile') # dont need to specify type (default is string)
args = parser.parse_args()


# method for waiting on pages to load
def wait_for_url(driver, url):
    # waiting to load main page
    try:
        WebDriverWait(driver, 10).until(EC.url_to_be(url))
        print('Succesful !')
    except:
        print('Connection error')
        driver.quit()
        sys.exit(1)

# web driver init
def webdriver_setup():

    driver_path = r'C:\Users\vlferko\Desktop\projects\jarvis_scraper\chromedriver.exe'
        
    chrome_options = Options()
    chrome_options.add_argument("accept-language=en-US")
    chrome_options.add_argument("--headless")
    chrome_options.add_argument("--log-level=OFF")
    driver = webdriver.Chrome(ChromeDriverManager().install(), options= chrome_options)

    driver.get("https://www.facebook.com/")
    return driver

# login to a facebook acc
def login(driver):
    print('Logging in')
    # allow cookies
    try:
        driver.find_element(By.XPATH, "//button[contains(string(), 'Decline optional cookies')]").click()
    except:
        pass
    
    
    # insert login data
    driver.find_element(By.NAME, "email").send_keys(os.environ['FB_EMAIL']) # type email
    driver.find_element(By.NAME, "pass").send_keys(os.environ['FB_PASSWD']) # type password

    # click -> log in 
    driver.find_element(By.NAME, "login").click()
    time.sleep(5)

# scrolling to the bottom of the page
def crawl_for_links(driver, url):
    print('Crawling')
    i = 1
    driver.get(url)
    time.sleep(2)
    name = driver.find_elements(By.TAG_NAME, 'h2')[-1].text
    

    for _ in range(0, 3):
        # Get scroll height
        last_height = driver.execute_script("return document.body.scrollHeight")
        for _ in range(50):
            # Scroll down to bottom
            driver.execute_script("var scrollingElement = (document.scrollingElement || document.body);scrollingElement.scrollTop = scrollingElement.scrollHeight;")

            # Wait to load page
            time.sleep(3)

            # Calculate new scroll height and compare with last scroll height
            new_height = driver.execute_script("return document.body.scrollHeight")
            if new_height == last_height:
                break
            last_height = new_height
            os.system('clear||cls')
            print(f'Iteration num: {i}')
            i += 1

    return driver.page_source, name

# parse HTML 
def parse_html(html):
    soup = BeautifulSoup(html, 'lxml')

    timeline = soup.find('div', {'class': 'x9f619 x1n2onr6 x1ja2u2z xeuugli xs83m0k x1xmf6yo x1emribx x1e56ztr x1i64zmx xjl7jj x19h7ccj xu9j1y6 x7ep2pv'})
    posts = timeline.find_all('div', {'class': 'x1yztbdb x1n2onr6 xh8yej3 x1ja2u2z'})
    arr = []
    for post in posts:
        try:
            commentsWidget = post.find('span', {'class': 'x193iq5w xeuugli x13faqbe x1vvkbs xlh3980 xvmahel x1n0sxbx x1lliihq x1s928wv xhkezso x1gmr53x x1cpjm7i x1fgarty x1943h6x x4zkp8e x3x7a5m x6prxxf xvq8zen xo1l8bm xi81zsa'})
            if approveComments(commentsWidget.text):
                links = post.find_all('a', {'role': 'link'})
                arr.append(extractPostLink(links))
        except AttributeError:
            pass
    
    return arr

def extractPostLink(links):
    for link in links:
        if '/videos/' in link['href'] or '/posts/' in link['href']:
            return link['href']

# check if post has at least 50 comments
def approveComments(text):
    nComments = text.split(' ')[0]
    try:
        num = int(nComments)
        return int(num > 50)
    except ValueError:
        return 'K' or 'M' in nComments

# write all the links to the .txt
def write_out(arr, name):
    
    with open(f"{os.getcwd()}/inputs/{name.strip().replace(' ', '_').lower()}.txt", 'w') as f:
        for item in arr:
            try:
                f.write(item + '\n')
            except TypeError:
                pass


if __name__ == '__main__':
    # driver init
    driver =webdriver_setup() 
    wait_for_url(driver, 'https://www.facebook.com/')
    
    # login
    login(driver)
    wait_for_url(driver, 'https://www.facebook.com/')
    
    # crawl
    html, name =crawl_for_links(driver, args.URL)
    driver.close()

    # parsing HTML
    arr =parse_html(html)

    # write out
    write_out(arr, name)