import os
import shutil
import tempfile
import subprocess
from time import sleep
from argparse import ArgumentParser

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC


STUDON_LOGIN_URL = 'https://www.studon.fau.de/studon/saml.php'


def parse_args():
    parser = ArgumentParser()
    parser.add_argument('url', help='Interactive StudOn screencast url')
    parser.add_argument('outfile', help='Destination file name without extension')
    return parser.parse_args()


def find_video_urls(url):
    driver = webdriver.Chrome()
    wait = WebDriverWait(driver, 10)

    try:
        driver.get(STUDON_LOGIN_URL)

        while not driver.current_url.startswith('https://www.studon.fau.de'):
            driver.implicitly_wait(1)

        driver.get(url)

        wait.until(EC.presence_of_element_located((By.TAG_NAME, 'iframe')))
        iframe = driver.find_element(By.TAG_NAME, 'iframe')
        driver.switch_to.frame(iframe)

        video_selector = (
            By.CSS_SELECTOR,
            '.h5p-current video'
        )

        prev_button_selector = (
            By.CSS_SELECTOR,
            '.h5p-footer-previous-slide[role="button"]'
        )

        next_button_selector = (
            By.CSS_SELECTOR,
            '.h5p-footer-next-slide[role="button"]'
        )

        wait.until(EC.presence_of_element_located(prev_button_selector))
        for i in range(100):
            prev_button = driver.find_element(*prev_button_selector)
            if prev_button.get_attribute('aria-disabled') == 'true':
                break

            prev_button.click()
            sleep(0.1)

        video_urls = []
        for i in range(100):
            wait.until(EC.presence_of_element_located(video_selector))
            video = driver.find_element(*video_selector)
            video_urls.append(video.get_attribute('src'))

            next_button = driver.find_element(*next_button_selector)
            if next_button.get_attribute('aria-disabled') == 'true':
                print('breaking')
                break

            next_button.click()
            sleep(0.25)

        return video_urls

    finally:
        driver.quit()


def download_and_merge_videos(urls, outfile):
    temp_dir = tempfile.mkdtemp()

    filenames = []

    for idx, url in enumerate(urls):
        ext = url.split('.')[-1]
        filename = os.path.join(temp_dir, f'video_{idx}.{ext}')
        filenames.append(filename)

        status = subprocess.call(['curl', '-o', filename, url])
        if status != 0:
            return False

    list_content = ''
    for filename in filenames:
        list_content += f"file '{filename}'\n"

    list_path = os.path.join(temp_dir, 'list.txt')
    with open(list_path, 'w') as f:
        f.write(list_content)

    ext = urls[0].split('.')[-1]
    status = subprocess.call(['ffmpeg', '-f', 'concat', '-safe', '0',
                              '-i', list_path, '-c', 'copy', outfile + '.' + ext])

    shutil.rmtree(temp_dir, ignore_errors=True)

    return status == 0


def main():
    args = parse_args()

    urls = find_video_urls(args.url)
    if not urls or len(urls) <= 0:
        exit(1)

    if not download_and_merge_videos(urls, args.outfile):
        exit(1)


main()