from bs4 import BeautifulSoup
import requests


start_url = "https://ru.wikipedia.org"


def get_soup(url):
    print(f'Parse {url} page.')
    response = requests.get(url)
    soup = BeautifulSoup(response.text, 'lxml')
    return soup


def find_links(soup):
    links = []
    for a in soup.find_all('a'):
        link = a.get('href', None)
        if link:
            if not link.startswith('https'):
                link = start_url + link
            elif link.startswith('//'):
                link = 'https' + link
            links.append(link)
    return links


def find_images(soup):
    images = []
    for img in soup.find_all('img'):
        src = img.get('src', None)
        if src:
            link = src
            if link.endswith('.png'):
                if link.startswith('//'):
                    link = 'https:' + link
                elif link.startswith('/'):
                    link = start_url + link
                images.append(link)
    return images


def writer(links):
    with open('links.txt', 'w') as file:
        file.write('\n'.join(links))


def main():
    seen = set()
    soup = get_soup(start_url)
    imgs = find_images(soup)
    for url in find_links(soup):
        if url not in seen:
            seen.add(url)
            try:
                soup = get_soup(url)
                for img in find_images(soup):
                    if img not in seen:
                        seen.add(img)
                        imgs.append(img)
            except requests.exceptions.ConnectionError:
                print(f'Error {url}')
        else:
            print(f'Pass {url}')
    writer(imgs)


if __name__ == '__main__':
    main()