import logging
import random
import re
import requests


def main():
    """
    Retrieve a random resource and run it against the production CiteAs API.
    """
    random_resource = random.choice(
        [
            random_cran_package(),
            random_doi(),
            random_github_url(),
            random_hacker_news_link(),
            random_software_keyword(),
        ]
    )
    logging.info(get_citeas_apa_citation(random_resource))


def get_citeas_apa_citation(resource):
    """
    Returns a dict with a resource and generated CiteAs citation in APA format.
    """
    r = requests.get("https://api.citeas.org/product/" + resource)
    citation = r.json()["citations"][0]["citation"]
    return {resource: citation}


def random_cran_package():
    """
    Returns a random cran package URL.
    """
    r = requests.get(
        "https://cran.r-project.org/web/packages/available_packages_by_name.html"
    )
    packages = re.findall("/web/packages/(\w+.?\w+)/index.html", r.text, re.DOTALL)
    url_formats = [
        "CRAN.R-project.org/package={}",
        "https://cran.r-project.org/web/packages/{}/index.html",
    ]
    return random.choice(url_formats).format(random.choice(packages))


def random_doi():
    """
    Returns a random DOI.
    """
    r = requests.get("https://api.crossref.org/works?sample=1")
    return r.json()["message"]["items"][0]["DOI"]


def random_github_url():
    """
    Returns a random URL from GitHub's trending repositories page.
    """
    r = requests.get("https://github-trending-api.now.sh/")
    trending_repos = [repo["url"] for repo in r.json()]
    return random.choice(trending_repos)


def random_hacker_news_link():
    """
    Returns a random Hacker News link from the front page stories.
    """
    r = requests.get("http://hn.algolia.com/api/v1/search?tags=front_page")
    stories = r.json()["hits"]
    story_links = [story["url"] for story in stories]
    return random.choice(story_links)


def random_software_keyword():
    """
    Returns a keyword based on the top GitHub projects written in a random programming language.
    """
    programming_language = random.choice(["java", "javascript", "go", "python", "r"])
    r = requests.get(
        "https://api.github.com/search/repositories?q=language:{}&sort=stars&order=desc".format(
            programming_language
        )
    )
    projects = r.json()["items"]
    keywords = [project["name"] for project in projects]
    return random.choice(keywords)


if __name__ == "__main__":
    main()