import os
import shutil
import time
from hashlib import md5
from ast import literal_eval as make_tuple
from pathlib import Path
from urllib.parse import urlparse
from re import sub

import arrow
import feedparser
import jinja2
import requests
from bs4 import BeautifulSoup
from slugify import slugify


def write_etag(feed_name, feed_data):
    """
    save timestamp of when feed was last modified
    """
    etag = ""
    modified = ""

    if "etag" in feed_data:
        etag = feed_data.etag
    if "modified" in feed_data:
        modified = feed_data.modified

    if etag or modified:
        with open(os.path.join("etags", feed_name + ".txt"), "w") as f:
            f.write(str((etag, modified)))


def get_etag(feed_name):
    """
    return timestamp of when feed was last modified
    """
    fn = os.path.join("etags", feed_name + ".txt")
    etag = ""
    modified = ""

    if os.path.exists(fn):
        etag, modified = make_tuple(open(fn, "r").read())

    return etag, modified


def create_frontmatter(entry):
    """
    parse RSS metadata and return as frontmatter
    """
    if "published" in entry:
        published = entry.published_parsed
    if "updated" in entry:
        published = entry.updated_parsed

    published = arrow.get(published)

    if "author" in entry:
        author = sub('"', '\\"', entry.author)
    else:
        author = ""

    if "title" in entry:
        title = sub('"', '\\"', entry.title)
    else:
        title = ""

    tags = []
    if "tags" in entry:
        # TODO finish categories
        for t in entry.tags:
            tags.append(t["term"])

    frontmatter = {
        "title": title,
        "date": published.format(),
        "summary": "",
        "author": author,
        "original_link": entry.link,
        "feed_name": entry["feed_name"],
        "tags": str(tags),
    }

    return frontmatter


def create_post(post_dir, entry):
    """
    write hugo post based on RSS entry
    """
    frontmatter = create_frontmatter(entry)

    if not os.path.exists(post_dir):
        os.makedirs(post_dir)

    if "content" in entry:
        post_content = entry.content[0].value
    else:
        post_content = entry.summary

    parsed_content = parse_posts(post_dir, post_content)

    template_dir = os.path.join(Path(__file__).parent.resolve(), "templates")
    env = jinja2.Environment(loader=jinja2.FileSystemLoader(template_dir))
    template = env.get_template("feed.md")
    with open(os.path.join(post_dir, "index.html"), "w") as f:  # n.b. .html
        post = template.render(frontmatter=frontmatter, content=parsed_content)
        f.write(post)
        print("created post for", entry.title, "({})".format(entry.link))


def grab_media(post_directory, url):
    """
    download media linked in post to have local copy
    if download succeeds return new local path otherwise return url
    """
    image = urlparse(url).path.split("/")[-1]

    try:
        if not os.path.exists(os.path.join(post_directory, image)):
            # TODO: stream is true is a conditional so we could check the headers for things, mimetype etc
            response = requests.get(url, stream=True)
            if response.ok:
                with open(os.path.join(post_directory, image), "wb") as img_file:
                    shutil.copyfileobj(response.raw, img_file)
                    print("Downloaded cover image", image)
                    return image
            return image
        elif os.path.exists(os.path.join(post_directory, image)):
            return image

    except Exception as e:
        print("Failed to download image", url)
        print(e)
    return url


def parse_posts(post_dir, post_content):
    """
    parse the post content to for media items
    replace foreign image with local copy
    filter out iframe sources not in allowlist
    """
    soup = BeautifulSoup(post_content, "html.parser")
    allowed_iframe_sources = ["youtube.com", "vimeo.com", "tv.lumbung.space"]

    for img in soup(["img", "object"]):
        local_image = grab_media(post_dir, img["src"])
        if img["src"] != local_image:
            img["src"] = local_image

    for iframe in soup(["iframe"]):
        if not any(source in iframe["src"] for source in allowed_iframe_sources):
            print("filtered iframe: {}...".format(iframe["src"][:25]))
            iframe.decompose()
    return soup.decode()


def grab_feed(feed_url):
    """
    check whether feed has been updated
    download & return it if it has
    """
    feed_name = urlparse(feed_url).netloc

    etag, modified = get_etag(feed_name)

    try:
        if modified:
            data = feedparser.parse(feed_url, modified=modified)
        elif etag:
            data = feedparser.parse(feed_url, etag=etag)
        else:
            data = feedparser.parse(feed_url)
    except Exception as e:
        print("Error grabbing feed")
        print(feed_name)
        print(e)
        return False

    print(data.status, feed_url)
    if data.status == 200:
        # 304 means the feed has not been modified since we last checked
        write_etag(feed_name, data)
        return data
    return False


def main():
    feed_urls = open("feeds_list.txt", "r").read().splitlines()

    start = time.time()

    if not os.path.exists("etags"):
        os.mkdir("etags")

    output_dir = os.environ.get("OUTPUT_DIR")

    if not os.path.exists(output_dir):
        os.makedirs(output_dir)

    feed_dict = dict()
    for url in feed_urls:
        feed_name = urlparse(url).netloc
        feed_dict[url] = feed_name

    feed_names = feed_dict.values()
    content_dirs = os.listdir(output_dir)
    for i in content_dirs:
        if i not in feed_names:
            shutil.rmtree(os.path.join(output_dir, i))
            print("%s not in feeds_list.txt, removing local data" %(i))

    # add iframe to the allowlist of feedparser's sanitizer,
    # this is now handled in parse_post()
    feedparser.sanitizer._HTMLSanitizer.acceptable_elements |= {"iframe"}

    for feed_url in feed_urls:

        feed_name = feed_dict[feed_url]

        feed_dir = os.path.join(output_dir, feed_name)

        if not os.path.exists(feed_dir):
            os.makedirs(feed_dir)

        existing_posts = os.listdir(feed_dir)

        data = grab_feed(feed_url)

        if data:
            for entry in data.entries:
                # if 'tags' in entry:
                #     for tag in entry.tags:
                #        for x in ['lumbung.space', 'D15', 'lumbung']:
                #            if x in tag['term']:
                #                print(entry.title)
                entry["feed_name"] = feed_name

                post_name = slugify(entry.title)
                # pixelfed returns the whole post text as the post name. max
                # filename length is 255 on many systems. here we're shortening
                # the name and adding a hash to it to avoid a conflict in a
                # situation where 2 posts start with exactly the same text.
                if len(post_name) > 150:
                    post_hash = md5(bytes(post_name, "utf-8"))
                    post_name = post_name[:150] + "-" + post_hash.hexdigest()
                post_dir = os.path.join(output_dir, feed_name, post_name)

                if post_name not in existing_posts:
                    # if there is a blog entry we dont already have, make it
                    create_post(post_dir, entry)

                elif post_name in existing_posts:
                    # if we already have it, update it
                    create_post(post_dir, entry)
                    existing_posts.remove(
                        post_name
                    )  # create list of posts which have not been returned by the feed

            for post in existing_posts:
                # remove blog posts no longer returned by the RSS feed
                print("deleted", post)
                shutil.rmtree(os.path.join(feed_dir, slugify(post)))

    end = time.time()

    print(end - start)