#!/usr/bin/python
import sys
import json
from urllib import parse as urlparse
from bs4 import BeautifulSoup
from datetime import datetime

"""
Unified Atom feed generator for fkfd.me and fkfd.me/comics.

Each time an entry is added, the oldest entry is automatically purged when
the list is at maximum capacity before atom.xml is generated.
"""

MAX_ENTRIES = 5

COMICS_DIR = "/home/fkfd/p/fkfd"
BLOG_DIR = "/home/fkfd/p/blog"


def utc_date() -> str:
    # UTC datetime: YYYY-MM-DDThh:mm:ssZ
    return datetime.utcnow().replace(microsecond=0).isoformat() + "Z"


def add_entry(entry: dict, dryrun=False):
    f = open("atom.xml")
    xml = f.read()
    f.close()
    soup = BeautifulSoup(xml, "xml")
    entries = soup.find_all("entry")
    if len(entries) >= MAX_ENTRIES:
        # truncate to (MAX_ENTRIES - 1) entries to make room
        for entry_to_remove in entries[(MAX_ENTRIES - 1) :]:
            entry_to_remove.decompose()

    new_entry = soup.new_tag("entry")
    new_id = soup.new_tag("id")
    new_id.string = entry["url"]
    new_title = soup.new_tag("title")
    new_title.string = entry["title"]
    new_updated = soup.new_tag("updated")
    new_updated.string = entry["date"]
    new_content = soup.new_tag("content", type="html")
    new_content.string = entry["html"]
    new_link = soup.new_tag("link", href=entry["url"], rel="alternate")

    for tag in [new_id, new_title, new_updated, new_content, new_link]:
        new_entry.append(tag)

    soup.find("entry").insert_before(new_entry)
    soup.find("updated").string = utc_date()

    if dryrun:
        print(soup.prettify())
    else:
        f = open("atom.xml", "w")
        f.write(str(soup))
        f.close()


def add_comic(num, dryrun=False):
    try:
        f = open(COMICS_DIR + f"/html/{num}/info.0.json")
    except FileNotFoundError:
        print(f"info.0.json for comic {num} not found. Skip.")
        return

    info = json.load(f)
    f.close()

    add_entry(
        {
            "url": f"https://fkfd.me/comics/{info['num']}",
            "title": "Comic: " + info["title"],
            "date": utc_date(),
            "html": '<p><img src="{0}" alt="{1}"></p><p>{2}</p>'.format(
                info["img"], info["transcript"], info["alt"]
            ),
        },
        dryrun=dryrun,
    )


def add_blogpost(path, dryrun=False):
    # example path: "shitpost/flat_egg", "projects/byseekel"
    path = path.strip("/")
    try:
        f = open(BLOG_DIR + f"/site/{path}/index.html")
    except FileNotFoundError:
        print(f"index.html for blogpost {path} not found. Skip.")
        return

    html = f.read()
    f.close()
    soup = BeautifulSoup(html, "html.parser")
    main = soup.find(role="main")
    url = f"https://fkfd.me/{path}/"  # trailing slash necessary

    # convert all relative paths to absolute URLs
    for img in main.find_all("img"):
        img["src"] = urlparse.urljoin(url, img["src"])

    for a in main.find_all("a"):
        try:
            if "headerlink" in a["class"]:  # remove "¶"
                a.decompose()
                continue
            a["href"] = urlparse.urljoin(url, a["href"])
        except KeyError: # just a regular link, no class attribute
            pass

    add_entry(
        {
            "url": url,
            "title": soup.title.text,
            "date": utc_date(),
            "html": main.decode_contents(),  # inner HTML of main container
        },
        dryrun=dryrun,
    )


if __name__ == "__main__":
    args = sys.argv

    if len(args) == 1:
        print(f"Usage: {args[0]} [<blogpath>|<comicnum>] [--dry]")
        exit(1)

    dryrun = len(args) >= 3 and args[2] == "--dry"

    if args[1].isdecimal():
        add_comic(args[1], dryrun)
    else:
        add_blogpost(args[1], dryrun)