#!/usr/bin/env python3

import arrow
from ics import Calendar
from jinja2 import Environment, FileSystemLoader, select_autoescape
from markdown2 import Markdown
from pathlib import Path
import re
import requests
import sys

basepath = Path(__file__).resolve().parent

env = Environment(
    loader=FileSystemLoader(basepath / "templates"),
    autoescape=select_autoescape()
)

def render_markdown(text):
    pattern = re.compile(
        r"""
            \b
            (
                (?:https?://|(?<!//)www\.)    # prefix - https:// or www.
                \w[\w_\-]*(?:\.\w[\w_\-]*)*   # host
                [^<>\s"']*                    # rest of url
                (?<![?!.,:*_~);])             # exclude trailing punctuation
                (?=[?!.,:*_~);]?(?:[<\s]|$))  # make sure that we're not followed by " or ', i.e. we're outside of href="...".
            )
        """,
        re.X
    )

    markdown = Markdown(
        extras=["link-patterns"], 
        link_patterns=[(pattern, r'\1')]
    )

    return markdown.convert('' if text is None else text)

def main(ics_url, out_path):

    (out_path / "style.css").write_text((basepath / "assets" / "style.css").read_text())

    r = requests.get(ics_url)


    c = Calendar(r.text)
    t = c.timeline

    for e in t:
        e.description_rendered = render_markdown(e.description)

    (out_path / "chaosevents.ics").write_text(r.text)

    events_by_year = {}

    for event in t:
        if event.begin.year not in events_by_year:
            events_by_year[event.begin.year] = []
        events_by_year[event.begin.year].append(event)

    years_index = sorted(events_by_year.keys())

    # Index page

    sections = {}
    if any(t.now()):
        sections["Current"] = t.now()
    sections["Upcoming"] = t.start_after(arrow.utcnow())

    (out_path / "index.html").write_text(
        env.get_template("index.html").render(
            sections=sections,
            years_index=years_index,
        )
    )

    # Year pages

    for year, year_events in events_by_year.items():
        year_directory = out_path / "year" / str(year)
        year_directory.mkdir(exist_ok=True, parents=True)

        (year_directory / "index.html").write_text(
            env.get_template("index.html").render(
                title=f"Year {year}",
                sections={f"Year {year}": year_events},
                years_index=years_index,
            )
        )


def cli():
    ics_url = "https://cloud.fem.tu-ilmenau.de/remote.php/dav/public-calendars/Q58G8xM52HXPc6Jj/?export"

    out_path = Path("html")

    if len(sys.argv) > 1:
        out_path = Path(sys.argv[1])

    out_path.mkdir(exist_ok=True)

    main(ics_url, out_path)

if __name__ == "__main__":
    cli()