import datetime
import glob
import os.path

from feedgen.feed import FeedGenerator

def find_files():
    files = []
    for extension in ("gmi", "gem", "gemini"):
        files.extend(glob.glob("*.{}".format(extension)))
        index = "index.{}".format(extension)
        if index in files:
            files.remove(index)
    return files

def populate_entry_from_file(filename, base_url, entry):
    url = base_url + filename
    entry.guid(url)
    entry.link(href=url)
    updated = os.path.getctime(filename)
    updated = datetime.datetime.fromtimestamp(updated, tz=datetime.timezone.utc)
    entry.updated(updated)
    with open(filename) as fp:
        for line in fp:
            if line.startswith("#"):
                while line[0] == "#":
                    line = line[1:]
                title = line.strip()
                break
        else:
            title = filename
    entry.title(title)

def main(base_url="gemini://gemini.circumlunar.space/"):

    # Setup feed
    feed = FeedGenerator()
    feed.id(base_url)
    feed.title('A Gemini feed.')
    feed.link(href=base_url, rel='alternate')
    feed.link(href=base_url + "atom.xml", rel='self')

    # Add one entry per .gmi file
    files = find_files()
    latest_update = datetime.datetime.fromtimestamp(0, tz=datetime.timezone.utc)
    for filename in files:
        entry = feed.add_entry()
        populate_entry_from_file(filename, base_url, entry)
        print("Adding {} with title '{}'...".format(filename, entry.title()))
        if entry.updated() > latest_update:
            latest_update = entry.updated()
    feed.updated(latest_update)

    # Write file
    feed.atom_file('atom.xml', pretty=True)

if __name__ == "__main__":
    main()