#!/usr/bin/env python3

import sys
import re
import time
import xml.etree.ElementTree as ET

INPUT = "/var/gemini/rfc-mirror/rfc-index.xml"
OUTPUT = "/var/gemini/rfc-mirror/rfc-index.gmi.tmp"

tree = ET.parse(INPUT)
output = open(OUTPUT, "w")
root = tree.getroot()
rfcs = {}
for child in root:
    if child.tag == "{http://www.rfc-editor.org/rfc-index}rfc-entry":
        num = None
        for subchild in child:
            if subchild.tag == "{http://www.rfc-editor.org/rfc-index}doc-id":
                match = re.match("^RFC([0-9]+)", subchild.text)
                if match:
                    num = int(match.group(1))
                    rfcs[num] = {}
                else:
                    print("<rfc-entry> without a RFC: %s" % subchild.text, file=sys.stderr)
            elif subchild.tag == "{http://www.rfc-editor.org/rfc-index}title":
                if num is not None:
                    rfcs[num]['title'] = subchild.text

print("# Index of RFCs", file=output)
print("""

This index was built on %s from the rfc-index.xml file found at rsync::ftp.rfc-editor.org::rfcs-text-only. 

=> https://forge.chapril.org/bortzmeyer/rfc2gemini Source code of the conversion program

""" % time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime(time.time())), file=output)
for rfc in sorted(rfcs.keys(), reverse=True):
    print("=> /rfc-mirror/rfc%s.txt RFC %s \"%s\"" % (rfc, rfc, rfcs[rfc]['title']), file=output)
output.close()