#!/usr/bin/env python3
# version 1: https://ar.noddex.com/raw/ea3o34y2PP0zAino1cWhh51XRJyYUhFWHar0UOYyEag
# version 2: this file = fix for content_hash being k51...

from dnslib import DNSRecord, RR, QTYPE, TXT
import os, sys, urllib.request, urllib.parse, json

# read raw DNS-wire POST body
length = int(os.environ.get('CONTENT_LENGTH') or 0)
raw = sys.stdin.buffer.read(length) if length else b''
if not raw:
    sys.stdout.buffer.write(b"Status: 400 Bad Request\r\nContent-Type: text/plain\r\n\r\nno body\n")
    sys.exit(0)

try:
    parsed = DNSRecord.parse(raw) # parsed DNS request
    qname = str(parsed.q.qname).rstrip('.') # e.g. "_dnslink.ipfs3.eth"
    if qname.startswith("_dnslink."):
        name = qname[len("_dnslink."):]
    else:
        name = qname
except Exception as e:
    sys.stdout.buffer.write(b"Status: 400 Bad Request\r\nContent-Type: text/plain\r\n\r\ninvalid DNS request\n")
    sys.exit(0)

try:
    url = f"https://api.ensdata.net/{urllib.parse.quote(name)}"
    with urllib.request.urlopen(urllib.request.Request(url, headers={"User-Agent": "curl/7.88.1"})) as r:
        data = json.load(r)
    content_hash = data.get("contentHash", "")
except Exception as e:
    sys.stdout.buffer.write(b"Status: 502 Bad Gateway\r\nContent-Type: text/plain\r\n\r\nupstream fetch error\n")
    sys.exit(0)

if content_hash.startswith("k"): # starts with 'k' -> IPNS name
    dnslink_value = "dnslink=/ipns/" + content_hash
else:
    dnslink_value = "dnslink=/ipfs/" + content_hash

q_resp = DNSRecord.question(name, qtype='TXT')
reply = q_resp.reply()
reply.add_answer(RR(name, QTYPE.TXT, rdata=TXT(dnslink_value), ttl=300))

body = reply.pack()
sys.stdout.buffer.write(b"Content-Type: application/dns-message\r\n\r\n")
sys.stdout.buffer.write(body)