#!/usr/bin/env python3
#
# This hacky script generates a go file with a map of version -> name for the
# entries in the TLS Cipher Suite Registry.

import csv
import urllib.request
import sys

# Where to get the TLS parameters from.
# See https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml.
URL = "https://www.iana.org/assignments/tls-parameters/tls-parameters-4.csv"


def getCiphers():
    req = urllib.request.urlopen(URL)
    data = req.read().decode("utf-8")

    ciphers = []
    reader = csv.DictReader(data.splitlines())
    for row in reader:
        desc = row["Description"]
        rawval = row["Value"]

        # Just plain TLS values for now, to keep it simple.
        if "-" in rawval or not desc.startswith("TLS"):
            continue

        rv1, rv2 = rawval.split(",")
        rv1, rv2 = int(rv1, 16), int(rv2, 16)

        val = "0x%02x%02x" % (rv1, rv2)
        ciphers.append((val, desc))

    return ciphers


ciphers = getCiphers()

out = open(sys.argv[1], "w")
out.write(
    """\
package tlsconst

// AUTOGENERATED - DO NOT EDIT
//
// This file was autogenerated by generate-ciphers.py.

var cipherSuiteName = map[uint16]string{
"""
)

for ver, desc in ciphers:
    out.write('\t%s: "%s",\n' % (ver, desc))

out.write("}\n")
