#!/usr/bin/env python3

# Copyright (c) 2020  Avatar Aaron Janse
# 
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import cgi
import os
import socket
import ssl
import sys
import urllib.parse

def absolutise_url(base, relative):
    # Absolutise relative links
    if "://" not in relative:
        # Python's URL tools somehow only work with known schemes?
        base = base.replace("gemini://","http://")
        relative = urllib.parse.urljoin(base, relative)
        relative = relative.replace("http://", "gemini://")
    return relative

if len(sys.argv) != 2:
    print("Usage:")
    print("gcat gemini://gemini.circumlunar.space")
    sys.exit(1)

url = sys.argv[1]
parsed_url = urllib.parse.urlparse(url)
if parsed_url.scheme == "":
    url = "gemini://"+url
    parsed_url = urllib.parse.urlparse(url)

if parsed_url.scheme != "gemini":
    print("Sorry, Gemini links only.")
    sys.exit(1)
if parsed_url.port is not None:
    useport = parsed_url.port
else:
    useport = 1965
# Do the Gemini transaction
while True:
    s = socket.create_connection((parsed_url.hostname, useport))
    context = ssl.SSLContext()
    context.check_hostname = False
    context.verify_mode = ssl.CERT_NONE
    s = context.wrap_socket(s, server_hostname = parsed_url.netloc)
    s.sendall((url + '\r\n').encode("UTF-8"))
    # Get header and check for redirects
    fp = s.makefile("rb")
    header = fp.readline()
    print(header.decode("UTF-8"), end="")
    header = header.decode("UTF-8").strip()
    status, mime = header.split()[:2]
    # Handle input requests
    if status.startswith("1"):
        # Prompt
        query = input("INPUT" + mime + "> ")
        url += "?" + urllib.parse.quote(query) # Bit lazy...
    # Follow redirects
    elif status.startswith("3"):
        url = absolutise_url(url, mime)
        parsed_url = urllib.parse.urlparse(url)
    # Otherwise, we're done.
    else:
        break
# Fail if transaction was not successful
if status.startswith("2"):
    if mime.startswith("text/"):
        # Decode according to declared charset
        mime, mime_opts = cgi.parse_header(mime)
        body = fp.read()
        body = body.decode(mime_opts.get("charset","UTF-8"))
        print(body, end="")
    else:
        print(fp.read(), end="")