#!/usr/bin/env python3

from http.server import SimpleHTTPRequestHandler,HTTPServer
import socket
import sys
import threading
import os
import traceback
import urllib.request
import subprocess


def is_ipv6(host):
    try:
        socket.inet_aton(host)
        return False
    except:
        return True

def get_local_port(host, ipv6):
    if ipv6:
        family = socket.AF_INET6
    else:
        family = socket.AF_INET

    with socket.socket(family) as fd:
        fd.bind((host, 0))
        return fd.getsockname()[1]

CLICKHOUSE_HOST = os.environ.get('CLICKHOUSE_HOST', 'localhost')
CLICKHOUSE_PORT_HTTP = os.environ.get('CLICKHOUSE_PORT_HTTP', '8123')

# Server returns this JSON response.
SERVER_JSON_RESPONSE = \
'''{
	"login": "ClickHouse",
	"id": 54801242,
	"name": "ClickHouse",
	"company": null
}'''

EXPECTED_ANSWER = \
'''{\\n\\t"login": "ClickHouse",\\n\\t"id": 54801242,\\n\\t"name": "ClickHouse",\\n\\t"company": null\\n}'''

#####################################################################################
# This test starts an HTTP server and serves data to clickhouse url-engine based table.
# The objective of this test is to check the ClickHouse server provides a User-Agent
# with HTTP requests.
# In order for it to work ip+port of http server (given below) should be
# accessible from clickhouse server.
#####################################################################################

# IP-address of this host accessible from the outside world. Get the first one
HTTP_SERVER_HOST = subprocess.check_output(['hostname', '-i']).decode('utf-8').strip().split()[0]
IS_IPV6 = is_ipv6(HTTP_SERVER_HOST)
HTTP_SERVER_PORT = get_local_port(HTTP_SERVER_HOST, IS_IPV6)

# IP address and port of the HTTP server started from this script.
HTTP_SERVER_ADDRESS = (HTTP_SERVER_HOST, HTTP_SERVER_PORT)
if IS_IPV6:
    HTTP_SERVER_URL_STR = 'http://' + f'[{str(HTTP_SERVER_ADDRESS[0])}]:{str(HTTP_SERVER_ADDRESS[1])}' + "/"
else:
    HTTP_SERVER_URL_STR = 'http://' + f'{str(HTTP_SERVER_ADDRESS[0])}:{str(HTTP_SERVER_ADDRESS[1])}' + "/"


def get_ch_answer(query):
    host = CLICKHOUSE_HOST
    if IS_IPV6:
        host = f'[{host}]'

    url = os.environ.get('CLICKHOUSE_URL', 'http://{host}:{port}'.format(host=CLICKHOUSE_HOST, port=CLICKHOUSE_PORT_HTTP))
    return urllib.request.urlopen(url, data=query.encode()).read().decode()

def check_answers(query, answer):
    ch_answer = get_ch_answer(query)
    if ch_answer.strip() != answer.strip():
        print("FAIL on query:", query, file=sys.stderr)
        print("Expected answer:", answer, file=sys.stderr)
        print("Fetched answer :", ch_answer, file=sys.stderr)
        raise Exception("Fail on query")

# Server with check for User-Agent headers.
class HttpProcessor(SimpleHTTPRequestHandler):
    def _set_headers(self):
        user_agent = self.headers.get('User-Agent')
        if user_agent and user_agent.startswith('ClickHouse/'):
            self.send_response(200)
        else:
            self.send_response(403)

        self.send_header('Content-Type', 'text/csv')
        self.end_headers()

    def do_GET(self):
        self._set_headers()
        self.wfile.write(SERVER_JSON_RESPONSE.encode())

    def log_message(self, format, *args):
        return

class HTTPServerV6(HTTPServer):
    address_family = socket.AF_INET6

def start_server(requests_amount):
    if IS_IPV6:
        httpd = HTTPServerV6(HTTP_SERVER_ADDRESS, HttpProcessor)
    else:
        httpd = HTTPServer(HTTP_SERVER_ADDRESS, HttpProcessor)

    def real_func():
        for i in range(requests_amount):
            httpd.handle_request()

    t = threading.Thread(target=real_func)
    return t

#####################################################################
# Testing area.
#####################################################################

def test_select():
    global HTTP_SERVER_URL_STR
    query = 'SELECT * FROM url(\'{}\',\'JSONAsString\');'.format(HTTP_SERVER_URL_STR)
    check_answers(query, EXPECTED_ANSWER)

def main():
    t = start_server(1)
    t.start()
    test_select()
    t.join()
    print("PASSED")

if __name__ == "__main__":
    try:
        main()
    except Exception as ex:
        exc_type, exc_value, exc_traceback = sys.exc_info()
        traceback.print_tb(exc_traceback, file=sys.stderr)
        print(ex, file=sys.stderr)
        sys.stderr.flush()

        os._exit(1)