import requests
import json
import re
from datetime import datetime

CONFIG_DIR="/opt/imh-cwp-dns/config"
DNS_AUTHORITY_SERVER="ash-sys-pro-dns4.inmotionhosting.com"
API_DEBUG=False
ZONE_DIR="/var/named"

if API_DEBUG:
    import logging
    import http.client as http_client
    http_client.HTTPConnection.debuglevel = 1
    logging.basicConfig()
    logging.getLogger().setLevel(logging.DEBUG)
    requests_log = logging.getLogger("requests.packages.urllib3")
    requests_log.setLevel(logging.DEBUG)
    requests_log.propagate = True


def getAPIAuth():
    with open(f"{CONFIG_DIR}/key", "r") as f:
        return f.readline().strip()


def imh_api_call(function, data):
    url = f"https://{DNS_AUTHORITY_SERVER}/api/{function}"
    headers = { "Accept": "application/json",
                "Content-type": "application/json",
                "API-Auth": "{}".format(getAPIAuth()) }
    if API_DEBUG:
        print(f"API Request to {url} data {data}")

    try:
        session = requests.Session()
        session.mount("https://", requests.adapters.HTTPAdapter(max_retries=10))

        result = session.post(url, json=data, headers=headers)
        result.raise_for_status()  # Throw an exception if the status is invalid
    except:
        if API_DEBUG:
            print(f"Failed API request to endpoint {function} data {data} failed with code {result.status_code}")
        return {"status": 1, "message": f"Failed API request to endpoint {function} data {data} failed with code {result.status_code}"}
    else:
        if API_DEBUG:
            print(f"Got API response {result.text}")
        return result.text


def removeZone(zone):
    imh_api_call("remove_zone",{"zone": zone})

def parse_serial(data):
    """
    Parse SOA record out of zone file
    Return serial number.
    """

    # this hacky removal of comments may remove data in a txt record
    # which does not matter.
    no_comments = re.sub(r";.*", "", data)
    zone_lines = no_comments.splitlines()
    soa_lines = None
    # Identify the SOA record
    for i, line in enumerate(zone_lines):
        record = line.split()
        open_paren_found = False
        close_paren_found = False
        if len(record) > 1 and "SOA" in record[1:4]:
            soa_lines = []
            # this is an soa record
            for n in range(i, len(zone_lines)):
                soa_line = zone_lines[n]
                soa_lines.append(soa_line)
                if "(" in soa_line:
                    open_paren_found = True

                if ")" in zone_lines[n]:
                    close_paren_found = True
                    break

            if open_paren_found and close_paren_found:
                break
            else:
                soa_lines = None

    if not soa_lines:
        return None

    soa_record = []
    for line in soa_lines:
        soa_record += line.split()

    return soa_record[soa_record.index("(") + 1]

def updateZone(zone):
    zone_file_path = f"{ZONE_DIR}/{zone}.db"

    # Read the zone file
    with open(zone_file_path, "r") as f:
        data = f.read()

    original_serial_s = parse_serial(data)
    original_serial = int(original_serial_s)
    # calculate the new 'base' number for today
    min_serial = int(datetime.now().strftime("%Y%m%d") + "00")
    serial_boundary = min_serial + 99

    if original_serial < min_serial: # 2024010203 < 2024020200
        new_serial = min_serial
    elif original_serial > serial_boundary: # 2024010203 > 2024020299
        new_serial = serial_boundary
    elif original_serial == serial_boundary:  # 2024010299 == 2024010299
        new_serial = min_serial # rotate back to min_seria
    else: # serial is in range
        new_serial = original_serial + 1

    data = re.sub(
        original_serial_s,
        f"{new_serial}",
        data,
    )

    # Write the updated data back to the zone file
    with open(zone_file_path, "w") as f:
        f.write(data)

    # Make the API call
    imh_api_call("update_zone", {"zone": zone, "data": data})


def addZone(zone):
    if zoneAvailable(zone):
        updateZone(zone)


def zoneAvailable(zone):
    result=json.loads(imh_api_call("is_zone_available", {"zone": zone}))
    if result["status"] == None or result["available"] == None:
        return False
    if result["status"] != 0:
        return False
    return result["available"] == True


def getZone(zone):
    result = json.loads(imh_api_call("get_zone", {"zone": zone }))
    if result["status"] == 0:
        return result["zone_data"]
    return -1