import requests, json, re, os
from datetime import datetime

def loadSettings(path = f"{os.path.expanduser('~')}/config.json") -> dict:
    # TODO: check integrity
    try:
        with open(path, 'r') as file:
            # Read if the API keys are path to files
            config = json.load(file)
            keys = config['api'].keys()
            mask = dict()
            for key in keys:
                api_key = key
                if os.path.exists(key):
                    with open(key, 'r') as file:
                        api_key = file.readline().strip()
                mask[key] = api_key
            config['api'] = { mask[key]: value for key, value in config['api'].items() }
    except FileNotFoundError:
        sample_config = {
            'api': {},
            'ttl': 3600,
            'resolvers': [ 'https://ifconfig.me' ],
            'log_path': './log.txt'
        }

        with open('config.json', 'w') as file:
            json.dump(sample_config, file, indent = 2)

        return sample_config

# Appends logline at the end of the file file with a timestamp
def log(logline: str, path: str = './log.txt') -> None:
    with open(path, 'a') as file:
        file.write(f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}]{logline}\n")

# Go through resolvers until one retuns an IP
def getCurrentIP(resolvers: list[str], log: callable) -> None | str:
    for resolver in resolvers:
        response = requests.get(resolver)
        if response.status_code == 200:
            current_ip = response.text.strip()
            is_ipv4 = re.search('^((25[0-5]|(2[0-4]|1\d|[1-9]|)\d)\.?\\b){4}$', current_ip) is not None
            if is_ipv4:
                log(f"[OK][{resolver}] Current IP: '{current_ip}'")
                return current_ip # Break if we have found our IP
            else:
                log(f"[ERROR][{resolver}] '{current_ip}' is not IPv4")
        else:
            log(f"[ERROR][{resolver}][{response.status_code}] {response.text}")
    return None

# Returns the records that need to be renewed
# TODO: Also detect TTL change
def checkRecords(api: dict, current_ip: str, log: callable) -> dict:
    records_to_renew = api
    for key, domains in api.items():
        headers = { 'authorization': f"Apikey {key}" }
        for domain, records in domains.items():
            response = requests.get(f"https://api.gandi.net/v5/livedns/domains/{domain}/records?rrset_type=A", headers = headers)
            if response.status_code == 200:
                records_to_renew[key][domain] = list(set(records_to_renew[key][domain]) - set(record['rrset_name'] for record in (filter(lambda x: current_ip in x['rrset_values'], json.loads(response.json())))))
            else:
                log(f"[ERROR][{domain}][{response.status_code}] {response.json()}")

    return records_to_renew

# Updates the records and reates them if they don't exist
def renewRecords(records, current_ip, log, ttl = 3600):
    payload = json.dumps({
        'items': [{
            'rrset_type': 'A',
            'rrset_values': [ current_ip ],
            'rrset_ttl': ttl
        }]
    })

    for key, domains in records.items():
        headers = {
            'authorization': f"Apikey {key}",
            'content-type': 'application/json',
        }

        for domain, records in domains.items():
            for record in records:
                response = requests.put(f"https://api.gandi.net/v5/livedns/domains/{domain}/records/{record}", data = payload, headers = headers)
                if response.status_code == 201:
                    log(f"[OK][{domain}][{record}] Renewed with IP '{current_ip}'")
                else:
                    log(f"[ERROR][{domain}][{record}][{response.status_code}] {response.json()}")

def main():
    settings = loadSettings()
    log_path = settings['log_path']
    ttl = settings['ttl']
    myLog = lambda x: log(x, log_path)

    current_ip = getCurrentIP(settings['resolvers'], myLog)
    records_to_renew = checkRecords(settings['api'], current_ip, myLog)
    renewRecords(records_to_renew, current_ip, myLog, ttl = ttl)

if __name__ == '__main__':
    main()