#
#
#

from __future__ import absolute_import, division, print_function, \
    unicode_literals

from requests import Session
from akamai.edgegrid import EdgeGridAuth
from collections import defaultdict
from urllib.parse import urljoin

from logging import getLogger
from ..record import Record
from . import ProviderException
from .base import BaseProvider


class AkamaiClientNotFound(ProviderException):

    def __init__(self, resp):
        message = "404: Resource not found"
        super(AkamaiClientNotFound, self).__init__(message)


class AkamaiClient(object):
    '''
    Client for making calls to Akamai Fast DNS API using Python Requests

    Edge DNS Zone Management API V2, found here:
    https://developer.akamai.com/api/cloud_security/edge_dns_zone_management/v2.html

    Info on Python Requests library:
    https://2.python-requests.org/en/master/

    '''

    def __init__(self, client_secret, host, access_token, client_token):

        self.base = "https://" + host + "/config-dns/v2/"

        sess = Session()
        sess.auth = EdgeGridAuth(
            client_token=client_token,
            client_secret=client_secret,
            access_token=access_token
        )
        self._sess = sess

    def _request(self, method, path, params=None, data=None, v1=False):

        url = urljoin(self.base, path)
        resp = self._sess.request(method, url, params=params, json=data)

        if resp.status_code == 404:
            raise AkamaiClientNotFound(resp)
        resp.raise_for_status()

        return resp

    def record_create(self, zone, name, record_type, content):
        path = f'zones/{zone}/names/{name}/types/{record_type}'
        result = self._request('POST', path, data=content)

        return result

    def record_delete(self, zone, name, record_type):
        path = f'zones/{zone}/names/{name}/types/{record_type}'
        result = self._request('DELETE', path)

        return result

    def record_replace(self, zone, name, record_type, content):
        path = f'zones/{zone}/names/{name}/types/{record_type}'
        result = self._request('PUT', path, data=content)

        return result

    def zone_get(self, zone):
        path = f'zones/{zone}'
        result = self._request('GET', path)

        return result

    def zone_create(self, contractId, params, gid=None):
        path = f'zones?contractId={contractId}'

        if gid is not None:
            path += f'&gid={gid}'

        result = self._request('POST', path, data=params)

        return result

    def zone_recordset_get(self, zone, page=None, pageSize=None, search=None,
                           showAll="true", sortBy="name", types=None):

        params = {
            'page': page,
            'pageSize': pageSize,
            'search': search,
            'showAll': showAll,
            'sortBy': sortBy,
            'types': types
        }

        path = f'zones/{zone}/recordsets'
        result = self._request('GET', path, params=params)

        return result


class AkamaiProvider(BaseProvider):

    '''
    Akamai Edge DNS Provider

    edgedns.py:

        Example config file with variables:
            "
            ---
            providers:
              config:
                class: octodns.provider.yaml.YamlProvider
                directory: ./config (example path to directory of zone files)
              edgedns:
                class: octodns.provider.edgedns.AkamaiProvider
                client_secret: env/AKAMAI_CLIENT_SECRET
                host: env/AKAMAI_HOST
                access_token: env/AKAMAI_ACCESS_TOKEN
                client_token: env/AKAMAI_CLIENT_TOKEN
                contract_id: env/AKAMAI_CONTRACT_ID (optional)

            zones:
              example.com.:
                sources:
                  - config
                targets:
                  - edgedns
            "

        The first four variables above can be hidden in environment variables
        and octoDNS will automatically search for them in the shell. It is
        possible to also hard-code into the config file: eg, contract_id.

        The first four values can be found by generating credentials:
        https://control.akamai.com/
        Configure > Organization > Manage APIs > New API Client for me
        Select appropriate group, and fill relevant fields.
        For API Service Name, select DNS-Zone Record Management
        and then set appropriate Access level (Read-Write to make changes).
        Then select the "New Credential" button to generate values for above

        The contract_id paramater is optional, and only required for creating
        a new zone. If the zone being managed already exists in Akamai for the
        user in question, then this paramater is not needed.

    '''

    SUPPORTS_GEO = False
    SUPPORTS_DYNAMIC = False

    SUPPORTS = set(('A', 'AAAA', 'CNAME', 'MX', 'NAPTR', 'NS', 'PTR', 'SPF',
                    'SRV', 'SSHFP', 'TXT'))

    def __init__(self, id, client_secret, host, access_token, client_token,
                 contract_id=None, gid=None, *args, **kwargs):

        self.log = getLogger(f'AkamaiProvider[{id}]')
        self.log.debug('__init__: id=%s, ')
        super(AkamaiProvider, self).__init__(id, *args, **kwargs)

        self._dns_client = AkamaiClient(client_secret, host, access_token,
                                        client_token)

        self._zone_records = {}
        self._contractId = contract_id
        self._gid = gid

    def zone_records(self, zone):
        """ returns records for a zone, looks for it if not present, or
            returns empty [] if can't find a match
        """
        if zone.name not in self._zone_records:
            try:
                name = zone.name[:-1]
                response = self._dns_client.zone_recordset_get(name)
                self._zone_records[zone.name] = response.json()["recordsets"]

            except (AkamaiClientNotFound, KeyError):
                return []

        return self._zone_records[zone.name]

    def populate(self, zone, target=False, lenient=False):
        self.log.debug('populate: name=%s', zone.name)

        values = defaultdict(lambda: defaultdict(list))
        for record in self.zone_records(zone):

            _type = record.get('type')
            # Akamai sends down prefix.zonename., while octodns expects prefix
            _name = record.get('name').split("." + zone.name[:-1], 1)[0]
            if _name == zone.name[:-1]:
                _name = ''  # root / @

            if _type not in self.SUPPORTS:
                continue
            values[_name][_type].append(record)

        before = len(zone.records)
        for name, types in values.items():
            for _type, records in types.items():
                data_for = getattr(self, f'_data_for_{_type}')
                record = Record.new(zone, name, data_for(_type, records[0]),
                                    source=self, lenient=lenient)
                zone.add_record(record, lenient=lenient)

        exists = zone.name in self._zone_records
        found = len(zone.records) - before
        self.log.info('populate:   found %s records, exists=%s', found, exists)

        return exists

    def _apply(self, plan):
        desired = plan.desired
        changes = plan.changes
        self.log.debug('apply: zone=%s, chnges=%d', desired.name, len(changes))

        zone_name = desired.name[:-1]
        try:
            self._dns_client.zone_get(zone_name)

        except AkamaiClientNotFound:
            self.log.info("zone not found, creating zone")
            params = self._build_zone_config(zone_name)
            self._dns_client.zone_create(self._contractId, params, self._gid)

        for change in changes:
            class_name = change.__class__.__name__
            getattr(self, f'_apply_{class_name}')(change)

        # Clear out the cache if any
        self._zone_records.pop(desired.name, None)

    def _apply_Create(self, change):

        new = change.new
        record_type = new._type

        params_for = getattr(self, f'_params_for_{record_type}')
        values = self._get_values(new.data)
        rdata = params_for(values)

        zone = new.zone.name[:-1]
        name = self._set_full_name(new.name, zone)

        content = {
            "name": name,
            "type": record_type,
            "ttl": new.ttl,
            "rdata": rdata
        }

        self._dns_client.record_create(zone, name, record_type, content)

        return

    def _apply_Delete(self, change):

        zone = change.existing.zone.name[:-1]
        name = self._set_full_name(change.existing.name, zone)
        record_type = change.existing._type

        self._dns_client.record_delete(zone, name, record_type)

        return

    def _apply_Update(self, change):

        new = change.new
        record_type = new._type

        params_for = getattr(self, f'_params_for_{record_type}')
        values = self._get_values(new.data)
        rdata = params_for(values)

        zone = new.zone.name[:-1]
        name = self._set_full_name(new.name, zone)

        content = {
            "name": name,
            "type": record_type,
            "ttl": new.ttl,
            "rdata": rdata
        }

        self._dns_client.record_replace(zone, name, record_type, content)

        return

    def _data_for_multiple(self, _type, records):

        return {
            'ttl': records['ttl'],
            'type': _type,
            'values': [r for r in records['rdata']]
        }

    _data_for_A = _data_for_multiple
    _data_for_AAAA = _data_for_multiple
    _data_for_NS = _data_for_multiple
    _data_for_SPF = _data_for_multiple

    def _data_for_CNAME(self, _type, records):
        value = records['rdata'][0]
        if (value[-1] != '.'):
            value = f'{value}.'

        return {
            'ttl': records['ttl'],
            'type': _type,
            'value': value
        }

    def _data_for_MX(self, _type, records):
        values = []
        for r in records['rdata']:
            preference, exchange = r.split(" ", 1)
            values.append({
                'preference': preference,
                'exchange': exchange
            })
        return {
            'ttl': records['ttl'],
            'type': _type,
            'values': values
        }

    def _data_for_NAPTR(self, _type, records):
        values = []
        for r in records['rdata']:
            order, preference, flags, service, regexp, repl = r.split(' ', 5)

            values.append({
                'flags': flags[1:-1],
                'order': order,
                'preference': preference,
                'regexp': regexp[1:-1],
                'replacement': repl,
                'service': service[1:-1]
            })
        return {
            'type': _type,
            'ttl': records['ttl'],
            'values': values
        }

    def _data_for_PTR(self, _type, records):

        return {
            'ttl': records['ttl'],
            'type': _type,
            'value': records['rdata'][0]
        }

    def _data_for_SRV(self, _type, records):
        values = []
        for r in records['rdata']:
            priority, weight, port, target = r.split(' ', 3)
            values.append({
                'port': port,
                'priority': priority,
                'target': target,
                'weight': weight
            })

        return {
            'type': _type,
            'ttl': records['ttl'],
            'values': values
        }

    def _data_for_SSHFP(self, _type, records):
        values = []
        for r in records['rdata']:
            algorithm, fp_type, fingerprint = r.split(' ', 2)
            values.append({
                'algorithm': algorithm,
                'fingerprint': fingerprint.lower(),
                'fingerprint_type': fp_type
            })

        return {
            'type': _type,
            'ttl': records['ttl'],
            'values': values
        }

    def _data_for_TXT(self, _type, records):
        values = []
        for r in records['rdata']:
            r = r[1:-1]
            values.append(r.replace(';', '\\;'))

        return {
            'ttl': records['ttl'],
            'type': _type,
            'values': values
        }

    def _params_for_multiple(self, values):
        return [r for r in values]

    def _params_for_single(self, values):
        return values

    _params_for_A = _params_for_multiple
    _params_for_AAAA = _params_for_multiple
    _params_for_NS = _params_for_multiple

    _params_for_CNAME = _params_for_single
    _params_for_PTR = _params_for_single

    def _params_for_MX(self, values):
        rdata = []

        for r in values:
            preference = r['preference']
            exchange = r['exchange']
            rdata.append(f'{preference} {exchange}')

        return rdata

    def _params_for_NAPTR(self, values):
        rdata = []

        for r in values:
            ordr = r['order']
            prf = r['preference']
            flg = "\"" + r['flags'] + "\""
            srvc = "\"" + r['service'] + "\""
            rgx = "\"" + r['regexp'] + "\""
            rpl = r['replacement']
            rdata.append(f'{ordr} {prf} {flg} {srvc} {rgx} {rpl}')

        return rdata

    def _params_for_SPF(self, values):
        rdata = []

        for r in values:
            txt = "\"" + r.replace('\\;', ';') + "\""
            rdata.append(txt)

        return rdata

    def _params_for_SRV(self, values):
        rdata = []
        for r in values:
            priority = r['priority']
            weight = r['weight']
            port = r['port']
            target = r['target']
            rdata.append(f'{priority} {weight} {port} {target}')

        return rdata

    def _params_for_SSHFP(self, values):
        rdata = []
        for r in values:
            algorithm = r['algorithm']
            fp_type = r['fingerprint_type']
            fp = r['fingerprint']

            rdata.append(f'{algorithm} {fp_type} {fp}')

        return rdata

    def _params_for_TXT(self, values):
        rdata = []

        for r in values:
            txt = "\"" + r.replace('\\;', ';') + "\""
            rdata.append(txt)

        return rdata

    def _build_zone_config(self, zone, _type="primary", comment=None,
                           masters=[]):

        if self._contractId is None:
            raise NameError("contractId not specified to create zone")

        return {
            "zone": zone,
            "type": _type,
            "comment": comment,
            "masters": masters
        }

    def _get_values(self, data):

        try:
            vals = data['values']
        except KeyError:
            vals = [data['value']]

        return vals

    def _set_full_name(self, name, zone):
        name = name + '.' + zone

        # octodns's name for root is ''
        if (name[0] == '.'):
            name = name[1:]

        return name