"""Bounded delivery to State Hub's retained memo-notification receipts."""
import hashlib
import json
import re
import uuid

from .http_transport import JSONTransport, fixed_origin


class HubDelivery:
    def __init__(self, origin, *, transport=None):
        self.origin = fixed_origin(origin, allow_internal_http=True)
        self.transport = transport or JSONTransport(allow_internal_http=True)

    def _request(self, method, url, payload, key):
        body = json.dumps(payload, sort_keys=True, separators=(',', ':'), allow_nan=False).encode()
        return self.transport.request(method, url, body=body if method == 'POST' else None,
            headers={'Content-Type': 'application/json', 'Idempotency-Key': key,
                     'X-StateHub-Source-Agent': 'informed-decision'})

    def notify(self, delivery_id, metadata):
        uuid.UUID(delivery_id)
        if set(metadata) != {'memo_id', 'question', 'memo_class', 'submitter'}:
            raise ValueError('invalid notification metadata')
        if any(not isinstance(v, str) or not v or len(v) > 4096 for v in metadata.values()):
            raise ValueError('invalid notification metadata')
        if not re.fullmatch(r'[A-Za-z0-9][A-Za-z0-9._:-]{0,255}', metadata['memo_id']):
            raise ValueError('invalid memo id')
        status, receipt = self._request('POST', self.origin + '/informed-decision/notifications',
                                        metadata, delivery_id)
        # A queued relay receipt is pending, not successful central delivery.
        if status not in (200, 201) or not isinstance(receipt, dict):
            return False
        try:
            uuid.UUID(receipt['message_id'])
        except (ValueError, TypeError, KeyError, AttributeError):
            return False
        return (receipt.get('delivery_id') == delivery_id and receipt.get('status') == 'accepted'
                and receipt.get('authoritative_review') == 'signed-in-overview'
                and all(receipt.get(k) == v for k, v in metadata.items()))

    def resolution(self, method, url, payload):
        suffix = '/resolve' if method == 'POST' else ''
        pattern = r'/decisions/[0-9a-f]{8}(?:-[0-9a-f]{4}){3}-[0-9a-f]{12}' + suffix
        if (method not in ('POST', 'GET') or not url.startswith(self.origin + '/decisions/')
                or not re.fullmatch(pattern, url[len(self.origin):])):
            raise ValueError('invalid hub resolution route')
        material = json.dumps([method, url, payload], sort_keys=True, separators=(',', ':')).encode()
        status, receipt = self._request(method, url, payload,
                                       'infd-resolution:' + hashlib.sha256(material).hexdigest())
        if 200 <= status < 300:
            ident = url[len(self.origin + '/decisions/'):].split('/')[0]
            if (status != 200 or not isinstance(receipt, dict) or receipt.get('id') != ident
                    or (method == 'POST' and (receipt.get('status') != 'resolved'
                        or any(receipt.get(k) != payload[k] for k in ('rationale', 'decided_by'))))):
                return 503, {}  # Queued or mismatched response is not a resolution receipt.
        return status, receipt