from datetime import datetime

import pymongo

from vendor_image_caching import config
from vendor_image_caching.cache.base import BaseClient
from vendor_image_caching.constants import CacheField, MONGO_URI_TEMPLATE_LOCAL, MONGO_URI_TEMPLATE_NON_LOCAL
from vendor_image_caching.utils import compress, decompress


class Client(BaseClient):
    def __init__(self):
        self.mongo_client: pymongo.MongoClient = self._get_mongo_client()

    @staticmethod
    def _get_mongo_client() -> pymongo.MongoClient:
        """Get mongo client.

        AWS DocDB reference
        Download CA wget https://s3.amazonaws.com/rds-downloads/rds-combined-ca-bundle.pem

        mongodb://{user}:{password}@{host}:{port}/{db}?ssl=true&ssl_ca_certs=rds-combined-ca-bundle.pem&replicaSet=rs0
        &readPreference=secondaryPreferred&retryWrites=false

        Returns:
            Pymongo client.

        """
        mongo_uri_template = MONGO_URI_TEMPLATE_LOCAL if config.IS_LOCAL else MONGO_URI_TEMPLATE_NON_LOCAL

        mongo_uri = mongo_uri_template.format(
            user=config.MONGODB_USER,
            password=config.MONGODB_PASSWORD,
            host=config.MONGODB_HOST,
            port=config.MONGODB_PORT,
            db=config.MONGODB_DATABASE,
            auth=config.MONGODB_AUTH_MECHANISM,
        )

        global mongo_client
        mongo_client = pymongo.MongoClient(mongo_uri)
        return mongo_client

    @staticmethod
    def _get_filter_condition(record_id: str, created_at: datetime, check_timeout: bool = False) -> dict:
        """Get MongoDB filter condition .

        Args:
            record_id: Record ID.
            created_at: Record created_at timestamp.

        Returns:
             Cached data or None.

        """
        return {
            CacheField.RECORD_ID: record_id,
            CacheField.CREATED_AT: created_at,
            CacheField.IMAGES_SAVED: None
        }

    def get_document(self, collection_name: str, record_id: str, created_at: datetime) -> dict or None:
        """Get data from MongoDB.

        Args:
            collection_name: Collection name.
            record_id: Record ID.
            created_at: Record created_at timestamp.

        Returns:
             Cached data or None.

        """
        result = (
            self.mongo_client[config.MONGODB_DATABASE][collection_name]
            .find_one(
                self._get_filter_condition(record_id, created_at),
                {
                    CacheField.CREATED_AT: 0,
                    CacheField.OBJECT_ID: 0,
                    CacheField.IMAGES_SAVED: 0,
                    CacheField.RECORD_ID: 0
                },
            )
        )
        return decompress(result[CacheField.COMPRESSION], result[CacheField.DATA]) if result else None

    def save_document(self, collection_name: str, record_id: str, created_at: datetime, data: dict):
        """Save data to MongoDB.

        Args:
            collection_name: Collection name.
            record_id: Record ID.
            created_at: Records created_at datetime.
            data: Data with new image URLs.

        """
        self.mongo_client[config.MONGODB_DATABASE][collection_name].update_one(
            self._get_filter_condition(record_id, created_at),
            {
                "$set": {
                    CacheField.DATA: compress(config.MONGODB_COMPRESSION_LIB, data),
                    CacheField.IMAGES_SAVED: True,
                },
            },
            upsert=False
        )