from datetime import datetime

import redis

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

CACHE_KEY_PREFIX = "cache"


class Client(BaseClient):

    def __init__(self):
        self.redis_client: redis.Redis = self._get_redis_client()

    @staticmethod
    def _get_redis_client() -> redis.Redis:
        """Get redis client.

        Returns:
            Redis client.

        """

        return redis.from_url(config.REDIS_URL)

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

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

        Returns:
             Cached data or None.

        """

        raw_value = self.redis_client.get(self.get_full_key(collection_name, record_id))

        if not raw_value:
            return None

        value = decompress(config.REDIS_COMPRESSION_LIB, raw_value)

        return value.get(CacheField.DATA) if value else None

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

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

        """

        raw_value = self.redis_client.get(self.get_full_key(collection_name, record_id))

        if not raw_value:
            return

        value = decompress(config.REDIS_COMPRESSION_LIB, raw_value)

        value[CacheField.DATA] = data
        value[CacheField.IMAGES_SAVED] = True

        self.redis_client.set(
            self.get_full_key(collection_name, record_id),
            compress(config.REDIS_COMPRESSION_LIB, value)
        )

    @staticmethod
    def get_full_key(collection_name, key):
        """
        Creates the full redis key from generic prefix,
        configured compression type and passed specific params

        Args:
            collection_name: Collection name for keys namespacing.
            key: key of the specific record.

        """

        return f"{CACHE_KEY_PREFIX}:{config.REDIS_COMPRESSION_LIB}:{collection_name}:{key}"