from abc import abstractmethod
from typing import Callable, Optional, Sequence
from chromadb.types import (
    SubmitEmbeddingRecord,
    EmbeddingRecord,
    SeqId,
    Vector,
    ScalarEncoding,
)
from chromadb.config import Component
from uuid import UUID
import array
from overrides import override


def encode_vector(vector: Vector, encoding: ScalarEncoding) -> bytes:
    """Encode a vector into a byte array."""

    if encoding == ScalarEncoding.FLOAT32:
        return array.array("f", vector).tobytes()
    elif encoding == ScalarEncoding.INT32:
        return array.array("i", vector).tobytes()
    else:
        raise ValueError(f"Unsupported encoding: {encoding.value}")


def decode_vector(vector: bytes, encoding: ScalarEncoding) -> Vector:
    """Decode a byte array into a vector"""

    if encoding == ScalarEncoding.FLOAT32:
        return array.array("f", vector).tolist()
    elif encoding == ScalarEncoding.INT32:
        return array.array("i", vector).tolist()
    else:
        raise ValueError(f"Unsupported encoding: {encoding.value}")


class Producer(Component):
    """Interface for writing embeddings to an ingest stream"""

    @abstractmethod
    def create_topic(self, topic_name: str) -> None:
        pass

    @abstractmethod
    def delete_topic(self, topic_name: str) -> None:
        pass

    @abstractmethod
    def submit_embedding(
        self, topic_name: str, embedding: SubmitEmbeddingRecord
    ) -> SeqId:
        """Add an embedding record to the given topic. Returns the SeqID of the record."""
        pass

    @abstractmethod
    @override
    def reset(self) -> None:
        """Delete all topics and data. For testing only, implementations intended for
        production may throw an exception instead of implementing this method."""
        pass


ConsumerCallbackFn = Callable[[Sequence[EmbeddingRecord]], None]


class Consumer(Component):
    """Interface for reading embeddings off an ingest stream"""

    @abstractmethod
    def subscribe(
        self,
        topic_name: str,
        consume_fn: ConsumerCallbackFn,
        start: Optional[SeqId] = None,
        end: Optional[SeqId] = None,
        id: Optional[UUID] = None,
    ) -> UUID:
        """Register a function that will be called to recieve embeddings for a given
        topic. The given function may be called any number of times, with any number of
        records, and may be called concurrently.

        Only records between start (exclusive) and end (inclusive) SeqIDs will be
        returned. If start is None, the first record returned will be the next record
        generated, not including those generated before creating the subscription. If
        end is None, the consumer will consume indefinitely, otherwise it will
        automatically be unsubscribed when the end SeqID is reached.

        If the function throws an exception, the function may be called again with the
        same or different records.

        Takes an optional UUID as a unique subscription ID. If no ID is provided, a new
        ID will be generated and returned."""
        pass

    @abstractmethod
    def unsubscribe(self, subscription_id: UUID) -> None:
        """Unregister a subscription. The consume function will no longer be invoked,
        and resources associated with the subscription will be released."""
        pass

    @abstractmethod
    def min_seqid(self) -> SeqId:
        """Return the minimum possible SeqID in this implementation."""
        pass

    @abstractmethod
    def max_seqid(self) -> SeqId:
        """Return the maximum possible SeqID in this implementation."""
        pass