from __future__ import annotations
import uuid
from typing import List
from langbot.pkg.rag.knowledge.services.base_service import BaseService
from langbot.pkg.entity.persistence import rag as persistence_rag
from langbot.pkg.core import app
from langbot.pkg.provider.modelmgr.requester import RuntimeEmbeddingModel
import sqlalchemy


class Embedder(BaseService):
    def __init__(self, ap: app.Application) -> None:
        super().__init__()
        self.ap = ap

    async def embed_and_store(
        self, kb_id: str, file_id: str, chunks: List[str], embedding_model: RuntimeEmbeddingModel
    ) -> list[persistence_rag.Chunk]:
        # save chunk to db
        chunk_entities: list[persistence_rag.Chunk] = []
        chunk_ids: list[str] = []

        for chunk_text in chunks:
            chunk_uuid = str(uuid.uuid4())
            chunk_ids.append(chunk_uuid)
            chunk_entity = persistence_rag.Chunk(uuid=chunk_uuid, file_id=file_id, text=chunk_text)
            chunk_entities.append(chunk_entity)

        chunk_dicts = [
            self.ap.persistence_mgr.serialize_model(persistence_rag.Chunk, chunk) for chunk in chunk_entities
        ]

        await self.ap.persistence_mgr.execute_async(sqlalchemy.insert(persistence_rag.Chunk).values(chunk_dicts))

        # get embeddings (batch size limit: 64 for OpenAI)
        MAX_BATCH_SIZE = 64
        embeddings_list: list[list[float]] = []

        for i in range(0, len(chunks), MAX_BATCH_SIZE):
            batch = chunks[i : i + MAX_BATCH_SIZE]
            batch_embeddings = await embedding_model.provider.invoke_embedding(
                model=embedding_model,
                input_text=batch,
                extra_args={},  # TODO: add extra args
                knowledge_base_id=kb_id,
                call_type='embedding',
            )
            embeddings_list.extend(batch_embeddings)

        # save embeddings to vdb
        await self.ap.vector_db_mgr.vector_db.add_embeddings(kb_id, chunk_ids, embeddings_list, chunk_dicts)

        self.ap.logger.info(f'Successfully saved {len(chunk_entities)} embeddings to Knowledge Base.')

        return chunk_entities