import json
from copy import deepcopy

from dotenv import find_dotenv, load_dotenv
from llama_index.core import StorageContext, VectorStoreIndex
from llama_index.core.node_parser import SentenceSplitter
from llama_index.core.schema import Document
from llama_index.embeddings.huggingface import HuggingFaceEmbedding
from llama_index.vector_stores.milvus import MilvusVectorStore
from llama_index.vector_stores.milvus.utils import BGEM3SparseEmbeddingFunction

from src.agent_hackathon.consts import PROJECT_ROOT_DIR
from src.agent_hackathon.logger import get_logger

logger = get_logger(log_name="create_vector_db", log_dir=PROJECT_ROOT_DIR / "logs")


class VectorDBCreator:
    """Handles creation of a Milvus vector database from arXiv data."""

    def __init__(
        self,
        data_path: str,
        db_uri: str,
        embedding_model: str = "Qwen/Qwen3-Embedding-0.6B",
        chunk_size: int = 20_000,
        chunk_overlap: int = 0,
        vector_dim: int = 1024,
        insert_batch_size: int = 8192,
    ) -> None:
        """
        Initialize the VectorDBCreator.

        Args:
            data_path: Path to the JSON data file.
            db_uri: URI for the Milvus database.
            embedding_model: Name of the embedding model.
            chunk_size: Size of text chunks for splitting.
            chunk_overlap: Overlap between text chunks.
            vector_dim: Dimension of the embedding vectors.
            insert_batch_size: Batch size for insertion.
        """
        self.data_path = data_path
        self.db_uri = db_uri
        self.embedding_model = embedding_model
        self.chunk_size = chunk_size
        self.chunk_overlap = chunk_overlap
        self.vector_dim = vector_dim
        self.insert_batch_size = insert_batch_size
        self.embed_model = HuggingFaceEmbedding(
            model_name=self.embedding_model, device="cpu"
        )
        self.sent_splitter = SentenceSplitter(
            chunk_size=self.chunk_size, chunk_overlap=self.chunk_overlap
        )
        logger.info("VectorDBCreator initialized.")

    def load_data(self) -> list[dict]:
        """
        Load and return data from the JSON file.

        Returns:
            List of dictionaries containing arXiv data.
        """
        logger.info(f"Loading data from {self.data_path}")
        with open(file=self.data_path) as f:
            data = json.load(fp=f)
        logger.info("Data loaded successfully.")
        return deepcopy(x=data)

    def prepare_documents(self, data: list[dict]) -> list[Document]:
        """
        Convert raw data into a list of Document objects.

        Args:
            data: List of dictionaries with arXiv data.

        Returns:
            List of Document objects.
        """
        logger.info("Preparing documents from data.")
        docs = [Document(text=d.pop("abstract"), metadata=d) for d in data]
        logger.info(f"Prepared {len(docs)} documents.")
        return docs

    def create_vector_store(self) -> MilvusVectorStore:
        """
        Create and return a MilvusVectorStore instance.

        Returns:
            Configured MilvusVectorStore.
        """
        logger.info(f"Creating MilvusVectorStore at {self.db_uri}")
        store = MilvusVectorStore(
            uri=self.db_uri,
            dim=self.vector_dim,
            enable_sparse=True,
            sparse_embedding_function=BGEM3SparseEmbeddingFunction(),
        )
        logger.info("MilvusVectorStore created.")
        return store

    def build_index(
        self, docs_list: list[Document], vector_store: MilvusVectorStore
    ) -> VectorStoreIndex:
        """
        Build and return a VectorStoreIndex from documents.

        Args:
            docs_list: List of Document objects.
            vector_store: MilvusVectorStore instance.

        Returns:
            VectorStoreIndex object.
        """
        logger.info("Building VectorStoreIndex.")
        storage_context = StorageContext.from_defaults(vector_store=vector_store)
        index = VectorStoreIndex.from_documents(
            documents=docs_list,
            storage_context=storage_context,
            embed_model=self.embed_model,
            transformations=[self.sent_splitter],
            show_progress=True,
            insert_batch_size=self.insert_batch_size,
        )
        logger.info("VectorStoreIndex built.")
        return index

    def run(self) -> None:
        """
        Execute the full pipeline: load data, prepare documents, create vector store, and build index.
        """
        logger.info("Running full vector DB creation pipeline.")
        data = self.load_data()
        docs_list = self.prepare_documents(data=data)
        vector_store = self.create_vector_store()
        self.build_index(docs_list=docs_list, vector_store=vector_store)
        logger.info("Pipeline finished.")


# if __name__ == "__main__":
#     logger.info("Script started.")
#     # Optionally load environment variables if needed
#     _ = load_dotenv(dotenv_path=find_dotenv(raise_error_if_not_found=True))
#     creator = VectorDBCreator(
#         data_path=f"{PROJECT_ROOT_DIR}/data/cs_data_arxiv.json", db_uri="arxiv_docs.db"
#     )
#     creator.run()
#     logger.info("Script finished.")