import sys
import subprocess
from typing import Any

import streamlit as st

from src.vectorstore import get_retriever
from src.qa_chain import make_conversational_chain
import os
import json
from typing import Dict, List, Tuple

try:
    from src.kg.store import KGStore
    from src.kg.retriever import KGRetriever
    _HAS_KG = True
except Exception:
    _HAS_KG = False


def run_ingest_cli(data_dir: str, persist_dir: str) -> None:
    """Run the ingestion module to rebuild the vectorstore.

    Args:
        data_dir: Directory containing the raw text files.
        persist_dir: Directory where embeddings and Chroma DB should be stored.

    Raises:
        CalledProcessError: If the underlying subprocess fails.
    """

    cmd = [
        sys.executable,
        "-m",
        "src.ingest",
        "--data-dir",
        data_dir,
        "--persist-dir",
        persist_dir,
    ]
    subprocess.run(cmd, check=True)

def _load_chunks_index(persist_dir: str) -> Dict[str, Dict]:
    idx_path = os.path.join(persist_dir, "chunks_index.json")
    if not os.path.exists(idx_path):
        return {}
    try:
        with open(idx_path, "r", encoding="utf-8") as fh:
            return json.load(fh)
    except Exception:
        return {}


def answer_with_kg(
        chain,
        question: str,
        chat_history: List[Tuple[str, str]],
        persist_dir: str,
        kg_hops: int = 1,
        kg_context_max_chars: int = 1000,
    ) -> Any:
    """Augment question with KG context (if available) and run the chain.

    This is a low-risk integration: we build a short textual summary from the KG
    (node labels and short chunk snippets from chunks_index.json) and prepend it to
    the question. The chain's retriever still runs; KG context is additional grounding.
    """
    kg_text_parts: List[str] = []
    # Load chunks index mapping
    chunks_index = _load_chunks_index(persist_dir)

    if _HAS_KG:
        kg_path = os.path.join(persist_dir, "kg_store.ttl")
        try:
            kg = KGStore(path=kg_path)
            retr = KGRetriever(kg)
            chunk_ids, summaries = retr.get_context_for_question(question, hops=kg_hops)
            if summaries:
                kg_text_parts.append("KG entities: " + ", ".join(summaries))
            # add chunk snippets
            for cid in chunk_ids:
                info = chunks_index.get(cid)
                if info:
                    txt = info.get("text", "")
                    if txt:
                        snippet = txt.strip().replace("\n", " ")[:min(len(txt), kg_context_max_chars)]
                        kg_text_parts.append(f"[KG chunk {cid}]: {snippet}")
        except Exception:
            # If KG load fails, skip KG augmentation
            kg_text_parts = []

    kg_context = "\n\n".join(kg_text_parts) if kg_text_parts else ""
    if kg_context:
        augmented_question = f"KG CONTEXT:\n{kg_context}\n\nUser Question:\n{question}"
    else:
        augmented_question = question

    return chain({"question": augmented_question, "chat_history": chat_history})


@st.cache_resource(show_spinner=False)
def build_or_load_retriever_cached(
        data_dir: str,
        persist_dir: str,
        top_k: int,
        retrieval_mode: str,
) -> Any:
    """Load a retriever from the persisted vectorstore or build a new one.

    If loading fails—usually because the vectorstore doesn't exist—this
    function triggers ingestion and retries loading.

    Args:
        data_dir: Directory containing input documents.
        persist_dir: Directory where the Chroma vectorstore is stored.
        top_k: Number of chunks to retrieve for queries.
        retrieval_mode: Retrieval strategy (mmr, similarity, hybrid).

    Returns:
        An initialized retriever instance.
    """
    try:
        return get_retriever(
            persist_dir=persist_dir,
            top_k=top_k,
            retrieval_mode=retrieval_mode,
        )
    except Exception:
        run_ingest_cli(data_dir=data_dir, persist_dir=persist_dir)
        return get_retriever(
            persist_dir=persist_dir,
            top_k=top_k,
            retrieval_mode=retrieval_mode,
        )


@st.cache_resource(show_spinner=False)
def get_chain_cached(
        model_name: str,
        top_k: int,
        retrieval_mode: str,
        data_dir: str,
        persist_dir: str,
) -> Any:
    """Create or load a cached conversational QA chain.

    Args:
        model_name: The OpenAI model to use (gpt-3.5-turbo, gpt-4).
        top_k: Number of chunks to retrieve.
        retrieval_mode: Retrieval mode for the retriever.
        data_dir: Path to data directory.
        persist_dir: Path to vectorstore directory.

    Returns:
        A fully configured conversational QA chain.
    """
    retriever = build_or_load_retriever_cached(
        data_dir=data_dir,
        persist_dir=persist_dir,
        top_k=top_k,
        retrieval_mode=retrieval_mode,
    )
    return make_conversational_chain(retriever, model_name=model_name)