"""Define API routes for status."""

import time
from typing import Any

from fastapi import APIRouter

from app.config.settings import settings
from app.shared.bootstrap import (
    get_bm25_retriever,
    get_binary_store,
    get_conversation_store,
    get_document_query_service,
    get_vector_index,
)

router = APIRouter(prefix="/status", tags=["系统状态"])

# ---------------------------------------------------------------------------
# Simple TTL cache for /stats (avoids O(N) doc scan on every request)
# ---------------------------------------------------------------------------
_stats_cache: dict[str, Any] = {}
_stats_cache_time: float = 0.0
_STATS_TTL_SECONDS: float = 10.0


@router.get("/stats")
async def get_stats():
    """Return document statistics (cached for 10 s)."""
    global _stats_cache, _stats_cache_time
    now = time.time()
    if _stats_cache and (now - _stats_cache_time) < _STATS_TTL_SECONDS:
        return _stats_cache

    documents = get_document_query_service().list_documents()
    indexed = sum(1 for d in documents if d.status.value == "indexed")
    failed = sum(1 for d in documents if d.status.value == "failed")
    _stats_cache = {
        "documents_total": len(documents),
        "documents_indexed": indexed,
        "documents_failed": failed,
        "chunks_total": sum(d.chunk_count for d in documents),
    }
    _stats_cache_time = now
    return _stats_cache


@router.get("/config")
async def get_config():
    """Return system configuration."""
    return {
        "embedding_model": settings.embedding_model,
        "embedding_dim": settings.embedding_dim,
        "embedding_base_url": settings.embedding_base_url,
        "milvus_collection": settings.milvus_collection,
        "parser_backend": settings.parser_backend,
        "chunk_backend": settings.chunk_backend,
        "artifact_prefix": settings.document_parse_artifact_prefix,
        "parser_failure_mode": settings.parser_failure_mode,
        "llm_provider": settings.llm_provider,
        "llm_model": settings.llm_model,
        "document_metadata_path": settings.document_metadata_path,
    }


@router.get("/milvus/health")
async def milvus_health():
    """Return Milvus health (kept for backwards compat)."""
    return get_vector_index().health()


@router.get("/health")
async def get_health():
    """Return aggregate health of all backend services."""
    # --- Milvus ---
    try:
        milvus_info = get_vector_index().health()
        milvus_status = "ok" if milvus_info.get("connected") else "error"
    except Exception as exc:  # noqa: BLE001
        milvus_info = {}
        milvus_status = "error"
        milvus_info["error"] = str(exc)

    # --- MinIO ---
    try:
        minio_connected = get_binary_store().client.connected
        minio_status = "ok" if minio_connected else "error"
    except Exception:  # noqa: BLE001
        minio_status = "error"
        minio_connected = False

    # --- BM25 ---
    bm25 = get_bm25_retriever()

    # --- Sessions ---
    try:
        session_count = len(get_conversation_store().list_sessions())
    except Exception:  # noqa: BLE001
        session_count = 0

    return {
        "milvus": {"status": milvus_status, **milvus_info},
        "minio": {"status": minio_status, "connected": minio_connected},
        "bm25": {"available": bm25 is not None},
        "reranker": {
            "enabled": settings.reranker_enabled,
            "model": settings.reranker_model if settings.reranker_enabled else None,
        },
        "sessions": {
            "active": session_count,
            "max": settings.session_max_sessions,
        },
    }