# src/api/routes.py

from fastapi import APIRouter, HTTPException
from fastapi.responses import StreamingResponse
from typing import Dict, Any, List, Optional
import asyncio
import time
import json
import logging
from datetime import datetime
import traceback

from pydantic import BaseModel
from langchain_core.messages import HumanMessage

from src.agents.agent_config import AGENT_GENERATION_TIMEOUT
from src.agents.tracing import get_langfuse_handler, get_langfuse_client, push_score, get_current_trace_id

logger = logging.getLogger(__name__)

# Global app state (will be set by main.py)
app_state = {}

router = APIRouter()

# Import models with fallback
try:
    from .models import QueryRequest, QueryResponse, SearchResult, QueryType
except ImportError:
    from pydantic import BaseModel
    from enum import Enum


    class QueryType(str, Enum):
        SEARCH = "search"
        CVE_LOOKUP = "cve_lookup"
        GENERAL = "general"


    class QueryRequest(BaseModel):
        query: str
        top_k: int = 10
        years: Optional[List[str]] = None
        max_context_docs: int = 5
        use_large_model: bool = False
        stream: bool = False
        severity_filter: Optional[str] = None
        vendor_filter: Optional[str] = None


    class SearchResult(BaseModel):
        id: str
        text: str
        metadata: Dict[str, Any]
        score: float
        distance: float


    class QueryResponse(BaseModel):
        query: str
        response: str
        search_results: List[SearchResult]
        query_type: QueryType
        processing_time: float
        model_used: str


def get_rag_system():
    """Get RAG system from app state"""
    if 'rag_system' not in app_state:
        raise HTTPException(status_code=503, detail="RAG system not initialized")
    return app_state['rag_system']


def get_llm_client():
    """Get LLM client from app state (optional)"""
    return app_state.get('llm_client', None)


def get_enhanced_processor():
    """Get enhanced processor from app state (optional)"""
    return app_state.get('enhanced_processor', None)


@router.get("/health")
async def health_check():
    """Fast health check endpoint"""
    try:
        # Quick health check with timeout
        rag_system = get_rag_system()

        # Get basic stats quickly
        stats = await asyncio.wait_for(
            asyncio.to_thread(rag_system.get_collection_stats),
            timeout=5.0  # 5 second timeout for health check
        )

        llm_client = get_llm_client()
        llm_status = llm_client is not None

        return {
            "status": "healthy",
            "documents": stats.get("total_documents", 0),
            "llm_available": llm_status,
            "timestamp": datetime.now().isoformat()
        }

    except asyncio.TimeoutError:
        return {
            "status": "slow",
            "message": "System responding slowly",
            "timestamp": datetime.now().isoformat()
        }
    except Exception as e:
        logger.error(f"Health check failed: {e}")
        raise HTTPException(status_code=503, detail=f"System unhealthy: {str(e)}")


@router.post("/search")
async def optimized_search(request: QueryRequest):
    """Optimized search endpoint with better performance"""
    start_time = time.time()

    try:
        # Validate input
        if not request.query or len(request.query.strip()) == 0:
            raise HTTPException(status_code=400, detail="Query cannot be empty")

        # Limit parameters for performance
        top_k = min(request.top_k, 20)  # Reduced from 50
        query = request.query.strip()[:500]  # Limit query length

        rag_system = get_rag_system()

        # Determine timeout based on query complexity
        search_timeout = 15.0  # Default timeout
        if len(query) > 100 or top_k > 10:
            search_timeout = 20.0

        # Execute search with timeout
        try:
            search_results = await asyncio.wait_for(
                asyncio.to_thread(rag_system.search_cves, query, top_k),
                timeout=search_timeout
            )
        except asyncio.TimeoutError:
            logger.warning(f"Search timeout for query: {query[:50]}...")
            raise HTTPException(
                status_code=408,
                detail=f"Search timed out after {search_timeout}s. Try a more specific query."
            )

        # Convert results
        formatted_results = []
        for result in search_results:
            formatted_results.append(SearchResult(
                id=result.get('id', ''),
                text=result.get('text', result.get('content', '')),
                metadata=result.get('metadata', {}),
                score=result.get('score', 0.0),
                distance=result.get('distance', 1.0)
            ))

        processing_time = time.time() - start_time

        return {
            "results": formatted_results,
            "query": query,
            "total_results": len(formatted_results),
            "processing_time": processing_time,
            "status": "success"
        }

    except HTTPException:
        raise
    except Exception as e:
        processing_time = time.time() - start_time
        logger.error(f"Search failed: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Search failed after {processing_time:.2f}s: {str(e)}"
        )


@router.post("/query")
async def optimized_query(request: QueryRequest):
    """Optimized query endpoint with LLM integration"""
    start_time = time.time()

    try:
        if not request.query or len(request.query.strip()) == 0:
            raise HTTPException(status_code=400, detail="Query cannot be empty")

        top_k = min(request.top_k, 15)
        query = request.query.strip()[:500]

        rag_system = get_rag_system()
        llm_client = get_llm_client()

        search_results = await asyncio.wait_for(
            asyncio.to_thread(rag_system.search_cves, query, top_k),
            timeout=15.0
        )

        formatted_results = []
        for result in search_results:
            formatted_results.append(SearchResult(
                id=result.get('id', ''),
                text=result.get('text', result.get('content', '')),
                metadata=result.get('metadata', {}),
                score=result.get('score', 0.0),
                distance=result.get('distance', 1.0)
            ))

        processing_time = time.time() - start_time

        if llm_client and search_results:
            try:
                context = "\n\n".join(
                    f"[{i+1}] {r.get('metadata', {}).get('cve_id', r.get('id', ''))}\n{r.get('text', '')[:800]}"
                    for i, r in enumerate(search_results[:request.max_context_docs])
                )
                llm_prompt = f"Using the CVE search results below, answer the question.\n\nRESULTS:\n{context}\n\nQUESTION: {query}\n\nANSWER:"

                llm_response = await asyncio.wait_for(
                    asyncio.to_thread(llm_client.generate, llm_prompt),
                    timeout=30.0
                )
                model_used = llm_client.get_model_info().get("model_name", "llm")
            except asyncio.TimeoutError:
                llm_response = "LLM generation timed out."
                model_used = "llm_timeout"
        elif search_results:
            cve_count = len(search_results)
            top_cve = search_results[0]['metadata'].get('cve_id', 'Unknown')
            llm_response = f"Found {cve_count} relevant vulnerabilities. Top result: {top_cve}. LLM processing unavailable — using basic search."
            model_used = "basic_search"
        else:
            llm_response = f"No vulnerabilities found for: {query}"
            model_used = "basic_search"

        return QueryResponse(
            query=query,
            response=llm_response,
            search_results=formatted_results,
            query_type=QueryType.GENERAL,
            processing_time=processing_time,
            model_used=model_used
        )

    except asyncio.TimeoutError:
        raise HTTPException(status_code=408, detail="Query processing timed out")
    except HTTPException:
        raise
    except Exception as e:
        processing_time = time.time() - start_time
        logger.error(f"Query processing failed: {e}")
        raise HTTPException(status_code=500, detail=f"Query failed after {processing_time:.2f}s: {str(e)}")


@router.post("/summary")
async def optimized_summary(request: QueryRequest):
    """Optimized summary endpoint"""
    start_time = time.time()

    try:
        query = request.query.strip()
        if not query:
            raise HTTPException(status_code=400, detail="Query cannot be empty")

        rag_system = get_rag_system()

        # Get more results for summary
        max_results = min(request.max_context_docs * 10, 50)

        search_results = await asyncio.wait_for(
            asyncio.to_thread(rag_system.search_cves, query, max_results),
            timeout=20.0
        )

        # Analyze results
        severities = {}
        vendors = []
        total_results = len(search_results)

        for result in search_results:
            metadata = result.get('metadata', {})

            # Count severities
            severity = metadata.get('severity', 'Unknown')
            severities[severity] = severities.get(severity, 0) + 1

            # Collect vendors (simplified)
            affected_products = metadata.get('affected_products', [])
            if affected_products:
                vendors.extend(affected_products[:2])  # Limit to avoid performance issues

        # Get top vendors
        from collections import Counter
        vendor_counts = Counter(vendors)
        top_vendors = [vendor for vendor, count in vendor_counts.most_common(5)]

        processing_time = time.time() - start_time

        return {
            "query": query,
            "total_results": total_results,
            "severity_distribution": severities,
            "top_vendors": top_vendors,
            "processing_time": processing_time,
            "sample_results": search_results[:5]  # Return top 5 as samples
        }

    except asyncio.TimeoutError:
        raise HTTPException(status_code=408, detail="Summary generation timed out")
    except Exception as e:
        processing_time = time.time() - start_time
        logger.error(f"Summary failed: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Summary failed after {processing_time:.2f}s: {str(e)}"
        )


@router.get("/stats")
async def get_stats():
    """Fast stats endpoint"""
    try:
        rag_system = get_rag_system()
        llm_client = get_llm_client()

        # Get basic stats with timeout
        stats = await asyncio.wait_for(
            asyncio.to_thread(rag_system.get_collection_stats),
            timeout=5.0
        )

        return {
            "status": "operational",
            "total_documents": stats.get("total_documents", 0),
            "collection_name": stats.get("collection_name", "unknown"),
            "llm_available": llm_client is not None,
            "llm_model": llm_client.get_model_info().get("model_name") if llm_client else None,
            "version": "2.0.0-optimized"
        }

    except asyncio.TimeoutError:
        return {
            "status": "slow",
            "message": "Stats loading slowly",
            "version": "2.0.0-optimized"
        }
    except Exception as e:
        logger.error(f"Stats failed: {e}")
        raise HTTPException(status_code=500, detail=f"Stats unavailable: {str(e)}")


# ── Neo4j graph endpoints ─────────────────────────────────────────────────────

def get_graph_service():
    return app_state.get("graph_service", None)


class SimilarCVERequest(BaseModel if "BaseModel" in dir() else object):
    cve_id: str
    k: int = 10


try:
    from pydantic import BaseModel as _BM
    class SimilarCVERequest(_BM):
        cve_id: str
        k: int = 10
except Exception:
    pass


@router.post("/graph/similar")
async def graph_similar_cves(request: SimilarCVERequest):
    """Find CVEs related to the given CVE via the Neo4j knowledge graph."""
    graph = get_graph_service()
    if graph is None:
        raise HTTPException(status_code=503, detail="Neo4j graph service not initialised")
    try:
        results = await asyncio.wait_for(
            asyncio.to_thread(graph.similar_cves, request.cve_id, request.k),
            timeout=10.0,
        )
        return {"cve_id": request.cve_id, "similar": results, "count": len(results)}
    except asyncio.TimeoutError:
        raise HTTPException(status_code=408, detail="Graph query timed out")
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.get("/graph/stats")
async def graph_stats():
    """Return Neo4j node counts per label."""
    graph = get_graph_service()
    if graph is None:
        raise HTTPException(status_code=503, detail="Neo4j graph service not initialised")
    stats = await asyncio.to_thread(graph.get_stats)
    return {"neo4j_counts": stats}


# ── Cross-collection search ───────────────────────────────────────────────────

@router.post("/search/{collection}")
async def search_collection(collection: str, request: QueryRequest):
    """Hybrid search across a specific Qdrant collection (cve/mitre/capec/cwe)."""
    valid = {"cve", "mitre", "capec", "cwe"}
    if collection not in valid:
        raise HTTPException(status_code=400, detail=f"Unknown collection. Choose from: {valid}")

    rag_system = get_rag_system()
    start_time = time.time()
    try:
        results = await asyncio.wait_for(
            asyncio.to_thread(rag_system.search, request.query, min(request.top_k, 20), collection),
            timeout=15.0,
        )
        formatted = [
            SearchResult(
                id=r.get("id", ""),
                text=r.get("text", ""),
                metadata=r.get("metadata", {}),
                score=r.get("score", 0.0),
                distance=r.get("distance", 1.0),
            )
            for r in results
        ]
        return {
            "results": formatted,
            "collection": collection,
            "query": request.query,
            "total_results": len(formatted),
            "processing_time": time.time() - start_time,
        }
    except asyncio.TimeoutError:
        raise HTTPException(status_code=408, detail="Search timed out")
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


# Health endpoint that doesn't require authentication
@router.get("/ping")
async def ping():
    """Ultra-fast ping endpoint"""
    return {"status": "alive", "timestamp": datetime.now().isoformat()}


@router.post("/query/stream")
async def query_stream(request: QueryRequest):
    """SSE streaming query endpoint with LLM integration."""
    if not request.query or len(request.query.strip()) == 0:
        raise HTTPException(status_code=400, detail="Query cannot be empty")

    rag_system = get_rag_system()
    llm_client = get_llm_client()

    async def event_generator():
        try:
            yield f"data: {json.dumps({'phase': 'searching', 'status': 'started'})}\n\n"

            search_results = await asyncio.wait_for(
                asyncio.to_thread(rag_system.search_cves, request.query.strip()[:500], min(request.top_k, 15)),
                timeout=15.0,
            )

            formatted = [
                {
                    "id": r.get("id", ""),
                    "text": r.get("text", r.get("content", ""))[:500],
                    "metadata": r.get("metadata", {}),
                    "score": r.get("score", 0.0),
                }
                for r in search_results
            ]

            yield f"data: {json.dumps({'phase': 'found', 'count': len(formatted), 'results': formatted})}\n\n"

            if not llm_client:
                yield f"data: {json.dumps({'phase': 'generate', 'status': 'llm_unavailable'})}\n\n"
                yield f"data: {json.dumps({'phase': 'done', 'response': 'LLM not available. Use /query/agent for agentic processing.'})}\n\n"
                yield "data: [DONE]\n\n"
                return

            context = "\n\n".join(
                f"[{i+1}] {r.get('metadata', {}).get('cve_id', r.get('id', ''))}\n{r.get('text', '')[:800]}"
                for i, r in enumerate(search_results[:request.max_context_docs])
            )
            llm_prompt = f"Using the CVE search results below, answer the question.\n\nRESULTS:\n{context}\n\nQUESTION: {request.query.strip()[:500]}\n\nANSWER:"

            yield f"data: {json.dumps({'phase': 'generating', 'status': 'started'})}\n\n"

            for token in llm_client.stream(llm_prompt):
                if token:
                    yield f"data: {json.dumps({'token': token})}\n\n"

            yield "data: [DONE]\n\n"

        except asyncio.TimeoutError:
            yield f"data: {json.dumps({'phase': 'error', 'error': 'timeout', 'message': 'Request timed out'})}\n\n"
        except Exception as e:
            yield f"data: {json.dumps({'phase': 'error', 'error': str(e)[:200], 'message': 'Internal error'})}\n\n"

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
        },
    )


# ── Agentic RAG endpoints ─────────────────────────────────────────────────────

def get_agent_graph():
    return app_state.get("agent_graph", None)


def get_memory():
    return app_state.get("memory", None)


try:
    from .models import AgentQueryRequest, AgentResponse, AgentEvent
except ImportError:
    class AgentQueryRequest(BaseModel if "BaseModel" in dir() else object):
        query: str
        session_id: str = "default_session"
        top_k: int = 10
        max_context_docs: int = 6


@router.post("/query/agent")
async def agentic_query(request: AgentQueryRequest):
    """Full agentic RAG query with adaptive retrieval, KG enrichment, and self-reflection."""
    start_time = time.time()
    try:
        if not request.query or len(request.query.strip()) == 0:
            raise HTTPException(status_code=400, detail="Query cannot be empty")

        agent_graph = get_agent_graph()
        if agent_graph is None:
            raise HTTPException(status_code=503, detail="Agent graph not initialized")

        llm_client = get_llm_client()
        model_name = "none"
        if llm_client:
            try:
                model_name = llm_client.get_model_info().get("model_name", "llm")
            except Exception:
                model_name = "llm"

        trace_id = ""
        lf_client = get_langfuse_client()
        if lf_client:
            try:
                trace = lf_client.trace(
                    name="agentic-rag-query",
                    session_id=request.session_id,
                    input=request.query.strip()[:500],
                    metadata={"model": model_name},
                )
                trace_id = trace.id
            except Exception:
                pass

        initial_state = {
            "messages": [HumanMessage(content=request.query.strip())],
            "original_query": request.query.strip()[:500],
            "rewritten_query": "",
            "route_decision": "",
            "rewrite_reason": "",
            "search_collections": ["cve"],
            "retrieved_docs": [],
            "kg_context": "",
            "kg_enriched": False,
            "memory_context": "",
            "generation": "",
            "reflection": {},
            "retry_count": 0,
            "_relevant_count": 0,
            "mem0_user_id": request.session_id,
            "tracing_trace_id": trace_id,
        }

        langfuse_handler = get_langfuse_handler()
        callbacks = [langfuse_handler] if langfuse_handler else []

        final_state = await asyncio.wait_for(
            asyncio.to_thread(
                agent_graph.invoke, initial_state,
                {
                    "configurable": {"thread_id": request.session_id},
                    "callbacks": callbacks,
                },
            ),
            timeout=AGENT_GENERATION_TIMEOUT,
        )

        processing_time = time.time() - start_time

        if trace_id and lf_client:
            reflection = final_state.get("reflection", {})
            push_score(trace_id, "hallucination_score", reflection.get("hallucination_score", 0.0))
            push_score(trace_id, "completeness_score", reflection.get("completeness_score", 0.0))
            verdict_val = 1.0 if reflection.get("verdict", "pass") == "pass" else 0.0
            push_score(trace_id, "verdict", verdict_val)
            push_score(trace_id, "retries_used", final_state.get("retry_count", 0))
            push_score(trace_id, "docs_retrieved", len(final_state.get("retrieved_docs", [])))
            push_score(trace_id, "processing_time", round(processing_time, 3))

        return {
            "query": request.query,
            "answer": final_state.get("generation", ""),
            "route_decision": final_state.get("route_decision", "unknown"),
            "search_collections": final_state.get("search_collections", []),
            "rewritten_query": final_state.get("rewritten_query", "") or None,
            "docs_retrieved": len(final_state.get("retrieved_docs", [])),
            "docs_relevant": final_state.get("_relevant_count", 0),
            "kg_enriched": final_state.get("kg_enriched", False),
            "hallucination_check": final_state.get("reflection", {}).get("hallucination"),
            "completeness_check": final_state.get("reflection", {}).get("completeness"),
            "retries_used": final_state.get("retry_count", 0),
            "memory_context_used": bool(final_state.get("memory_context", "")),
            "processing_time": processing_time,
            "model_used": model_name,
            "search_results": [
                {
                    "id": r.get("id", ""),
                    "text": r.get("text", "")[:300],
                    "metadata": r.get("metadata", {}),
                    "score": r.get("score", 0.0),
                }
                for r in final_state.get("retrieved_docs", [])[:5]
            ],
        }

    except asyncio.TimeoutError:
        raise HTTPException(status_code=408, detail="Agent query timed out")
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Agent query failed: {e}")
        raise HTTPException(status_code=500, detail=f"Agent query failed: {str(e)[:200]}")


@router.post("/query/agent/stream")
async def agentic_query_stream(request: AgentQueryRequest):
    """SSE streaming agentic RAG — emits events for each graph node phase."""
    if not request.query or len(request.query.strip()) == 0:
        raise HTTPException(status_code=400, detail="Query cannot be empty")

    agent_graph = get_agent_graph()
    if agent_graph is None:
        raise HTTPException(status_code=503, detail="Agent graph not compiled")

    config = {"configurable": {"thread_id": request.session_id}}
    langfuse_handler = get_langfuse_handler()
    if langfuse_handler:
        config["callbacks"] = [langfuse_handler]

    lf_client = get_langfuse_client()
    trace_id = ""
    if lf_client:
        try:
            trace = lf_client.trace(
                name="agentic-rag-query",
                session_id=request.session_id,
                input=request.query.strip()[:500],
            )
            trace_id = trace.id
        except Exception:
            pass

    async def event_generator():
        try:
            initial_state = {
                "messages": [HumanMessage(content=request.query.strip())],
                "original_query": request.query.strip()[:500],
                "rewritten_query": "",
                "route_decision": "",
                "rewrite_reason": "",
                "search_collections": ["cve"],
                "retrieved_docs": [],
                "kg_context": "",
                "kg_enriched": False,
                "memory_context": "",
                "generation": "",
                "reflection": {},
                "retry_count": 0,
                "_relevant_count": 0,
                "mem0_user_id": request.session_id,
                "tracing_trace_id": trace_id,
            }

            ref = {}
            # astream_events(v2) fires per-event including on_chain_stream for
            # BaseLLMRunnable.stream() tokens inside the generate_answer node.
            async for ev in agent_graph.astream_events(initial_state, config, version="v2"):
                et = ev["event"]
                name = ev.get("name", "")
                data = ev.get("data", {})
                metadata = ev.get("metadata", {})

                # ── Node completion events → phase SSE ──────────────────────
                if et == "on_chain_end" and metadata.get("langgraph_node") == name:
                    node_name = name
                    state = data.get("output", {})

                    if node_name == "memory_retrieve":
                        ctx = state.get("memory_context", "")
                        yield f"data: {json.dumps({'phase': 'memory_retrieve', 'has_context': bool(ctx)})}\n\n"

                    elif node_name == "route_query":
                        yield f"data: {json.dumps({'phase': 'route_query', 'decision': state.get('route_decision', ''), 'collections': state.get('search_collections', [])})}\n\n"

                    elif node_name == "rewrite_query":
                        rq = state.get("rewritten_query", "")
                        yield f"data: {json.dumps({'phase': 'rewrite_query', 'rewritten': rq[:100]})}\n\n"

                    elif node_name == "retrieve":
                        docs = state.get("retrieved_docs", [])
                        yield f"data: {json.dumps({'phase': 'retrieve', 'found': len(docs), 'kg_enriched': state.get('kg_enriched', False)})}\n\n"

                    elif node_name == "grade_documents":
                        relevant = state.get("_relevant_count", 0)
                        yield f"data: {json.dumps({'phase': 'grade_documents', 'relevant': relevant})}\n\n"

                    elif node_name == "generate_answer":
                        gen = state.get("generation", "")
                        yield f"data: {json.dumps({'phase': 'generation_complete', 'chars': len(gen)})}\n\n"

                    elif node_name == "self_reflect":
                        ref = state.get("reflection", {})
                        yield f"data: {json.dumps({'phase': 'self_reflect', 'verdict': ref.get('verdict', 'pass'), 'hallucination': ref.get('hallucination'), 'completeness': ref.get('completeness')})}\n\n"

                    elif node_name == "memory_store":
                        yield f"data: {json.dumps({'phase': 'memory_store', 'saved': True})}\n\n"

                # ── Token streaming from BaseLLMRunnable inside generate_answer ──
                elif et == "on_chain_stream" and metadata.get("langgraph_node") == "generate_answer":
                    token = data.get("chunk", "")
                    if token:
                        yield f"data: {json.dumps({'token': token})}\n\n"

            yield "data: [DONE]\n\n"

            if trace_id and lf_client:
                push_score(trace_id, "hallucination_score", ref.get("hallucination_score", 0.0))
                push_score(trace_id, "completeness_score", ref.get("completeness_score", 0.0))
                verdict_val = 1.0 if ref.get("verdict", "pass") == "pass" else 0.0
                push_score(trace_id, "verdict", verdict_val)

        except asyncio.TimeoutError:
            yield f"data: {json.dumps({'phase': 'error', 'error': 'timeout', 'fallback': 'search_only', 'message': 'Agent processing timed out'})}\n\n"
        except Exception as e:
            yield f"data: {json.dumps({'phase': 'error', 'error': 'internal', 'fallback': 'search_only', 'message': str(e)[:200]})}\n\n"

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
        },
    )


@router.get("/query/agent/health")
async def agent_health():
    """Agent-specific health check with degradation flags."""
    return {
        "agent_graph_compiled": get_agent_graph() is not None,
        "mem0_enabled": (get_memory() is not None and get_memory().enabled) if get_memory() else False,
        "llm_available": get_llm_client() is not None,
        "neo4j_available": app_state.get("graph_service") is not None,
        "agent_degraded": get_agent_graph() is None,
    }