"""RAG retrieval pipelines: Base-RAG and Hier-RAG."""

import time
import logging
from typing import List, Dict, Any, Optional, Tuple
from core.index import VectorStore, IndexManager
from openai import OpenAI
import openai
import os
from tenacity import retry, stop_after_attempt, wait_exponential, retry_if_exception_type

logger = logging.getLogger(__name__)


class BaseRAG:
    """Standard RAG pipeline without hierarchical filtering."""
    
    def __init__(
        self,
        vector_store: VectorStore,
        llm_model: str = "gpt-3.5-turbo",
        api_key: Optional[str] = None
    ):
        """
        Initialize Base RAG pipeline.
        
        Args:
            vector_store: Vector store instance
            llm_model: OpenAI model name
            api_key: OpenAI API key
        """
        self.vector_store = vector_store
        self.llm_model = llm_model
        
        # Set OpenAI API key
        self.api_key = api_key or os.getenv("OPENAI_API_KEY")
        self.client = OpenAI(api_key=self.api_key)
    
    def retrieve(
        self,
        query: str,
        n_results: int = 5
    ) -> Tuple[List[Dict[str, Any]], float]:
        """
        Retrieve relevant documents.
        
        Args:
            query: Search query
            n_results: Number of results to retrieve
            
        Returns:
            Tuple of (results, retrieval_time)
        """
        start_time = time.time()
        results = self.vector_store.search(query, n_results=n_results)
        retrieval_time = time.time() - start_time
        
        logger.info(f"Retrieved {len(results)} documents in {retrieval_time:.3f}s")
        return results, retrieval_time
    
    @retry(
        retry=retry_if_exception_type((openai.RateLimitError, openai.APITimeoutError)),
        stop=stop_after_attempt(3),
        wait=wait_exponential(multiplier=1, min=2, max=10),
        reraise=True
    )
    def generate(
        self,
        query: str,
        contexts: List[str],
        max_tokens: int = 500
    ) -> Tuple[str, float]:
        """
        Generate answer using LLM with retry logic.
        
        Args:
            query: User query
            contexts: Retrieved context documents
            max_tokens: Maximum tokens in response
            
        Returns:
            Tuple of (answer, generation_time)
        """
        # Build prompt
        context_text = "\n\n".join([f"Context {i+1}:\n{ctx}" for i, ctx in enumerate(contexts)])
        
        prompt = f"""Based on the following context documents, please answer the question.

{context_text}

Question: {query}

Answer:"""
        
        start_time = time.time()
        
        try:
            response = self.client.chat.completions.create(
                model=self.llm_model,
                messages=[
                    {"role": "system", "content": "You are a helpful assistant that answers questions based on provided context."},
                    {"role": "user", "content": prompt}
                ],
                max_tokens=max_tokens,
                temperature=0.3
            )
            
            answer = response.choices[0].message.content
            generation_time = time.time() - start_time
            
            logger.info(f"Generated answer in {generation_time:.3f}s")
            return answer, generation_time
            
        except openai.AuthenticationError as e:
            logger.error(f"Authentication failed: {str(e)}")
            return "❌ **Authentication Error**: Invalid OpenAI API key. Please check your credentials in Settings → Secrets.", 0
            
        except openai.RateLimitError as e:
            logger.error(f"Rate limit exceeded: {str(e)}")
            return "⚠️ **Rate Limit Exceeded**: Too many requests. Please wait a moment and try again.", 0
            
        except openai.APITimeoutError as e:
            logger.error(f"API timeout: {str(e)}")
            return "⏱️ **Timeout Error**: Request took too long. Please try again with a shorter query.", 0
            
        except openai.APIConnectionError as e:
            logger.error(f"Connection error: {str(e)}")
            return "🌐 **Connection Error**: Unable to reach OpenAI API. Please check your internet connection.", 0
            
        except Exception as e:
            logger.error(f"Unexpected error during generation: {str(e)}")
            return f"❌ **Error**: {str(e)}", 0
    
    def query(
        self,
        query: str,
        n_results: int = 5,
        max_tokens: int = 500
    ) -> Dict[str, Any]:
        """
        Complete RAG pipeline: retrieve + generate.
        
        Args:
            query: User query
            n_results: Number of documents to retrieve
            max_tokens: Maximum tokens in response
            
        Returns:
            Dictionary with answer, contexts, and timing info
        """
        # Retrieve
        results, retrieval_time = self.retrieve(query, n_results)
        
        # Extract contexts
        contexts = [r["document"] for r in results]
        
        # Generate
        answer, generation_time = self.generate(query, contexts, max_tokens)
        
        total_time = retrieval_time + generation_time
        
        logger.info(f"Base-RAG query completed in {total_time:.3f}s (retrieval: {retrieval_time:.3f}s, generation: {generation_time:.3f}s)")
        
        return {
            "query": query,
            "answer": answer,
            "contexts": results,
            "retrieval_time": retrieval_time,
            "generation_time": generation_time,
            "total_time": total_time,
            "pipeline": "Base-RAG"
        }


class HierarchicalRAG:
    """Hierarchical RAG pipeline with metadata filtering."""
    
    def __init__(
        self,
        vector_store: VectorStore,
        llm_model: str = "gpt-3.5-turbo",
        api_key: Optional[str] = None
    ):
        """
        Initialize Hierarchical RAG pipeline.
        
        Args:
            vector_store: Vector store instance
            llm_model: OpenAI model name
            api_key: OpenAI API key
        """
        self.vector_store = vector_store
        self.llm_model = llm_model
        
        # Set OpenAI API key
        self.api_key = api_key or os.getenv("OPENAI_API_KEY")
        self.client = OpenAI(api_key=self.api_key)
    
    def infer_hierarchy_from_query(self, query: str) -> Dict[str, Optional[str]]:
        """
        Infer hierarchical filters from query using simple keyword matching.
        
        Args:
            query: User query
            
        Returns:
            Dictionary with level1, level2, level3, doc_type filters
        """
        query_lower = query.lower()
        
        # This is a simple heuristic - in production, use an LLM classifier
        filters = {
            "level1": None,
            "level2": None,
            "level3": None,
            "doc_type": None
        }
        
        # Simple keyword-based inference (can be enhanced with LLM)
        # Hospital domain keywords
        if any(kw in query_lower for kw in ["patient", "clinical", "medical", "treatment", "admission", "hospital", "nurse", "doctor"]):
            filters["level1"] = "Clinical Care"
        elif any(kw in query_lower for kw in ["policy", "compliance", "administrative", "staff"]):
            filters["level1"] = "Administrative"
        elif any(kw in query_lower for kw in ["infection", "safety", "quality", "incident", "error"]):
            filters["level1"] = "Quality & Safety"
        elif any(kw in query_lower for kw in ["training", "education", "course", "certification"]):
            filters["level1"] = "Education & Training"
        
        # Bank domain keywords
        elif any(kw in query_lower for kw in ["account", "loan", "banking", "retail", "customer", "deposit"]):
            filters["level1"] = "Retail Banking"
        elif any(kw in query_lower for kw in ["risk", "credit", "fraud", "default"]):
            filters["level1"] = "Risk Management"
        elif any(kw in query_lower for kw in ["compliance", "kyc", "aml", "regulatory", "legal"]):
            filters["level1"] = "Compliance & Legal"
        elif any(kw in query_lower for kw in ["corporate", "business", "commercial", "treasury"]):
            filters["level1"] = "Corporate Banking"
        
        # Fluid simulation keywords
        elif any(kw in query_lower for kw in ["turbulence", "flow", "simulation", "cfd", "solver", "algorithm"]):
            filters["level1"] = "Physical Models"
        elif any(kw in query_lower for kw in ["mesh", "grid", "discretization", "numerical", "finite"]):
            filters["level1"] = "Numerical Methods"
        elif any(kw in query_lower for kw in ["validation", "verification", "benchmark", "accuracy"]):
            filters["level1"] = "Validation & Verification"
        elif any(kw in query_lower for kw in ["software", "tool", "platform", "parallel", "computing"]):
            filters["level1"] = "Software & Tools"
        
        # Doc type inference
        if any(kw in query_lower for kw in ["policy", "policies"]):
            filters["doc_type"] = "policy"
        elif any(kw in query_lower for kw in ["manual", "guide", "handbook"]):
            filters["doc_type"] = "manual"
        elif any(kw in query_lower for kw in ["report", "analysis", "findings"]):
            filters["doc_type"] = "report"
        elif any(kw in query_lower for kw in ["protocol", "procedure", "standard"]):
            filters["doc_type"] = "protocol"
        elif any(kw in query_lower for kw in ["paper", "research", "study"]):
            filters["doc_type"] = "paper"
        
        logger.info(f"Inferred filters: {filters}")
        return filters
    
    def retrieve(
        self,
        query: str,
        n_results: int = 5,
        level1: Optional[str] = None,
        level2: Optional[str] = None,
        level3: Optional[str] = None,
        doc_type: Optional[str] = None,
        auto_infer: bool = True
    ) -> Tuple[List[Dict[str, Any]], float, Dict[str, Optional[str]]]:
        """
        Retrieve relevant documents with hierarchical filtering.
        
        Args:
            query: Search query
            n_results: Number of results to retrieve
            level1: Domain filter
            level2: Section filter
            level3: Topic filter
            doc_type: Document type filter
            auto_infer: Whether to auto-infer filters from query
            
        Returns:
            Tuple of (results, retrieval_time, applied_filters)
        """
        # Auto-infer filters if enabled and no explicit filters provided
        if auto_infer and not any([level1, level2, level3, doc_type]):
            inferred = self.infer_hierarchy_from_query(query)
            level1 = level1 or inferred["level1"]
            level2 = level2 or inferred["level2"]
            level3 = level3 or inferred["level3"]
            doc_type = doc_type or inferred["doc_type"]
        
        applied_filters = {
            "level1": level1,
            "level2": level2,
            "level3": level3,
            "doc_type": doc_type
        }
        
        start_time = time.time()
        results = self.vector_store.search_with_hierarchy(
            query=query,
            n_results=n_results,
            level1=level1,
            level2=level2,
            level3=level3,
            doc_type=doc_type
        )
        retrieval_time = time.time() - start_time
        
        logger.info(f"Retrieved {len(results)} documents with filters in {retrieval_time:.3f}s. Filters: {applied_filters}")
        
        return results, retrieval_time, applied_filters
    
    @retry(
        retry=retry_if_exception_type((openai.RateLimitError, openai.APITimeoutError)),
        stop=stop_after_attempt(3),
        wait=wait_exponential(multiplier=1, min=2, max=10),
        reraise=True
    )
    def generate(
        self,
        query: str,
        contexts: List[str],
        max_tokens: int = 500
    ) -> Tuple[str, float]:
        """
        Generate answer using LLM with retry logic.
        
        Args:
            query: User query
            contexts: Retrieved context documents
            max_tokens: Maximum tokens in response
            
        Returns:
            Tuple of (answer, generation_time)
        """
        # Build prompt
        context_text = "\n\n".join([f"Context {i+1}:\n{ctx}" for i, ctx in enumerate(contexts)])
        
        prompt = f"""Based on the following context documents, please answer the question.

{context_text}

Question: {query}

Answer:"""
        
        start_time = time.time()
        
        try:
            response = self.client.chat.completions.create(
                model=self.llm_model,
                messages=[
                    {"role": "system", "content": "You are a helpful assistant that answers questions based on provided context."},
                    {"role": "user", "content": prompt}
                ],
                max_tokens=max_tokens,
                temperature=0.3
            )
            
            answer = response.choices[0].message.content
            generation_time = time.time() - start_time
            
            logger.info(f"Generated answer in {generation_time:.3f}s")
            return answer, generation_time
            
        except openai.AuthenticationError as e:
            logger.error(f"Authentication failed: {str(e)}")
            return "❌ **Authentication Error**: Invalid OpenAI API key. Please check your credentials.", 0
            
        except openai.RateLimitError as e:
            logger.error(f"Rate limit exceeded: {str(e)}")
            return "⚠️ **Rate Limit Exceeded**: Too many requests. Please wait a moment and try again.", 0
            
        except openai.APITimeoutError as e:
            logger.error(f"API timeout: {str(e)}")
            return "⏱️ **Timeout Error**: Request took too long. Please try again.", 0
            
        except openai.APIConnectionError as e:
            logger.error(f"Connection error: {str(e)}")
            return "🌐 **Connection Error**: Unable to reach OpenAI API. Check your connection.", 0
            
        except Exception as e:
            logger.error(f"Unexpected error: {str(e)}")
            return f"❌ **Error**: {str(e)}", 0
    
    def query(
        self,
        query: str,
        n_results: int = 5,
        max_tokens: int = 500,
        level1: Optional[str] = None,
        level2: Optional[str] = None,
        level3: Optional[str] = None,
        doc_type: Optional[str] = None,
        auto_infer: bool = True
    ) -> Dict[str, Any]:
        """
        Complete Hierarchical RAG pipeline: filter + retrieve + generate.
        
        Args:
            query: User query
            n_results: Number of documents to retrieve
            max_tokens: Maximum tokens in response
            level1: Domain filter
            level2: Section filter
            level3: Topic filter
            doc_type: Document type filter
            auto_infer: Whether to auto-infer filters from query
            
        Returns:
            Dictionary with answer, contexts, filters, and timing info
        """
        # Retrieve with hierarchy
        results, retrieval_time, applied_filters = self.retrieve(
            query=query,
            n_results=n_results,
            level1=level1,
            level2=level2,
            level3=level3,
            doc_type=doc_type,
            auto_infer=auto_infer
        )
        
        # Extract contexts
        contexts = [r["document"] for r in results]
        
        # Generate
        answer, generation_time = self.generate(query, contexts, max_tokens)
        
        total_time = retrieval_time + generation_time
        
        logger.info(f"Hier-RAG query completed in {total_time:.3f}s (retrieval: {retrieval_time:.3f}s, generation: {generation_time:.3f}s)")
        
        return {
            "query": query,
            "answer": answer,
            "contexts": results,
            "applied_filters": applied_filters,
            "retrieval_time": retrieval_time,
            "generation_time": generation_time,
            "total_time": total_time,
            "pipeline": "Hier-RAG"
        }


class RAGComparator:
    """Compare Base-RAG and Hier-RAG side-by-side."""
    
    def __init__(
        self,
        vector_store: VectorStore,
        llm_model: str = "gpt-3.5-turbo",
        api_key: Optional[str] = None
    ):
        """
        Initialize RAG comparator.
        
        Args:
            vector_store: Vector store instance
            llm_model: OpenAI model name
            api_key: OpenAI API key
        """
        self.base_rag = BaseRAG(vector_store, llm_model, api_key)
        self.hier_rag = HierarchicalRAG(vector_store, llm_model, api_key)
    
    def compare(
        self,
        query: str,
        n_results: int = 5,
        max_tokens: int = 500,
        level1: Optional[str] = None,
        level2: Optional[str] = None,
        level3: Optional[str] = None,
        doc_type: Optional[str] = None,
        auto_infer: bool = True
    ) -> Dict[str, Any]:
        """
        Run both pipelines and compare results.
        
        Args:
            query: User query
            n_results: Number of documents to retrieve
            max_tokens: Maximum tokens in response
            level1: Domain filter (Hier-RAG only)
            level2: Section filter (Hier-RAG only)
            level3: Topic filter (Hier-RAG only)
            doc_type: Document type filter (Hier-RAG only)
            auto_infer: Whether to auto-infer filters (Hier-RAG only)
            
        Returns:
            Dictionary with results from both pipelines
        """
        logger.info(f"Comparing pipelines for query: {query}")
        
        # Run Base-RAG
        base_results = self.base_rag.query(query, n_results, max_tokens)
        
        # Run Hier-RAG
        hier_results = self.hier_rag.query(
            query=query,
            n_results=n_results,
            max_tokens=max_tokens,
            level1=level1,
            level2=level2,
            level3=level3,
            doc_type=doc_type,
            auto_infer=auto_infer
        )
        
        # Calculate speedup
        speedup = base_results["total_time"] / hier_results["total_time"] if hier_results["total_time"] > 0 else 0
        
        logger.info(f"Comparison complete. Speedup: {speedup:.2f}x")
        
        return {
            "query": query,
            "base_rag": base_results,
            "hier_rag": hier_results,
            "speedup": speedup
        }