How to build an advanced proxy search generation (RAG) system using dynamic strategies and intelligent search?

import numpy as np
import faiss
from sentence_transformers import SentenceTransformer
import json
import re
from typing import List, Dict, Any, Optional
from dataclasses import dataclass
from enum import Enum


class MockLLM:
   def generate(self, prompt: str, max_tokens: int = 150) -> str:
       prompt_lower = prompt.lower()
      
       if "decide whether to retrieve" in prompt_lower:
           if any(word in prompt_lower for word in ["specific", "recent", "data", "facts", "when", "who", "what"]):
               return "RETRIEVE: The query requires specific factual information that needs to be retrieved."
           else:
               return "NO_RETRIEVE: This is a general question that can be answered with existing knowledge."
      
       elif "choose retrieval strategy" in prompt_lower:
           if "comparison" in prompt_lower or "versus" in prompt_lower:
               return "STRATEGY: multi_query - Need to retrieve information about multiple entities for comparison."
           elif "recent" in prompt_lower or "latest" in prompt_lower:
               return "STRATEGY: temporal - Focus on recent information."
           else:
               return "STRATEGY: semantic - Standard semantic similarity search."
      
       elif "synthesize" in prompt_lower and "context:" in prompt_lower:
           return "Based on the retrieved information, here's a comprehensive answer that combines multiple sources and provides specific details with proper context."
      
       return "This is a mock response. In practice, use a real LLM like OpenAI's GPT or similar."


class RetrievalStrategy(Enum):
   SEMANTIC = "semantic"
   MULTI_QUERY = "multi_query"
   TEMPORAL = "temporal"
   HYBRID = "hybrid"


@dataclass
class Document:
   id: str
   content: str
   metadata: Dict[str, Any]
   embedding: Optional[np.ndarray] = None

class AgenticRAGSystem:
   def __init__(self, model_name: str = "all-MiniLM-L6-v2"):
       self.encoder = SentenceTransformer(model_name)
       self.llm = MockLLM()
       self.documents: List[Document] = []
       self.index: Optional[faiss.Index] = None
      
   def add_documents(self, documents: List[Dict[str, Any]]) -> None:
       print(f"Processing {len(documents)} documents...")
      
       for i, doc in enumerate(documents):
           doc_obj = Document(
               id=doc.get('id', str(i)),
               content=doc['content'],
               metadata=doc.get('metadata', {})
           )
           self.documents.append(doc_obj)
      
       contents = [doc.content for doc in self.documents]
       embeddings = self.encoder.encode(contents, show_progress_bar=True)
      
       for doc, embedding in zip(self.documents, embeddings):
           doc.embedding = embedding
      
       dimension = embeddings.shape[1]
       self.index = faiss.IndexFlatIP(dimension)
      
       faiss.normalize_L2(embeddings)
       self.index.add(embeddings.astype('float32'))
      
       print(f"Knowledge base built with {len(self.documents)} documents")

 def decide_retrieval(self, query: str) -> bool:
       decision_prompt = f"""
       Analyze the following query and decide whether to retrieve information:
       Query: "{query}"
      
       Decide whether to retrieve information from the knowledge base.
       Consider if this needs specific facts, recent data, or can be answered generally.
      
       Respond with either:
       RETRIEVE: [reason] or NO_RETRIEVE: [reason]
       """
      
       response = self.llm.generate(decision_prompt)
       should_retrieve = response.startswith("RETRIEVE:")
      
       print(f"🤖 Agent Decision: {'Retrieve' if should_retrieve else 'Direct Answer'}")
       print(f"   Reasoning: {response.split(':', 1)[1].strip() if ':' in response else response}")
      
       return should_retrieve
  
   def choose_strategy(self, query: str) -> RetrievalStrategy:
       strategy_prompt = f"""
       Choose the best retrieval strategy for this query:
       Query: "{query}"
      
       Available strategies:
       - semantic: Standard similarity search
       - multi_query: Multiple related queries (for comparisons)
       - temporal: Focus on recent information
       - hybrid: Combination approach
      
       Choose retrieval strategy and explain why.
       Respond with: STRATEGY: [strategy_name] - [reasoning]
       """
      
       response = self.llm.generate(strategy_prompt)
      
       if "multi_query" in response.lower():
           strategy = RetrievalStrategy.MULTI_QUERY
       elif "temporal" in response.lower():
           strategy = RetrievalStrategy.TEMPORAL
       elif "hybrid" in response.lower():
           strategy = RetrievalStrategy.HYBRID
       else:
           strategy = RetrievalStrategy.SEMANTIC
      
       print(f"🎯 Retrieval Strategy: {strategy.value}")
       print(f"   Reasoning: {response.split('-', 1)[1].strip() if '-' in response else response}")
      
       return strategy

  def retrieve_documents(self, query: str, strategy: RetrievalStrategy, k: int = 3) -> List[Document]:
       if not self.index:
           print("❌ No knowledge base available")
           return []
      
       if strategy == RetrievalStrategy.MULTI_QUERY:
           queries = [query, f"advantages of {query}", f"disadvantages of {query}"]
           all_docs = []
           for q in queries:
               docs = self._semantic_search(q, k=2)
               all_docs.extend(docs)
           seen_ids = set()
           unique_docs = []
           for doc in all_docs:
               if doc.id not in seen_ids:
                   unique_docs.append(doc)
                   seen_ids.add(doc.id)
           return unique_docs[:k]
      
       elif strategy == RetrievalStrategy.TEMPORAL:
           docs = self._semantic_search(query, k=k*2)
           docs_with_dates = [(doc, doc.metadata.get('date', '1900-01-01')) for doc in docs]
           docs_with_dates.sort(key=lambda x: x[1], reverse=True)
           return [doc for doc, _ in docs_with_dates[:k]]
      
       else:
           return self._semantic_search(query, k=k)
  
   def _semantic_search(self, query: str, k: int) -> List[Document]:
       query_embedding = self.encoder.encode([query])
       faiss.normalize_L2(query_embedding)
      
       scores, indices = self.index.search(query_embedding.astype('float32'), k)
      
       results = []
       for score, idx in zip(scores[0], indices[0]):
           if idx  str:
       if not retrieved_docs:
           return self.llm.generate(f"Answer this query: {query}")
      
       context = "nn".join([f"Document {i+1}: {doc.content}"
                             for i, doc in enumerate(retrieved_docs)])
      
       synthesis_prompt = f"""
       Query: {query}
      
       Context: {context}
      
       Synthesize a comprehensive answer using the provided context.
       Be specific and reference the information sources when relevant.
       """
      
       return self.llm.generate(synthesis_prompt, max_tokens=200)

   def query(self, query: str) -> str:
       print(f"n🔍 Processing Query: '{query}'")
       print("=" * 50)
      
       if not self.decide_retrieval(query):
           print("n📝 Generating direct response...")
           return self.llm.generate(f"Answer this query: {query}")
      
       strategy = self.choose_strategy(query)
      
       print(f"n📚 Retrieving documents using {strategy.value} strategy...")
       retrieved_docs = self.retrieve_documents(query, strategy)
       print(f"   Retrieved {len(retrieved_docs)} documents")
      
       print("n🧠 Synthesizing response...")
       response = self.synthesize_response(query, retrieved_docs)
      
       if retrieved_docs:
           print("n📄 Retrieved Context:")
           for i, doc in enumerate(retrieved_docs[:2], 1):
               print(f"   {i}. {doc.content[:100]}...")
      
       return response

def create_sample_knowledge_base():
   return [
       {
           "id": "ai_1",
           "content": "Artificial Intelligence (AI) refers to computer systems that can perform tasks requiring human intelligence",
           "metadata": {"topic": "AI basics", "date": "2024-01-15"}
       },
       {
           "id": "ml_1",
           "content": "ML is a subset of AI.",
           "metadata": {"topic": "Machine Learning", "date": "2024-02-10"}
       },
       {
           "id": "rag_1",
           "content": "Retrieval-Augmented Generation (RAG) combines the power of large language models with external knowledge retrieval to provide more accurate and up-to-date responses.",
           "metadata": {"topic": "RAG", "date": "2024-03-05"}
       },
       {
           "id": "agents_1",
           "content": "AI agents",
           "metadata": {"topic": "AI Agents", "date": "2024-03-20"}
       }
   ]


if __name__ == "__main__":
   print("🚀 Initializing Agentic RAG System...")
  
   rag_system = AgenticRAGSystem()
  
   docs = create_sample_knowledge_base()
   rag_system.add_documents(docs)
  
   demo_queries = [
       "What is artificial intelligence?",
       "How are you today?",
       "Compare AI and Machine Learning",
   ]
  
   for query in demo_queries:
       response = rag_system.query(query)
       print(f"n💬 Final Response: {response}")
       print("n" + "="*80)
  
   print("n✅ Agentic RAG Tutorial Complete!")
   print("nKey Features Demonstrated:")
   print("• Agent-driven retrieval decisions")
   print("• Dynamic strategy selection")
   print("• Multi-modal retrieval approaches")
   print("• Transparent reasoning process")