"""
DAARION Platform - Intent Router
Routes messages to appropriate agents based on content analysis
"""
import re
import yaml
from typing import Optional, Dict, List, Tuple
from pathlib import Path
import structlog

logger = structlog.get_logger()


class IntentRouter:
    """Routes messages to agents based on intent detection"""
    
    def __init__(self, registry_path: str = "agents_registry.yaml"):
        self.registry_path = Path(registry_path)
        self.registry = self._load_registry()
        self.hard_routes = self._compile_hard_routes()
        self.intent_keywords = self._build_keyword_index()
        logger.info("intent_router_initialized", 
                    agents=len(self.registry.get("agents", {})),
                    hard_routes=len(self.hard_routes))
    
    def _load_registry(self) -> Dict:
        """Load agent registry from YAML"""
        if not self.registry_path.exists():
            logger.warning("registry_not_found", path=str(self.registry_path))
            return {"agents": {}, "routing": {}}
        
        with open(self.registry_path) as f:
            return yaml.safe_load(f)
    
    def _compile_hard_routes(self) -> List[Tuple[re.Pattern, str]]:
        """Compile regex patterns for hard routes"""
        routes = []
        for route in self.registry.get("routing", {}).get("hard_routes", []):
            pattern = re.compile(route["pattern"], re.IGNORECASE)
            routes.append((pattern, route["agent"]))
        return routes
    
    def _build_keyword_index(self) -> Dict[str, List[Tuple[str, float]]]:
        """Build keyword → agent mapping with confidence"""
        index = {}
        for route in self.registry.get("routing", {}).get("intent_routes", []):
            agent = route["agent"]
            threshold = route.get("confidence_threshold", 0.5)
            for keyword in route["keywords"]:
                kw = keyword.lower()
                if kw not in index:
                    index[kw] = []
                index[kw].append((agent, threshold))
        return index
    
    def route(self, message: str, source_agent: Optional[str] = None) -> Tuple[str, float, str]:
        """
        Route message to appropriate agent.
        
        Returns:
            (agent_id, confidence, reason)
        """
        message_lower = message.lower().strip()
        
        # 1. Check hard routes first (commands)
        for pattern, agent in self.hard_routes:
            if pattern.match(message):
                logger.info("hard_route_matched", agent=agent, pattern=pattern.pattern)
                return (agent, 1.0, "hard_route")
        
        # 2. Intent-based routing (keyword matching)
        agent_scores = {}
        matched_keywords = {}
        
        for keyword, agents in self.intent_keywords.items():
            if keyword in message_lower:
                for agent, threshold in agents:
                    if agent not in agent_scores:
                        agent_scores[agent] = 0.0
                        matched_keywords[agent] = []
                    agent_scores[agent] += threshold
                    matched_keywords[agent].append(keyword)
        
        if agent_scores:
            # Normalize scores
            max_score = max(agent_scores.values())
            for agent in agent_scores:
                agent_scores[agent] /= max(1, len(matched_keywords[agent]))
            
            # Select best agent
            best_agent = max(agent_scores, key=agent_scores.get)
            confidence = min(agent_scores[best_agent], 1.0)
            
            # Check if active
            if self.is_agent_active(best_agent):
                logger.info("intent_route_matched", 
                           agent=best_agent, 
                           confidence=confidence,
                           keywords=matched_keywords[best_agent])
                return (best_agent, confidence, f"keywords: {matched_keywords[best_agent][:3]}")
        
        # 3. Fallback
        fallback = self.registry.get("routing", {}).get("fallback", {})
        fallback_agent = fallback.get("agent", "helion")
        logger.info("fallback_route", agent=fallback_agent)
        return (fallback_agent, 0.3, "fallback")
    
    def is_agent_active(self, agent_id: str) -> bool:
        """Check if agent is active"""
        agent = self.registry.get("agents", {}).get(agent_id)
        return agent and agent.get("active", False)
    
    def get_agent_config(self, agent_id: str) -> Optional[Dict]:
        """Get full agent configuration"""
        return self.registry.get("agents", {}).get(agent_id)
    
    def get_memory_policy(self, agent_id: str) -> Dict:
        """Get agent memory access policy"""
        agent = self.get_agent_config(agent_id)
        if not agent:
            return {}
        return agent.get("memory_policy", {})
    
    def get_data_policy(self, agent_id: str) -> Dict:
        """Get agent data sharing policy"""
        agent = self.get_agent_config(agent_id)
        if not agent:
            return {}
        return agent.get("data_policy", {})
    
    def can_handoff(self, source_agent: str, target_agent: str) -> bool:
        """Check if handoff is allowed between agents"""
        policy = self.get_data_policy(source_agent)
        allowed = policy.get("handoff_allow", [])
        return target_agent in allowed
    
    def get_rate_limit(self, agent_id: str) -> int:
        """Get rate limit (requests per minute) for agent"""
        agent = self.get_agent_config(agent_id)
        if not agent:
            return 30  # default
        return agent.get("sla", {}).get("rate_limit_rpm", 30)
    
    def list_active_agents(self) -> List[str]:
        """List all active agents"""
        return [
            agent_id 
            for agent_id, config in self.registry.get("agents", {}).items()
            if config.get("active", False)
        ]


# Singleton instance
_router_instance = None

def get_intent_router() -> IntentRouter:
    """Get or create intent router instance"""
    global _router_instance
    if _router_instance is None:
        _router_instance = IntentRouter()
    return _router_instance