"""
Deterministic Validator for LLM Router Proposals

This module provides fast, deterministic validation of LLM routing proposals
focused on tool selection, task orchestration, and security policies.

Purpose:
- Validate tool availability and task selection
- Orchestrate multi-tool and multi-task workflows
- Enforce security policies and rate limits
- Provide clear rejection reasons for transparency

Architecture:
- ProposalValidator: Main validation orchestrator
- ToolValidator: Tool existence and task validation
- SecurityValidator: Security policy enforcement
- ValidationResult: Structured validation outcome

Design Principles:
- Fast deterministic checks (no LLM calls)
- Focus on routing and orchestration decisions
- Clear pass/fail decisions with explanations
- Fail-safe defaults (reject when in doubt)
- Delegate detailed parameter validation to tools

Future Extensions:
- TODO: Add service health checking before tool execution
- TODO: Add rate limiting per user/session
- TODO: Add emergency priority validation and bypass rules
- TODO: Add multi-tool dependency validation and sequencing
- TODO: Add RAG knowledge base integration for procedure validation
- TODO: Add bulletin alert context for enhanced routing logic
"""

import re
import logging
import yaml
from typing import Dict, Any, List, Optional, Tuple, Set
from dataclasses import dataclass
from datetime import datetime, timedelta
from enum import Enum

from .llm_client import ToolProposal


class ValidationResult(Enum):
    """Validation decision outcomes"""
    APPROVED = "approved"        # Execute the proposal
    REJECTED = "rejected"        # Reject with explanation
    CLARIFICATION = "clarification"  # Need more info from user


@dataclass
class ValidationOutcome:
    """
    Structured result of proposal validation
    
    This provides clear feedback on validation decisions
    with specific reasons and suggested actions.
    
    Attributes:
        result: Validation decision (approved/rejected/clarification)
        confidence: Confidence in validation decision (0.0-1.0)
        reason: Detailed explanation of decision
        suggested_action: What should happen next
        modified_params: Any parameter modifications made during validation
        warnings: Non-fatal issues detected
        execution_approved: Whether tool execution should proceed
    """
    result: ValidationResult
    confidence: float
    reason: str
    suggested_action: str
    modified_params: Optional[Dict[str, Any]] = None
    warnings: List[str] = None
    execution_approved: bool = False


class ProposalValidator:
    """
    Main validator for LLM router proposals
    
    This orchestrates validation focused on tool selection,
    task routing, and security policies.
    """
    
    def __init__(self):
        """Initialize validator with focused sub-validators"""
        self.tool_validator = ToolValidator()
        self.security_validator = SecurityValidator()
        
        # TODO: Add future validators for orchestration
        # self.service_health_validator = ServiceHealthValidator()
        # self.rate_limit_validator = RateLimitValidator()
        # self.emergency_priority_validator = EmergencyPriorityValidator()
        # self.workflow_orchestrator = WorkflowOrchestrator()
        
        logging.info("🛡️ ProposalValidator initialized (tool/task focus)")
    
    async def validate_proposal(
        self, 
        proposal: ToolProposal, 
        user_context: Optional[Dict[str, Any]] = None
    ) -> ValidationOutcome:
        """
        Validate LLM router proposal for tool selection and security
        
        This focuses on routing decisions and delegates detailed
        parameter validation to the individual tools.
        
        Args:
            proposal: LLM router proposal to validate
            user_context: Additional context (user_id, session, etc.)
            
        Returns:
            ValidationOutcome with routing decision and reasoning
        """
        start_time = datetime.now()
        logging.info(f"🔍 Validating routing for: {proposal.tool}/{proposal.task}")
        
        try:
            # 1. Tool and task selection validation
            tool_result = await self.tool_validator.validate(proposal)
            if tool_result.result != ValidationResult.APPROVED:
                return tool_result
            
            # 2. Security policy validation
            security_result = self.security_validator.validate(proposal, user_context)
            if security_result.result != ValidationResult.APPROVED:
                return security_result
            
            # TODO: Future orchestration checks
            # 3. Multi-tool workflow validation
            # workflow_result = self.workflow_orchestrator.validate(proposal, user_context)
            # if workflow_result.result != ValidationResult.APPROVED:
            #     return workflow_result
            
            # 4. Service health validation
            # health_result = await self.service_health_validator.validate(proposal)
            # if health_result.result != ValidationResult.APPROVED:
            #     return health_result
            
            # 5. Rate limiting validation  
            # rate_result = self.rate_limit_validator.validate(proposal, user_context)
            # if rate_result.result != ValidationResult.APPROVED:
            #     return rate_result
            
            # All validations passed
            validation_time = (datetime.now() - start_time).total_seconds()
            logging.info(f"✅ Routing validated successfully ({validation_time:.3f}s)")
            
            return ValidationOutcome(
                result=ValidationResult.APPROVED,
                confidence=1.0,
                reason="Tool selection and security validation passed",
                suggested_action="Execute tool with provided parameters (detailed validation delegated to tool)",
                execution_approved=True,
                warnings=self._collect_warnings([tool_result, security_result])
            )
            
        except Exception as e:
            logging.error(f"❌ Validation error: {e}")
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason=f"Validation system error: {str(e)}",
                suggested_action="Request user to try again later",
                execution_approved=False
            )
    
    def _collect_warnings(self, validation_results: List[ValidationOutcome]) -> List[str]:
        """Collect warnings from all validation results"""
        warnings = []
        for result in validation_results:
            if result.warnings:
                warnings.extend(result.warnings)
        return warnings


class ToolValidator:
    """
    Validates tool selection and task routing decisions
    
    This ensures requested tools and tasks exist and are properly
    configured, focusing on routing decisions rather than detailed
    parameter validation.
    """
    
    def __init__(self):
        """Initialize with available tools from configuration"""
        self._load_tool_registry()
    
    def _load_tool_registry(self):
        """Load tool specifications from configuration"""
        try:
            import os
            
            # Load tool registry configuration
            config_path = os.path.join(os.path.dirname(__file__), 'config', 'tool_registry.yaml')
            with open(config_path, 'r') as f:
                config = yaml.safe_load(f)
            
            # Build available_tools from registry configuration
            self.available_tools = {}
            if "tools" in config:
                for tool_name, tool_config in config["tools"].items():
                    # Extract tasks and their configurations
                    tasks = tool_config.get("tasks", {})
                    
                    self.available_tools[tool_name] = {
                        "name": tool_config.get("name", tool_name),
                        "display_name": tool_config.get("display_name", tool_name),
                        "description": tool_config.get("description", ""),
                        "enabled": tool_config.get("enabled", True),
                        "priority": tool_config.get("priority", 0.5),
                        "capabilities": tool_config.get("capabilities", []),
                        "geographic_scope": tool_config.get("geographic_scope", "liguria"),
                        "data_types": tool_config.get("data_types", []),
                        "tasks": list(tasks.keys()),
                        "task_configs": tasks
                    }
            
            logging.info(f"🔧 ToolValidator loaded registry: {list(self.available_tools.keys())}")
            
        except Exception as e:
            # Fallback to basic configuration
            logging.warning(f"⚠️ Could not load tool registry, using fallback: {e}")
            self.available_tools = {
                "omirl_tool": {
                    "name": "omirl_tool",
                    "display_name": "OMIRL Weather Monitoring",
                    "description": "Real-time weather monitoring for Liguria region",
                    "enabled": True,
                    "priority": 0.8,
                    "capabilities": ["real_time_weather_data", "station_monitoring"],
                    "geographic_scope": "liguria",
                    "data_types": ["real_time", "observational"],
                    "tasks": ["valori_stazioni", "massimi_precipitazione"],
                    "task_configs": {
                        "valori_stazioni": {"enabled": True},
                        "massimi_precipitazione": {"enabled": True}
                    }
                }
            }
    
    async def validate(self, proposal: ToolProposal) -> ValidationOutcome:
        """
        Validate tool selection and task routing
        
        Args:
            proposal: Tool proposal to validate
            
        Returns:
            ValidationOutcome for routing validation
        """
        # Check tool exists and is enabled
        if proposal.tool not in self.available_tools:
            available_tools = list(self.available_tools.keys())
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason=f"Tool '{proposal.tool}' not available",
                suggested_action=f"Available tools: {', '.join(available_tools)}"
            )
        
        tool_spec = self.available_tools[proposal.tool]
        
        # Check if tool is enabled
        if not tool_spec.get("enabled", True):
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason=f"Tool '{proposal.tool}' is currently disabled",
                suggested_action="Contact administrator or try alternative tools"
            )
        
        # Check task exists within tool
        if proposal.task not in tool_spec["tasks"]:
            available_tasks = ", ".join(tool_spec["tasks"])
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason=f"Task '{proposal.task}' not available for {proposal.tool}",
                suggested_action=f"Available tasks for {tool_spec['display_name']}: {available_tasks}"
            )
        
        # Check if specific task is enabled
        task_config = tool_spec["task_configs"].get(proposal.task, {})
        if not task_config.get("enabled", True):
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason=f"Task '{proposal.task}' is currently disabled for {proposal.tool}",
                suggested_action=f"Try other available tasks: {', '.join([t for t in tool_spec['tasks'] if tool_spec['task_configs'].get(t, {}).get('enabled', True)])}"
            )
        
        # Basic parameter structure validation
        if not isinstance(proposal.params, dict):
            return ValidationOutcome(
                result=ValidationResult.REJECTED,
                confidence=1.0,
                reason="Parameters must be provided as a dictionary",
                suggested_action="Provide parameters in correct format"
            )
        
        # Log routing decision for debugging
        logging.info(f"🎯 Routing approved: {proposal.tool}/{proposal.task} (priority: {tool_spec.get('priority', 'unknown')})")
        
        # TODO: Add multi-tool orchestration logic here
        # TODO: Add task sequencing validation
        # TODO: Add capability matching validation
        
        return ValidationOutcome(
            result=ValidationResult.APPROVED,
            confidence=1.0,
            reason=f"Tool routing validated: {tool_spec['display_name']} -> {proposal.task}",
            suggested_action="Proceed with tool execution (parameter validation delegated to tool)",
            execution_approved=True
        )


class SecurityValidator:
    """
    Validates security policies and access controls
    
    This enforces security policies to prevent abuse
    and ensure compliance with operational guidelines.
    """
    
    # TODO: Load from configuration
    BLOCKED_PATTERNS = [
        # Potential injection attempts
        r"<script.*?>",
        r"javascript:",
        r"eval\s*\(",
        
        # File system attempts
        r"\.\./",
        r"/etc/",
        r"C:\\",
        
        # Command injection attempts
        r";\s*(rm|del|format)",
        r"\|\s*(curl|wget)"
    ]
    
    def validate(
        self, 
        proposal: ToolProposal, 
        user_context: Optional[Dict[str, Any]] = None
    ) -> ValidationOutcome:
        """
        Validate security policies
        
        Args:
            proposal: Tool proposal to validate
            user_context: User session information
            
        Returns:
            ValidationOutcome for security validation
        """
        # Check for malicious patterns in parameters
        for param_name, param_value in proposal.params.items():
            if isinstance(param_value, str):
                for pattern in self.BLOCKED_PATTERNS:
                    if re.search(pattern, param_value, re.IGNORECASE):
                        logging.warning(f"🚨 Blocked malicious pattern in {param_name}: {pattern}")
                        return ValidationOutcome(
                            result=ValidationResult.REJECTED,
                            confidence=1.0,
                            reason=f"Security policy violation in parameter '{param_name}'",
                            suggested_action="Block request and log security event"
                        )
        
        # TODO: Add user authentication validation
        # TODO: Add session validation
        # TODO: Add rate limiting checks
        # TODO: Add emergency bypass validation
        
        return ValidationOutcome(
            result=ValidationResult.APPROVED,
            confidence=1.0,
            reason="Security validation passed",
            suggested_action="Proceed with security clearance"
        )


# TODO: Future orchestration capabilities
class WorkflowOrchestrator:
    """
    Orchestrates multi-tool and multi-task workflows
    
    This will handle complex scenarios requiring multiple tools
    or sequential task execution.
    """
    pass


# TODO: Future service health validator
class ServiceHealthValidator:
    """
    Validates service availability before tool execution
    
    This checks if external services (OMIRL, bulletins, etc.)
    are available before attempting tool execution.
    """
    pass


# TODO: Future rate limiting validator  
class RateLimitValidator:
    """
    Validates rate limits and usage quotas
    
    This prevents abuse by enforcing per-user and per-session
    rate limits on tool execution.
    """
    pass


# TODO: Future emergency priority validator
class EmergencyPriorityValidator:
    """
    Validates emergency scenarios and priority handling
    
    This provides bypass mechanisms for emergency situations
    and ensures critical requests are prioritized.
    """
    pass