"""
LLM Provider - Handles different LLM services for ChatCal Voice.

Implements the same fallback chain as the original ChatCal:
Groq (primary) -> Anthropic (fallback) -> Mock (development)
"""

import logging
from typing import Optional
from llama_index.core.llms import LLM
from llama_index.llms.groq import Groq
from llama_index.llms.anthropic import Anthropic

from .config import config

logger = logging.getLogger(__name__)


class MockLLM:
    """Mock LLM for development and testing."""
    
    async def achat(self, messages):
        """Mock async chat method."""
        last_message = messages[-1].content if messages else "Hello"
        
        # Simple rule-based responses for development
        if any(word in last_message.lower() for word in ["book", "schedule", "appointment"]):
            response = "I'd be happy to help you book an appointment! Please provide your name, preferred date and time."
        elif any(word in last_message.lower() for word in ["cancel", "delete"]):
            response = "I can help you cancel an appointment. Could you tell me which meeting you'd like to cancel?"
        elif any(word in last_message.lower() for word in ["available", "availability", "free"]):
            response = "Let me check Peter's availability for you. What dates are you considering?"
        else:
            response = "Hello! I'm ChatCal, your voice-enabled scheduling assistant. I can help you book appointments with Peter. What would you like to schedule?"
        
        class MockResponse:
            def __init__(self, content):
                self.message = self
                self.content = content
        
        return MockResponse(response)
    
    async def acomplete(self, prompt):
        """Mock async completion method."""
        class MockCompletion:
            def __init__(self, content):
                self.text = content
        
        # Mock JSON response for booking parsing
        if "Parse this booking request" in prompt:
            return MockCompletion('{"date_time": "2024-01-01 14:00", "duration": 30, "meeting_type": "google_meet", "topic": "Meeting", "needs_clarification": true, "clarification_message": "Could you please specify the exact date and time?"}')
        
        return MockCompletion("Mock response for development")


def get_llm() -> LLM:
    """
    Get the appropriate LLM based on available configuration.
    Implements fallback chain: Groq -> Anthropic -> Mock
    """
    
    # Try Groq first (primary)
    if config.groq_api_key:
        try:
            logger.info("🚀 Using Groq LLM (primary)")
            return Groq(
                model="llama-3.1-8b-instant",
                api_key=config.groq_api_key,
                temperature=0.1
            )
        except Exception as e:
            logger.warning(f"❌ Groq LLM failed to initialize: {e}")
    
    # Fallback to Anthropic
    if config.anthropic_api_key:
        try:
            logger.info("🧠 Using Anthropic Claude (fallback)")
            return Anthropic(
                model="claude-3-sonnet-20240229",
                api_key=config.anthropic_api_key,
                temperature=0.1
            )
        except Exception as e:
            logger.warning(f"❌ Anthropic LLM failed to initialize: {e}")
    
    # Final fallback to Mock LLM
    logger.warning("⚠️ Using Mock LLM (development/fallback)")
    return MockLLM()


class LLMService:
    """Service wrapper for LLM operations."""
    
    def __init__(self):
        self.llm = get_llm()
        self.is_mock = isinstance(self.llm, MockLLM)
    
    async def chat(self, messages, temperature: float = 0.1):
        """Send chat messages to LLM."""
        if self.is_mock:
            return await self.llm.achat(messages)
        
        # For real LLMs, set temperature if supported
        try:
            if hasattr(self.llm, 'temperature'):
                original_temp = self.llm.temperature
                self.llm.temperature = temperature
                result = await self.llm.achat(messages)
                self.llm.temperature = original_temp
                return result
            else:
                return await self.llm.achat(messages)
        except Exception as e:
            logger.error(f"LLM chat error: {e}")
            # Return a graceful error response
            class ErrorResponse:
                def __init__(self, content):
                    self.message = self
                    self.content = content
            
            return ErrorResponse("I apologize, but I'm having trouble processing your request right now. Please try again.")
    
    async def complete(self, prompt: str, temperature: float = 0.1):
        """Send completion prompt to LLM."""
        if self.is_mock:
            return await self.llm.acomplete(prompt)
        
        try:
            if hasattr(self.llm, 'temperature'):
                original_temp = self.llm.temperature
                self.llm.temperature = temperature
                result = await self.llm.acomplete(prompt)
                self.llm.temperature = original_temp
                return result
            else:
                return await self.llm.acomplete(prompt)
        except Exception as e:
            logger.error(f"LLM completion error: {e}")
            class ErrorCompletion:
                def __init__(self, content):
                    self.text = content
            
            return ErrorCompletion("Error processing request")


# Global LLM service instance
llm_service = LLMService()