"""
FastAPI main server for IITM LLM Quiz Solver.
"""
import os
import logging
import asyncio
from typing import Dict, Any, Optional
from fastapi import FastAPI, HTTPException, Request
from fastapi.responses import JSONResponse
from pydantic import BaseModel, Field, field_validator
import uvicorn

# Try to load .env file if python-dotenv is available
try:
    from dotenv import load_dotenv
    load_dotenv()
except ImportError:
    pass  # python-dotenv is optional

from app.solver import solve_quiz
from app.utils import validate_secret
from app.browser import cleanup_browser

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)

# Get secret from environment
EXPECTED_SECRET = os.getenv("QUIZ_SECRET", "default_secret_change_me")

# Lifespan context manager for startup and shutdown
from contextlib import asynccontextmanager

@asynccontextmanager
async def lifespan(app: FastAPI):
    """Lifespan context manager for startup and shutdown."""
    # Startup
    logger.info("Application starting up...")
    yield
    # Shutdown
    logger.info("Shutting down, cleaning up browser...")
    await cleanup_browser()

# Initialize FastAPI app with lifespan
app = FastAPI(
    title="IITM LLM Quiz Solver",
    description="API endpoint to automatically solve dynamic quiz tasks",
    version="1.0.0",
    lifespan=lifespan
)


class QuizRequest(BaseModel):
    """Request model for quiz solving."""
    email: str = Field(..., description="User email address")
    secret: str = Field(..., description="Secret key for authentication")
    url: str = Field(..., description="Quiz page URL")
    
    @field_validator('email')
    @classmethod
    def validate_email(cls, v):
        if not v or '@' not in v:
            raise ValueError('Invalid email format')
        return v
    
    @field_validator('url')
    @classmethod
    def validate_url(cls, v):
        if not v or not v.startswith(('http://', 'https://')):
            raise ValueError('Invalid URL format')
        return v


@app.get("/")
async def root():
    """Root endpoint."""
    return {
        "message": "IITM LLM Quiz Solver API",
        "version": "1.0.0",
        "endpoints": {
            "/solve": "POST - Solve a quiz",
            "/health": "GET - Health check",
            "/demo": "POST - Demo endpoint"
        }
    }


@app.get("/health")
async def health_check():
    """Health check endpoint."""
    return {"status": "healthy"}


@app.get("/env-check")
async def env_check():
    """
    Check environment variables status (returns JSON).
    Useful for verifying configuration.
    """
    quiz_secret = os.getenv("QUIZ_SECRET")
    openai_key = os.getenv("OPENAI_API_KEY")
    openrouter_key = os.getenv("OPENROUTER_API_KEY")
    port = os.getenv("PORT", "8000")
    
    return {
        "status": "ok",
        "variables": {
            "QUIZ_SECRET": {
                "set": quiz_secret is not None,
                "length": len(quiz_secret) if quiz_secret else 0,
                "preview": f"{quiz_secret[:4]}...{quiz_secret[-4:]}" if quiz_secret and len(quiz_secret) > 8 else "***" if quiz_secret else None
            },
            "OPENAI_API_KEY": {
                "set": openai_key is not None,
                "length": len(openai_key) if openai_key else 0,
                "preview": f"{openai_key[:7]}...{openai_key[-4:]}" if openai_key and len(openai_key) > 11 else "***" if openai_key else None,
                "valid_format": openai_key.startswith("sk-") if openai_key else False
            },
            "OPENROUTER_API_KEY": {
                "set": openrouter_key is not None,
                "length": len(openrouter_key) if openrouter_key else 0,
                "preview": f"{openrouter_key[:7]}...{openrouter_key[-4:]}" if openrouter_key and len(openrouter_key) > 11 else "***" if openrouter_key else None,
                "valid_format": openrouter_key.startswith("sk-or-") if openrouter_key else False
            },
            "PORT": {
                "set": True,
                "value": port
            }
        },
        "ready": quiz_secret is not None,
        "llm_enabled": any([openai_key, openrouter_key])
    }


@app.post("/solve")
async def solve_quiz_endpoint(request: QuizRequest):
    """
    Main endpoint to solve a quiz.
    
    Validates secret and solves the quiz recursively.
    """
    try:
        # Validate secret
        if not validate_secret(request.secret, EXPECTED_SECRET):
            logger.warning(f"Invalid secret provided for email: {request.email}")
            raise HTTPException(
                status_code=403,
                detail={"error": "forbidden"}
            )
        
        logger.info(f"Solving quiz for {request.email} at {request.url}")
        
        # Solve quiz with timeout
        try:
            result = await asyncio.wait_for(
                solve_quiz(request.url, request.email, request.secret),
                timeout=180.0  # 3 minutes
            )
            return result
        except asyncio.TimeoutError:
            logger.error("Quiz solving timed out")
            raise HTTPException(
                status_code=504,
                detail={"error": "Request timeout - quiz solving took too long"}
            )
        except Exception as e:
            logger.error(f"Error solving quiz: {e}", exc_info=True)
            raise HTTPException(
                status_code=500,
                detail={"error": str(e)}
            )
            
    except HTTPException:
        raise
    except ValueError as e:
        logger.error(f"Validation error: {e}")
        raise HTTPException(
            status_code=400,
            detail={"error": "Invalid request format", "message": str(e)}
        )
    except Exception as e:
        logger.error(f"Unexpected error: {e}", exc_info=True)
        raise HTTPException(
            status_code=500,
            detail={"error": "Internal server error", "message": str(e)}
        )


@app.post("/demo")
async def demo_endpoint(request: QuizRequest):
    """
    Demo endpoint for testing.
    
    Same as /solve but with more lenient error handling.
    """
    try:
        # Validate secret (can be more lenient for demo)
        if not validate_secret(request.secret, EXPECTED_SECRET):
            logger.warning(f"Invalid secret in demo request")
            return JSONResponse(
                status_code=403,
                content={"error": "forbidden"}
            )
        
        logger.info(f"Demo: Solving quiz for {request.email} at {request.url}")
        
        # Solve quiz
        try:
            result = await asyncio.wait_for(
                solve_quiz(request.url, request.email, request.secret),
                timeout=180.0
            )
            return result
        except asyncio.TimeoutError:
            return JSONResponse(
                status_code=504,
                content={"error": "Request timeout"}
            )
        except Exception as e:
            logger.error(f"Error in demo: {e}", exc_info=True)
            return JSONResponse(
                status_code=500,
                content={"error": str(e)}
            )
            
    except ValueError as e:
        return JSONResponse(
            status_code=400,
            content={"error": "Invalid request format", "message": str(e)}
        )
    except Exception as e:
        logger.error(f"Unexpected error in demo: {e}", exc_info=True)
        return JSONResponse(
            status_code=500,
            content={"error": "Internal server error", "message": str(e)}
        )


if __name__ == "__main__":
    port = int(os.getenv("PORT", 8000))
    uvicorn.run(
        "app.main:app",
        host="0.0.0.0",
        port=port,
        log_level="info"
    )