"""
FastAPI backend wrapper for HF Spaces
Provides REST API endpoints while keeping Streamlit UI
"""

# Load environment variables FIRST before any other imports
from dotenv import load_dotenv
load_dotenv()

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import Dict, List, Any, Optional
import pandas as pd
import sys
import os
import uvicorn
import asyncio
from threading import Thread
from concurrent.futures import ThreadPoolExecutor
import subprocess

# Add src to path for imports
current_dir = os.path.dirname(os.path.abspath(__file__))
src_path = os.path.join(current_dir, 'src')
if src_path not in sys.path:
    sys.path.insert(0, src_path)

from utils.data_processor import DataProcessor
from utils.task_manager import get_task_manager
from utils.rate_limit_middleware import RateLimitMiddleware
from utils.mongodb_service import get_mongodb_service
from utils.redis_service import get_redis_service
from utils.task_queue import get_task_queue
from utils.ip_location_service import get_ip_location_service
from utils.admin_endpoints import router as admin_router

app = FastAPI(title="ABSA ML Backend API", version="1.0.0")

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Add rate limiting middleware
app.add_middleware(RateLimitMiddleware, max_requests=100, window_seconds=60)

# Include admin router
app.include_router(admin_router)

# Initialize processor and task manager
processor = None
task_manager = get_task_manager()
executor = ThreadPoolExecutor(max_workers=int(os.getenv('MAX_WORKERS', '2')))

# Initialize services
mongodb_service = get_mongodb_service()
redis_service = get_redis_service()
ip_location_service = get_ip_location_service()

# Initialize task queue with processor (will be set later)
task_queue = None

def get_processor():
    """Get or initialize processor with task manager."""
    global processor, task_queue
    if processor is None:
        processor = DataProcessor()
        processor.set_task_manager(task_manager)
        # Initialize task queue with processor
        task_queue = get_task_queue(processor)
        task_queue.start_worker()
    return processor

def calculate_timeout(num_reviews: int) -> float:
    """
    Calculate dynamic timeout based on dataset size.
    
    Args:
        num_reviews: Number of reviews to process
        
    Returns:
        Timeout in seconds
    """
    base_timeout = 300.0  # 5 minutes
    per_review_time = 0.3  # 0.3 seconds per review
    calculated = base_timeout + (num_reviews * per_review_time)
    max_timeout = 900.0  # 15 minutes absolute max
    
    return min(calculated, max_timeout)

class ReviewData(BaseModel):
    id: int
    reviews_title: str
    review: str
    date: str
    user_id: str

class ProcessRequest(BaseModel):
    data: List[ReviewData]
    options: Optional[Dict[str, Any]] = {}
    user_id: Optional[str] = "default"

class ProcessResponse(BaseModel):
    status: str
    data: Optional[Dict[str, Any]] = None
    message: Optional[str] = None

@app.get("/")
async def root():
    return {"message": "ABSA ML Backend API", "status": "running"}

@app.post("/log-session")
async def log_session(request: dict):
    """
    Log session metadata with IP and location (gated by Redis).
    
    Expected payload:
    {
        "device_id": "string",
        "user_id": "string (optional)",
        "ip_address": "string",
        "user_agent": "string (optional)"
    }
    """
    device_id = request.get("device_id")
    user_id = request.get("user_id")
    ip_address = request.get("ip_address")
    user_agent = request.get("user_agent")
    
    if not device_id or not ip_address:
        raise HTTPException(status_code=400, detail="device_id and ip_address required")
    
    # Log session metadata (gated by Redis)
    logged = ip_location_service.log_session_metadata(
        device_id=device_id,
        ip_address=ip_address,
        user_id=user_id,
        user_agent=user_agent
    )
    
    return {
        "status": "success",
        "logged": logged,
        "message": "Session metadata logged" if logged else "Already logged within TTL window"
    }

@app.post("/log-event")
async def log_event(request: dict):
    """
    Log a telemetry event to MongoDB.
    
    Expected payload:
    {
        "event_type": "DASHBOARD_VIEW | ANALYSIS_REQUEST | etc.",
        "device_id": "string",
        "user_id": "string (optional)",
        "metadata": {} (optional)
    }
    """
    event_type = request.get("event_type")
    device_id = request.get("device_id")
    user_id = request.get("user_id")
    metadata = request.get("metadata")
    
    if not event_type or not device_id:
        raise HTTPException(status_code=400, detail="event_type and device_id required")
    
    success = mongodb_service.log_event(
        event_type=event_type,
        device_id=device_id,
        user_id=user_id,
        metadata=metadata
    )
    
    return {
        "status": "success" if success else "error",
        "logged": success
    }

@app.get("/health")
async def health_check():
    try:
        proc = get_processor()
        return {
            "status": "healthy",
            "translation_service": "available" if hasattr(proc.translator, 'model') else "unavailable",
            "absa_service": "available" if hasattr(proc.absa_processor, 'aspect_extractor') else "unavailable",
            "mongodb": "connected" if mongodb_service._client else "disconnected",
            "redis": "connected" if redis_service.is_connected() else "disconnected"
        }
    except Exception as e:
        return {"status": "error", "message": str(e)}

@app.post("/submit-job", response_model=Dict[str, Any])
async def submit_job(request: ProcessRequest):
    """
    Submit ABSA job to async queue.
    
    Returns job_id for status tracking.
    """
    try:
        # Get device_id and user_id from request headers or body
        device_id = request.options.get("device_id", "unknown")
        user_id = request.user_id
        
        # Convert request data to dict
        data_list = [item.model_dump() if hasattr(item, 'model_dump') else item.dict() for item in request.data]
        
        # Ensure task_queue is initialized
        get_processor()
        
        # Submit job to queue
        job_id = task_queue.submit_job(
            data={"csv_data": data_list, "options": request.options},
            device_id=device_id,
            user_id=user_id
        )
        
        return {
            "status": "queued",
            "job_id": job_id,
            "message": "Job submitted successfully. Use /job-status/{job_id} to check progress."
        }
        
    except Exception as e:
        import logging
        logger = logging.getLogger(__name__)
        logger.error(f"Failed to submit job: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))

@app.get("/job-status/{job_id}")
async def get_job_status(job_id: str):
    """Get status of queued job."""
    get_processor()  # Ensure task_queue is initialized
    
    status = task_queue.get_job_status(job_id)
    
    if status is None:
        raise HTTPException(status_code=404, detail="Job not found")
    
    response = {
        "job_id": job_id,
        "status": status
    }
    
    # If job is done, include result
    if status == "DONE":
        result = task_queue.get_job_result(job_id)
        if result:
            response["result"] = result
    
    return response

@app.post("/process-reviews", response_model=ProcessResponse)
async def process_reviews(request: ProcessRequest):
    """
    Process reviews with cancellation support and timeout.
    Rate limited to 10 requests per minute for AI processing.
    """
    # Specific rate limit for AI processing endpoint (10 per minute)
    user_id = request.user_id or "default"
    is_allowed, current_count = redis_service.check_rate_limit(
        identifier=user_id,
        max_requests=10,
        window_seconds=60
    )
    
    if not is_allowed:
        # Log rate limit hit
        mongodb_service.log_event(
            event_type="RATE_LIMIT_HIT",
            device_id="unknown",
            user_id=user_id,
            metadata={"endpoint": "/process-reviews", "limit": 10}
        )
        raise HTTPException(
            status_code=429,
            detail=f"Rate limit exceeded. Maximum 10 AI processing requests per minute. Current: {current_count}/10. Please wait."
        )
    
    # Create task for tracking
    task_id = task_manager.create_task(user_id=request.user_id)
    
    try:
        # Convert request data to DataFrame (using model_dump for Pydantic v2)
        data_list = [item.model_dump() if hasattr(item, 'model_dump') else item.dict() for item in request.data]
        df = pd.DataFrame(data_list)
        
        # Calculate dynamic timeout
        timeout = calculate_timeout(len(df))
        
        # Update task status
        task_manager.update_task(task_id, status='processing', message=f'Processing {len(df)} reviews')
        
        # Run processing in background thread with timeout
        proc = get_processor()
        loop = asyncio.get_event_loop()
        
        try:
            results = await asyncio.wait_for(
                loop.run_in_executor(
                    executor,
                    proc.process_uploaded_data,
                    df,
                    task_id
                ),
                timeout=timeout
            )
        except asyncio.TimeoutError:
            # Mark task as failed and cleanup
            task_manager.complete_task(task_id, success=False, message=f'Processing timeout ({timeout}s exceeded)')
            task_manager.cleanup_task(task_id)
            
            return ProcessResponse(
                status="timeout",
                message=f"Processing exceeded {timeout:.0f} second limit. Try with fewer reviews or wait and retry."
            )
        
        # Check if cancelled during processing
        if isinstance(results, dict) and results.get('status') == 'cancelled':
            task_manager.mark_cancelled(task_id)
            task_manager.cleanup_task(task_id)
            
            return ProcessResponse(
                status="cancelled",
                message=results.get('message', 'Task was cancelled by user')
            )
        
        # Check for errors
        if 'error' in results:
            task_manager.complete_task(task_id, success=False, message=str(results['error']))
            raise HTTPException(status_code=400, detail=results['error'])
        
        # Mark task as complete
        task_manager.complete_task(task_id, success=True, message='Processing completed successfully')
        
        # Serialize for API response
        serialized_results = serialize_for_api(results)
        serialized_results['task_id'] = task_id
        serialized_results['timeout_used'] = timeout
        
        return ProcessResponse(
            status="success",
            data=serialized_results
        )
    
    except HTTPException:
        raise
    except Exception as e:
        import traceback
        error_detail = {
            "error": str(e),
            "traceback": traceback.format_exc(),
            "task_id": task_id
        }
        
        task_manager.complete_task(task_id, success=False, message=str(e))
        task_manager.cleanup_task(task_id)
        
        # Log full error
        import logging
        logger = logging.getLogger(__name__)
        logger.error(f"Processing error for task {task_id}: {str(e)}")
        logger.error(f"Traceback: {traceback.format_exc()}")
        
        raise HTTPException(status_code=500, detail=error_detail)

@app.post("/cancel-task/{task_id}")
async def cancel_task(task_id: str):
    """Cancel a running task."""
    success = task_manager.cancel_task(task_id)
    
    if success:
        return {
            "status": "success",
            "message": f"Task {task_id} cancellation requested",
            "task_id": task_id
        }
    else:
        return {
            "status": "error",
            "message": "Task not found or already completed",
            "task_id": task_id
        }

@app.get("/task-status/{task_id}")
async def get_task_status(task_id: str):
    """Get status of a specific task."""
    status = task_manager.get_task_status(task_id)
    
    if status:
        return {
            "status": "success",
            "task": status
        }
    else:
        raise HTTPException(status_code=404, detail="Task not found")

@app.post("/cancel-user-tasks/{user_id}")
async def cancel_user_tasks(user_id: str):
    """Cancel all tasks for a specific user."""
    count = task_manager.cancel_user_tasks(user_id)
    
    return {
        "status": "success",
        "message": f"Cancelled {count} tasks for user {user_id}",
        "cancelled_count": count
    }

@app.get("/user-tasks/{user_id}")
async def get_user_tasks(user_id: str):
    """Get all tasks for a specific user."""
    tasks = task_manager.get_user_tasks(user_id)
    
    return {
        "status": "success",
        "user_id": user_id,
        "task_count": len(tasks),
        "tasks": tasks
    }

@app.get("/task-stats")
async def get_task_stats():
    """Get overall task statistics."""
    stats = task_manager.get_stats()
    
    return {
        "status": "success",
        "stats": stats
    }

@app.post("/cleanup-old-tasks")
async def cleanup_old_tasks(max_age_hours: int = 1):
    """Clean up old completed tasks."""
    max_age_seconds = max_age_hours * 3600
    task_manager.cleanup_old_tasks(max_age_seconds)
    
    return {
        "status": "success",
        "message": f"Cleaned up tasks older than {max_age_hours} hour(s)"
    }

def serialize_for_api(results: Dict) -> Dict:
    """Convert complex objects to JSON-serializable format."""
    serialized = {}
    
    for key, value in results.items():
        if key == 'processed_data':
            # Convert DataFrame to dict
            serialized[key] = value.to_dict('records') if hasattr(value, 'to_dict') else value
        elif key == 'aspect_network':
            # Convert NetworkX graph to dict
            import networkx as nx
            if hasattr(value, 'nodes'):
                serialized[key] = nx.node_link_data(value)
            else:
                serialized[key] = value
        elif hasattr(value, 'to_dict'):
            # Convert DataFrames
            serialized[key] = value.to_dict('records')
        elif isinstance(value, pd.DataFrame):
            serialized[key] = value.to_dict('records')
        else:
            # Keep as is for basic types
            serialized[key] = value
    
    return serialized

def run_streamlit():
    """Run Streamlit in a separate thread (optional - only if app file exists)"""
    import logging
    logger = logging.getLogger(__name__)
    
    # Check if streamlit app exists
    streamlit_files = ["frontend_light.py", "app_enhanced.py", "app.py"]
    streamlit_app = None
    
    for file in streamlit_files:
        if os.path.exists(file):
            streamlit_app = file
            break
    
    if streamlit_app:
        logger.info(f"Starting Streamlit UI with {streamlit_app}")
        subprocess.run([
            "streamlit", "run", streamlit_app, 
            "--server.port=8502", 
            "--server.address=0.0.0.0"
        ])
    else:
        logger.info("No Streamlit app found. Running FastAPI only (API-only mode)")

if __name__ == "__main__":
    import logging
    logging.basicConfig(level=logging.INFO)
    logger = logging.getLogger(__name__)
    
    # Try to start Streamlit in background (optional)
    streamlit_available = any(os.path.exists(f) for f in ["frontend_light.py", "app_enhanced.py", "app.py"])
    
    if streamlit_available:
        logger.info("🎨 Starting Streamlit UI in background...")
        streamlit_thread = Thread(target=run_streamlit, daemon=True)
        streamlit_thread.start()
    else:
        logger.info("📡 Running in API-only mode (no Streamlit UI)")
    
    # Start FastAPI
    logger.info("🚀 Starting FastAPI server on http://0.0.0.0:7860")
    uvicorn.run(app, host="0.0.0.0", port=7860)