"""
OCR Worker - обработка файлов в фоне через RabbitMQ + Redis Pub/Sub
"""
import asyncio
import json
import logging
from typing import Dict, Any
from aio_pika import connect_robust, IncomingMessage
from app.config import settings
from app.services.ocr_service import ocr_service
from app.services.redis_service import redis_service

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


class OCRWorker:
    """Worker для обработки OCR задач в фоне"""
    
    def __init__(self):
        self.connection = None
        self.channel = None
        self.queue_name = "erv_ocr_processing"
    
    async def connect(self):
        """Подключение к RabbitMQ"""
        self.connection = await connect_robust(settings.rabbitmq_url)
        self.channel = await self.connection.channel()
        await self.channel.set_qos(prefetch_count=1)  # По одной задаче
        
        self.queue = await self.channel.declare_queue(
            self.queue_name,
            durable=True
        )
        
        logger.info(f"✅ Worker connected to RabbitMQ: {self.queue_name}")
    
    async def publish_event(self, task_id: str, event: Dict[str, Any]):
        """
        Публикация события в Redis для real-time обновлений
        
        Args:
            task_id: ID задачи
            event: Данные события
        """
        channel = f"ocr_events:{task_id}"
        event_json = json.dumps(event, ensure_ascii=False)
        
        try:
            await redis_service.publish(channel, event_json)
            logger.info(f"📢 Event published to {channel}: {event['status']}")
        except Exception as e:
            logger.error(f"❌ Failed to publish event: {e}")
    
    async def process_task(self, message: IncomingMessage):
        """
        Обработка задачи OCR
        
        Args:
            message: Сообщение из RabbitMQ
        """
        async with message.process():
            try:
                # Парсим задачу
                task = json.loads(message.body.decode())
                task_id = task["task_id"]
                file_content = bytes.fromhex(task["file_content_hex"])
                filename = task["filename"]
                
                logger.info(f"🔄 Processing task {task_id}: {filename}")
                
                # Событие: начало обработки
                await self.publish_event(task_id, {
                    "status": "processing",
                    "message": "Начата обработка файла",
                    "filename": filename
                })
                
                # Шаг 1: OCR обработка
                await self.publish_event(task_id, {
                    "status": "ocr_started",
                    "message": "Запущено распознавание текста"
                })
                
                result = await ocr_service.process_document(file_content, filename)
                
                # Событие: OCR завершён
                await self.publish_event(task_id, {
                    "status": "ocr_completed",
                    "message": f"Распознано {len(result['ocr_text'])} символов",
                    "chars": len(result['ocr_text'])
                })
                
                # Шаг 2: AI анализ (если есть текст)
                if result['ocr_text']:
                    await self.publish_event(task_id, {
                        "status": "ai_started",
                        "message": "Запущен AI анализ документа"
                    })
                
                # Событие: всё готово
                await self.publish_event(task_id, {
                    "status": "completed",
                    "message": "Обработка завершена",
                    "result": {
                        "document_type": result["document_type"],
                        "is_valid": result["is_valid"],
                        "confidence": result["confidence"],
                        "extracted_data": result["extracted_data"],
                        "ocr_text_length": len(result["ocr_text"])
                    }
                })
                
                # Сохраняем результат в Redis (TTL 1 час)
                cache_key = f"ocr_result:{task_id}"
                await redis_service.set_json(cache_key, result, ttl=3600)
                
                logger.info(f"✅ Task {task_id} completed successfully")
                
            except Exception as e:
                logger.error(f"❌ Task processing error: {e}")
                
                # Событие: ошибка
                await self.publish_event(task_id, {
                    "status": "error",
                    "message": f"Ошибка обработки: {str(e)}"
                })
    
    async def start(self):
        """Запуск worker"""
        await self.connect()
        
        logger.info(f"🚀 OCR Worker started, waiting for tasks...")
        
        # Слушаем очередь
        await self.queue.consume(self.process_task)
        
        # Держим worker живым
        try:
            await asyncio.Future()
        except KeyboardInterrupt:
            logger.info("👋 Worker stopped")


async def main():
    """Точка входа"""
    worker = OCRWorker()
    await worker.start()


if __name__ == "__main__":
    asyncio.run(main())