"""
Lemontropia Suite - EasyOCR Backend
Text recognition using EasyOCR - lighter than PaddleOCR.
"""

import numpy as np
import logging
from typing import List, Optional

from . import BaseOCRBackend, OCRTextRegion

logger = logging.getLogger(__name__)


class EasyOCRBackend(BaseOCRBackend):
    """
    OCR backend using EasyOCR.
    
    Pros:
    - Lighter than PaddleOCR
    - Good accuracy
    - Supports many languages
    - Can run on CPU reasonably well
    
    Cons:
    - First run downloads models (~100MB)
    - Slower than OpenCV EAST
    
    Installation: pip install easyocr
    """
    
    NAME = "easyocr"
    SUPPORTS_GPU = True
    
    def __init__(self, use_gpu: bool = True, lang: str = 'en', **kwargs):
        super().__init__(use_gpu=use_gpu, lang=lang, **kwargs)
        
        self.reader = None
        self._gpu_available = False
        
        # Language mapping
        self.lang_map = {
            'en': 'en',
            'sv': 'sv',  # Swedish
            'de': 'de',
            'fr': 'fr',
            'es': 'es',
            'latin': 'latin',
        }
    
    def _initialize(self) -> bool:
        """Initialize EasyOCR reader."""
        try:
            import easyocr
            
            # Map language code
            easyocr_lang = self.lang_map.get(self.lang, 'en')
            
            # Check GPU availability
            self._gpu_available = self._check_gpu()
            use_gpu_flag = self.use_gpu and self._gpu_available
            
            logger.info(f"Initializing EasyOCR (lang={easyocr_lang}, gpu={use_gpu_flag})")
            
            # Create reader
            # EasyOCR downloads models automatically on first run
            self.reader = easyocr.Reader(
                [easyocr_lang],
                gpu=use_gpu_flag,
                verbose=False
            )
            
            self._available = True
            self._version = easyocr.__version__ if hasattr(easyocr, '__version__') else 'unknown'
            
            logger.info(f"EasyOCR initialized successfully (GPU: {use_gpu_flag})")
            return True
            
        except ImportError:
            self._error_msg = "EasyOCR not installed. Run: pip install easyocr"
            logger.warning(self._error_msg)
            return False
            
        except Exception as e:
            # Handle specific PyTorch/CUDA errors
            error_str = str(e).lower()
            
            if 'cuda' in error_str or 'c10' in error_str or 'gpu' in error_str:
                self._error_msg = f"EasyOCR GPU initialization failed: {e}"
                logger.warning(f"{self._error_msg}. Try with use_gpu=False")
                
                # Try CPU fallback
                if self.use_gpu:
                    logger.info("Attempting EasyOCR CPU fallback...")
                    self.use_gpu = False
                    return self._initialize()
                    
            else:
                self._error_msg = f"EasyOCR initialization failed: {e}"
                logger.error(self._error_msg)
            
            return False
    
    def _check_gpu(self) -> bool:
        """Check if GPU is available for EasyOCR."""
        try:
            import torch
            
            if torch.cuda.is_available():
                logger.info(f"CUDA available: {torch.cuda.get_device_name(0)}")
                return True
            
            # Check MPS (Apple Silicon)
            if hasattr(torch.backends, 'mps') and torch.backends.mps.is_available():
                logger.info("Apple MPS available")
                return True
                
            return False
            
        except ImportError:
            return False
        except Exception as e:
            logger.debug(f"GPU check failed: {e}")
            return False
    
    def extract_text(self, image: np.ndarray) -> List[OCRTextRegion]:
        """
        Extract text from image using EasyOCR.
        
        Args:
            image: Input image (BGR format from OpenCV)
            
        Returns:
            List of detected text regions with recognized text
        """
        if not self._available or self.reader is None:
            logger.error("EasyOCR backend not initialized")
            return []
        
        try:
            # EasyOCR expects RGB format
            if len(image.shape) == 3:
                import cv2
                image_rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
            else:
                image_rgb = image
            
            # Run OCR
            results = self.reader.readtext(image_rgb)
            
            regions = []
            for detection in results:
                # EasyOCR returns: (bbox, text, confidence)
                bbox, text, conf = detection
                
                # Calculate bounding box from polygon
                # bbox is list of 4 points: [[x1,y1], [x2,y2], [x3,y3], [x4,y4]]
                x_coords = [p[0] for p in bbox]
                y_coords = [p[1] for p in bbox]
                
                x = int(min(x_coords))
                y = int(min(y_coords))
                w = int(max(x_coords) - x)
                h = int(max(y_coords) - y)
                
                regions.append(OCRTextRegion(
                    text=text.strip(),
                    confidence=float(conf),
                    bbox=(x, y, w, h),
                    language=self.lang
                ))
            
            logger.debug(f"EasyOCR detected {len(regions)} text regions")
            return regions
            
        except Exception as e:
            logger.error(f"EasyOCR extraction failed: {e}")
            return []
    
    def get_info(self):
        """Get backend information."""
        info = super().get_info()
        info.gpu_accelerated = self._gpu_available and self.use_gpu
        return info