"""
Utility functions for Pixagram AI Pixel Art Generator
"""
import numpy as np
import cv2
import math
from PIL import Image, ImageEnhance, ImageFilter, ImageDraw
from config import COLOR_MATCH_CONFIG, FACE_MASK_CONFIG, AGE_BRACKETS


def sanitize_text(text):
    """
    Remove or replace problematic characters (emojis, special unicode) 
    that might cause encoding errors.
    """
    if not text:
        return text
    try:
        # Encode/decode to remove invalid bytes
        text = text.encode('utf-8', errors='ignore').decode('utf-8')
        # Keep only characters within safe unicode range
        text = ''.join(char for char in text if ord(char) < 65536)
    except Exception as e:
        print(f"[WARNING] Text sanitization warning: {e}")
    return text


def color_match_lab(target, source, preserve_saturation=True):
    """
    LAB color space matching for better skin tones with saturation preservation.
    GENTLE version to prevent color fading.
    
    Args:
        target: Target image to adjust
        source: Source image to match colors from
        preserve_saturation: If True, preserves original saturation levels
    """
    try:
        target_lab = cv2.cvtColor(target.astype(np.uint8), cv2.COLOR_RGB2LAB).astype(np.float32)
        source_lab = cv2.cvtColor(source.astype(np.uint8), cv2.COLOR_RGB2LAB).astype(np.float32)
        
        result_lab = np.copy(target_lab)
        
        # Very gentle L channel matching
        t_mean, t_std = target_lab[:,:,0].mean(), target_lab[:,:,0].std()
        s_mean, s_std = source_lab[:,:,0].mean(), source_lab[:,:,0].std()
        if t_std > 1e-6:
            matched = (target_lab[:,:,0] - t_mean) * (s_std / t_std) * 0.5 + s_mean
            result_lab[:,:,0] = target_lab[:,:,0] * (1 - COLOR_MATCH_CONFIG['lab_lightness_blend']) + matched * COLOR_MATCH_CONFIG['lab_lightness_blend']
        
        if preserve_saturation:
            # Minimal adjustment to A and B channels
            for i in [1, 2]:
                t_mean, t_std = target_lab[:,:,i].mean(), target_lab[:,:,i].std()
                s_mean, s_std = source_lab[:,:,i].mean(), source_lab[:,:,i].std()
                if t_std > 1e-6:
                    matched = (target_lab[:,:,i] - t_mean) * (s_std / t_std) + s_mean
                    blend_factor = COLOR_MATCH_CONFIG['lab_color_blend_preserved']
                    result_lab[:,:,i] = target_lab[:,:,i] * (1 - blend_factor) + matched * blend_factor
        else:
            # Gentle full matching
            for i in [1, 2]:
                t_mean, t_std = target_lab[:,:,i].mean(), target_lab[:,:,i].std()
                s_mean, s_std = source_lab[:,:,i].mean(), source_lab[:,:,i].std()
                if t_std > 1e-6:
                    matched = (target_lab[:,:,i] - t_mean) * (s_std / t_std) + s_mean
                    blend_factor = COLOR_MATCH_CONFIG['lab_color_blend_full']
                    result_lab[:,:,i] = target_lab[:,:,i] * (1 - blend_factor) + matched * blend_factor
        
        return cv2.cvtColor(result_lab.astype(np.uint8), cv2.COLOR_LAB2RGB)
    except Exception as e:
        print(f"LAB conversion error: {e}")
        return target.astype(np.uint8)


def enhance_saturation(image, boost=1.05):
    """
    Minimal saturation enhancement (disabled by default).
    
    Args:
        image: PIL Image
        boost: Saturation multiplier (1.0 = no change, >1.0 = more saturated)
    """
    if boost <= 1.0:
        return image
    enhancer = ImageEnhance.Color(image)
    return enhancer.enhance(boost)


def enhanced_color_match(target_img, source_img, face_bbox=None, preserve_vibrance=False):
    """
    Enhanced color matching with face-aware processing.
    Very gentle to prevent color fading.
    
    Args:
        target_img: Generated image to adjust
        source_img: Original image to match colors from
        face_bbox: Optional [x1, y1, x2, y2] for face region
        preserve_vibrance: If True, adds minimal saturation boost (disabled by default)
    """
    try:
        target = np.array(target_img).astype(np.float32)
        source = np.array(source_img).astype(np.float32)
        
        if face_bbox is not None:
            # Create face mask
            x1, y1, x2, y2 = [int(c) for c in face_bbox]
            x1, y1 = max(0, x1), max(0, y1)
            x2, y2 = min(target.shape[1], x2), min(target.shape[0], y2)
            
            face_mask = np.zeros((target.shape[0], target.shape[1]), dtype=np.float32)
            face_mask[y1:y2, x1:x2] = 1.0
            
            # Blur mask for smooth transition
            face_mask = cv2.GaussianBlur(
                face_mask, 
                COLOR_MATCH_CONFIG['gaussian_blur_kernel'], 
                COLOR_MATCH_CONFIG['gaussian_blur_sigma']
            )
            face_mask = face_mask[:, :, np.newaxis]
            
            # Match colors for face region with saturation preservation
            if y2 > y1 and x2 > x1:
                face_result = color_match_lab(
                    target[y1:y2, x1:x2], 
                    source[y1:y2, x1:x2],
                    preserve_saturation=True
                )
                target[y1:y2, x1:x2] = face_result
                
                # Blend with original using mask
                result = target * face_mask + target * (1 - face_mask)
            else:
                result = color_match_lab(target, source, preserve_saturation=True)
        else:
            # Standard LAB color matching with saturation preservation
            result = color_match_lab(target, source, preserve_saturation=True)
        
        result_img = Image.fromarray(result.astype(np.uint8))
        
        # NO saturation boost by default
        if preserve_vibrance:
            result_img = enhance_saturation(result_img, boost=COLOR_MATCH_CONFIG['saturation_boost'])
        
        return result_img
    
    except Exception as e:
        print(f"Enhanced color matching failed: {e}, returning target image")
        return target_img


def color_match(target_img, source_img, mode='mkl'):
    """
    Legacy color matching function - kept for compatibility.
    Use enhanced_color_match for better results.
    """
    try:
        target = np.array(target_img).astype(np.float32)
        source = np.array(source_img).astype(np.float32)
        
        if mode == 'simple':
            result = np.zeros_like(target)
            for i in range(3):
                t_mean, t_std = target[:,:,i].mean(), target[:,:,i].std()
                s_mean, s_std = source[:,:,i].mean(), source[:,:,i].std()
                
                result[:,:,i] = (target[:,:,i] - t_mean) * (s_std / (t_std + 1e-6)) + s_mean
                result[:,:,i] = np.clip(result[:,:,i], 0, 255)
        
        elif mode == 'mkl':
            result = color_match_lab(target, source)
        
        else:  # pdf mode
            result = np.zeros_like(target)
            for i in range(3):
                result[:,:,i] = np.interp(
                    target[:,:,i].flatten(),
                    np.linspace(target[:,:,i].min(), target[:,:,i].max(), 256),
                    np.linspace(source[:,:,i].min(), source[:,:,i].max(), 256)
                ).reshape(target[:,:,i].shape)
        
        return Image.fromarray(result.astype(np.uint8))
    
    except Exception as e:
        print(f"Color matching failed: {e}, returning target image")
        return target_img


def create_face_mask(image, face_bbox, feather=None):
    """
    Create a soft mask around the detected face for better blending.
    
    Args:
        image: PIL Image
        face_bbox: [x1, y1, x2, y2]
        feather: blur radius for soft edges (uses config default if None)
    """
    if feather is None:
        feather = FACE_MASK_CONFIG['feather']
    
    mask = Image.new('L', image.size, 0)
    draw = ImageDraw.Draw(mask)
    
    # Expand bbox slightly
    x1, y1, x2, y2 = face_bbox
    padding = int((x2 - x1) * FACE_MASK_CONFIG['padding'])
    x1 = max(0, x1 - padding)
    y1 = max(0, y1 - padding)
    x2 = min(image.width, x2 + padding)
    y2 = min(image.height, y2 + padding)
    
    # Draw ellipse for more natural face shape
    draw.ellipse([x1, y1, x2, y2], fill=255)
    
    # Apply gaussian blur for soft edges
    mask = mask.filter(ImageFilter.GaussianBlur(feather))
    
    return mask


def draw_kps(image_pil, kps, color_list=[(255, 0, 0), (0, 255, 0), (0, 0, 255), (255, 255, 0), (255, 0, 255)]):
    """Draw facial keypoints on image for InstantID ControlNet"""
    stickwidth = 4
    limbSeq = np.array([[0, 2], [1, 2], [3, 2], [4, 2]])
    kps = np.array(kps)

    w, h = image_pil.size
    out_img = np.zeros([h, w, 3])

    for i in range(len(limbSeq)):
        index = limbSeq[i]
        color = color_list[index[0]]

        x = kps[index][:, 0]
        y = kps[index][:, 1]
        length = ((x[0] - x[1]) ** 2 + (y[0] - y[1]) ** 2) ** 0.5
        angle = math.degrees(math.atan2(y[0] - y[1], x[0] - x[1]))
        polygon = cv2.ellipse2Poly(
            (int(np.mean(x)), int(np.mean(y))), (int(length / 2), stickwidth), int(angle), 0, 360, 1
        )
        out_img = cv2.fillConvexPoly(out_img.copy(), polygon, color)
    out_img = (out_img * 0.6).astype(np.uint8)

    for idx_kp, kp in enumerate(kps):
        color = color_list[idx_kp]
        x, y = kp
        out_img = cv2.circle(out_img.copy(), (int(x), int(y)), 10, color, -1)

    out_img_pil = Image.fromarray(out_img.astype(np.uint8))
    return out_img_pil


def get_facial_attributes(face):
    """
    Extract comprehensive facial attributes.
    Returns dict with age, gender, expression, quality metrics.
    """
    attributes = {
        'age': None,
        'gender': None,
        'expression': None,
        'quality': 1.0,
        'pose_angle': 0,
        'description': []
    }
    
    # Age extraction
    try:
        if hasattr(face, 'age'):
            age = int(face.age)
            attributes['age'] = age
            for min_age, max_age, label in AGE_BRACKETS:
                if min_age <= age < max_age:
                    attributes['description'].append(label)
                    break
    except (ValueError, TypeError, AttributeError) as e:
        print(f"[WARNING] Age extraction failed: {e}")
    
    # Gender extraction
    try:
        if hasattr(face, 'gender'):
            gender_code = int(face.gender)
            attributes['gender'] = gender_code
            if gender_code == 1:
                attributes['description'].append("male")
            elif gender_code == 0:
                attributes['description'].append("female")
    except (ValueError, TypeError, AttributeError) as e:
        print(f"[WARNING] Gender extraction failed: {e}")
    
    # Expression/emotion detection (if available)
    try:
        if hasattr(face, 'emotion'):
            # Some InsightFace models provide emotion
            emotion = face.emotion
            if isinstance(emotion, (list, tuple)) and len(emotion) > 0:
                emotions = ['neutral', 'happiness', 'surprise', 'sadness', 'anger', 'disgust', 'fear']
                emotion_idx = int(np.argmax(emotion))
                emotion_name = emotions[emotion_idx] if emotion_idx < len(emotions) else 'neutral'
                confidence = float(emotion[emotion_idx])
                
                if confidence > 0.4:  # Only add if confident
                    if emotion_name == 'happiness':
                        attributes['expression'] = 'smiling'
                        attributes['description'].append('smiling')
                    elif emotion_name not in ['neutral']:
                        attributes['expression'] = emotion_name
    except (ValueError, TypeError, AttributeError, IndexError) as e:
        # Expression not available in this model
        pass
    
    # Pose angle (profile detection)
    try:
        if hasattr(face, 'pose'):
            pose = face.pose
            if len(pose) > 1:
                yaw = float(pose[1])
                attributes['pose_angle'] = abs(yaw)
    except (ValueError, TypeError, AttributeError, IndexError):
        pass
    
    # Detection quality
    try:
        if hasattr(face, 'det_score'):
            attributes['quality'] = float(face.det_score)
    except (ValueError, TypeError, AttributeError):
        pass
    
    return attributes


def build_enhanced_prompt(base_prompt, facial_attributes, trigger_word):
    """
    Build enhanced prompt with facial attributes intelligently integrated.
    """
    prompt = base_prompt
    descriptions = facial_attributes['description']
    
    if not descriptions:
        return base_prompt
    
    # Check if demographics already in prompt
    prompt_lower = prompt.lower()
    has_demographics = any(desc.lower() in prompt_lower for desc in descriptions)
    
    if not has_demographics:
        # Insert after trigger word for better integration
        demographic_str = ", ".join(descriptions) + " person"
        prompt = prompt.replace(
            trigger_word,
            f"{trigger_word}, {demographic_str}",
            1
        )
        
        age = facial_attributes.get('age')
        quality = facial_attributes.get('quality')
        expression = facial_attributes.get('expression')
        
        print(f"[FACE] Detected: {', '.join(descriptions)}")
        print(f"  Age: {age if age else 'N/A'}, Quality: {quality:.2f}")
        if expression:
            print(f"  Expression: {expression}")
    
    return prompt


def get_demographic_description(age, gender_code):
    """
    Legacy function - kept for compatibility.
    Use get_facial_attributes() for new code.
    """
    demo_desc = []
    
    if age is not None:
        try:
            age_int = int(age)
            for min_age, max_age, label in AGE_BRACKETS:
                if min_age <= age_int < max_age:
                    demo_desc.append(label)
                    break
        except (ValueError, TypeError):
            pass
    
    if gender_code is not None:
        try:
            if int(gender_code) == 1:
                demo_desc.append("male")
            elif int(gender_code) == 0:
                demo_desc.append("female")
        except (ValueError, TypeError):
            pass
    
    return demo_desc


def calculate_optimal_size(original_width, original_height, recommended_sizes=None, max_dimension=1536):
    """
    Calculate optimal size maintaining aspect ratio with dimensions as multiples of 8.
    
    This updated version supports ANY aspect ratio (not just predefined ones),
    while ensuring dimensions are multiples of 8 and keeping total pixels reasonable.
    
    Args:
        original_width: Original image width
        original_height: Original image height  
        recommended_sizes: Optional list of (width, height) tuples (legacy support)
        max_dimension: Maximum allowed dimension (default 1536)
    
    Returns:
        Tuple of (optimal_width, optimal_height) as multiples of 8
    """
    aspect_ratio = original_width / original_height
    
    # Legacy mode: use recommended sizes if provided
    if recommended_sizes is not None:
        best_match = None
        best_diff = float('inf')
        
        for width, height in recommended_sizes:
            rec_aspect = width / height
            diff = abs(rec_aspect - aspect_ratio)
            if diff < best_diff:
                best_diff = diff
                best_match = (width, height)
        
        # Ensure dimensions are multiples of 8
        width, height = best_match
        width = int((width // 64) * 64)
        height = int((height // 64) * 64)
        
        return width, height
    
    # NEW: Support any aspect ratio
    # Strategy: Keep aspect ratio, scale to reasonable total pixels, round to multiples of 8
    
    # Target total pixels (around 1 megapixel for SDXL, adjustable)
    target_pixels = 1024 * 1024  # ~1MP, good balance for SDXL
    
    # Calculate dimensions that maintain aspect ratio and hit target pixels
    # width * height = target_pixels
    # width / height = aspect_ratio
    # => width = aspect_ratio * height
    # => aspect_ratio * height^2 = target_pixels
    # => height = sqrt(target_pixels / aspect_ratio)
    
    optimal_height = math.sqrt(target_pixels / aspect_ratio)
    optimal_width = optimal_height * aspect_ratio
    
    # Ensure we don't exceed max_dimension
    if optimal_width > max_dimension:
        optimal_width = max_dimension
        optimal_height = optimal_width / aspect_ratio
    
    if optimal_height > max_dimension:
        optimal_height = max_dimension
        optimal_width = optimal_height * aspect_ratio
    
    # Round to nearest multiple of 8
    width = int(round(optimal_width / 64) * 64)
    height = int(round(optimal_height / 64) * 64)
    
    # Ensure minimum size (at least 512 on shortest side)
    min_dimension = 512
    if min(width, height) < min_dimension:
        if width < height:
            width = min_dimension
            height = int(round((width / aspect_ratio) / 64) * 64)
        else:
            height = min_dimension
            width = int(round((height * aspect_ratio) / 64) * 64)
    
    # Final safety check: ensure multiples of 8
    width = max(8, int((width // 64) * 64))
    height = max(8, int((height // 64) * 64))
    
    print(f"[SIZING] Aspect ratio: {aspect_ratio:.3f}, Output: {width}x{height} ({width*height/1e6:.2f}MP)")
    
    return width, height


def enhance_face_crop(face_crop):
    """
    Multi-stage enhancement for better feature preservation.
    
    Args:
        face_crop: PIL Image of face region
    
    Returns:
        Enhanced PIL Image
    """
    # Stage 1: Resize to optimal size for CLIP (224x224)
    face_crop_resized = face_crop.resize((224, 224), Image.LANCZOS)
    
    # Stage 2: Enhance sharpness (helps with facial features)
    enhancer = ImageEnhance.Sharpness(face_crop_resized)
    face_crop_sharp = enhancer.enhance(1.5)
    
    # Stage 3: Enhance contrast slightly (helps with lighting)
    enhancer = ImageEnhance.Contrast(face_crop_sharp)
    face_crop_enhanced = enhancer.enhance(1.1)
    
    # Stage 4: Slight brightness adjustment to normalize lighting
    enhancer = ImageEnhance.Brightness(face_crop_enhanced)
    face_crop_final = enhancer.enhance(1.05)
    
    return face_crop_final


print("[OK] Utilities loaded")