src/layout_evaluation.py

from rapidfuzz import fuzz
from src.geometry import is_included


def _normalize_coords(coordinates):
    """Convert coordinates to list of [x, y] pairs.

    Accepts either [{"x": x, "y": y}, ...] or [[x, y], ...].
    """
    return [
        [coord["x"], coord["y"]] if isinstance(coord, dict) else list(coord)
        for coord in coordinates
    ]

def calc_nid(
    gt_text : list,
    pred_text : list,
) -> float:
    """Calculate the Normalized InDel score between the gt and pred text.

    Args:
        gt_text (str): The string of gt text to compare.
        pred_text (str): The string of pred text to compare.

    Returns:
        float: The nid score between gt and pred text.
    """

    # if gt and pred is empty, return 1
    if len(gt_text) == 0 and len(pred_text) == 0:
        score = 1
    # if pred is empty while gt is not, return 0
    elif len(gt_text) > 0 and len(pred_text) == 0:
        score = 0
    else:
        score = fuzz.ratio(gt_text, pred_text)

    return score


def extract_text(
    gt_data : dict,
    pred_data : dict,
    ignore_classes : list = [],
    strings_to_remove : list = ["\n"],
    filter_by_gt_area : bool = True,
) -> tuple:
    """Extract text from both GT and prediction data, optionally filtering out 
    predictions that fall within GT ignored regions.

    Args:
        gt_data (dict): The GT data to extract text from.
        pred_data (dict): The prediction data to extract text from.
        ignore_classes (list): A list of classes to ignore during extraction.
        strings_to_remove (list): A list of strings to remove from the extracted text.
        filter_by_gt_area (bool): If True, filter out prediction text within GT ignored regions.
                                  If False, only filter by category. Defaults to True.

    Returns:
        tuple: (gt_text, pred_text) - The concatenated text extracted from GT and predictions.
    """

    ignore_classes = [x.lower() for x in ignore_classes]

    # Collect GT ignored regions' coordinates (only if spatial filtering is enabled)
    gt_ignored_regions = []
    if filter_by_gt_area:
        for elem in gt_data["elements"]:
            if elem["category"].lower() in ignore_classes:
                coords = _normalize_coords(elem["coordinates"])
                gt_ignored_regions.append(coords)

    # Extract GT text (excluding ignored classes)
    gt_text = ""
    for elem in gt_data["elements"]:
        if elem["category"].lower() in ignore_classes:
            continue
        gt_text += elem["content"]["text"] + ' '

    # Extract prediction text (excluding ignored classes AND optionally elements within GT ignored regions)
    pred_text = ""
    if pred_data is not None:
        for elem in pred_data["elements"]:
            if elem["category"].lower() in ignore_classes:
                continue
            
            # Check if this prediction element is included in any GT ignored region (only if enabled)
            if filter_by_gt_area:
                elem_coords = _normalize_coords(elem["coordinates"])
                is_in_ignored_region = False
                
                for ignored_region in gt_ignored_regions:
                    if is_included(ignored_region, elem_coords, soft=0.2):
                        is_in_ignored_region = True
                        break
                
                if is_in_ignored_region:
                    continue
                
            pred_text += elem["content"]["text"] + ' '

    # Remove unwanted strings from both texts
    for string in strings_to_remove:
        gt_text = gt_text.replace(string, '')
        pred_text = pred_text.replace(string, '')

    return gt_text, pred_text


def evaluate_layout(
    gt : dict,
    pred : dict,
    ignore_classes : list = [],
    filter_by_gt_area : bool = True,
) -> tuple:
    """Evaluate the layout of the gt against the pred.

    Args:
        gt (dict): The gt layout to evaluate.
        pred (dict): The pred layout to evaluate against.
        ignore_classes (list): A list of classes to ignore during evaluation.
        filter_by_gt_area (bool): If True, filter out prediction text within GT ignored regions.
                                  If False, only filter by category. Defaults to True.

    Returns:
        tuple: (avg_score, per_image_scores) - The average layout evaluation score and per-image scores dict.
    """
    scores = []
    per_image_scores = {}
    
    for image_key in gt.keys():
        gt_data = gt.get(image_key)
        pred_data = pred.get(image_key)

        gt_text, pred_text = extract_text(gt_data, pred_data, ignore_classes, filter_by_gt_area=filter_by_gt_area)

        score = calc_nid(gt_text, pred_text)

        scores.append(score)
        per_image_scores[image_key] = {
            "nid_score": score / 100.0
        }

    if len(scores) > 0:
        avg_score = sum(scores) / (len(scores) * 100)
    else:
        avg_score = 0

    return avg_score, per_image_scores