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from __future__ import annotations

import cv2
import numpy as np

from .models import (
    BitmapExtractor,
    BitmapRegion,
    Box,
    DocumentSpec,
    LinearGradientPaint,
    ShapeRegion,
    SolidPaint,
)
from .shape_recognition import geometry_mask, shape_source_mask


def extract_bitmap_layers(
    rgba: np.ndarray,
    document: DocumentSpec,
    text_mask: np.ndarray,
    extractor: BitmapExtractor,
    device: str,
) -> tuple[list[BitmapRegion], dict[str, np.ndarray]]:
    height, width = rgba.shape[:2]
    rgb = rgba[:, :, :3]
    text_exclusion = cv2.dilate(text_mask, np.ones((5, 5), np.uint8))
    for region in document.regions:
        polygon = np.array(
            [(point.x, point.y) for point in region.source_quad],
            dtype=np.int32,
        )
        cv2.fillPoly(text_exclusion, [polygon], 255)
    vector_foreground = np.zeros((height, width), dtype=np.uint8)
    for shape in document.shapes:
        if not shape.is_container and shape.include_overlay:
            vector_foreground = cv2.bitwise_or(
                vector_foreground,
                geometry_mask(shape.geometry, width, height),
            )

    regions: list[BitmapRegion] = []
    assets: dict[str, np.ndarray] = {}
    for shape in document.shapes:
        if not shape.is_container or not shape.include_overlay:
            continue
        container_mask = geometry_mask(shape.geometry, width, height)
        predicted = render_fill(shape, width, height)
        source_lab = cv2.cvtColor(rgb, cv2.COLOR_RGB2LAB).astype(np.float32)
        predicted_lab = cv2.cvtColor(predicted, cv2.COLOR_RGB2LAB).astype(np.float32)
        delta = np.linalg.norm(source_lab - predicted_lab, axis=2)
        border_exclusion = cv2.subtract(
            container_mask,
            cv2.erode(container_mask, np.ones((7, 7), np.uint8)),
        )
        eligible = (
            (container_mask > 0)
            & (text_exclusion == 0)
            & (vector_foreground == 0)
            & (border_exclusion == 0)
        )
        values = delta[eligible]
        if values.size < 20:
            continue
        baseline = float(np.percentile(values, 35))
        threshold = max(9.0, baseline + 6.0)
        initial = np.zeros((height, width), dtype=np.uint8)
        initial[eligible & (delta >= threshold * 0.65)] = cv2.GC_PR_FGD
        initial[eligible & (delta >= threshold * 1.35)] = cv2.GC_FGD
        initial[(container_mask > 0) & (initial == 0)] = cv2.GC_BGD
        if np.count_nonzero(initial == cv2.GC_FGD) < 8:
            continue
        mask = refine_opencv(rgb, initial, container_mask)
        if extractor == BitmapExtractor.SAM2:
            from .sam2 import refine_with_sam2

            mask = refine_with_sam2(rgb, mask, container_mask, device)
        mask[text_exclusion > 0] = 0
        mask[vector_foreground > 0] = 0
        mask = filter_components(mask, max(8, int(width * height * 0.00001)))
        if cv2.countNonZero(mask) < 12:
            continue
        alpha = soft_alpha(delta, mask, threshold)
        x, y, w, h = cv2.boundingRect((alpha > 0).astype(np.uint8))
        if w <= 0 or h <= 0:
            continue
        padding = 2
        x0, y0 = max(0, x - padding), max(0, y - padding)
        x1, y1 = min(width, x + w + padding), min(height, y + h + padding)
        crop = np.dstack([rgb[y0:y1, x0:x1], alpha[y0:y1, x0:x1]])
        asset_name = f"bitmap-{len(regions) + 1:04d}.png"
        region = BitmapRegion(
            id=f"bitmap-{len(regions) + 1:04d}",
            asset_name=asset_name,
            box=Box(x=x0, y=y0, width=x1 - x0, height=y1 - y0),
            z_index=500,
        )
        regions.append(region)
        assets[region.id] = crop
    return regions, assets


def refine_opencv(rgb: np.ndarray, initial: np.ndarray, container_mask: np.ndarray) -> np.ndarray:
    mask = initial.copy()
    try:
        cv2.grabCut(
            cv2.cvtColor(rgb, cv2.COLOR_RGB2BGR),
            mask,
            None,
            np.zeros((1, 65), np.float64),
            np.zeros((1, 65), np.float64),
            2,
            cv2.GC_INIT_WITH_MASK,
        )
        output = np.isin(mask, [cv2.GC_FGD, cv2.GC_PR_FGD]).astype(np.uint8) * 255
    except cv2.error:
        output = (initial >= cv2.GC_PR_FGD).astype(np.uint8) * 255
    output[container_mask == 0] = 0
    return output


def filter_components(mask: np.ndarray, minimum_area: int) -> np.ndarray:
    count, labels, stats, _ = cv2.connectedComponentsWithStats((mask > 0).astype(np.uint8), 8)
    output = np.zeros_like(mask, dtype=np.uint8)
    for index in range(1, count):
        if stats[index, cv2.CC_STAT_AREA] >= minimum_area:
            output[labels == index] = 255
    return output


def soft_alpha(delta: np.ndarray, mask: np.ndarray, threshold: float) -> np.ndarray:
    strength = np.clip((delta - threshold * 0.45) / max(threshold, 1), 0, 1)
    alpha = np.rint(strength * 255).astype(np.uint8)
    alpha[mask == 0] = 0
    alpha = cv2.GaussianBlur(alpha, (3, 3), 0.65)
    alpha[cv2.dilate(mask, np.ones((3, 3), np.uint8)) == 0] = 0
    return alpha


def render_fill(shape: ShapeRegion, width: int, height: int) -> np.ndarray:
    paint = shape.style.fill
    if isinstance(paint, SolidPaint):
        color = parse_hex(paint.color)
        return np.broadcast_to(color, (height, width, 3)).copy()
    assert isinstance(paint, LinearGradientPaint)
    first, last = paint.stops[0], paint.stops[-1]
    color0 = parse_hex(first.color).astype(np.float32)
    color1 = parse_hex(last.color).astype(np.float32)
    radians = np.deg2rad(paint.angle)
    direction = np.array([np.cos(radians), np.sin(radians)], dtype=np.float32)
    yy, xx = np.mgrid[0:height, 0:width]
    projection = xx * direction[0] + yy * direction[1]
    minimum, maximum = float(projection.min()), float(projection.max())
    t = (projection - minimum) / max(maximum - minimum, 1)
    result = color0[None, None, :] * (1 - t[:, :, None]) + color1[None, None, :] * t[:, :, None]
    return np.clip(np.rint(result), 0, 255).astype(np.uint8)


def reconstruct_background(
    rgba: np.ndarray,
    document: DocumentSpec,
    combined_mask: np.ndarray,
    inpaint_callback,
) -> np.ndarray:
    height, width = rgba.shape[:2]
    working = rgba.copy()
    container_union = np.zeros((height, width), dtype=np.uint8)
    for shape in sorted(document.shapes, key=lambda item: geometry_area(item), reverse=True):
        if not shape.is_container or not shape.remove_source:
            continue
        mask = shape_source_mask(shape, width, height)
        if not cv2.countNonZero(mask):
            continue
        ring = cv2.subtract(
            cv2.dilate(mask, np.ones((15, 15), np.uint8)),
            cv2.dilate(mask, np.ones((3, 3), np.uint8)),
        )
        samples = working[:, :, :3][ring > 0]
        fill = np.median(samples, axis=0) if samples.size else np.array([255, 255, 255])
        working[:, :, :3][mask > 0] = np.rint(fill).astype(np.uint8)
        container_union = cv2.bitwise_or(container_union, mask)
    remaining = combined_mask.copy()
    remaining[container_union > 0] = 0
    if cv2.countNonZero(remaining):
        working = inpaint_callback(working, remaining)
    return working


def geometry_area(shape: ShapeRegion) -> float:
    geometry = shape.geometry
    if hasattr(geometry, "box"):
        return geometry.box.width * geometry.box.height
    if hasattr(geometry, "rx"):
        return float(np.pi * geometry.rx * geometry.ry)
    points = np.array([(point.x, point.y) for point in geometry.points], dtype=np.float32)
    return abs(float(cv2.contourArea(points))) if len(points) >= 3 else 0


def parse_hex(value: str) -> np.ndarray:
    value = value.lstrip("#")
    if len(value) == 3:
        value = "".join(character * 2 for character in value)
    return np.array([int(value[index:index + 2], 16) for index in (0, 2, 4)], dtype=np.uint8)