import cv2
import numpy as np


def insert_person_V2(
    left_image_path, right_image_path, person_image_path, depth="medium"
):
    # Load left and right stereoscopic images
    left_image = cv2.imread(left_image_path)
    right_image = cv2.imread(right_image_path)

    # Load the segmented person image with alpha channel (transparency)
    person = cv2.imread(person_image_path, cv2.IMREAD_UNCHANGED)

    # Define scaling and disparity values for each depth level
    depth_settings = {
        "close": {"scale": 1.2, "disparity": 15},
        "medium": {"scale": 1.0, "disparity": 10},
        "far": {"scale": 0.7, "disparity": 5},
    }
    scale_factor = depth_settings[depth]["scale"]
    disparity = depth_settings[depth]["disparity"]

    # Resize person image according to the scale factor
    person_resized = cv2.resize(
        person, None, fx=scale_factor, fy=scale_factor, interpolation=cv2.INTER_AREA
    )
    (ph, pw) = person_resized.shape[:2]

    # Extract color and alpha channels from person image
    person_rgb = person_resized[:, :, :3]
    person_alpha = person_resized[:, :, 3] / 255.0  # Normalize alpha channel to [0, 1]

    # Match brightness and contrast of the person to the background
    person_rgb = match_brightness_contrast(left_image, person_rgb, person_alpha)

    # Color match person to the background
    person_rgb = match_color_tone(left_image, person_rgb, person_alpha)

    # Create a blended version of the person with soft edges
    person_blended = soft_edge_blending(person_rgb, person_alpha)

    # Determine insertion position in the left image
    x_offset, y_offset = 100, left_image.shape[0] - ph - 20
    left_image[y_offset : y_offset + ph, x_offset : x_offset + pw] = blend_images(
        left_image[y_offset : y_offset + ph, x_offset : x_offset + pw],
        person_blended,
        person_alpha,
    )

    # Create stereoscopic effect by shifting the person image in the right image
    x_offset_right = x_offset + disparity
    right_image[y_offset : y_offset + ph, x_offset_right : x_offset_right + pw] = (
        blend_images(
            right_image[y_offset : y_offset + ph, x_offset_right : x_offset_right + pw],
            person_blended,
            person_alpha,
        )
    )

    return left_image, right_image


def match_brightness_contrast(background, person, alpha):
    # Calculate the mean brightness of the background where the person will be placed
    background_mean = np.mean(background, axis=(0, 1))
    person_mean = np.mean(person, axis=(0, 1))
    adjustment = background_mean / (person_mean + 1e-6)
    return cv2.convertScaleAbs(person, alpha=adjustment[0], beta=adjustment[1])


def match_color_tone(background, person, alpha):
    # Adjust color tone to match background
    bg_mean, bg_std = cv2.meanStdDev(background)
    person_mean, person_std = cv2.meanStdDev(person)
    scale = (bg_std + 1e-6) / (person_std + 1e-6)
    person = cv2.convertScaleAbs(
        person, alpha=scale[0][0], beta=(bg_mean - person_mean)[0][0]
    )
    return person


def soft_edge_blending(person, alpha):
    # Apply Gaussian blur to soften the edges for better blending
    blurred_alpha = cv2.GaussianBlur(alpha, (15, 15), 0)
    person = cv2.merge(
        (
            person[:, :, 0] * blurred_alpha,
            person[:, :, 1] * blurred_alpha,
            person[:, :, 2] * blurred_alpha,
        )
    )
    return person


def blend_images(background, person, alpha):
    # Blend person into background using the alpha mask
    blended = (alpha[..., None] * person + (1 - alpha[..., None]) * background).astype(
        np.uint8
    )
    return blended