import numpy as np

import cv2

from math import sqrt

_LINE_THICKNESS_SCALING = 500.0

np.random.seed(69)
RAND_COLORS = np.random.randint(10, 255, (80, 3), "int")  # used for class visu

def render_box(img, box, color=(200, 200, 200)):
    """
    Render a box. Calculates scaling and thickness automatically.
    :param img: image to render into
    :param box: (x1, y1, x2, y2) - box coordinates
    :param color: (b, g, r) - box color
    :return: updated image
    """
    x1, y1, x2, y2 = box
    thickness = int(
        round(
            (img.shape[0] * img.shape[1])
            / (_LINE_THICKNESS_SCALING * _LINE_THICKNESS_SCALING)
        )
    )
    thickness = max(1, thickness)
    img = cv2.rectangle(
        img,
        (int(x1), int(y1)),
        (int(x2), int(y2)),
        color,
        thickness=thickness
    )
    return img

def render_filled_box(img, box, color=(200, 200, 200)):
    """
    Render a box. Calculates scaling and thickness automatically.
    :param img: image to render into
    :param box: (x1, y1, x2, y2) - box coordinates
    :param color: (b, g, r) - box color
    :return: updated image
    """
    x1, y1, x2, y2 = box
    img = cv2.rectangle(
        img,
        (int(x1), int(y1)),
        (int(x2), int(y2)),
        color,
        thickness=cv2.FILLED
    )
    return img

_TEXT_THICKNESS_SCALING = 700.0
_TEXT_SCALING = 520.0


def get_text_size(img, text, normalised_scaling=1.0):
    """
    Get calculated text size (as box width and height)
    :param img: image reference, used to determine appropriate text scaling
    :param text: text to display
    :param normalised_scaling: additional normalised scaling. Default 1.0.
    :return: (width, height) - width and height of text box
    """
    thickness = int(
        round(
            (img.shape[0] * img.shape[1])
            / (_TEXT_THICKNESS_SCALING * _TEXT_THICKNESS_SCALING)
        )
        * normalised_scaling
    )
    thickness = max(1, thickness)
    scaling = img.shape[0] / _TEXT_SCALING * normalised_scaling
    return cv2.getTextSize(text, cv2.FONT_HERSHEY_SIMPLEX, scaling, thickness)[0]


def render_text(img, text, pos, color=(200, 200, 200), normalised_scaling=1.0):
    """
    Render a text into the image. Calculates scaling and thickness automatically.
    :param img: image to render into
    :param text: text to display
    :param pos: (x, y) - upper left coordinates of render position
    :param color: (b, g, r) - text color
    :param normalised_scaling: additional normalised scaling. Default 1.0.
    :return: updated image
    """
    x, y = pos
    thickness = int(
        round(
            (img.shape[0] * img.shape[1])
            / (_TEXT_THICKNESS_SCALING * _TEXT_THICKNESS_SCALING)
        )
        * normalised_scaling
    )
    thickness = max(2, thickness)
    scaling = img.shape[0] / _TEXT_SCALING * normalised_scaling
    size = get_text_size(img, text, normalised_scaling)
    cv2.putText(
        img,
        text,
        (int(x), int(y + size[1])),
        cv2.FONT_HERSHEY_SIMPLEX,
        scaling,
        color,
        thickness=thickness,
    )
    return img

def plot_one_box(x, img, color=None, label=None, line_thickness=None):
    """
    description: Plots one bounding box on image img,
                 this function comes from YoLov5 project.
    param: 
        x:      a box likes [x1,y1,x2,y2]
        img:    a opencv image object
        color:  color to draw rectangle, such as (0,255,0)
        label:  str
        line_thickness: int
    return:
        no return

    """
    tl = (
        line_thickness or round(0.002 * (img.shape[0] + img.shape[1]) / 2) + 1
    )  # line/font thickness
    if color == None:
        color = [np.random.randint(0, 255) for _ in range(3)]
    c1, c2 = (int(x[0]), int(x[1])), (int(x[2]), int(x[3]))
    
    cv2.rectangle(img, c1, c2, color, thickness=tl, lineType=cv2.LINE_AA)
    if label:
        tf = max(tl - 1, 1)  # font thickness
        t_size = cv2.getTextSize(label, 0, fontScale=tl / 3, thickness=tf)[0]
        c2 = c1[0] + t_size[0], c1[1] - t_size[1] - 3
        cv2.rectangle(img, c1, c2, color, -1, cv2.LINE_AA)  # filled
        cv2.putText(
            img,
            label,
            (c1[0], c1[1] - 2),
            0,
            tl / 3,
            [225, 255, 255],
            thickness=tf,
            lineType=cv2.LINE_AA,
        )