#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# Copyright (c) Megvii Inc. All rights reserved.

import cv2
import numpy as np
COCO_CLASSES = ("red", "green", "yellow", "empty", "straight", "left", "right", "other")

__all__ = ["vis"]


def is_nearby(box1, box2, threshold=40):
    # Compute the centroid of both boxes
    cx1 = (box1[0] + box1[2]) / 2
    cy1 = (box1[1] + box1[3]) / 2
    cx2 = (box2[0] + box2[2]) / 2
    cy2 = (box2[1] + box2[3]) / 2

    # Compute the distance between centroids
    distance = ((cx1 - cx2) ** 2 + (cy1 - cy2) ** 2) ** 0.5

    return distance < threshold


def vis(img, boxes, scores, cls_ids, conf, class_names):
    arrow_offsets = {}
    seen_boxes = []
    for i in range(len(boxes)):
        box = boxes[i]
        cls_id = int(cls_ids[i])
        score = scores[i]
        if score < conf:
            continue

        x0, y0, x1, y1 = map(int, box)

        color = (_COLORS[cls_id] * 255).astype(np.uint8).tolist()
        text = "{}:{:.1f}%".format(class_names[cls_id], score * 100)
        txt_color = (0, 0, 0) if np.mean(_COLORS[cls_id]) > 0.5 else (255, 255, 255)
        font = cv2.FONT_HERSHEY_SIMPLEX

        txt_size = cv2.getTextSize(text, font, 0.4, 1)[0]
        if cls_id < 4:
            overlay = img.copy()
            cv2.rectangle(overlay, (x0, y0), (x1, y1), color, -1)  # -1 fills the rectangle
            alpha = 0.4  # Transparency factor.
            cv2.addWeighted(overlay, alpha, img, 1 - alpha, 0, img)
            cv2.rectangle(img, (x0, y0), (x1, y1), color, 2)

            txt_bk_color = (_COLORS[cls_id] * 255 * 0.7).astype(np.uint8).tolist()
            cv2.rectangle(
                img,
                (x0, y0 + 1),
                (x0 + txt_size[0] + 1, y0 + int(1.5 * txt_size[1])),
                txt_bk_color,
                -1,
            )
            cv2.putText(img, text, (x0, y0 + txt_size[1]), font, 0.4, txt_color, thickness=1)
        else:
            nearby_box_idx = None
            for idx, seen_box in enumerate(seen_boxes):
                if is_nearby(seen_box, box):
                    nearby_box_idx = idx
                    break
            offset = 0
            if nearby_box_idx is not None:
                arrow_offsets[nearby_box_idx] = arrow_offsets.get(nearby_box_idx, 0) + 1
                offset = arrow_offsets[nearby_box_idx] * (txt_size[1] + 5)
            else:
                seen_boxes.append(box)

            txt_bk_color = (_COLORS[cls_id] * 255 * 0.7).astype(np.uint8).tolist()
            cv2.rectangle(
                img,
                (x0, y1 + 1 + offset),
                (x0 + txt_size[0] + 1, y1 + int(1.5 * txt_size[1]) + offset),
                txt_bk_color,
                -1,
            )
            cv2.putText(
                img, text, (x0, y1 + txt_size[1] + offset), font, 0.4, txt_color, thickness=1
            )
    return img


_COLORS = np.array(
    [   # B  , G    , R
        0.000, 0.000, 1.000,
        1.000, 0.300, 0.000,
        0.000, 1.000, 1.000,
        0.494, 0.184, 0.556,
        0.466, 0.674, 0.188,
        0.301, 0.745, 0.933,
        0.635, 0.078, 0.184,
        0.300, 0.300, 0.300,
        0.600, 0.600, 0.600,
        1.000, 0.000, 0.000,
        1.000, 0.500, 0.000,
        0.749, 0.749, 0.000,
        0.000, 1.000, 0.000,
        0.000, 0.000, 1.000,
        0.667, 0.000, 1.000,
        0.333, 0.333, 0.000,
        0.333, 0.667, 0.000,
        0.333, 1.000, 0.000,
        0.667, 0.333, 0.000,
        0.667, 0.667, 0.000,
        0.667, 1.000, 0.000,
        1.000, 0.333, 0.000,
        1.000, 0.667, 0.000,
        1.000, 1.000, 0.000,
        0.000, 0.333, 0.500,
        0.000, 0.667, 0.500,
        0.000, 1.000, 0.500,
        0.333, 0.000, 0.500,
        0.333, 0.333, 0.500,
        0.333, 0.667, 0.500,
        0.333, 1.000, 0.500,
        0.667, 0.000, 0.500,
        0.667, 0.333, 0.500,
        0.667, 0.667, 0.500,
        0.667, 1.000, 0.500,
        1.000, 0.000, 0.500,
        1.000, 0.333, 0.500,
        1.000, 0.667, 0.500,
        1.000, 1.000, 0.500,
        0.000, 0.333, 1.000,
        0.000, 0.667, 1.000,
        0.000, 1.000, 1.000,
        0.333, 0.000, 1.000,
        0.333, 0.333, 1.000,
        0.333, 0.667, 1.000,
        0.333, 1.000, 1.000,
        0.667, 0.000, 1.000,
        0.667, 0.333, 1.000,
        0.667, 0.667, 1.000,
        0.667, 1.000, 1.000,
        1.000, 0.000, 1.000,
        1.000, 0.333, 1.000,
        1.000, 0.667, 1.000,
        0.333, 0.000, 0.000,
        0.500, 0.000, 0.000,
        0.667, 0.000, 0.000,
        0.833, 0.000, 0.000,
        1.000, 0.000, 0.000,
        0.000, 0.167, 0.000,
        0.000, 0.333, 0.000,
        0.000, 0.500, 0.000,
        0.000, 0.667, 0.000,
        0.000, 0.833, 0.000,
        0.000, 1.000, 0.000,
        0.000, 0.000, 0.167,
        0.000, 0.000, 0.333,
        0.000, 0.000, 0.500,
        0.000, 0.000, 0.667,
        0.000, 0.000, 0.833,
        0.000, 0.000, 1.000,
        0.000, 0.000, 0.000,
        0.143, 0.143, 0.143,
        0.286, 0.286, 0.286,
        0.429, 0.429, 0.429,
        0.571, 0.571, 0.571,
        0.714, 0.714, 0.714,
        0.857, 0.857, 0.857,
        0.000, 0.447, 0.741,
        0.314, 0.717, 0.741,
        0.50, 0.5, 0
    ]
).astype(np.float32).reshape(-1, 3)