#-------------------------------------#
#       创建YOLO类
#-------------------------------------#
import colorsys
import os

import cv2
import numpy as np
import torch
import torch.backends.cudnn as cudnn
import torch.nn as nn
from PIL import Image, ImageDraw, ImageFont
from torch.autograd import Variable

from nets.yolo3 import YoloBody
from utils.config import Config
from utils.utils import (DecodeBox, bbox_iou, letterbox_image,
                         non_max_suppression, yolo_correct_boxes)


#--------------------------------------------#
#   使用自己训练好的模型预测需要修改2个参数
#   model_path和classes_path都需要修改！
#   如果出现shape不匹配，一定要注意
#   训练时的model_path和classes_path参数的修改
#--------------------------------------------#
class YOLO(object):
    _defaults = {
        "model_path"        : 'model_data/yolo_weights.pth',
        "classes_path"      : 'model_data/coco_classes.txt',
        "model_image_size"  : (416, 416, 3),
        "confidence"        : 0.5,
        "iou"               : 0.3,
        "cuda"              : True
    }

    @classmethod
    def get_defaults(cls, n):
        if n in cls._defaults:
            return cls._defaults[n]
        else:
            return "Unrecognized attribute name '" + n + "'"

    #---------------------------------------------------#
    #   初始化YOLO
    #---------------------------------------------------#
    def __init__(self, **kwargs):
        self.__dict__.update(self._defaults)
        self.class_names = self._get_class()
        self.config = Config
        self.generate()
    #---------------------------------------------------#
    #   获得所有的分类
    #---------------------------------------------------#
    def _get_class(self):
        classes_path = os.path.expanduser(self.classes_path)
        with open(classes_path) as f:
            class_names = f.readlines()
        class_names = [c.strip() for c in class_names]
        return class_names

    #---------------------------------------------------#
    #   生成模型
    #---------------------------------------------------#
    def generate(self):
        self.config["yolo"]["classes"] = len(self.class_names)
        #---------------------------------------------------#
        #   建立yolov3模型
        #---------------------------------------------------#
        self.net = YoloBody(self.config)

        #---------------------------------------------------#
        #   载入yolov3模型的权重
        #---------------------------------------------------#
        print('Loading weights into state dict...')
        device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
        state_dict = torch.load(self.model_path, map_location=device)
        self.net.load_state_dict(state_dict)
        self.net = self.net.eval()

        if self.cuda:
            os.environ["CUDA_VISIBLE_DEVICES"] = '0'
            self.net = nn.DataParallel(self.net)
            self.net = self.net.cuda()

        #---------------------------------------------------#
        #   建立三个特征层解码用的工具
        #---------------------------------------------------#
        self.yolo_decodes = []
        for i in range(3):
            self.yolo_decodes.append(DecodeBox(self.config["yolo"]["anchors"][i], self.config["yolo"]["classes"], (self.model_image_size[1], self.model_image_size[0])))

        print('{} model, anchors, and classes loaded.'.format(self.model_path))
        # 画框设置不同的颜色
        hsv_tuples = [(x / len(self.class_names), 1., 1.)
                      for x in range(len(self.class_names))]
        self.colors = list(map(lambda x: colorsys.hsv_to_rgb(*x), hsv_tuples))
        self.colors = list(
            map(lambda x: (int(x[0] * 255), int(x[1] * 255), int(x[2] * 255)),
                self.colors))

    #---------------------------------------------------#
    #   检测图片
    #---------------------------------------------------#
    def detect_image(self, image):
        image_shape = np.array(np.shape(image)[0:2])

        #---------------------------------------------------------#
        #   给图像增加灰条，实现不失真的resize
        #---------------------------------------------------------#
        crop_img = np.array(letterbox_image(image, (self.model_image_size[1],self.model_image_size[0])))
        photo = np.array(crop_img,dtype = np.float32) / 255.0
        photo = np.transpose(photo, (2, 0, 1))
        #---------------------------------------------------------#
        #   添加上batch_size维度
        #---------------------------------------------------------#
        images = [photo]

        with torch.no_grad():
            images = torch.from_numpy(np.asarray(images))
            if self.cuda:
                images = images.cuda()

            #---------------------------------------------------------#
            #   将图像输入网络当中进行预测！
            #---------------------------------------------------------#
            outputs = self.net(images)
            output_list = []
            for i in range(3):
                output_list.append(self.yolo_decodes[i](outputs[i]))
                
            #---------------------------------------------------------#
            #   将预测框进行堆叠，然后进行非极大抑制
            #---------------------------------------------------------#
            output = torch.cat(output_list, 1)
            batch_detections = non_max_suppression(output, self.config["yolo"]["classes"],
                                                    conf_thres=self.confidence,
                                                    nms_thres=self.iou)
                                                    
            #---------------------------------------------------------#
            #   如果没有检测出物体，返回原图
            #---------------------------------------------------------#
            try :
                batch_detections = batch_detections[0].cpu().numpy()
            except:
                return image

            #---------------------------------------------------------#
            #   对预测框进行得分筛选
            #---------------------------------------------------------#
            top_index = batch_detections[:,4] * batch_detections[:,5] > self.confidence
            top_conf = batch_detections[top_index,4]*batch_detections[top_index,5]
            top_label = np.array(batch_detections[top_index,-1],np.int32)
            top_bboxes = np.array(batch_detections[top_index,:4])
            top_xmin, top_ymin, top_xmax, top_ymax = np.expand_dims(top_bboxes[:,0],-1),np.expand_dims(top_bboxes[:,1],-1),np.expand_dims(top_bboxes[:,2],-1),np.expand_dims(top_bboxes[:,3],-1)

            #-----------------------------------------------------------------#
            #   在图像传入网络预测前会进行letterbox_image给图像周围添加灰条
            #   因此生成的top_bboxes是相对于有灰条的图像的
            #   我们需要对其进行修改，去除灰条的部分。
            #-----------------------------------------------------------------#
            boxes = yolo_correct_boxes(top_ymin,top_xmin,top_ymax,top_xmax,np.array([self.model_image_size[0],self.model_image_size[1]]),image_shape)

        font = ImageFont.truetype(font='model_data/simhei.ttf',size=np.floor(3e-2 * np.shape(image)[1] + 0.5).astype('int32'))

        thickness = max((np.shape(image)[0] + np.shape(image)[1]) // self.model_image_size[0], 1)

        for i, c in enumerate(top_label):
            predicted_class = self.class_names[c]
            score = top_conf[i]

            top, left, bottom, right = boxes[i]
            top = top - 5
            left = left - 5
            bottom = bottom + 5
            right = right + 5

            top = max(0, np.floor(top + 0.5).astype('int32'))
            left = max(0, np.floor(left + 0.5).astype('int32'))
            bottom = min(np.shape(image)[0], np.floor(bottom + 0.5).astype('int32'))
            right = min(np.shape(image)[1], np.floor(right + 0.5).astype('int32'))

            # 画框框
            label = '{} {:.2f}'.format(predicted_class, score)
            draw = ImageDraw.Draw(image)
            label_size = draw.textsize(label, font)
            label = label.encode('utf-8')
            print(label, top, left, bottom, right)
            
            if top - label_size[1] >= 0:
                text_origin = np.array([left, top - label_size[1]])
            else:
                text_origin = np.array([left, top + 1])

            for i in range(thickness):
                draw.rectangle(
                    [left + i, top + i, right - i, bottom - i],
                    outline=self.colors[self.class_names.index(predicted_class)])
            draw.rectangle(
                [tuple(text_origin), tuple(text_origin + label_size)],
                fill=self.colors[self.class_names.index(predicted_class)])
            draw.text(text_origin, str(label,'UTF-8'), fill=(0, 0, 0), font=font)
            del draw
        return image

