import torch 
from torch.utils import data
import os
from PIL import Image
import numpy as np
import pickle
 
class Fire_Unfire(data.Dataset):
  def __init__(self,fire_path,unfire_path):
    self.pickle_fire = open(fire_path,'rb')
    self.pickle_unfire = open(unfire_path,'rb')
    
  def __getitem__(self,index):
    if index <2504:
      fire = pickle.load(self.pickle_fire)#高*宽*通道
      fire = fire.transpose(2,0,1)#通道*高*宽
      data = torch.from_numpy(fire)
      label = 1
      return data,label
    elif index>=2504 and index<6489:
      unfire = pickle.load(self.pickle_unfire)
      unfire = unfire.transpose(2,0,1)
      data = torch.from_numpy(unfire)
      label = 0
      return data,label
    
  def __len__(self):
    return 6489

root_path = './datasets/train'
dataset = Fire_Unfire(root_path +'/fire_train.pkl',root_path +'/unfire_train.pkl')
 
#转换成pytorch网络输入的格式(批量大小,通道数,高,宽)
from torch.utils.data import DataLoader
fire_dataloader = DataLoader(dataset,batch_size=4,shuffle=True,drop_last = True)

import torch
from torch.utils import data
from nets.mobilenet import mobilenet
from config.config import default_config
from torch.autograd import Variable as V
import numpy as np
import sys
import time
 
opt = default_config()
def train():
  #模型定义
  model = mobilenet().cuda()
  if opt.pretrain_model:
    model.load_state_dict(torch.load(opt.pretrain_model))
  
  #损失函数
  criterion = torch.nn.CrossEntropyLoss().cuda()
  
  #学习率
  lr = opt.lr
  
  #优化器
  optimizer = torch.optim.SGD(model.parameters(),lr = lr,weight_decay=opt.weight_decay)
  
  
  pre_loss = 0.0
  #训练
  for epoch in range(opt.max_epoch):
     #训练数据
    train_data = Fire_Unfire(opt.root_path +'/fire_train.pkl',opt.root_path +'/unfire_train.pkl')
    train_dataloader = data.DataLoader(train_data,batch_size=opt.batch_size,shuffle=True,drop_last = True)
    loss_sum = 0.0
    for i,(datas,labels) in enumerate(train_dataloader):
      #print(i,datas.size(),labels)
      #梯度清零
      optimizer.zero_grad()
      #输入
      input = V(datas.cuda()).float()
      #目标
      target = V(labels.cuda()).long()
      #输出
      score = model(input).cuda()
      #损失
      loss = criterion(score,target)
      loss_sum += loss
      #反向传播
      loss.backward()
      #梯度更新
      optimizer.step()      
    print('{}{}{}{}{}'.format('epoch:',epoch,',','loss:',loss))
    torch.save(model.state_dict(),'models/mobilenet_%d.pth'%(epoch+370))