import gym
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
import rltorch
import rltorch.network as rn
import rltorch.memory as M
import rltorch.env as E
from rltorch.action_selector import StochasticSelector
from tensorboardX import SummaryWriter
import torch.multiprocessing as mp
import signal
from copy import deepcopy

class Value(nn.Module):
  def __init__(self, state_size, action_size):
    super(Value, self).__init__()
    self.state_size = state_size
    self.action_size = action_size

    self.fc1 = rn.NoisyLinear(state_size, 64)
    self.fc_norm = nn.LayerNorm(64)
    
    self.value_fc = rn.NoisyLinear(64, 64)
    self.value_fc_norm = nn.LayerNorm(64)
    self.value = rn.NoisyLinear(64, 1)
    
    self.advantage_fc = rn.NoisyLinear(64, 64)
    self.advantage_fc_norm = nn.LayerNorm(64)
    self.advantage = rn.NoisyLinear(64, action_size)

  def forward(self, x):
    x = F.relu(self.fc_norm(self.fc1(x)))
    
    state_value = F.relu(self.value_fc_norm(self.value_fc(x)))
    state_value = self.value(state_value)
    
    advantage = F.relu(self.advantage_fc_norm(self.advantage_fc(x)))
    advantage = self.advantage(advantage)
    
    x = F.softmax(state_value + advantage - advantage.mean(), dim = 1)
    
    return x


config = {}
config['seed'] = 901
config['environment_name'] = 'Acrobot-v1'
config['memory_size'] = 2000
config['total_training_episodes'] = 500
config['total_evaluation_episodes'] = 10
config['batch_size'] = 32
config['learning_rate'] = 1e-3
config['target_sync_tau'] = 1e-1
config['discount_rate'] = 0.99
config['replay_skip'] = 0
# How many episodes between printing out the episode stats
config['print_stat_n_eps'] = 1
config['disable_cuda'] = False

def train(env, agent, actor, memory, config, logger = None, logwriter = None):
    finished = False
    episode_num = 1
    while not finished:
        rltorch.env.simulateEnvEps(env, actor, config, memory = memory, logger = logger, name = "Training")
        episode_num += 1
        agent.learn()
        # When the episode number changes, log network paramters
        if logwriter is not None:
          agent.net.log_named_parameters()
          logwriter.write(logger)
        finished = episode_num > config['total_training_episodes']



if __name__ == "__main__":
  torch.multiprocessing.set_sharing_strategy('file_system') # To not hit file descriptor memory limit

  # Setting up the environment
  rltorch.set_seed(config['seed'])
  print("Setting up environment...", end = " ")
  env = E.TorchWrap(gym.make(config['environment_name']))
  env.seed(config['seed'])
  print("Done.")
      
  state_size = env.observation_space.shape[0]
  action_size = env.action_space.n

  # Logging
  logger = rltorch.log.Logger()
  logwriter = rltorch.log.LogWriter(SummaryWriter())

  # Setting up the networks
  device = torch.device("cuda:0" if torch.cuda.is_available() and not config['disable_cuda'] else "cpu")
  net = rn.Network(Value(state_size, action_size), 
                      torch.optim.Adam, config, device = device, name = "DQN")
  target_net = rn.TargetNetwork(net, device = device)
  net.model.share_memory()
  target_net.model.share_memory()

  # Memory stores experiences for later training
  memory = M.EpisodeMemory()

  # Actor takes a net and uses it to produce actions from given states
  actor = StochasticSelector(net, action_size, memory, device = device)

  # Agent is what performs the training
  agent = rltorch.agents.REINFORCEAgent(net, memory, config, target_net = target_net, logger = logger)
    
  print("Training...")

  train(env, agent, actor, memory, config, logger = logger, logwriter = logwriter) 

  # For profiling...
  # import cProfile
  # cProfile.run('train(runner, agent, config, logger = logger, logwriter = logwriter )')
  # python -m torch.utils.bottleneck /path/to/source/script.py [args] is also a good solution...

  print("Training Finished.")

  print("Evaluating...")
  rltorch.env.simulateEnvEps(env, actor, config, total_episodes = config['total_evaluation_episodes'], logger = logger, name = "Evaluation")
  print("Evaulations Done.")

  logwriter.close() # We don't need to write anything out to disk anymore