import gym
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

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

    self.fc1 = rn.NoisyLinear(state_size, 64)
    self.fc_norm = nn.LayerNorm(64)

    self.fc2 = rn.NoisyLinear(64, 64)
    self.fc2_norm = nn.LayerNorm(64)

    self.fc3 = rn.NoisyLinear(64, 1)

  def forward(self, x):
    x = F.relu(self.fc_norm(self.fc1(x)))
    x = F.relu(self.fc2_norm(self.fc2(x)))
    x = self.fc3(x)
    return x

class Policy(nn.Module):
  def __init__(self, state_size, action_size):
    super(Policy, 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.fc2 = rn.NoisyLinear(64, 64)
    self.fc2_norm = nn.LayerNorm(64)

    self.fc3 = rn.NoisyLinear(64, action_size)

  def forward(self, x):
    x = F.relu(self.fc_norm(self.fc1(x)))
    x = F.relu(self.fc2_norm(self.fc2(x)))
    x = F.softmax(self.fc3(x), dim = 1)
    return x

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

#
## Training Loop
#
def train(runner, agent, config, logger = None, logwriter = None):
    finished = False
    while not finished:
        runner.run()
        agent.learn()
        if logwriter is not None:
          agent.value_net.log_named_parameters()
          agent.policy_net.log_named_parameters()
          logwriter.write(logger)
        finished = runner.episode_num > config['total_training_episodes']


if __name__ == "__main__":
  # 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")
  policy_net = rn.Network(Policy(state_size, action_size), 
                      torch.optim.Adam, config, device = device, name = "Policy")
  value_net = rn.Network(Value(state_size), 
                      torch.optim.Adam, config, device = device, name = "DQN")


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

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

  # Agent is what performs the training
  agent = rltorch.agents.A2CSingleAgent(policy_net, value_net, memory, config, logger = logger)

  # Runner performs one episode in the environment
  runner = rltorch.env.EnvironmentEpisodeSync(env, actor, config, name = "Training", memory = memory, logwriter = logwriter)
    
  print("Training...")
  train(runner, agent, 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