import numpy as np
import torch
import torch.optim as optim

from tugo import encoders
from tugo.game_logic import goboard
from tugo.agents import Agent
from tugo.agents.helpers import is_point_an_eye

class ACAgent(Agent):
    def __init__(self, model, encoder):
        super().__init__()
        self.model = model
        self.encoder = encoder
        self.collector = None
        self.temperature = 1.0
        self.device = 'cuda' if torch.cuda.is_available() else 'cpu'
        self.model = self.model.to(self.device)
        self.last_state_value = 0

    def set_temperature(self, temperature):
        self.temperature = temperature

    def set_collector(self, collector):
        self.collector = collector

    def select_move(self, game_state):
        num_moves = self.encoder.board_width * self.encoder.board_height

        board_tensor = self.encoder.encode(game_state)
        x = torch.tensor([board_tensor], dtype=torch.float32).to(self.device)

        actions, values = self.model(x)
        move_probs = actions[0].cpu().detach().numpy()
        estimated_value = values[0][0].cpu().detach().numpy()
        self.last_state_value = float(estimated_value)

        # Prevent move probs from getting stuck at 0 or 1.
        move_probs = np.power(move_probs, 1.0 / self.temperature)
        move_probs = move_probs / np.sum(move_probs)
        eps = 1e-6
        move_probs = np.clip(move_probs, eps, 1 - eps)
        # Re-normalize to get another probability distribution.
        move_probs = move_probs / np.sum(move_probs)

        # Turn the probabilities into a ranked list of moves.
        candidates = np.arange(num_moves)
        ranked_moves = np.random.choice(
            candidates, num_moves, replace=False, p=move_probs)
        for point_idx in ranked_moves:
            point = self.encoder.decode_point_index(point_idx)
            if game_state.is_valid_move(goboard.Move.play(point)) and \
                    not is_point_an_eye(game_state.board,
                                        point,
                                        game_state.next_player):
                if self.collector is not None:
                    self.collector.record_decision(
                        state=board_tensor,
                        action=point_idx,
                        estimated_value=estimated_value
                    )
                return goboard.Move.play(point)
        # No legal, non-self-destructive moves less.
        return goboard.Move.pass_turn()

    def train(self, experience, lr=0.1, batch_size=128):
        opt = optim.Adam(self.model.parameters(), lr=lr)

        n = experience.states.shape[0]
        num_moves = self.encoder.num_points()
        policy_target = np.zeros((n, num_moves))
        value_target = np.zeros((n,))
        for i in range(n):
            action = experience.actions[i]
            reward = experience.rewards[i]
            policy_target[i][action] = experience.advantages[i]
            value_target[i] = reward

        policy_target = torch.tensor(policy_target, dtype=torch.float32).to(self.device)
        value_target = torch.tensor(value_target, dtype=torch.float32).to(self.device)
        states = torch.tensor(experience.states, dtype=torch.float32).to(self.device)

        for _ in range(n // batch_size):
            self.model.train()
            opt.zero_grad()
            action_pred, value_pred = self.model(states)
            value_loss = ((value_target - value_pred) ** 2).mean()
            policy_loss = -(policy_target * torch.log(action_pred)).sum(1).mean()
            loss = policy_loss + value_loss
            loss.backward()
            opt.step()

    def diagnostics(self):
        return {'value': self.last_state_value}

    def save(self, file_path):
        torch.save(self.model.state_dict(), file_path)

    @classmethod
    def load(cls, file_path, encoder):
        device = 'cuda' if torch.cuda.is_available() else 'cpu'
        model = AlphaGoModel(encoder.get_input_shape(), is_policy_net=True).to(device)
        model.load_state_dict(torch.load(file_path))
        return cls(model, encoder)

# def load_ac_agent(path, encoder):
#     # 在这个转换中，MyModel() 是你的 PyTorch 模型的实例化方法，你需要将其替换为你实际使用的模型。并且，假设你的模型接受一个状态并输出行动和值。
#     model = MyModel()  # Initialize your model
#     model.load_state_dict(torch.load(path))
#     return ACAgent(model, encoder)