import pytest
import unittest

import ray
import ray.rllib.agents.dqn.apex as apex
from ray.rllib.utils.test_utils import check, check_compute_single_action, \
    framework_iterator


class TestApexDQN(unittest.TestCase):
    def setUp(self):
        ray.init(num_cpus=4)

    def tearDown(self):
        ray.shutdown()

    def test_apex_zero_workers(self):
        config = apex.APEX_DEFAULT_CONFIG.copy()
        config["num_workers"] = 0
        config["num_gpus"] = 0
        config["learning_starts"] = 1000
        config["prioritized_replay"] = True
        config["timesteps_per_iteration"] = 100
        config["min_iter_time_s"] = 1
        config["optimizer"]["num_replay_buffer_shards"] = 1
        for _ in framework_iterator(config):
            trainer = apex.ApexTrainer(config=config, env="CartPole-v0")
            trainer.train()
            trainer.stop()

    def test_apex_dqn_compilation_and_per_worker_epsilon_values(self):
        """Test whether an APEX-DQNTrainer can be built on all frameworks."""
        config = apex.APEX_DEFAULT_CONFIG.copy()
        config["num_workers"] = 3
        config["num_gpus"] = 0
        config["learning_starts"] = 1000
        config["prioritized_replay"] = True
        config["timesteps_per_iteration"] = 100
        config["min_iter_time_s"] = 1
        config["optimizer"]["num_replay_buffer_shards"] = 1

        for _ in framework_iterator(config):
            plain_config = config.copy()
            trainer = apex.ApexTrainer(config=plain_config, env="CartPole-v0")

            # Test per-worker epsilon distribution.
            infos = trainer.workers.foreach_policy(
                lambda p, _: p.get_exploration_state())
            expected = [0.4, 0.016190862, 0.00065536]
            check([i["cur_epsilon"] for i in infos], [0.0] + expected)

            check_compute_single_action(trainer)

            for i in range(2):
                print(trainer.train())

            # Test again per-worker epsilon distribution
            # (should not have changed).
            infos = trainer.workers.foreach_policy(
                lambda p, _: p.get_exploration_state())
            check([i["cur_epsilon"] for i in infos], [0.0] + expected)

            trainer.stop()


if __name__ == "__main__":
    import sys
    sys.exit(pytest.main(["-v", __file__]))