import os
import shutil
import sys
import tempfile
import time
import unittest
from unittest.mock import patch
from collections import OrderedDict

import ray
from ray import tune
from ray.air._internal.checkpoint_manager import _TrackedCheckpoint, CheckpointStorage
from ray.air.constants import TRAINING_ITERATION
from ray.rllib import _register_all
from ray.tune.execution.ray_trial_executor import (
    _ExecutorEvent,
    _ExecutorEventType,
    RayTrialExecutor,
)

from ray.tune.callback import warnings
from ray.tune.experiment import Trial
from ray.tune.execution.trial_runner import TrialRunner
from ray.tune import Callback
from ray.tune.experiment import Experiment


class TestCallback(Callback):
    def __init__(self):
        self.state = OrderedDict()

    def setup(self, **info):
        self.state["setup"] = info

    def on_step_begin(self, **info):
        self.state["step_begin"] = info

    def on_step_end(self, **info):
        self.state["step_end"] = info

    def on_trial_start(self, **info):
        self.state["trial_start"] = info

    def on_trial_restore(self, **info):
        self.state["trial_restore"] = info

    def on_trial_save(self, **info):
        self.state["trial_save"] = info

    def on_trial_result(self, **info):
        self.state["trial_result"] = info
        result = info["result"]
        trial = info["trial"]
        assert result.get(TRAINING_ITERATION, None) != trial.last_result.get(
            TRAINING_ITERATION, None
        )

    def on_trial_complete(self, **info):
        self.state["trial_complete"] = info

    def on_trial_error(self, **info):
        self.state["trial_fail"] = info

    def on_experiment_end(self, **info):
        self.state["experiment_end"] = info


# TODO(xwjiang): Move this to a testing util.
class _MockTrialExecutor(RayTrialExecutor):
    def __init__(self):
        super().__init__()
        self.next_future_result = None

    def start_trial(self, trial: Trial):
        trial.status = Trial.RUNNING
        return True

    def continue_training(self, trial: Trial):
        pass

    def get_next_executor_event(self, live_trials, next_trial_exists):
        return self.next_future_result


class TrialRunnerCallbacks(unittest.TestCase):
    def setUp(self):
        ray.init()
        self.tmpdir = tempfile.mkdtemp()
        self.callback = TestCallback()
        self.executor = _MockTrialExecutor()
        self.trial_runner = TrialRunner(
            trial_executor=self.executor, callbacks=[self.callback]
        )
        # experiment would never be None normally, but it's fine for testing
        self.trial_runner.setup_experiments(experiments=[None], total_num_samples=1)

    def tearDown(self):
        ray.shutdown()
        _register_all()  # re-register the evicted objects
        if "CUDA_VISIBLE_DEVICES" in os.environ:
            del os.environ["CUDA_VISIBLE_DEVICES"]
        shutil.rmtree(self.tmpdir)

    def testCallbackSteps(self):
        trials = [Trial("__fake", trial_id="one"), Trial("__fake", trial_id="two")]
        for t in trials:
            self.trial_runner.add_trial(t)

        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.PG_READY
        )
        self.trial_runner.step()

        # Trial 1 has been started
        self.assertEqual(self.callback.state["trial_start"]["iteration"], 0)
        self.assertEqual(self.callback.state["trial_start"]["trial"].trial_id, "one")

        # All these events haven't happened, yet
        self.assertTrue(
            all(
                k not in self.callback.state
                for k in [
                    "trial_restore",
                    "trial_save",
                    "trial_result",
                    "trial_complete",
                    "trial_fail",
                    "experiment_end",
                ]
            )
        )

        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.PG_READY
        )
        self.trial_runner.step()

        # Iteration not increased yet
        self.assertEqual(self.callback.state["step_begin"]["iteration"], 1)

        # Iteration increased
        self.assertEqual(self.callback.state["step_end"]["iteration"], 2)

        # Second trial has been just started
        self.assertEqual(self.callback.state["trial_start"]["iteration"], 1)
        self.assertEqual(self.callback.state["trial_start"]["trial"].trial_id, "two")

        # Just a placeholder object ref for cp.value.
        cp = _TrackedCheckpoint(
            dir_or_data=ray.put(1),
            storage_mode=CheckpointStorage.PERSISTENT,
            metrics={TRAINING_ITERATION: 0},
        )
        trials[0].temporary_state.saving_to = cp

        # Let the first trial save a checkpoint
        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.SAVING_RESULT,
            trial=trials[0],
            result={_ExecutorEvent.KEY_FUTURE_RESULT: "__checkpoint"},
        )
        self.trial_runner.step()
        self.assertEqual(self.callback.state["trial_save"]["iteration"], 2)
        self.assertEqual(self.callback.state["trial_save"]["trial"].trial_id, "one")

        # Let the second trial send a result
        result = {TRAINING_ITERATION: 1, "metric": 800, "done": False}
        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.TRAINING_RESULT,
            trial=trials[1],
            result={_ExecutorEvent.KEY_FUTURE_RESULT: result},
        )
        self.assertTrue(not trials[1].has_reported_at_least_once)
        self.trial_runner.step()
        self.assertEqual(self.callback.state["trial_result"]["iteration"], 3)
        self.assertEqual(self.callback.state["trial_result"]["trial"].trial_id, "two")
        self.assertEqual(self.callback.state["trial_result"]["result"]["metric"], 800)
        self.assertEqual(trials[1].last_result["metric"], 800)

        # Let the second trial restore from a checkpoint
        trials[1].temporary_state.restoring_from = cp
        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.RESTORING_RESULT,
            trial=trials[1],
            result={_ExecutorEvent.KEY_FUTURE_RESULT: None},
        )
        self.trial_runner.step()
        self.assertEqual(self.callback.state["trial_restore"]["iteration"], 4)
        self.assertEqual(self.callback.state["trial_restore"]["trial"].trial_id, "two")

        # Let the second trial finish
        trials[1].temporary_state.restoring_from = None
        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.TRAINING_RESULT,
            trial=trials[1],
            result={
                _ExecutorEvent.KEY_FUTURE_RESULT: {
                    TRAINING_ITERATION: 2,
                    "metric": 900,
                    "done": True,
                }
            },
        )
        self.trial_runner.step()
        self.assertEqual(self.callback.state["trial_complete"]["iteration"], 5)
        self.assertEqual(self.callback.state["trial_complete"]["trial"].trial_id, "two")

        # Let the first trial error
        self.executor.next_future_result = _ExecutorEvent(
            event_type=_ExecutorEventType.TRAINING_RESULT,
            trial=trials[0],
            result={_ExecutorEvent.KEY_EXCEPTION: Exception()},
        )
        self.trial_runner.step()
        self.assertEqual(self.callback.state["trial_fail"]["iteration"], 6)
        self.assertEqual(self.callback.state["trial_fail"]["trial"].trial_id, "one")

    def testCallbacksEndToEnd(self):
        def train_fn(config):
            if config["do"] == "save":
                with tune.checkpoint_dir(0):
                    pass
                tune.report(metric=1)
            elif config["do"] == "fail":
                raise RuntimeError("I am failing on purpose.")
            elif config["do"] == "delay":
                time.sleep(2)
                tune.report(metric=20)

        config = {"do": tune.grid_search(["save", "fail", "delay"])}

        tune.run(
            train_fn,
            config=config,
            raise_on_failed_trial=False,
            callbacks=[self.callback],
        )

        self.assertIn("setup", self.callback.state)
        self.assertTrue(self.callback.state["setup"] is not None)
        keys = Experiment.PUBLIC_KEYS.copy()
        keys.add("total_num_samples")
        for key in keys:
            self.assertIn(key, self.callback.state["setup"])
        # check if it was added first
        self.assertTrue(list(self.callback.state)[0] == "setup")
        self.assertEqual(
            self.callback.state["trial_fail"]["trial"].config["do"], "fail"
        )
        self.assertEqual(
            self.callback.state["trial_save"]["trial"].config["do"], "save"
        )
        self.assertEqual(
            self.callback.state["trial_result"]["trial"].config["do"], "delay"
        )
        self.assertEqual(
            self.callback.state["trial_complete"]["trial"].config["do"], "delay"
        )
        self.assertIn("experiment_end", self.callback.state)
        # check if it was added last
        self.assertTrue(list(self.callback.state)[-1] == "experiment_end")

    @patch.object(warnings, "warn")
    def testCallbackSetupBackwardsCompatible(self, mocked_warning_method):
        class NoExperimentInSetupCallback(Callback):
            # Old method definition didn't take in **experiment.public_spec
            def setup(self):
                return

        callback = NoExperimentInSetupCallback()
        trial_runner = TrialRunner(callbacks=[callback])
        trial_runner.setup_experiments(
            experiments=[Experiment("", lambda x: x)], total_num_samples=1
        )
        mocked_warning_method.assert_called_once()
        self.assertIn("Please update", mocked_warning_method.call_args_list[0][0][0])


if __name__ == "__main__":
    import pytest

    sys.exit(pytest.main(["-v", __file__]))
