import os
import shutil
import sys
import tempfile
import time
import unittest

import ray
from ray import tune
from ray.rllib import _register_all
from ray.tune.checkpoint_manager import Checkpoint
from ray.tune.logger import DEFAULT_LOGGERS, LoggerCallback, \
    LegacyLoggerCallback
from ray.tune.ray_trial_executor import RayTrialExecutor
from ray.tune.result import TRAINING_ITERATION
from ray.tune.syncer import SyncConfig, SyncerCallback

from ray.tune.trial import Trial
from ray.tune.trial_runner import TrialRunner
from ray.tune import Callback
from ray.tune.utils.callback import create_default_callbacks


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

    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


class _MockTrialExecutor(RayTrialExecutor):
    def __init__(self):
        super().__init__()
        self.results = {}
        self.next_trial = None
        self.failed_trial = None

    def fetch_result(self, trial):
        return [self.results.get(trial, {})]

    def get_next_available_trial(self):
        return self.next_trial or super().get_next_available_trial()

    def get_next_failed_trial(self):
        return self.failed_trial or super().get_next_failed_trial()


class TrialRunnerCallbacks(unittest.TestCase):
    def setUp(self):
        self.tmpdir = tempfile.mkdtemp()
        self.callback = TestCallback()
        self.executor = _MockTrialExecutor()
        self.trial_runner = TrialRunner(
            trial_executor=self.executor, callbacks=[self.callback])

    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_trial = trials[0]
        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"
            ]))

        self.executor.next_trial = trials[1]
        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")

        cp = Checkpoint(Checkpoint.PERSISTENT, "__checkpoint",
                        {TRAINING_ITERATION: 0})

        # Let the first trial save a checkpoint
        self.executor.next_trial = trials[0]
        trials[0].saving_to = cp
        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.results[trials[1]] = result
        self.executor.next_trial = trials[1]
        self.assertEqual(trials[1].last_result, {})
        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].restoring_from = cp
        self.executor.results[trials[1]] = trials[1].last_result
        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].restoring_from = None
        self.executor.results[trials[1]] = {
            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.failed_trial = trials[0]
        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(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,
            config=config,
            raise_on_failed_trial=False,
            callbacks=[self.callback])

        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")

    def testCallbackReordering(self):
        """SyncerCallback should come after LoggerCallback callbacks"""

        def get_positions(callbacks):
            first_logger_pos = None
            last_logger_pos = None
            syncer_pos = None
            for i, callback in enumerate(callbacks):
                if isinstance(callback, LoggerCallback):
                    if first_logger_pos is None:
                        first_logger_pos = i
                    last_logger_pos = i
                elif isinstance(callback, SyncerCallback):
                    syncer_pos = i
            return first_logger_pos, last_logger_pos, syncer_pos

        # Auto creation of loggers, no callbacks, no syncer
        callbacks = create_default_callbacks(None, SyncConfig(), None)
        first_logger_pos, last_logger_pos, syncer_pos = get_positions(
            callbacks)
        self.assertLess(last_logger_pos, syncer_pos)

        # Auto creation of loggers with callbacks
        callbacks = create_default_callbacks([Callback()], SyncConfig(), None)
        first_logger_pos, last_logger_pos, syncer_pos = get_positions(
            callbacks)
        self.assertLess(last_logger_pos, syncer_pos)

        # Auto creation of loggers with existing logger (but no CSV/JSON)
        callbacks = create_default_callbacks([LoggerCallback()], SyncConfig(),
                                             None)
        first_logger_pos, last_logger_pos, syncer_pos = get_positions(
            callbacks)
        self.assertLess(last_logger_pos, syncer_pos)

        # This should throw an error as the syncer comes before the logger
        with self.assertRaises(ValueError):
            callbacks = create_default_callbacks(
                [SyncerCallback(None), LoggerCallback()], SyncConfig(), None)

        # This should be reordered but preserve the regular callback order
        [mc1, mc2, mc3] = [Callback(), Callback(), Callback()]
        # Has to be legacy logger to avoid logger callback creation
        lc = LegacyLoggerCallback(logger_classes=DEFAULT_LOGGERS)
        callbacks = create_default_callbacks([mc1, mc2, lc, mc3], SyncConfig(),
                                             None)
        print(callbacks)
        first_logger_pos, last_logger_pos, syncer_pos = get_positions(
            callbacks)
        self.assertLess(last_logger_pos, syncer_pos)
        self.assertLess(callbacks.index(mc1), callbacks.index(mc2))
        self.assertLess(callbacks.index(mc2), callbacks.index(mc3))
        self.assertLess(callbacks.index(lc), callbacks.index(mc3))
        # Syncer callback is appended
        self.assertLess(callbacks.index(mc3), syncer_pos)


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