import os
import pickle

import tests.utils as tutils
from pytorch_lightning import Trainer
from pytorch_lightning.logging import LightningLoggerBase, rank_zero_only
from pytorch_lightning.testing import LightningTestModel


def test_testtube_logger(tmpdir):
    """Verify that basic functionality of test tube logger works."""
    tutils.reset_seed()
    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    logger = tutils.get_test_tube_logger(tmpdir, False)

    trainer_options = dict(
        max_num_epochs=1,
        train_percent_check=0.01,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    result = trainer.fit(model)

    assert result == 1, "Training failed"


def test_testtube_pickle(tmpdir):
    """Verify that pickling a trainer containing a test tube logger works."""
    tutils.reset_seed()

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    logger = tutils.get_test_tube_logger(tmpdir, False)
    logger.log_hyperparams(hparams)
    logger.save()

    trainer_options = dict(
        max_num_epochs=1,
        train_percent_check=0.01,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    pkl_bytes = pickle.dumps(trainer)
    trainer2 = pickle.loads(pkl_bytes)
    trainer2.logger.log_metrics({"acc": 1.0})


def test_mlflow_logger(tmpdir):
    """Verify that basic functionality of mlflow logger works."""
    tutils.reset_seed()

    try:
        from pytorch_lightning.logging import MLFlowLogger
    except ModuleNotFoundError:
        return

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    mlflow_dir = os.path.join(tmpdir, "mlruns")

    logger = MLFlowLogger("test", f"file://{mlflow_dir}")

    trainer_options = dict(
        max_num_epochs=1,
        train_percent_check=0.01,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    result = trainer.fit(model)

    print('result finished')
    assert result == 1, "Training failed"


def test_mlflow_pickle(tmpdir):
    """Verify that pickling trainer with mlflow logger works."""
    tutils.reset_seed()

    try:
        from pytorch_lightning.logging import MLFlowLogger
    except ModuleNotFoundError:
        return

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    mlflow_dir = os.path.join(tmpdir, "mlruns")

    logger = MLFlowLogger("test", f"file://{mlflow_dir}")

    trainer_options = dict(
        max_num_epochs=1,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    pkl_bytes = pickle.dumps(trainer)
    trainer2 = pickle.loads(pkl_bytes)
    trainer2.logger.log_metrics({"acc": 1.0})


def test_comet_logger(tmpdir, monkeypatch):
    """Verify that basic functionality of Comet.ml logger works."""

    # prevent comet logger from trying to print at exit, since
    # pytest's stdout/stderr redirection breaks it
    import atexit
    monkeypatch.setattr(atexit, "register", lambda _: None)

    tutils.reset_seed()

    try:
        from pytorch_lightning.logging import CometLogger
    except ModuleNotFoundError:
        return

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    comet_dir = os.path.join(tmpdir, "cometruns")

    # We test CometLogger in offline mode with local saves
    logger = CometLogger(
        save_dir=comet_dir,
        project_name="general",
        workspace="dummy-test",
    )

    trainer_options = dict(
        max_num_epochs=1,
        train_percent_check=0.01,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    result = trainer.fit(model)

    print('result finished')
    assert result == 1, "Training failed"


def test_comet_pickle(tmpdir, monkeypatch):
    """Verify that pickling trainer with comet logger works."""

    # prevent comet logger from trying to print at exit, since
    # pytest's stdout/stderr redirection breaks it
    import atexit
    monkeypatch.setattr(atexit, "register", lambda _: None)

    tutils.reset_seed()

    try:
        from pytorch_lightning.logging import CometLogger
    except ModuleNotFoundError:
        return

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    comet_dir = os.path.join(tmpdir, "cometruns")

    # We test CometLogger in offline mode with local saves
    logger = CometLogger(
        save_dir=comet_dir,
        project_name="general",
        workspace="dummy-test",
    )

    trainer_options = dict(
        max_num_epochs=1,
        logger=logger
    )

    trainer = Trainer(**trainer_options)
    pkl_bytes = pickle.dumps(trainer)
    trainer2 = pickle.loads(pkl_bytes)
    trainer2.logger.log_metrics({"acc": 1.0})


def test_custom_logger(tmpdir):
    class CustomLogger(LightningLoggerBase):
        def __init__(self):
            super().__init__()
            self.hparams_logged = None
            self.metrics_logged = None
            self.finalized = False

        @rank_zero_only
        def log_hyperparams(self, params):
            self.hparams_logged = params

        @rank_zero_only
        def log_metrics(self, metrics, step_idx):
            self.metrics_logged = metrics

        @rank_zero_only
        def finalize(self, status):
            self.finalized_status = status

        @property
        def name(self):
            return "name"

        @property
        def version(self):
            return "1"

    hparams = tutils.get_hparams()
    model = LightningTestModel(hparams)

    logger = CustomLogger()

    trainer_options = dict(
        max_num_epochs=1,
        train_percent_check=0.01,
        logger=logger,
        default_save_path=tmpdir
    )

    trainer = Trainer(**trainer_options)
    result = trainer.fit(model)
    assert result == 1, "Training failed"
    assert logger.hparams_logged == hparams
    assert logger.metrics_logged != {}
    assert logger.finalized_status == "success"