"""
 Copyright 2020 Tianshu AI Platform. All Rights Reserved.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 =============================================================
"""

from .base import Callback
import numbers
from tqdm import tqdm

class MetricsLogging(Callback):
    def __init__(self, keys):
        super(MetricsLogging, self).__init__()
        self._keys = keys

    def __call__(self, engine):
        if engine.logger==None:
            return
        state = engine.state
        content = "Iter %d/%d (Epoch %d/%d, Batch %d/%d)"%(
            state.iter, state.max_iter, 
            state.current_epoch, state.max_epoch, 
            state.current_batch_index, state.max_batch_index
        )
        for key in self._keys:
            value = state.metrics.get(key, None)
            if value is not None:
                if isinstance(value, numbers.Number):
                    content += " %s=%.4f"%(key, value)
                    if engine.tb_writer is not None:
                        engine.tb_writer.add_scalar(key, value, global_step=state.iter)
                elif isinstance(value, (list, tuple)):
                    content += " %s=%s"%(key, value)
                
        engine.logger.info(content)
    
class ProgressCallback(Callback):
    def __init__(self, max_iter=100, tag=None):
        self._max_iter = max_iter
        self._tag = tag
        #self._pbar = tqdm(total=self._max_iter, desc=self._tag)
    
    def __call__(self, engine):
        self._pbar.update(1)
        if self._pbar.n==self._max_iter:
            self._pbar.close()
    
    def reset(self):
        self._pbar = tqdm(total=self._max_iter, desc=self._tag)