# Copyright 2018 The Kubeflow Authors
#
# 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.

import kfp.dsl as dsl
import kfp.gcp as gcp


class GetFrequentWordOp(dsl.ContainerOp):
    """A get frequent word class representing a component in ML Pipelines.

    The class provides a nice interface to users by hiding details such
    as container, command, arguments.
    """

    def __init__(self, name, message):
        """Args:
         name: An identifier of the step which needs to be unique within a pipeline.
         message: a dsl.PipelineParam object representing an input message.
    """
        super(GetFrequentWordOp, self).__init__(
            name=name,
            image='python:3.5-jessie',
            command=['sh', '-c'],
            arguments=[
                'python -c "from collections import Counter; '
                'words = Counter(\'%s\'.split()); print(max(words, key=words.get))" '
                '| tee /tmp/message.txt' % message
            ],
            file_outputs={'word': '/tmp/message.txt'})


class SaveMessageOp(dsl.ContainerOp):
    """A class representing a component in ML Pipelines.

    It saves a message to a given output_path.
    """

    def __init__(self, name, message, output_path):
        """Args:
         name: An identifier of the step which needs to be unique within a pipeline.
         message: a dsl.PipelineParam object representing the message to be saved.
         output_path: a dsl.PipelineParam object representing the GCS path for output file.
    """
        super(SaveMessageOp, self).__init__(
            name=name,
            image='google/cloud-sdk',
            command=['sh', '-c'],
            arguments=[
                'echo %s | tee /tmp/results.txt | gsutil cp /tmp/results.txt %s'
                % (message, output_path)
            ])


class ExitHandlerOp(dsl.ContainerOp):
    """A class representing a component in ML Pipelines."""

    def __init__(self, name):
        super(ExitHandlerOp, self).__init__(
            name=name,
            image='python:3.5-jessie',
            command=['sh', '-c'],
            arguments=['echo exit!'])


@dsl.pipeline(
    name='Save Most Frequent',
    description='Get Most Frequent Word and Save to GCS')
def save_most_frequent_word(message: str, outputpath: str):
    """A pipeline function describing the orchestration of the workflow."""

    exit_op = ExitHandlerOp('exiting')
    with dsl.ExitHandler(exit_op):
        counter = GetFrequentWordOp(name='get-Frequent', message=message)
        counter.container.set_memory_request('200M')

        saver = SaveMessageOp(
            name='save', message=counter.output, output_path=outputpath)
        saver.container.set_cpu_limit('0.5')
        saver.container.set_gpu_limit('2')
        saver.add_node_selector_constraint('cloud.google.com/gke-accelerator',
                                           'nvidia-tesla-k80')
        saver.apply(
            gcp.use_tpu(tpu_cores=8, tpu_resource='v2', tf_version='1.12'))