# Copyright 2021 Google LLC
#
# 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 typing import Dict, NamedTuple, Optional, Union

from absl import logging
import fire
from google.protobuf import json_format
import os

from kfp.containers import _gcs_helper
from kfp.containers import entrypoint_utils
from kfp.dsl import artifact
from kfp.pipeline_spec import pipeline_spec_pb2

FN_SOURCE = 'ml/main.py'
FN_NAME_ARG = 'function_name'

PARAM_METADATA_SUFFIX = '_input_param_metadata_file'
ARTIFACT_METADATA_SUFFIX = '_input_artifact_metadata_file'
FIELD_NAME_SUFFIX = '_input_field_name'
ARGO_PARAM_SUFFIX = '_input_argo_param'
INPUT_URI_SUFFIX = '_input_uri'
PRODUCER_POD_ID_SUFFIX = '_pod_id'
OUTPUT_NAME_SUFFIX = '_input_output_name'

OUTPUT_PARAM_PATH_SUFFIX = '_parameter_output_path'
OUTPUT_ARTIFACT_PATH_SUFFIX = '_artifact_output_uri'

METADATA_FILE_ARG = 'executor_metadata_json_file'


class InputParam(object):
  """POD that holds an input parameter."""

  def __init__(self,
      value: Optional[Union[str, float, int]] = None,
      metadata_file: Optional[str] = None,
      field_name: Optional[str] = None):
    """Instantiates an InputParam object.

    Args:
      value: The actual value of the parameter.
      metadata_file: The location of the metadata JSON file output by the
        producer step.
      field_name: The output name of the producer.

    Raises:
      ValueError: when neither of the following is true:
        1) value is provided, and metadata_file and field_name are not; or
        2) both metadata_file and field_name are provided, and value is not.
    """
    if not (value is not None and not (metadata_file or field_name) or (
        metadata_file and field_name and value is None)):
      raise ValueError('Either value or both metadata_file and field_name '
                       'needs to be provided. Got value={value}, field_name='
                       '{field_name}, metadata_file={metadata_file}'.format(
          value=value,
          field_name=field_name,
          metadata_file=metadata_file
      ))
    if value is not None:
      self._value = value
    else:
      # Parse the value by inspecting the producer's metadata JSON file.
      self._value = entrypoint_utils.get_parameter_from_output(
          metadata_file, field_name)

    self._metadata_file = metadata_file
    self._field_name = field_name

  # Following properties are read-only
  @property
  def value(self) -> Union[float, str, int]:
    return self._value

  @property
  def metadata_file(self) -> str:
    return self._metadata_file

  @property
  def field_name(self) -> str:
    return self._field_name


class InputArtifact(object):
  """POD that holds an input artifact."""

  def __init__(self,
      uri: Optional[str] = None,
      metadata_file: Optional[str] = None,
      output_name: Optional[str] = None
  ):
    """Instantiates an InputParam object.

    Args:
      uri: The uri holds the input artifact.
      metadata_file: The location of the metadata JSON file output by the
        producer step.
      output_name: The output name of the artifact in producer step.

    Raises:
      ValueError: when neither of the following is true:
        1) uri is provided, and metadata_file and output_name are not; or
        2) both metadata_file and output_name are provided, and uri is not.
    """
    if not ((uri and not (metadata_file or output_name) or (
        metadata_file and output_name and not uri))):
      raise ValueError('Either uri or both metadata_file and output_name '
                       'needs to be provided. Got uri={uri}, output_name='
                       '{output_name}, metadata_file={metadata_file}'.format(
          uri=uri,
          output_name=output_name,
          metadata_file=metadata_file
      ))

    self._metadata_file = metadata_file
    self._output_name = output_name
    if uri:
      self._uri = uri
    else:
      self._uri = self.get_artifact().uri

  # Following properties are read-only.
  @property
  def uri(self) -> str:
    return self._uri

  @property
  def metadata_file(self) -> str:
    return self._metadata_file

  @property
  def output_name(self) -> str:
    return self._output_name

  def get_artifact(self) -> artifact.Artifact:
    """Gets an artifact object by parsing metadata or creating one from uri."""
    if self.metadata_file and self.output_name:
      return entrypoint_utils.get_artifact_from_output(
          self.metadata_file, self.output_name)
    else:
      # Provide an empty schema when returning a raw Artifact.
      result = artifact.Artifact(
          instance_schema=artifact.DEFAULT_ARTIFACT_SCHEMA)
      result.uri = self.uri
      return result


def _write_output_metadata_file(
    fn_res: Union[int, str, float, NamedTuple],
    output_artifacts: Dict[str, artifact.Artifact],
    output_metadata_path: str
):
  """Writes the output metadata file to the designated place."""
  # If output_params is a singleton value, needs to transform it to a mapping.
  output_parameters = {}
  if isinstance(fn_res, (int, str, float)):
    output_parameters['output'] = fn_res
  else:
    # When multiple outputs, we'll need to match each field to the output paths.
    for idx, output_name in enumerate(fn_res._fields):
      output_parameters[output_name] = fn_res[idx]

  executor_output = entrypoint_utils.get_executor_output(
      output_artifacts=output_artifacts,
      output_params=output_parameters)

  with open(output_metadata_path, 'w') as f:
    f.write(json_format.MessageToJson(executor_output))

  return executor_output


def main(
    executor_input_str: str,
    function_name: str,
    output_metadata_path: Optional[str] = None):
  """Container entrypoint used by KFP Python function based component

  executor_input_str: A serialized ExecutorInput proto message.
  function_name: The name of the user-defined function.
  output_metadata_path: A local path where the output metadata JSON file should
    be written to.
  """
  executor_input = pipeline_spec_pb2.ExecutorInput()
  json_format.Parse(text=executor_input_str, message=executor_input)
  output_metadata_path = output_metadata_path or executor_input.outputs.output_file
  parameter_dict = {}  # kwargs to be passed to UDF.
  for name, input_param in executor_input.inputs.parameters.items():
    parameter_dict[name] = entrypoint_utils.get_python_value(input_param)

  for name, input_artifacts in executor_input.inputs.artifacts.items():
    parameter_dict[name] = artifact.Artifact.get_from_runtime_artifact(
        input_artifacts.artifacts[0])

  # Also, determine a way to inspect the function signature to decide the type
  # of output artifacts.
  fn = entrypoint_utils.import_func_from_source(FN_SOURCE, function_name)

  # In the ExeuctorInput message passed into the entrypoint, the output artifact
  # URIs are already specified. The output artifact is constructed according to
  # the specified URIs + type information retrieved from function signature.
  output_uris = {}
  for name, output_artifacts in executor_input.outputs.artifacts.items():
    output_uris[name] = output_artifacts.artifacts[0].uri

  output_artifacts = entrypoint_utils.get_output_artifacts(
      fn, output_uris)
  for name, art in output_artifacts.items():
    parameter_dict[name] = art

  # Execute the user function. fn_res is expected to contain output parameters
  # only. It's either an namedtuple or a single primitive value.
  fn_res = fn(**parameter_dict)

  _write_output_metadata_file(
      fn_res=fn_res,
      output_artifacts=output_artifacts,
      output_metadata_path=output_metadata_path)


if __name__ == '__main__':
  fire.Fire(main)