# Copyright 2021-2022 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 dataclasses
import inspect
import itertools
import pathlib
import re
import textwrap
from typing import Callable, List, Mapping, Optional, Tuple, Type, Union
import warnings

import docstring_parser
from kfp.dsl import container_component_artifact_channel
from kfp.dsl import container_component_class
from kfp.dsl import graph_component
from kfp.dsl import placeholders
from kfp.dsl import python_component
from kfp.dsl import structures
from kfp.dsl import task_final_status
from kfp.dsl.types import artifact_types
from kfp.dsl.types import custom_artifact_types
from kfp.dsl.types import type_annotations
from kfp.dsl.types import type_utils

_DEFAULT_BASE_IMAGE = 'python:3.7'


@dataclasses.dataclass
class ComponentInfo():
    """A dataclass capturing registered components.

    This will likely be subsumed/augmented with BaseComponent.
    """
    name: str
    function_name: str
    func: Callable
    target_image: str
    module_path: pathlib.Path
    component_spec: structures.ComponentSpec
    output_component_file: Optional[str] = None
    base_image: str = _DEFAULT_BASE_IMAGE
    packages_to_install: Optional[List[str]] = None
    pip_index_urls: Optional[List[str]] = None


# A map from function_name to components.  This is always populated when a
# module containing KFP components is loaded. Primarily used by KFP CLI
# component builder to package components in a file into containers.
REGISTERED_MODULES = None


def _python_function_name_to_component_name(name):
    name_with_spaces = re.sub(' +', ' ', name.replace('_', ' ')).strip(' ')
    return name_with_spaces[0].upper() + name_with_spaces[1:]


def make_index_url_options(pip_index_urls: Optional[List[str]]) -> str:
    """Generates index url options for pip install command based on provided
    pip_index_urls.

    Args:
        pip_index_urls: Optional list of pip index urls

    Returns:
        - Empty string if pip_index_urls is empty/None.
        - '--index-url url --trusted-host url ' if pip_index_urls contains 1
        url
        - the above followed by '--extra-index-url url --trusted-host url '
        for
        each next url in pip_index_urls if pip_index_urls contains more than 1
        url

        Note: In case pip_index_urls is not empty, the returned string will
        contain space at the end.
    """
    if not pip_index_urls:
        return ''

    index_url = pip_index_urls[0]
    extra_index_urls = pip_index_urls[1:]

    options = [f'--index-url {index_url} --trusted-host {index_url}']
    options.extend(
        f'--extra-index-url {extra_index_url} --trusted-host {extra_index_url}'
        for extra_index_url in extra_index_urls)

    return ' '.join(options) + ' '


_install_python_packages_script_template = '''
if ! [ -x "$(command -v pip)" ]; then
    python3 -m ensurepip || python3 -m ensurepip --user || apt-get install python3-pip
fi

PIP_DISABLE_PIP_VERSION_CHECK=1 python3 -m pip install --quiet \
    --no-warn-script-location {index_url_options}{concat_package_list} && "$0" "$@"
'''


def _get_packages_to_install_command(
        package_list: Optional[List[str]] = None,
        pip_index_urls: Optional[List[str]] = None) -> List[str]:

    if not package_list:
        return []

    concat_package_list = ' '.join(
        [repr(str(package)) for package in package_list])
    index_url_options = make_index_url_options(pip_index_urls)
    install_python_packages_script = _install_python_packages_script_template.format(
        index_url_options=index_url_options,
        concat_package_list=concat_package_list)
    return ['sh', '-c', install_python_packages_script]


def _get_default_kfp_package_path() -> str:
    import kfp
    return f'kfp=={kfp.__version__}'


def _get_function_source_definition(func: Callable) -> str:
    func_code = inspect.getsource(func)

    # Function might be defined in some indented scope (e.g. in another
    # function). We need to handle this and properly dedent the function source
    # code
    func_code = textwrap.dedent(func_code)
    func_code_lines = func_code.split('\n')

    # Removing possible decorators (can be multiline) until the function
    # definition is found
    func_code_lines = itertools.dropwhile(lambda x: not x.startswith('def'),
                                          func_code_lines)

    if not func_code_lines:
        raise ValueError(
            f'Failed to dedent and clean up the source of function "{func.__name__}". It is probably not properly indented.'
        )

    return '\n'.join(func_code_lines)


def _maybe_make_unique(name: str, names: List[str]):
    if name not in names:
        return name

    for i in range(2, 100):
        unique_name = f'{name}_{i}'
        if unique_name not in names:
            return unique_name

    raise RuntimeError(f'Too many arguments with the name {name}')


def extract_component_interface(
    func: Callable,
    containerized: bool = False,
    description: Optional[str] = None,
    name: Optional[str] = None,
) -> structures.ComponentSpec:
    single_output_name_const = 'Output'

    signature = inspect.signature(func)
    parameters = list(signature.parameters.values())

    original_docstring = inspect.getdoc(func)
    parsed_docstring = docstring_parser.parse(original_docstring)

    inputs = {}
    outputs = {}

    input_names = set()
    output_names = set()
    for parameter in parameters:
        parameter_type = type_annotations.maybe_strip_optional_from_annotation(
            parameter.annotation)
        passing_style = None
        io_name = parameter.name
        is_artifact_list = False

        if type_annotations.is_Input_Output_artifact_annotation(parameter_type):
            # passing_style is either type_annotations.InputAnnotation or
            # type_annotations.OutputAnnotation.
            passing_style = type_annotations.get_io_artifact_annotation(
                parameter_type)

            # parameter_type is a type like typing_extensions.Annotated[kfp.dsl.types.artifact_types.Artifact, <class 'kfp.dsl.types.type_annotations.OutputAnnotation'>] OR typing_extensions.Annotated[typing.List[kfp.dsl.types.artifact_types.Artifact], <class 'kfp.dsl.types.type_annotations.OutputAnnotation'>]

            is_artifact_list = type_annotations.is_list_of_artifacts(
                parameter_type.__origin__)

            parameter_type = type_annotations.get_io_artifact_class(
                parameter_type)
            if not type_annotations.is_artifact_class(parameter_type):
                raise ValueError(
                    f'Input[T] and Output[T] are only supported when T is an artifact or list of artifacts. Found `{io_name} with type {parameter_type}`'
                )

            if parameter.default is not inspect.Parameter.empty:
                if passing_style in [
                        type_annotations.OutputAnnotation,
                        type_annotations.OutputPath,
                ]:
                    raise ValueError(
                        'Default values for Output artifacts are not supported.'
                    )
                elif parameter.default is not None:
                    raise ValueError(
                        f'Optional Input artifacts may only have default value None. Got: {parameter.default}.'
                    )

        elif isinstance(
                parameter_type,
            (type_annotations.InputPath, type_annotations.OutputPath)):
            passing_style = type(parameter_type)
            parameter_type = parameter_type.type
            if parameter.default is not inspect.Parameter.empty and not (
                    passing_style == type_annotations.InputPath and
                    parameter.default is None):
                raise ValueError(
                    'Path inputs only support default values of None. Default'
                    ' values for outputs are not supported.')

        type_struct = type_utils._annotation_to_type_struct(parameter_type)
        if type_struct is None:
            raise TypeError(
                f'Missing type annotation for argument: {parameter.name}')

        if passing_style in [
                type_annotations.OutputAnnotation, type_annotations.OutputPath
        ]:
            if io_name == single_output_name_const:
                raise ValueError(
                    f'"{single_output_name_const}" is an invalid parameter name.'
                )
            io_name = _maybe_make_unique(io_name, output_names)
            output_names.add(io_name)
            if type_annotations.is_artifact_class(parameter_type):
                schema_version = parameter_type.schema_version
                output_spec = structures.OutputSpec(
                    type=type_utils.create_bundled_artifact_type(
                        type_struct, schema_version),
                    is_artifact_list=is_artifact_list)
            else:
                output_spec = structures.OutputSpec(type=type_struct)
            outputs[io_name] = output_spec
        else:
            io_name = _maybe_make_unique(io_name, input_names)
            input_names.add(io_name)
            type_ = type_utils.create_bundled_artifact_type(
                type_struct, parameter_type.schema_version
            ) if type_annotations.is_artifact_class(
                parameter_type) else type_struct
            default = None if parameter.default == inspect.Parameter.empty or type_annotations.is_artifact_class(
                parameter_type) else parameter.default
            optional = parameter.default is not inspect.Parameter.empty or type_utils.is_task_final_status_type(
                type_struct)
            input_spec = structures.InputSpec(
                type=type_,
                default=default,
                optional=optional,
                is_artifact_list=is_artifact_list,
            )

            inputs[io_name] = input_spec

    #Analyzing the return type annotations.
    return_ann = signature.return_annotation
    if not containerized:
        if hasattr(return_ann, '_fields'):  #NamedTuple
            # Getting field type annotations.
            # __annotations__ does not exist in python 3.5 and earlier
            # _field_types does not exist in python 3.9 and later
            field_annotations = getattr(return_ann, '__annotations__',
                                        None) or getattr(
                                            return_ann, '_field_types', None)
            for field_name in return_ann._fields:
                output_name = _maybe_make_unique(field_name, output_names)
                output_names.add(output_name)
                type_var = field_annotations.get(field_name)
                if type_annotations.is_list_of_artifacts(type_var):
                    artifact_cls = type_var.__args__[0]
                    output_spec = structures.OutputSpec(
                        type=type_utils.create_bundled_artifact_type(
                            artifact_cls.schema_title,
                            artifact_cls.schema_version),
                        is_artifact_list=True)
                elif type_annotations.is_artifact_class(type_var):
                    output_spec = structures.OutputSpec(
                        type=type_utils.create_bundled_artifact_type(
                            type_var.schema_title, type_var.schema_version))
                else:
                    type_struct = type_utils._annotation_to_type_struct(
                        type_var)
                    output_spec = structures.OutputSpec(type=type_struct)
                outputs[output_name] = output_spec
        # Deprecated dict-based way of declaring multiple outputs. Was only used by
        # the @component decorator
        elif isinstance(return_ann, dict):
            warnings.warn(
                'The ability to specify multiple outputs using the dict syntax'
                ' has been deprecated. It will be removed soon after release'
                ' 0.1.32. Please use typing.NamedTuple to declare multiple'
                ' outputs.')
            for output_name, output_type_annotation in return_ann.items():
                output_type_struct = type_utils._annotation_to_type_struct(
                    output_type_annotation)
                output_spec = structures.OutputSpec(type=output_type_struct)
                outputs[name] = output_spec
        elif signature.return_annotation is not None and signature.return_annotation != inspect.Parameter.empty:
            output_name = _maybe_make_unique(single_output_name_const,
                                             output_names)
            # Fixes exotic, but possible collision:
            #   `def func(output_path: OutputPath()) -> str: ...`
            output_names.add(output_name)
            return_ann = signature.return_annotation
            if type_annotations.is_list_of_artifacts(return_ann):
                artifact_cls = return_ann.__args__[0]
                output_spec = structures.OutputSpec(
                    type=type_utils.create_bundled_artifact_type(
                        artifact_cls.schema_title, artifact_cls.schema_version),
                    is_artifact_list=True)
            elif type_annotations.is_artifact_class(return_ann):
                output_spec = structures.OutputSpec(
                    type=type_utils.create_bundled_artifact_type(
                        return_ann.schema_title, return_ann.schema_version),
                    is_artifact_list=False)
            else:
                type_struct = type_utils._annotation_to_type_struct(return_ann)
                output_spec = structures.OutputSpec(type=type_struct)

            outputs[output_name] = output_spec
    elif return_ann != inspect.Parameter.empty and return_ann != structures.ContainerSpec:
        raise TypeError(
            'Return annotation should be either ContainerSpec or omitted for container components.'
        )

    component_name = name or _python_function_name_to_component_name(
        func.__name__)

    def assign_descriptions(
        inputs_or_outputs: Mapping[str, Union[structures.InputSpec,
                                              structures.OutputSpec]],
        docstring_params: List[docstring_parser.DocstringParam],
    ) -> None:
        """Assigns descriptions to InputSpec or OutputSpec for each component
        input/output found in the parsed docstring parameters."""
        docstring_inputs = {param.arg_name: param for param in docstring_params}
        for name, spec in inputs_or_outputs.items():
            if name in docstring_inputs:
                spec.description = docstring_inputs[name].description

    def parse_docstring_with_return_as_args(
            docstring: Union[str,
                             None]) -> Union[docstring_parser.Docstring, None]:
        """Modifies docstring so that a return section can be treated as an
        args section, then parses the docstring."""
        if docstring is None:
            return None

        # Returns and Return are the only two keywords docstring_parser uses for returns
        # use newline to avoid replacements that aren't in the return section header
        return_keywords = ['Returns:\n', 'Returns\n', 'Return:\n', 'Return\n']
        for keyword in return_keywords:
            if keyword in docstring:
                modified_docstring = docstring.replace(keyword.strip(), 'Args:')
                return docstring_parser.parse(modified_docstring)

        return None

    assign_descriptions(inputs, parsed_docstring.params)

    modified_parsed_docstring = parse_docstring_with_return_as_args(
        original_docstring)
    if modified_parsed_docstring is not None:
        assign_descriptions(outputs, modified_parsed_docstring.params)

    description = get_pipeline_description(
        decorator_description=description,
        docstring=parsed_docstring,
    )

    return structures.ComponentSpec(
        name=component_name,
        description=description,
        inputs=inputs or None,
        outputs=outputs or None,
        implementation=structures.Implementation(),
    )


def _get_command_and_args_for_lightweight_component(
        func: Callable) -> Tuple[List[str], List[str]]:
    imports_source = [
        'import kfp',
        'from kfp import dsl',
        'from kfp.dsl import *',
        'from typing import *',
    ] + custom_artifact_types.get_custom_artifact_type_import_statements(func)

    func_source = _get_function_source_definition(func)
    source = textwrap.dedent('''
        {imports_source}

        {func_source}\n''').format(
        imports_source='\n'.join(imports_source), func_source=func_source)
    command = [
        'sh',
        '-ec',
        textwrap.dedent('''\
                    program_path=$(mktemp -d)
                    printf "%s" "$0" > "$program_path/ephemeral_component.py"
                    python3 -m kfp.dsl.executor_main \
                        --component_module_path \
                        "$program_path/ephemeral_component.py" \
                        "$@"
                '''),
        source,
    ]

    args = [
        '--executor_input',
        placeholders.ExecutorInputPlaceholder(),
        '--function_to_execute',
        func.__name__,
    ]

    return command, args


def _get_command_and_args_for_containerized_component(
        function_name: str) -> Tuple[List[str], List[str]]:
    command = [
        'python3',
        '-m',
        'kfp.dsl.executor_main',
    ]

    args = [
        '--executor_input',
        placeholders.ExecutorInputPlaceholder()._to_string(),
        '--function_to_execute',
        function_name,
    ]
    return command, args


def create_component_from_func(
    func: Callable,
    base_image: Optional[str] = None,
    target_image: Optional[str] = None,
    packages_to_install: List[str] = None,
    pip_index_urls: Optional[List[str]] = None,
    output_component_file: Optional[str] = None,
    install_kfp_package: bool = True,
    kfp_package_path: Optional[str] = None,
) -> python_component.PythonComponent:
    """Implementation for the @component decorator.

    The decorator is defined under component_decorator.py. See the
    decorator for the canonical documentation for this function.
    """
    packages_to_install = packages_to_install or []

    if install_kfp_package and target_image is None:
        if kfp_package_path is None:
            kfp_package_path = _get_default_kfp_package_path()
        packages_to_install.append(kfp_package_path)

    packages_to_install_command = _get_packages_to_install_command(
        package_list=packages_to_install, pip_index_urls=pip_index_urls)

    command = []
    args = []
    if base_image is None:
        base_image = _DEFAULT_BASE_IMAGE

    component_image = base_image

    if target_image:
        component_image = target_image
        command, args = _get_command_and_args_for_containerized_component(
            function_name=func.__name__,)
    else:
        command, args = _get_command_and_args_for_lightweight_component(
            func=func)

    component_spec = extract_component_interface(func)
    component_spec.implementation = structures.Implementation(
        container=structures.ContainerSpecImplementation(
            image=component_image,
            command=packages_to_install_command + command,
            args=args,
        ))

    module_path = pathlib.Path(inspect.getsourcefile(func))
    module_path.resolve()

    component_name = _python_function_name_to_component_name(func.__name__)
    component_info = ComponentInfo(
        name=component_name,
        function_name=func.__name__,
        func=func,
        target_image=target_image,
        module_path=module_path,
        component_spec=component_spec,
        output_component_file=output_component_file,
        base_image=base_image,
        packages_to_install=packages_to_install,
        pip_index_urls=pip_index_urls)

    if REGISTERED_MODULES is not None:
        REGISTERED_MODULES[component_name] = component_info

    if output_component_file:
        component_spec.save_to_component_yaml(output_component_file)

    return python_component.PythonComponent(
        component_spec=component_spec, python_func=func)


def make_input_for_parameterized_container_component_function(
    name: str, annotation: Union[Type[List[artifact_types.Artifact]],
                                 Type[artifact_types.Artifact]]
) -> Union[placeholders.Placeholder, container_component_artifact_channel
           .ContainerComponentArtifactChannel]:
    if type_annotations.is_input_artifact(annotation):

        if type_annotations.is_list_of_artifacts(annotation.__origin__):
            return placeholders.InputListOfArtifactsPlaceholder(name)
        else:
            return container_component_artifact_channel.ContainerComponentArtifactChannel(
                io_type='input', var_name=name)

    elif type_annotations.is_output_artifact(annotation):

        if type_annotations.is_list_of_artifacts(annotation.__origin__):
            return placeholders.OutputListOfArtifactsPlaceholder(name)
        else:
            return container_component_artifact_channel.ContainerComponentArtifactChannel(
                io_type='output', var_name=name)

    elif isinstance(
            annotation,
        (type_annotations.OutputAnnotation, type_annotations.OutputPath)):
        return placeholders.OutputParameterPlaceholder(name)

    else:
        placeholder = placeholders.InputValuePlaceholder(name)
        # small hack to encode the runtime value's type for a custom json.dumps function
        if (annotation == task_final_status.PipelineTaskFinalStatus or
                type_utils.is_task_final_status_type(annotation)):
            placeholder._ir_type = 'STRUCT'
        else:
            placeholder._ir_type = type_utils.get_parameter_type_name(
                annotation)
        return placeholder


def create_container_component_from_func(
        func: Callable) -> container_component_class.ContainerComponent:
    """Implementation for the @container_component decorator.

    The decorator is defined under container_component_decorator.py. See
    the decorator for the canonical documentation for this function.
    """

    component_spec = extract_component_interface(func, containerized=True)
    signature = inspect.signature(func)
    parameters = list(signature.parameters.values())
    arg_list = []
    for parameter in parameters:
        parameter_type = type_annotations.maybe_strip_optional_from_annotation(
            parameter.annotation)
        arg_list.append(
            make_input_for_parameterized_container_component_function(
                parameter.name, parameter_type))

    container_spec = func(*arg_list)
    container_spec_implementation = structures.ContainerSpecImplementation.from_container_spec(
        container_spec)
    component_spec.implementation = structures.Implementation(
        container_spec_implementation)
    component_spec._validate_placeholders()
    return container_component_class.ContainerComponent(component_spec, func)


def create_graph_component_from_func(
    func: Callable,
    name: Optional[str] = None,
    description: Optional[str] = None,
    display_name: Optional[str] = None,
) -> graph_component.GraphComponent:
    """Implementation for the @pipeline decorator.

    The decorator is defined under pipeline_context.py. See the
    decorator for the canonical documentation for this function.
    """

    component_spec = extract_component_interface(
        func,
        description=description,
        name=name,
    )
    return graph_component.GraphComponent(
        component_spec=component_spec,
        pipeline_func=func,
        display_name=display_name,
    )


def get_pipeline_description(
    decorator_description: Union[str, None],
    docstring: docstring_parser.Docstring,
) -> Union[str, None]:
    """Obtains the correct pipeline description from the pipeline decorator's
    description argument and the parsed docstring.

    Gives precedence to the decorator argument.
    """
    if decorator_description:
        return decorator_description

    short_description = docstring.short_description
    long_description = docstring.long_description
    docstring_description = short_description + '\n' + long_description if (
        short_description and long_description) else short_description
    return docstring_description.strip() if docstring_description else None
