#
# Copyright 2018-2022 Elyra 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 json
import os
import shutil
from typing import Any
from typing import List
from typing import Optional
import uuid

from elyra.pipeline.pipeline import GenericOperation
from elyra.pipeline.pipeline import Pipeline


def _read_pipeline_resource(pipeline_filename):
    root = os.path.realpath(os.path.join(os.getcwd(), os.path.dirname(__file__)))
    pipeline_path = os.path.join(root, pipeline_filename)

    with open(pipeline_path, "r") as f:
        pipeline_json = json.load(f)

    return pipeline_json


class NodeBase(object):
    """Represents a node of a constructed pipeline based on files in resources/node_util."""

    id: str
    name: str
    outputs: List[str]
    dependencies: List[str]
    env_vars: List[str]
    image_name: str
    fail: bool
    # from subclasses
    classifier: str
    filename: str
    pipeline_name: str  # Set during pipeline construction

    def __init__(
        self,
        name: str,
        num_outputs: Optional[int] = 0,
        input_nodes: Optional[List[Any]] = None,
        image_name: Optional[str] = None,
        fail: Optional[bool] = False,
    ):
        self.id = str(uuid.uuid4())
        self.name = name
        self.fail = fail
        self.image_name = image_name
        self.outputs = []
        for i in range(1, num_outputs + 1):
            self.outputs.append(f"{self.name}_{i}.out")

        self.inputs = []
        self.parent_operations = []
        if input_nodes:
            for node in input_nodes:
                self.inputs.extend(node.outputs)
                self.parent_operations.append(node.id)

        self.dependencies = ["node_util/*"]

    def get_operation(self) -> GenericOperation:

        self.env_vars = []
        if self.fail:  # NODE_FILENAME is required, so skip if triggering failure
            if "NODE_FILENAME" in os.environ:  # remove entry if present
                os.environ.pop("NODE_FILENAME")
        else:
            self.env_vars.append(f"NODE_FILENAME={self.filename}")

        if self.inputs:
            self.env_vars.append(f"INPUT_FILENAMES={';'.join(self.inputs)}")
        if self.outputs:
            self.env_vars.append(f"OUTPUT_FILENAMES={';'.join(self.outputs)}")

        # Convey the pipeline name
        assert self.pipeline_name is not None, "Pipeline name has not been set during construction!"
        self.env_vars.append(f"PIPELINE_NAME={self.pipeline_name}")

        # Add system-owned here with bogus or no value...
        self.env_vars.append("ELYRA_RUNTIME_ENV=bogus_runtime")

        component_parameters = {
            "filename": self.filename,
            "runtime_image": self.image_name or "NA",
            "dependencies": self.dependencies,
            "env_vars": self.env_vars,
            "inputs": self.inputs,
            "outputs": self.outputs,
        }
        return GenericOperation(
            self.id,
            "execution_node",
            self.name,
            self.classifier,
            parent_operation_ids=self.parent_operations,
            component_params=component_parameters,
        )


class NotebookNode(NodeBase):
    def __init__(
        self,
        name: str,
        num_outputs: Optional[int] = 0,
        input_nodes: Optional[List[Any]] = None,
        image_name: Optional[str] = None,
        fail: Optional[bool] = False,
    ):

        super().__init__(name, num_outputs=num_outputs, input_nodes=input_nodes, image_name=image_name, fail=fail)
        self.classifier = "execute-notebook-node"
        self.filename = f"{self.name}.ipynb"


class PythonNode(NodeBase):
    def __init__(
        self,
        name: str,
        num_outputs: Optional[int] = 0,
        input_nodes: Optional[List[Any]] = None,
        image_name: Optional[str] = None,
        fail: Optional[bool] = False,
    ):

        super().__init__(name, num_outputs=num_outputs, input_nodes=input_nodes, image_name=image_name, fail=fail)
        self.classifier = "execute-python-node"
        self.filename = f"{self.name}.py"


def construct_pipeline(
    name: str,
    nodes: List[NodeBase],
    location: str,
    runtime_type: Optional[str] = "local",
    runtime_config: Optional[str] = "local",
) -> Pipeline:
    """Returns an instance of a local Pipeline consisting of each node and populates the
    specified location with the necessary files to run the pipeline from that location.
    """
    pipeline = Pipeline(str(uuid.uuid4()), name, runtime_type, runtime_config)
    for node in nodes:
        node.pipeline_name = name
        pipeline.operations[node.id] = node.get_operation()
        # copy the node file into the "working directory"
        if isinstance(node, NotebookNode):
            src_file = os.path.join(os.path.dirname(__file__), "resources/node_util/node.ipynb")
        elif isinstance(node, PythonNode):
            src_file = os.path.join(os.path.dirname(__file__), "resources/node_util/node.py")
        else:
            assert False, f"Invalid node type detected: {node.__class__.__name__}"

        shutil.copy(src_file, os.path.join(location, node.filename))

    # copy the node_util directory into the "working directory"
    shutil.copytree(os.path.join(os.path.dirname(__file__), "resources/node_util"), os.path.join(location, "node_util"))

    return pipeline