# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

from __future__ import absolute_import, print_function, unicode_literals

import attr


@attr.s
class Task(object):
    """
    Representation of a task in a TaskGraph.  Each Task has, at creation:

    - kind: the name of the task kind
    - label; the label for this task
    - attributes: a dictionary of attributes for this task (used for filtering)
    - task: the task definition (JSON-able dictionary)
    - optimization: optimization to apply to the task (see taskgraph.optimize)
    - dependencies: tasks this one depends on, in the form {name: label}, for example
      {'build': 'build-linux64/opt', 'docker-image': 'docker-image-desktop-test'}
    - soft_dependencies: tasks this one may depend on if they are available post
      optimisation. They are set as a list of tasks label.
    - if_dependencies: only run this task if at least one of these dependencies
      are present.

    And later, as the task-graph processing proceeds:

    - task_id -- TaskCluster taskId under which this task will be created

    This class is just a convenience wrapper for the data type and managing
    display, comparison, serialization, etc. It has no functionality of its own.
    """

    kind = attr.ib()
    label = attr.ib()
    attributes = attr.ib()
    task = attr.ib()
    description = attr.ib(default="")
    task_id = attr.ib(default=None, init=False)
    optimization = attr.ib(default=None)
    dependencies = attr.ib(factory=dict)
    soft_dependencies = attr.ib(factory=list)
    if_dependencies = attr.ib(factory=list)
    release_artifacts = attr.ib(
        converter=attr.converters.optional(frozenset),
        default=None,
    )

    def __attrs_post_init__(self):
        self.attributes["kind"] = self.kind

    @property
    def name(self):
        if self.label.startswith(self.kind + "-"):
            return self.label[len(self.kind) + 1 :]
        else:
            raise AttributeError("Task {} does not have a name.".format(self.label))

    def to_json(self):
        rv = {
            "kind": self.kind,
            "label": self.label,
            "description": self.description,
            "attributes": self.attributes,
            "dependencies": self.dependencies,
            "soft_dependencies": sorted(self.soft_dependencies),
            "if_dependencies": self.if_dependencies,
            "optimization": self.optimization,
            "task": self.task,
        }
        if self.task_id:
            rv["task_id"] = self.task_id
        if self.release_artifacts:
            rv["release_artifacts"] = sorted(self.release_artifacts)
        return rv

    @classmethod
    def from_json(cls, task_dict):
        """
        Given a data structure as produced by taskgraph.to_json, re-construct
        the original Task object.  This is used to "resume" the task-graph
        generation process, for example in Action tasks.
        """
        rv = cls(
            kind=task_dict["kind"],
            label=task_dict["label"],
            description=task_dict.get("description", ""),
            attributes=task_dict["attributes"],
            task=task_dict["task"],
            optimization=task_dict["optimization"],
            dependencies=task_dict.get("dependencies"),
            soft_dependencies=task_dict.get("soft_dependencies"),
            if_dependencies=task_dict.get("if_dependencies"),
            release_artifacts=task_dict.get("release-artifacts"),
        )
        if "task_id" in task_dict:
            rv.task_id = task_dict["task_id"]
        return rv