# 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/.

import copy

from voluptuous import Required

from taskgraph.task import Task
from taskgraph.util.schema import Schema

from . import group_tasks


schema = Schema(
    {
        Required("primary-dependency", "primary dependency task"): Task,
        Required(
            "dependent-tasks",
            "dictionary of dependent tasks, keyed by kind",
        ): {str: Task},
    }
)


def loader(kind, path, config, params, loaded_tasks):
    """
    Load tasks based on the jobs dependant kinds, designed for use as
    multiple-dependent needs.
    Required ``group-by-fn`` is used to define how we coalesce the
    multiple deps together to pass to transforms, e.g. all kinds specified get
    collapsed by platform with `platform`
    Optional ``primary-dependency`` (ordered list or string) is used to determine
    which upstream kind to inherit attrs from. See ``get_primary_dep``.
    The `only-for-build-type` kind configuration, if specified, will limit
    the build types for which a job will be created.
    Optional ``job-template`` kind configuration value, if specified, will be used to
    pass configuration down to the specified transforms used.
    """
    job_template = config.get("job-template")

    for dep_tasks in group_tasks(config, loaded_tasks):
        kinds = [dep.kind for dep in dep_tasks]
        kinds_occurrences = {kind: kinds.count(kind) for kind in kinds}

        dep_tasks_per_unique_key = {
            dep.kind if kinds_occurrences[dep.kind] == 1 else dep.label: dep
            for dep in dep_tasks
        }

        job = {"dependent-tasks": dep_tasks_per_unique_key}
        job["primary-dependency"] = get_primary_dep(config, dep_tasks_per_unique_key)
        if job_template:
            job.update(copy.deepcopy(job_template))

        yield job


def get_primary_dep(config, dep_tasks):
    """Find the dependent task to inherit attributes from.
    If ``primary-dependency`` is defined in ``kind.yml`` and is a string,
    then find the first dep with that task kind and return it. If it is
    defined and is a list, the first kind in that list with a matching dep
    is the primary dependency. If it's undefined, return the first dep.
    """
    primary_dependencies = config.get("primary-dependency")
    if isinstance(primary_dependencies, str):
        primary_dependencies = [primary_dependencies]
    if not primary_dependencies:
        assert len(dep_tasks) == 1, "Must define a primary-dependency!"
        return dep_tasks.values()[0]
    primary_dep = None
    for primary_kind in primary_dependencies:
        for dep_kind in dep_tasks:
            if dep_kind == primary_kind:
                assert (
                    primary_dep is None
                ), "Too many primary dependent tasks in dep_tasks: {}!".format(
                    [t.label for t in dep_tasks]
                )
                primary_dep = dep_tasks[dep_kind]
    if primary_dep is None:
        raise Exception(
            "Can't find dependency of {}: {}".format(
                config["primary-dependency"], config
            )
        )
    return primary_dep