# 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 logging
import sys
from abc import ABC, abstractmethod
from dataclasses import dataclass, field
from typing import Callable, Dict, List, Union

from taskgraph.config import GraphConfig
from taskgraph.parameters import Parameters
from taskgraph.taskgraph import TaskGraph
from taskgraph.util.attributes import match_run_on_projects
from taskgraph.util.treeherder import join_symbol

logger = logging.getLogger(__name__)


@dataclass(frozen=True)
class Verification(ABC):
    func: Callable

    @abstractmethod
    def verify(self, **kwargs) -> None:
        pass


@dataclass(frozen=True)
class InitialVerification(Verification):
    """Verification that doesn't depend on any generation state."""

    def verify(self):
        self.func()


@dataclass(frozen=True)
class GraphVerification(Verification):
    """Verification for a TaskGraph object."""

    run_on_projects: Union[List, None] = field(default=None)

    def verify(
        self, graph: TaskGraph, graph_config: GraphConfig, parameters: Parameters
    ):
        if self.run_on_projects and not match_run_on_projects(
            parameters["project"], self.run_on_projects
        ):
            return

        scratch_pad = {}
        graph.for_each_task(
            self.func,
            scratch_pad=scratch_pad,
            graph_config=graph_config,
            parameters=parameters,
        )
        self.func(
            None,
            graph,
            scratch_pad=scratch_pad,
            graph_config=graph_config,
            parameters=parameters,
        )


@dataclass(frozen=True)
class ParametersVerification(Verification):
    """Verification for a set of parameters."""

    def verify(self, parameters: Parameters):
        self.func(parameters)


@dataclass(frozen=True)
class KindsVerification(Verification):
    """Verification for kinds."""

    def verify(self, kinds: dict):
        self.func(kinds)


@dataclass(frozen=True)
class VerificationSequence:
    """
    Container for a sequence of verifications over a TaskGraph. Each
    verification is represented as a callable taking (task, taskgraph,
    scratch_pad), called for each task in the taskgraph, and one more
    time with no task but with the taskgraph and the same scratch_pad
    that was passed for each task.
    """

    _verifications: Dict = field(default_factory=dict)
    _verification_types = {
        "graph": GraphVerification,
        "initial": InitialVerification,
        "kinds": KindsVerification,
        "parameters": ParametersVerification,
    }

    def __call__(self, name, *args, **kwargs):
        for verification in self._verifications.get(name, []):
            verification.verify(*args, **kwargs)

    def add(self, name, **kwargs):
        cls = self._verification_types.get(name, GraphVerification)

        def wrap(func):
            self._verifications.setdefault(name, []).append(cls(func, **kwargs))
            return func

        return wrap


verifications = VerificationSequence()


@verifications.add("full_task_graph")
def verify_task_graph_symbol(task, taskgraph, scratch_pad, graph_config, parameters):
    """
    This function verifies that tuple
    (collection.keys(), machine.platform, groupSymbol, symbol) is unique
    for a target task graph.
    """
    if task is None:
        return
    task_dict = task.task
    if "extra" in task_dict:
        extra = task_dict["extra"]
        if "treeherder" in extra:
            treeherder = extra["treeherder"]

            collection_keys = tuple(sorted(treeherder.get("collection", {}).keys()))
            if len(collection_keys) != 1:
                raise Exception(
                    f"Task {task.label} can't be in multiple treeherder collections "
                    f"(the part of the platform after `/`): {collection_keys}"
                )
            platform = treeherder.get("machine", {}).get("platform")
            group_symbol = treeherder.get("groupSymbol")
            symbol = treeherder.get("symbol")

            key = (platform, collection_keys[0], group_symbol, symbol)
            if key in scratch_pad:
                raise Exception(
                    "Duplicate treeherder platform and symbol in tasks "
                    "`{}`and `{}`: {} {}".format(
                        task.label,
                        scratch_pad[key],
                        f"{platform}/{collection_keys[0]}",
                        join_symbol(group_symbol, symbol),
                    )
                )
            else:
                scratch_pad[key] = task.label


@verifications.add("full_task_graph")
def verify_trust_domain_v2_routes(
    task, taskgraph, scratch_pad, graph_config, parameters
):
    """
    This function ensures that any two tasks have distinct ``index.{trust-domain}.v2`` routes.
    """
    if task is None:
        return
    route_prefix = "index.{}.v2".format(graph_config["trust-domain"])
    task_dict = task.task
    routes = task_dict.get("routes", [])

    for route in routes:
        if route.startswith(route_prefix):
            if route in scratch_pad:
                raise Exception(
                    f"conflict between {task.label}:{scratch_pad[route]} for route: {route}"
                )
            else:
                scratch_pad[route] = task.label


@verifications.add("full_task_graph")
def verify_routes_notification_filters(
    task, taskgraph, scratch_pad, graph_config, parameters
):
    """
    This function ensures that only understood filters for notifications are
    specified.

    See: https://docs.taskcluster.net/reference/core/taskcluster-notify/docs/usage
    """
    if task is None:
        return
    route_prefix = "notify."
    valid_filters = ("on-any", "on-completed", "on-failed", "on-exception")
    task_dict = task.task
    routes = task_dict.get("routes", [])

    for route in routes:
        if route.startswith(route_prefix):
            # Get the filter of the route
            route_filter = route.split(".")[-1]
            if route_filter not in valid_filters:
                raise Exception(
                    f"{task.label} has invalid notification filter ({route_filter})"
                )


@verifications.add("full_task_graph")
def verify_dependency_tiers(task, taskgraph, scratch_pad, graph_config, parameters):
    tiers = scratch_pad
    if task is not None:
        tiers[task.label] = (
            task.task.get("extra", {}).get("treeherder", {}).get("tier", sys.maxsize)
        )
    else:

        def printable_tier(tier):
            if tier == sys.maxsize:
                return "unknown"
            return tier

        for task in taskgraph.tasks.values():
            tier = tiers[task.label]
            for d in task.dependencies.values():
                if taskgraph[d].task.get("workerType") == "always-optimized":
                    continue
                if "dummy" in taskgraph[d].kind:
                    continue
                if tier < tiers[d]:
                    raise Exception(
                        f"{task.label} (tier {printable_tier(tier)}) cannot depend on {d} (tier {printable_tier(tiers[d])})"
                    )


@verifications.add("full_task_graph")
def verify_toolchain_alias(task, taskgraph, scratch_pad, graph_config, parameters):
    """
    This function verifies that toolchain aliases are not reused.
    """
    if task is None:
        return
    attributes = task.attributes
    if "toolchain-alias" in attributes:
        keys = attributes["toolchain-alias"]
        if not keys:
            keys = []
        elif isinstance(keys, str):
            keys = [keys]
        for key in keys:
            if key in scratch_pad:
                raise Exception(
                    "Duplicate toolchain-alias in tasks "
                    f"`{task.label}`and `{scratch_pad[key]}`: {key}"
                )
            else:
                scratch_pad[key] = task.label


@verifications.add("optimized_task_graph")
def verify_always_optimized(task, taskgraph, scratch_pad, graph_config, parameters):
    """
    This function ensures that always-optimized tasks have been optimized.
    """
    if task is None:
        return
    if task.task.get("workerType") == "always-optimized":
        raise Exception(f"Could not optimize the task {task.label!r}")