# Copyright 2017 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

import os
import subprocess
from contextlib import contextmanager

from pants.base.exceptions import TaskError

from pants.contrib.go.subsystems.gofmt import Gofmt
from pants.contrib.go.targets.go_local_source import GoLocalSource
from pants.contrib.go.tasks.go_workspace_task import GoWorkspaceTask


class GoFmtTaskBase(GoWorkspaceTask):
    """Base class for tasks that run gofmt."""

    def _resolve_conflicting_skip(self, *, old_scope: str):
        # Skip mypy because this is a temporary hack, and mypy doesn't follow the inheritance chain
        # properly.
        return self.resolve_conflicting_skip_options(  # type: ignore
            old_scope=old_scope, new_scope="gofmt", subsystem=Gofmt.global_instance(),
        )

    @classmethod
    def is_checked(cls, target):
        return isinstance(target, GoLocalSource) and not target.is_synthetic

    @classmethod
    def calculate_sources(cls, targets):
        sources = set()
        for target in targets:
            sources.update(
                source
                for source in target.sources_relative_to_buildroot()
                if GoLocalSource.is_go_source(source)
            )
        return sources

    @classmethod
    def subsystem_dependencies(cls):
        return super().subsystem_dependencies() + (Gofmt,)

    @contextmanager
    def go_fmt_invalid_targets(self, flags):
        targets = self.get_targets(self.is_checked)
        with self.invalidated(targets) as invalidation_check:
            invalid_targets = [vt.target for vt in invalidation_check.invalid_vts]
            sources = self.calculate_sources(invalid_targets)
            if sources:
                args = [os.path.join(self.go_dist.goroot, "bin", "gofmt")] + flags + list(sources)
                try:
                    output = subprocess.check_output(args).decode()
                except subprocess.CalledProcessError as e:
                    raise TaskError(
                        f"{' '.join(args)} failed with exit code {e.returncode}",
                        exit_code=e.returncode,
                    )
                yield output
            else:
                yield None