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"""GitHub custom subjects for prs/issues/discussions etc"""

from . import directive, ASFGitHubFeature, constants
import re


def validate_github_subject(subject):
    """Validates a github subject template:
    - MUST only contain valid references
    - MUST be a non-empty string
    - MUST not contain any reserved chars (newlines etc)
    """
    bad_chars = ("\r", "\n")
    assert isinstance(subject, str), "Subject template must be a string"
    assert subject, "Subject template must not be empty"
    assert not any(bad_char in subject for bad_char in bad_chars), "Subject template must not contain newlines!"
    found_refs = [x.group(1) for x in re.finditer(r"{(.+?)}", subject)]
    for ref in found_refs:
        assert ref in constants.VALID_GITHUB_SUBJECT_VARIABLES, f"Unknown variable '{ref}' found in subject template."


@directive
def config_custom_subjects(self: ASFGitHubFeature):
    # Custom subjects for events
    custom_subjects = self.yaml.get("custom_subjects")
    if custom_subjects and isinstance(custom_subjects, dict):
        # Validate each template
        for key, subject in custom_subjects.items():
            assert key in constants.VALID_GITHUB_ACTIONS, f"Unknown action '{key}' found in custom_subjects!"
            validate_github_subject(subject)