"""Read management intents and corroborate their existing terminal receipts."""
import json
from pathlib import Path
import re


TERMINAL_STATUSES = frozenset({'done', 'failed', 'rejected', 'stale'})
INTENT_FIELDS = ('request_id', 'submission_id', 'task_name', 'track_id', 'action',
                 'requested_by', 'hf_subject', 'researcher_identity_id',
                 'replace_submission_id', 'publication_sequence', 'requested_at')


def read_request(path: str | Path) -> dict | None:
    path = Path(path)
    try:
        with path.open('rb') as handle:
            raw = handle.read(1_000_001)
    except FileNotFoundError:
        return None
    if len(raw) > 1_000_000:
        raise ValueError('Management request exceeds size limit')
    record = json.loads(raw)
    if (not isinstance(record, dict) or not record.get('submission_id')
            or record.get('request_id') != path.stem
            or not re.fullmatch(r'[A-Za-z0-9_-]+', path.stem)):
        raise ValueError('Invalid management request identity')
    return record


def matching_terminal(request: dict, receipt: dict | None) -> bool:
    return (receipt is not None and receipt.get('status') in TERMINAL_STATUSES
            and all(request.get(key) == receipt.get(key) for key in INTENT_FIELDS))


def active_requests(pending: str | Path, processing: str | Path, complete: str | Path) -> list[tuple[Path, dict]]:
    found = {}
    for directory in (Path(pending), Path(processing)):
        try:
            paths = sorted(directory.iterdir())
        except FileNotFoundError:
            continue
        for path in paths:
            if path.suffix != '.json' or path.name.startswith('.'):
                continue
            record = read_request(path)
            if record is None:
                continue
            receipt = read_request(Path(complete) / path.name)
            if matching_terminal(record, receipt):
                continue
            previous = found.get(record['request_id'])
            if previous and any(previous[1].get(key) != record.get(key) for key in INTENT_FIELDS):
                raise ValueError('Conflicting copies of a management request')
            found[record['request_id']] = (path, record)
    return list(found.values())