"""Bound unproven sibling routes while awaiting actual validation results."""
from collections import Counter
from typing import Any


def profile_key(row: dict[str, Any]) -> tuple[str, ...] | None:
    profile = row.get("preflightMetadata") or row.get("modelProfile") or {}
    model_type = str(profile.get("modelType") or "").strip()
    if not model_type:
        return None
    return (str(row.get("targetGpu") or row.get("gpuType") or ""),
            str(row.get("framework") or ""), str(row.get("taskType") or ""),
            model_type, str(profile.get("quantizationSignature") or profile.get("quantizationMethod") or "none"))


def filter_profile_batch(candidates, pending, stats, *, limit=2):
    """Reservations include the whole proposed batch; deferred rows are retryable.

    Broad public framework statistics are not proof for a specific encoding.
    Exact-encoding successes can lift the cap, provided the observed success
    rate remains at least 50%. Missing legacy signatures cannot grant this.
    """
    counts = Counter(profile_key(row) for row in pending if row.get("outcome") == "pending")
    selected, deferred = [], []
    for candidate in candidates:
        key = profile_key(candidate)
        evidence = (stats.get("encodingCombinationStats") or {}).get("|".join(key or ())) or {}
        successes = int(evidence.get("successCount") or 0)
        failures = max(0, int(evidence.get("failureCount") or 0) - int(evidence.get("platformFailureCount") or 0))
        proven = successes >= 3 and successes / max(1, successes + failures) >= 0.5
        # Count legacy records with the same method as well, conservatively.
        legacy = 0
        if key and ":" in key[-1]:
            legacy = counts.get((*key[:-1], key[-1].split(":", 1)[0]), 0)
        if key and not proven and counts[key] + legacy >= limit:
            deferred.append(candidate)
            continue
        selected.append(candidate)
        if key:
            counts[key] += 1
    return selected, deferred