"""Allowlisted, non-secret summaries over local append-only evidence."""
from __future__ import annotations

import json
import re
import uuid
from collections import Counter
from dataclasses import asdict, dataclass
from datetime import datetime, timezone
from pathlib import Path
from typing import Any

_LABEL = re.compile(r"^[a-z][a-z0-9-]{0,79}$")
_DECISION_REF = re.compile(r"^[A-Z][A-Z0-9-]{2,80}$")
_DELIVERY_RESULTS = {"delivered", "failed", "queued", "skipped-no-topic"}
_VERIFY_RESULT = re.compile(r"^(positive|negative):(pass|fail)$")
_ERROR_RESULT = re.compile(
    r"^failed-(Catalog|Decision|PolicyGuard|Backend|Provisioning|Verification|Delivery)Error$"
)


def _safe_label(value: object) -> str:
    text = value if isinstance(value, str) else ""
    return text if _LABEL.fullmatch(text) else "invalid-label"


def _safe_result(value: object) -> str:
    text = value if isinstance(value, str) else ""
    if (
        _LABEL.fullmatch(text)
        or _VERIFY_RESULT.fullmatch(text)
        or _ERROR_RESULT.fullmatch(text)
    ):
        return text
    return "invalid-label"


def _safe_decision_ref(value: object) -> str:
    text = value if isinstance(value, str) else ""
    if not text:
        return ""
    try:
        return str(uuid.UUID(text))
    except ValueError:
        return text if _DECISION_REF.fullmatch(text) else ""


def _safe_timestamp(value: object) -> str:
    if not isinstance(value, str):
        return ""
    try:
        parsed = datetime.fromisoformat(value.replace("Z", "+00:00"))
        if parsed.tzinfo is None:
            return ""
        return parsed.astimezone(timezone.utc).isoformat()
    except ValueError:
        return ""


@dataclass(frozen=True)
class LaneAuditSummary:
    catalog_id: str
    operation_records: int
    malformed_records: int
    first_ts: str
    last_ts: str
    actions: dict[str, int]
    results: dict[str, int]
    decision_refs: list[str]
    session_cleanup: dict[str, int]
    hub_delivery: dict[str, int]

    def to_json(self) -> dict[str, Any]:
        return asdict(self)

    def render(self) -> str:
        lines = [
            f"Lane audit summary for '{self.catalog_id}'",
            f"  operation records: {self.operation_records}",
            f"  malformed records: {self.malformed_records}",
            f"  first: {self.first_ts or 'n/a'}",
            f"  last:  {self.last_ts or 'n/a'}",
            "  actions: " + _render_counts(self.actions),
            "  results: " + _render_counts(self.results),
            "  decisions: " + (", ".join(self.decision_refs) or "none"),
            "  session cleanup: " + _render_counts(self.session_cleanup),
            "  hub delivery: " + _render_counts(self.hub_delivery),
        ]
        return "\n".join(lines)


def _render_counts(counts: dict[str, int]) -> str:
    return ", ".join(f"{key}={value}" for key, value in sorted(counts.items())) or "none"


def summarize_lane_evidence(evidence_dir: Path, catalog_id: str) -> LaneAuditSummary:
    """Summarize one lane without returning arbitrary record fields or detail."""
    actions: Counter[str] = Counter()
    results: Counter[str] = Counter()
    cleanup: Counter[str] = Counter()
    hub_delivery: Counter[str] = Counter()
    decisions: set[str] = set()
    timestamps: list[str] = []
    malformed = 0
    operation_records = 0

    for path in sorted(Path(evidence_dir).glob("evidence-*.jsonl")):
        try:
            lines = path.read_text(encoding="utf-8").splitlines()
        except OSError:
            malformed += 1
            continue
        for line in lines:
            try:
                record = json.loads(line)
            except (json.JSONDecodeError, TypeError):
                malformed += 1
                continue
            if not isinstance(record, dict):
                malformed += 1
                continue
            if record.get("catalog_id") != catalog_id:
                continue
            action = _safe_label(record.get("action"))
            result = _safe_result(record.get("result"))
            if action == "evidence-delivery":
                if result in _DELIVERY_RESULTS:
                    hub_delivery[result] += 1
                else:
                    hub_delivery["invalid"] += 1
                continue

            operation_records += 1
            actions[action] += 1
            results[result] += 1
            timestamp = _safe_timestamp(record.get("ts"))
            if timestamp:
                timestamps.append(timestamp)
            decision = _safe_decision_ref(record.get("decision_id"))
            if decision:
                decisions.add(decision)

            detail = record.get("detail")
            session = detail.get("session") if isinstance(detail, dict) else None
            if isinstance(session, dict):
                attempted = session.get("revocation_attempted") is True
                succeeded = session.get("revocation_succeeded") is True
                if succeeded:
                    cleanup["succeeded"] += 1
                elif attempted:
                    cleanup["failed"] += 1
                else:
                    cleanup["not-attempted"] += 1

    timestamps.sort()
    return LaneAuditSummary(
        catalog_id=catalog_id,
        operation_records=operation_records,
        malformed_records=malformed,
        first_ts=timestamps[0] if timestamps else "",
        last_ts=timestamps[-1] if timestamps else "",
        actions=dict(sorted(actions.items())),
        results=dict(sorted(results.items())),
        decision_refs=sorted(decisions),
        session_cleanup=dict(sorted(cleanup.items())),
        hub_delivery=dict(sorted(hub_delivery.items())),
    )