from __future__ import annotations

import json
import logging
import os
from datetime import UTC, datetime
from logging.handlers import RotatingFileHandler
from pathlib import Path
from typing import Final

SCANNER_LOGGER_NAME: Final = "k1link.device_plugins.xgrids_k1"
SCANNER_DIAGNOSTIC_FILE: Final = "scanner-diagnostics.jsonl"
_HANDLER_MARKER: Final = "_mission_core_scanner_diagnostics_path"
_EXTRA_FIELDS: Final = (
    "event_code",
    "reason_code",
    "failed_phase",
    "dialogue_stage",
    "transport_state",
    "publish_attempts",
    "modeling_command_attempted",
    "outcome_unknown",
    "safe_to_retry",
    "status_reconciliation",
    "network_change_admissible",
    "network_change_reconciliation",
    "mqtt_loop_result_code",
    "mqtt_loop_result_name",
    "mqtt_loop_phase",
    "automatic_retry",
    "camera_source_id",
    "evidence_session_id",
    "activation_trigger",
    "lease_generation",
    "lease_state",
    "recovery_strategy",
    "endpoint_reachable",
    "host_route_class",
    "address_changed",
    "device_write_performed",
    "failure_stage",
    "start_checkpoint_released",
    "stale_session_retired",
    "stream_id",
    "backend_activity_sequence",
    "viewer_range_max_ns",
    "stalled_for_ms",
    "recovery_attempt",
    "preferred_port",
    "selected_port",
)


class ScannerDiagnosticJsonFormatter(logging.Formatter):
    """Serialize a bounded, secret-free scanner diagnostic record."""

    def format(self, record: logging.LogRecord) -> str:
        document: dict[str, object] = {
            "timestamp_utc": datetime.fromtimestamp(record.created, UTC)
            .isoformat()
            .replace("+00:00", "Z"),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage()[:1000],
        }
        for field in _EXTRA_FIELDS:
            value = getattr(record, field, None)
            if value is not None and isinstance(value, (str, int, bool)):
                document[field] = value
        return json.dumps(document, ensure_ascii=False, separators=(",", ":"))


def configure_scanner_diagnostics(logs_root: Path) -> Path:
    """Install one private rotating JSONL handler for K1 field diagnostics."""

    logs_root.mkdir(mode=0o700, parents=True, exist_ok=True)
    os.chmod(logs_root, 0o700)
    target = (logs_root / SCANNER_DIAGNOSTIC_FILE).resolve()
    logger = logging.getLogger(SCANNER_LOGGER_NAME)
    for handler in logger.handlers:
        if getattr(handler, _HANDLER_MARKER, None) == str(target):
            return target

    handler = RotatingFileHandler(
        target,
        maxBytes=5 * 1024 * 1024,
        backupCount=5,
        encoding="utf-8",
        delay=False,
    )
    os.chmod(target, 0o600)
    handler.setLevel(logging.INFO)
    handler.setFormatter(ScannerDiagnosticJsonFormatter())
    setattr(handler, _HANDLER_MARKER, str(target))
    logger.addHandler(handler)
    logger.setLevel(logging.INFO)
    return target