"""CSV export/import of the device list, including AES keys."""

from __future__ import annotations

import csv
import time
from typing import Dict, Iterable, List

from .models import Device

FIELDNAMES = [
    "id",
    "manufacturer",
    "manufacturer_name",
    "media",
    "driver",
    "version",
    "first_seen",
    "last_seen",
    "count",
    "rssi",
    "interval_s",
    "interval_samples",
    "encryption",
    "security_mode",
    "status",
    "aes_key",
]


def _fmt_time(ts: float) -> str:
    if not ts:
        return ""
    return time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(ts))


def export_devices(path: str, devices: Iterable[Device]) -> int:
    n = 0
    with open(path, "w", newline="") as f:
        writer = csv.DictWriter(f, fieldnames=FIELDNAMES)
        writer.writeheader()
        for d in devices:
            writer.writerow(
                {
                    "id": d.id,
                    "manufacturer": d.manufacturer,
                    "manufacturer_name": d.manufacturer_name,
                    "media": d.media,
                    "driver": d.driver,
                    "version": d.version,
                    "first_seen": _fmt_time(d.first_seen),
                    "last_seen": _fmt_time(d.last_seen),
                    "count": d.count,
                    "rssi": "" if d.rssi is None else d.rssi,
                    "interval_s": (
                        "" if d.interval_estimate is None
                        else round(d.interval_estimate, 1)
                    ),
                    "interval_samples": d.interval_samples,
                    "encryption": d.encryption,
                    "security_mode": d.sec_mode or "",
                    "status": d.status,
                    "aes_key": d.key or "",
                }
            )
            n += 1
    return n


def import_rows(path: str) -> List[Dict[str, str]]:
    """Read a previously exported CSV. Returns a list of row dicts.

    Only ``id`` is required; ``aes_key`` and the metadata columns are optional,
    so hand-written key files with just ``id,aes_key`` import fine too.
    """
    rows: List[Dict[str, str]] = []
    with open(path, newline="") as f:
        reader = csv.DictReader(f)
        for row in reader:
            device_id = (row.get("id") or "").strip()
            if not device_id:
                continue
            rows.append({k: (v or "").strip() for k, v in row.items()})
    return rows