"""Historique des sessions de connexion WGSecure."""
import json
import os
from datetime import datetime
from app.utils.platform_utils import get_config_dir

_FILE = "sessions.json"
_MAX  = 200


def _path() -> str:
    return os.path.join(get_config_dir(), _FILE)


def start_session(server: str, profile: str) -> int:
    """Démarre une nouvelle session, retourne son id."""
    sid = int(datetime.now().timestamp())
    sessions = _load()
    sessions.append({
        "id":       sid,
        "start":    datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
        "end":      None,
        "duration": None,
        "server":   server,
        "profile":  profile,
        "rx":       0,
        "tx":       0,
    })
    _save(sessions)
    return sid


def end_session(sid: int, rx: int = 0, tx: int = 0) -> None:
    sessions = _load()
    for s in sessions:
        if s.get("id") == sid:
            start_dt = datetime.strptime(s["start"], "%Y-%m-%d %H:%M:%S")
            secs = int((datetime.now() - start_dt).total_seconds())
            s["end"]      = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
            s["duration"] = secs
            s["rx"]       = rx
            s["tx"]       = tx
            break
    _save(sessions)


def get_sessions(n: int = 50) -> list[dict]:
    return list(reversed(_load()[-n:]))


def clear() -> None:
    _save([])


def fmt_duration(secs: int | None) -> str:
    if secs is None:
        return "—"
    h, r = divmod(int(secs), 3600)
    m, s = divmod(r, 60)
    if h:
        return f"{h}h {m:02d}m"
    if m:
        return f"{m}m {s:02d}s"
    return f"{s}s"


def fmt_bytes(n: int) -> str:
    for unit, div in [("GB", 1_073_741_824), ("MB", 1_048_576), ("KB", 1024)]:
        if n >= div:
            return f"{n/div:.1f} {unit}"
    return f"{n} B"


def _load() -> list[dict]:
    p = _path()
    if not os.path.exists(p):
        return []
    try:
        with open(p, "r", encoding="utf-8") as f:
            return json.load(f)
    except Exception:
        return []


def _save(sessions: list[dict]) -> None:
    try:
        with open(_path(), "w", encoding="utf-8") as f:
            json.dump(sessions[-_MAX:], f, indent=2, ensure_ascii=False)
    except Exception:
        pass