import json
from datetime import datetime
from pathlib import Path

from config import ADMIN_ID, DATABASE_DIR
from db.storage import load_stats, save_stats
from models.user import UserProfile


def _user_dir(user_id: int) -> Path:
    return DATABASE_DIR / str(user_id)


def path(user_id: int) -> Path:
    return _user_dir(user_id) / "config.json"


def register(user_id: int, username: str | None = None, referrer: int | None = None) -> bool:
    user_path = path(user_id)
    is_new = False

    if not user_path.parent.exists():
        user_path.parent.mkdir(parents=True, exist_ok=True)
        profile = UserProfile.default(
            user_id=user_id,
            username=username,
            registered=datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            referrer=referrer if referrer and referrer != user_id else None,
            is_admin=(user_id == ADMIN_ID),
        )
        save(user_id, profile)
        is_new = True

        stats = load_stats()
        stats.total_users += 1
        save_stats(stats)

        if referrer and referrer != user_id:
            ref_profile = get(referrer)
            if ref_profile and user_id not in ref_profile.referrals:
                ref_profile.referrals.append(user_id)
                save(referrer, ref_profile)
    elif username:
        profile = get(user_id)
        if profile and profile.username != username:
            profile.username = username
            save(user_id, profile)

    return is_new


def get(user_id: int) -> UserProfile | None:
    user_path = path(user_id)
    if not user_path.exists():
        return None
    with user_path.open("r", encoding="utf-8") as fh:
        return UserProfile.from_dict(json.load(fh))


def save(user_id: int, data: UserProfile | dict) -> None:
    profile = data if isinstance(data, UserProfile) else UserProfile.from_dict(data)
    user_path = path(user_id)
    user_path.parent.mkdir(parents=True, exist_ok=True)
    with user_path.open("w", encoding="utf-8") as fh:
        json.dump(profile.to_dict(), fh, indent=4, ensure_ascii=False)


def all_users() -> list[int]:
    if not DATABASE_DIR.exists():
        return []
    return [int(item.name) for item in DATABASE_DIR.iterdir() if item.is_dir() and item.name.isdigit()]


def find_by_username(username: str) -> int | None:
    username = username.lstrip("@").lower()
    for uid in all_users():
        profile = get(uid)
        if profile and (profile.username or "").lower() == username:
            return uid
    return None