from pathlib import Path

from sqlalchemy.orm import Session

from app.config import ROOT
from app.models import AppSettings

UPLOAD_DIR = ROOT / "backend" / "data" / "uploads"
LOGO_BASENAME = "site_logo"
DEFAULT_SYSTEM_NAME = "考试阅卷系统"


def ensure_upload_dir() -> None:
    UPLOAD_DIR.mkdir(parents=True, exist_ok=True)


def get_or_create_settings(db: Session) -> AppSettings:
    row = db.get(AppSettings, 1)
    if not row:
        row = AppSettings(id=1, system_name=DEFAULT_SYSTEM_NAME, logo_ext="")
        db.add(row)
        db.commit()
        db.refresh(row)
    return row


def logo_path(ext: str) -> Path:
    return UPLOAD_DIR / f"{LOGO_BASENAME}.{ext}"


def find_logo_file(ext: str | None) -> Path | None:
    if ext:
        p = logo_path(ext)
        if p.is_file():
            return p
    ensure_upload_dir()
    for p in UPLOAD_DIR.glob(f"{LOGO_BASENAME}.*"):
        if p.is_file():
            return p
    return None


def clear_logo_files() -> None:
    ensure_upload_dir()
    for p in UPLOAD_DIR.glob(f"{LOGO_BASENAME}.*"):
        p.unlink(missing_ok=True)


def public_logo_url(ext: str | None) -> str | None:
    if ext and find_logo_file(ext):
        return "/api/settings/logo"
    if find_logo_file(None):
        return "/api/settings/logo"
    return None