from __future__ import annotations

import os
import secrets
from pathlib import Path

BASE_DIR = Path(__file__).resolve().parent.parent
DATA_DIR = BASE_DIR / "data"
STATIC_DIR = BASE_DIR / "static"
UPLOAD_DIR = BASE_DIR / "uploads"
IMAGE_DIR = STATIC_DIR / "images"


def env_int(name: str, default: int) -> int:
    try:
        return int(os.environ.get(name, str(default)))
    except ValueError:
        return default


def env_bool(name: str, default: bool = False) -> bool:
    value = os.environ.get(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


class Config:
    DEBUG = env_bool("DEBUG", False)
    SECRET_KEY = os.environ.get("SECRET_KEY") or secrets.token_hex(32)
    SECRET_KEY_GENERATED = not bool(os.environ.get("SECRET_KEY"))
    SQLALCHEMY_DATABASE_URI = os.environ.get(
        "DATABASE_URL",
        f"sqlite:///{DATA_DIR / 'pipe_survival_0331.db'}",
    )
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    MAX_CONTENT_LENGTH = env_int("MAX_UPLOAD_BYTES", 16 * 1024 * 1024)
    SESSION_COOKIE_HTTPONLY = True
    SESSION_COOKIE_SAMESITE = "Lax"
    FUSION_MODEL_CORE_DIR = os.environ.get(
        "FUSION_MODEL_CORE_DIR",
        str(BASE_DIR / "model_core"),
    )
    ALLOW_REGISTRATION = env_bool("ALLOW_REGISTRATION", False)
    ADMIN_USERNAME = os.environ.get("ADMIN_USERNAME", "admin").strip() or "admin"
    ADMIN_PASSWORD = os.environ.get("ADMIN_PASSWORD")
    APP_TIMEZONE = os.environ.get("APP_TIMEZONE", "Asia/Shanghai").strip() or "Asia/Shanghai"
    PASSWORD_RESET_TOKEN_MINUTES = env_int("PASSWORD_RESET_TOKEN_MINUTES", 30)


def ensure_dirs() -> None:
    for path in (DATA_DIR, STATIC_DIR, IMAGE_DIR, UPLOAD_DIR):
        path.mkdir(parents=True, exist_ok=True)