import os
import secrets


class Config:
    """Base config."""

    SECRET_KEY = os.environ.get('SECRET_KEY') or secrets.token_hex(32)
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or 'sqlite:///instance/app.db'
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    WTF_CSRF_ENABLED = True
    WTF_CSRF_SECRET_KEY = os.environ.get('CSRF_SECRET_KEY') or secrets.token_hex(32)
    SESSION_TYPE = 'filesystem'
    SESSION_PERMANENT = False
    PERMANENT_SESSION_LIFETIME = 3600  # 1 hour
    REMEMBER_COOKIE_DURATION = 2592000  # 30 days


class DevelopmentConfig(Config):
    """Development config."""

    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get("DATABASE_URL", "sqlite:///app.db")
    SQLALCHEMY_ECHO = True


class ProductionConfig(Config):
    """Production config."""

    DEBUG = False
    TESTING = False
    SQLALCHEMY_DATABASE_URI = os.environ.get("DATABASE_URL", "sqlite:///app.db")
    SESSION_COOKIE_SECURE = True
    REMEMBER_COOKIE_SECURE = True


class TestingConfig(Config):
    """Testing config."""

    TESTING = True
    SQLALCHEMY_DATABASE_URI = "sqlite:///:memory:"
    WTF_CSRF_ENABLED = False