"""
Key/value store for admin-configurable site settings.

Values are strings on disk; the typed helpers below do the coercion. Reads
are cached per process and the cache is dropped on write, so the settings
page is authoritative without hitting the database on every request.

Created by: Jess Rogerson (yelling commands at Claude.AI)
"""

from datetime import datetime
import threading

from app import db

# Defaults are the behaviour LIM had before settings existed, except where
# noted — anything not yet stored falls back to these.
DEFAULTS = {
    'allow_registration': 'true',
    # Visibility given to newly created sets.
    'default_visibility': 'private',
    # Send logged-in users straight to their dashboard instead of the
    # marketing homepage.
    'home_redirect_dashboard': 'true',
}

VISIBILITIES = ('private', 'shared', 'public')

_cache = {}
_cache_lock = threading.Lock()


class SiteSetting(db.Model):
    """One configurable setting."""

    __tablename__ = 'site_settings'

    id = db.Column(db.Integer, primary_key=True)
    key = db.Column(db.String(64), unique=True, nullable=False, index=True)
    value = db.Column(db.Text, nullable=True)
    updated_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow,
                           onupdate=datetime.utcnow)

    def __repr__(self):
        return f'<SiteSetting {self.key}={self.value!r}>'

    # -- reads --------------------------------------------------------------

    @classmethod
    def get(cls, key, default=None):
        with _cache_lock:
            if key in _cache:
                return _cache[key]
        try:
            row = cls.query.filter_by(key=key).first()
        except Exception:
            # Table may not exist yet (first boot, before create_all).
            return DEFAULTS.get(key, default)
        value = row.value if row else DEFAULTS.get(key, default)
        with _cache_lock:
            _cache[key] = value
        return value

    @classmethod
    def get_bool(cls, key, default=False):
        value = cls.get(key)
        if value is None:
            return default
        return str(value).strip().lower() in ('1', 'true', 'yes', 'on')

    @classmethod
    def all_settings(cls):
        merged = dict(DEFAULTS)
        try:
            for row in cls.query.all():
                merged[row.key] = row.value
        except Exception:
            pass
        return merged

    # -- writes -------------------------------------------------------------

    @classmethod
    def set(cls, key, value):
        if isinstance(value, bool):
            value = 'true' if value else 'false'
        row = cls.query.filter_by(key=key).first()
        if row:
            row.value = value
        else:
            db.session.add(cls(key=key, value=value))
        cls.clear_cache()
        return value

    @classmethod
    def clear_cache(cls):
        with _cache_lock:
            _cache.clear()