from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.models import SystemSetting
from app.core.config import settings
from pathlib import Path
import os

DEFAULT_SETTINGS = {
    "storage_root": settings.STORAGE_ROOT,
    "global_quota_gb": "1000",
    "default_client_quota_gb": "100",
    "default_keep_daily": str(settings.DEFAULT_RETENTION_DAILY),
    "default_keep_weekly": str(settings.DEFAULT_RETENTION_WEEKLY),
    "default_keep_monthly": str(settings.DEFAULT_RETENTION_MONTHLY),
}

async def get_setting(db: AsyncSession, key: str) -> str:
    result = await db.execute(select(SystemSetting).where(SystemSetting.key == key))
    setting = result.scalar_one_or_none()
    if setting:
        return setting.value
    return DEFAULT_SETTINGS.get(key, "")

async def get_all_settings(db: AsyncSession) -> dict:
    result = await db.execute(select(SystemSetting))
    db_settings = {s.key: s.value for s in result.scalars().all()}
    
    # Merge defaults and add them if not present in db
    updated = False
    for k, v in DEFAULT_SETTINGS.items():
        if k not in db_settings:
            db_settings[k] = v
            db.add(SystemSetting(key=k, value=v))
            updated = True
    if updated:
        await db.commit()
    return db_settings

async def update_settings_service(db: AsyncSession, new_settings: dict) -> dict:
    from app.storage.local import storage_provider
    
    for k, v in new_settings.items():
        if k in DEFAULT_SETTINGS and v is not None:
            # If changing storage root, validate and apply
            if k == "storage_root":
                path = Path(v).resolve()
                try:
                    os.makedirs(path, exist_ok=True)
                    # Test write access
                    test_file = path / ".write_test"
                    test_file.touch()
                    test_file.unlink()
                except Exception as e:
                    raise ValueError(f"Invalid or unwritable storage root path: {str(e)}")
                
                # Apply to in-memory storage provider
                storage_provider.root_dir = path
                
            result = await db.execute(select(SystemSetting).where(SystemSetting.key == k))
            setting = result.scalar_one_or_none()
            if setting:
                setting.value = str(v)
            else:
                db.add(SystemSetting(key=k, value=str(v)))
                
    await db.commit()
    return await get_all_settings(db)