"""Server-side device configuration management for Phase 25.5a sync.

Provides API endpoints for Pi to fetch device config and portal to update it.
"""

from . import db


def get_device_config(device_id):
    """Get device config for a specific device.
    
    Returns dict with owner_name, car_model, device_name, avatar_path, config_version.
    """
    dev = db.get_device_by_id(device_id)
    if not dev:
        return None
    
    return {
        "owner_name": dev.get("owner_name") or "",
        "car_model": dev.get("car_model") or "",
        "device_name": dev.get("device_name") or "",
        "avatar_path": dev.get("avatar_path") or "img/yaris.png",
        "config_version": dev.get("config_version") or 0,
    }


def update_device_config(device_id, data):
    """Update device config. Returns (success, errors_dict).
    
    Validates input and updates config_version on change.
    """
    errors = {}
    
    if not isinstance(data, dict):
        return False, {"error": "Invalid request body"}
    
    # Validate fields
    owner_name = data.get("owner_name", "").strip() if "owner_name" in data else None
    car_model = data.get("car_model", "").strip() if "car_model" in data else None
    device_name = data.get("device_name", "").strip() if "device_name" in data else None
    avatar_path = data.get("avatar_path", "").strip() if "avatar_path" in data else None
    
    if owner_name is not None and len(owner_name) > 100:
        errors["owner_name"] = "Owner name must be 1-100 characters."
    
    if car_model is not None and len(car_model) > 100:
        errors["car_model"] = "Car model must be 1-100 characters."
    
    if device_name is not None and len(device_name) > 100:
        errors["device_name"] = "Device name must be 1-100 characters."
    
    if avatar_path is not None and len(avatar_path) > 255:
        errors["avatar_path"] = "Avatar path must be 1-255 characters."
    
    if errors:
        return False, errors
    
    # Build update dict (only include provided fields)
    with db.get_cursor(commit=True) as cur:
        # Increment config_version if any field changed
        if owner_name is not None or car_model is not None or device_name is not None or avatar_path is not None:
            cur.execute(
                "UPDATE devices SET config_version = config_version + 1, config_updated_at = now() WHERE id = %s",
                (device_id,)
            )
        
        # Update individual fields
        if owner_name is not None:
            cur.execute(
                "UPDATE devices SET owner_name = %s WHERE id = %s",
                (owner_name, device_id)
            )
        if car_model is not None:
            cur.execute(
                "UPDATE devices SET car_model = %s WHERE id = %s",
                (car_model, device_id)
            )
        if device_name is not None:
            cur.execute(
                "UPDATE devices SET device_name = %s WHERE id = %s",
                (device_name, device_id)
            )
        if avatar_path is not None:
            cur.execute(
                "UPDATE devices SET avatar_path = %s WHERE id = %s",
                (avatar_path, device_id)
            )
    
    return True, {}