"""API for persistent storage for the frontend."""
from functools import wraps
import voluptuous as vol

from homeassistant.components import websocket_api

DATA_STORAGE = 'frontend_storage'
STORAGE_VERSION_USER_DATA = 1
STORAGE_KEY_USER_DATA = 'frontend.user_data_{}'


async def async_setup_frontend_storage(hass):
    """Set up frontend storage."""
    hass.data[DATA_STORAGE] = ({}, {})
    hass.components.websocket_api.async_register_command(
        websocket_set_user_data
    )
    hass.components.websocket_api.async_register_command(
        websocket_get_user_data
    )


def with_store(orig_func):
    """Decorate function to provide data."""
    @wraps(orig_func)
    async def with_store_func(hass, connection, msg):
        """Provide user specific data and store to function."""
        stores, data = hass.data[DATA_STORAGE]
        user_id = connection.user.id
        store = stores.get(user_id)

        if store is None:
            store = stores[user_id] = hass.helpers.storage.Store(
                STORAGE_VERSION_USER_DATA,
                STORAGE_KEY_USER_DATA.format(connection.user.id)
            )

        if user_id not in data:
            data[user_id] = await store.async_load() or {}

        await orig_func(
            hass, connection, msg,
            store,
            data[user_id],
        )
    return with_store_func


@websocket_api.websocket_command({
    vol.Required('type'): 'frontend/set_user_data',
    vol.Required('key'): str,
    vol.Required('value'): vol.Any(bool, str, int, float, dict, list, None),
})
@websocket_api.async_response
@with_store
async def websocket_set_user_data(hass, connection, msg, store, data):
    """Handle set global data command.

    Async friendly.
    """
    data[msg['key']] = msg['value']
    await store.async_save(data)
    connection.send_message(websocket_api.result_message(
        msg['id'],
    ))


@websocket_api.websocket_command({
    vol.Required('type'): 'frontend/get_user_data',
    vol.Optional('key'): str,
})
@websocket_api.async_response
@with_store
async def websocket_get_user_data(hass, connection, msg, store, data):
    """Handle get global data command.

    Async friendly.
    """
    connection.send_message(websocket_api.result_message(
        msg['id'], {
            'value': data.get(msg['key']) if 'key' in msg else data
        }
    ))
