"""Helpers for config validation using voluptuous."""
import voluptuous as vol

from homeassistant.const import (
    CONF_PLATFORM, CONF_SCAN_INTERVAL, TEMP_CELCIUS, TEMP_FAHRENHEIT)
from homeassistant.helpers.entity import valid_entity_id
import homeassistant.util.dt as dt_util

# pylint: disable=invalid-name

PLATFORM_SCHEMA = vol.Schema({
    vol.Required(CONF_PLATFORM): str,
    CONF_SCAN_INTERVAL: vol.All(vol.Coerce(int), vol.Range(min=1)),
}, extra=vol.ALLOW_EXTRA)

byte = vol.All(vol.Coerce(int), vol.Range(min=0, max=255))
small_float = vol.All(vol.Coerce(float), vol.Range(min=0, max=1))
latitude = vol.All(vol.Coerce(float), vol.Range(min=-90, max=90))
longitude = vol.All(vol.Coerce(float), vol.Range(min=-180, max=180))


def entity_id(value):
    """Validate Entity ID."""
    if valid_entity_id(value):
        return value
    raise vol.Invalid('Entity ID {} does not match format <domain>.<object_id>'
                      .format(value))


def entity_ids(value):
    """Validate Entity IDs."""
    if isinstance(value, str):
        value = [ent_id.strip() for ent_id in value.split(',')]

    for ent_id in value:
        entity_id(ent_id)

    return value


def icon(value):
    """Validate icon."""
    value = str(value)

    if value.startswith('mdi:'):
        return value

    raise vol.Invalid('Icons should start with prefix "mdi:"')


def string(value):
    """Coerce value to string, except for None."""
    if value is not None:
        return str(value)
    raise vol.Invalid('Value should not be None')


def temperature_unit(value):
    """Validate and transform temperature unit."""
    if isinstance(value, str):
        value = value.upper()
        if value == 'C':
            return TEMP_CELCIUS
        elif value == 'F':
            return TEMP_FAHRENHEIT
    raise vol.Invalid('Invalid temperature unit. Expected: C or F')


def time_zone(value):
    """Validate timezone."""
    if dt_util.get_time_zone(value) is not None:
        return value
    raise vol.Invalid(
        'Invalid time zone passed in. Valid options can be found here: '
        'http://en.wikipedia.org/wiki/List_of_tz_database_time_zones')