"""Component to count within automations."""
import logging

import voluptuous as vol

from homeassistant.const import CONF_ICON, CONF_MAXIMUM, CONF_MINIMUM, CONF_NAME
import homeassistant.helpers.config_validation as cv
from homeassistant.helpers.entity_component import EntityComponent
from homeassistant.helpers.restore_state import RestoreEntity

_LOGGER = logging.getLogger(__name__)

ATTR_INITIAL = "initial"
ATTR_STEP = "step"
ATTR_MINIMUM = "minimum"
ATTR_MAXIMUM = "maximum"
VALUE = "value"

CONF_INITIAL = "initial"
CONF_RESTORE = "restore"
CONF_STEP = "step"

DEFAULT_INITIAL = 0
DEFAULT_STEP = 1
DOMAIN = "counter"

ENTITY_ID_FORMAT = DOMAIN + ".{}"

SERVICE_DECREMENT = "decrement"
SERVICE_INCREMENT = "increment"
SERVICE_RESET = "reset"
SERVICE_CONFIGURE = "configure"


def _none_to_empty_dict(value):
    if value is None:
        return {}
    return value


CONFIG_SCHEMA = vol.Schema(
    {
        DOMAIN: cv.schema_with_slug_keys(
            vol.All(
                _none_to_empty_dict,
                {
                    vol.Optional(CONF_ICON): cv.icon,
                    vol.Optional(
                        CONF_INITIAL, default=DEFAULT_INITIAL
                    ): cv.positive_int,
                    vol.Optional(CONF_NAME): cv.string,
                    vol.Optional(CONF_MAXIMUM, default=None): vol.Any(
                        None, vol.Coerce(int)
                    ),
                    vol.Optional(CONF_MINIMUM, default=None): vol.Any(
                        None, vol.Coerce(int)
                    ),
                    vol.Optional(CONF_RESTORE, default=True): cv.boolean,
                    vol.Optional(CONF_STEP, default=DEFAULT_STEP): cv.positive_int,
                },
            )
        )
    },
    extra=vol.ALLOW_EXTRA,
)


async def async_setup(hass, config):
    """Set up the counters."""
    component = EntityComponent(_LOGGER, DOMAIN, hass)

    entities = []

    for object_id, cfg in config[DOMAIN].items():
        if not cfg:
            cfg = {}

        name = cfg.get(CONF_NAME)
        initial = cfg[CONF_INITIAL]
        restore = cfg[CONF_RESTORE]
        step = cfg[CONF_STEP]
        icon = cfg.get(CONF_ICON)
        minimum = cfg[CONF_MINIMUM]
        maximum = cfg[CONF_MAXIMUM]

        entities.append(
            Counter(object_id, name, initial, minimum, maximum, restore, step, icon)
        )

    if not entities:
        return False

    component.async_register_entity_service(SERVICE_INCREMENT, {}, "async_increment")
    component.async_register_entity_service(SERVICE_DECREMENT, {}, "async_decrement")
    component.async_register_entity_service(SERVICE_RESET, {}, "async_reset")
    component.async_register_entity_service(
        SERVICE_CONFIGURE,
        {
            vol.Optional(ATTR_MINIMUM): vol.Any(None, vol.Coerce(int)),
            vol.Optional(ATTR_MAXIMUM): vol.Any(None, vol.Coerce(int)),
            vol.Optional(ATTR_STEP): cv.positive_int,
            vol.Optional(ATTR_INITIAL): cv.positive_int,
            vol.Optional(VALUE): cv.positive_int,
        },
        "async_configure",
    )

    await component.async_add_entities(entities)
    return True


class Counter(RestoreEntity):
    """Representation of a counter."""

    def __init__(self, object_id, name, initial, minimum, maximum, restore, step, icon):
        """Initialize a counter."""
        self.entity_id = ENTITY_ID_FORMAT.format(object_id)
        self._name = name
        self._restore = restore
        self._step = step
        self._state = self._initial = initial
        self._min = minimum
        self._max = maximum
        self._icon = icon

    @property
    def should_poll(self):
        """If entity should be polled."""
        return False

    @property
    def name(self):
        """Return name of the counter."""
        return self._name

    @property
    def icon(self):
        """Return the icon to be used for this entity."""
        return self._icon

    @property
    def state(self):
        """Return the current value of the counter."""
        return self._state

    @property
    def state_attributes(self):
        """Return the state attributes."""
        ret = {ATTR_INITIAL: self._initial, ATTR_STEP: self._step}
        if self._min is not None:
            ret[CONF_MINIMUM] = self._min
        if self._max is not None:
            ret[CONF_MAXIMUM] = self._max
        return ret

    def compute_next_state(self, state):
        """Keep the state within the range of min/max values."""
        if self._min is not None:
            state = max(self._min, state)
        if self._max is not None:
            state = min(self._max, state)

        return state

    async def async_added_to_hass(self):
        """Call when entity about to be added to Home Assistant."""
        await super().async_added_to_hass()
        # __init__ will set self._state to self._initial, only override
        # if needed.
        if self._restore:
            state = await self.async_get_last_state()
            if state is not None:
                self._state = self.compute_next_state(int(state.state))
                self._initial = state.attributes.get(ATTR_INITIAL)
                self._max = state.attributes.get(ATTR_MAXIMUM)
                self._min = state.attributes.get(ATTR_MINIMUM)
                self._step = state.attributes.get(ATTR_STEP)

    async def async_decrement(self):
        """Decrement the counter."""
        self._state = self.compute_next_state(self._state - self._step)
        await self.async_update_ha_state()

    async def async_increment(self):
        """Increment a counter."""
        self._state = self.compute_next_state(self._state + self._step)
        await self.async_update_ha_state()

    async def async_reset(self):
        """Reset a counter."""
        self._state = self.compute_next_state(self._initial)
        await self.async_update_ha_state()

    async def async_configure(self, **kwargs):
        """Change the counter's settings with a service."""
        if CONF_MINIMUM in kwargs:
            self._min = kwargs[CONF_MINIMUM]
        if CONF_MAXIMUM in kwargs:
            self._max = kwargs[CONF_MAXIMUM]
        if CONF_STEP in kwargs:
            self._step = kwargs[CONF_STEP]
        if CONF_INITIAL in kwargs:
            self._initial = kwargs[CONF_INITIAL]
        if VALUE in kwargs:
            self._state = kwargs[VALUE]

        self._state = self.compute_next_state(self._state)
        await self.async_update_ha_state()
