"""Support for scripts."""
import asyncio
import logging

import voluptuous as vol

from homeassistant.const import (
    ATTR_ENTITY_ID, SERVICE_TURN_OFF, SERVICE_TURN_ON,
    SERVICE_TOGGLE, SERVICE_RELOAD, STATE_ON, CONF_ALIAS,
    EVENT_SCRIPT_STARTED, ATTR_NAME)
from homeassistant.loader import bind_hass
from homeassistant.helpers.entity import ToggleEntity
from homeassistant.helpers.entity_component import EntityComponent
import homeassistant.helpers.config_validation as cv

from homeassistant.helpers.script import Script

_LOGGER = logging.getLogger(__name__)

DOMAIN = 'script'
ATTR_CAN_CANCEL = 'can_cancel'
ATTR_LAST_ACTION = 'last_action'
ATTR_LAST_TRIGGERED = 'last_triggered'
ATTR_VARIABLES = 'variables'

CONF_SEQUENCE = 'sequence'

ENTITY_ID_FORMAT = DOMAIN + '.{}'

GROUP_NAME_ALL_SCRIPTS = 'all scripts'

SCRIPT_ENTRY_SCHEMA = vol.Schema({
    CONF_ALIAS: cv.string,
    vol.Required(CONF_SEQUENCE): cv.SCRIPT_SCHEMA,
})

CONFIG_SCHEMA = vol.Schema({
    DOMAIN: cv.schema_with_slug_keys(SCRIPT_ENTRY_SCHEMA)
}, extra=vol.ALLOW_EXTRA)

SCRIPT_SERVICE_SCHEMA = vol.Schema(dict)
SCRIPT_TURN_ONOFF_SCHEMA = vol.Schema({
    vol.Optional(ATTR_ENTITY_ID): cv.entity_ids,
    vol.Optional(ATTR_VARIABLES): dict,
})
RELOAD_SERVICE_SCHEMA = vol.Schema({})


@bind_hass
def is_on(hass, entity_id):
    """Return if the script is on based on the statemachine."""
    return hass.states.is_state(entity_id, STATE_ON)


async def async_setup(hass, config):
    """Load the scripts from the configuration."""
    component = EntityComponent(
        _LOGGER, DOMAIN, hass, group_name=GROUP_NAME_ALL_SCRIPTS)

    await _async_process_config(hass, config, component)

    async def reload_service(service):
        """Call a service to reload scripts."""
        conf = await component.async_prepare_reload()
        if conf is None:
            return

        await _async_process_config(hass, conf, component)

    async def turn_on_service(service):
        """Call a service to turn script on."""
        # We could turn on script directly here, but we only want to offer
        # one way to do it. Otherwise no easy way to detect invocations.
        var = service.data.get(ATTR_VARIABLES)
        for script in await component.async_extract_from_service(service):
            await hass.services.async_call(DOMAIN, script.object_id, var,
                                           context=service.context)

    async def turn_off_service(service):
        """Cancel a script."""
        # Stopping a script is ok to be done in parallel
        await asyncio.wait([
            script.async_turn_off() for script
            in await component.async_extract_from_service(service)
        ])

    async def toggle_service(service):
        """Toggle a script."""
        for script in await component.async_extract_from_service(service):
            await script.async_toggle(context=service.context)

    hass.services.async_register(DOMAIN, SERVICE_RELOAD, reload_service,
                                 schema=RELOAD_SERVICE_SCHEMA)
    hass.services.async_register(DOMAIN, SERVICE_TURN_ON, turn_on_service,
                                 schema=SCRIPT_TURN_ONOFF_SCHEMA)
    hass.services.async_register(DOMAIN, SERVICE_TURN_OFF, turn_off_service,
                                 schema=SCRIPT_TURN_ONOFF_SCHEMA)
    hass.services.async_register(DOMAIN, SERVICE_TOGGLE, toggle_service,
                                 schema=SCRIPT_TURN_ONOFF_SCHEMA)

    return True


async def _async_process_config(hass, config, component):
    """Process script configuration."""
    async def service_handler(service):
        """Execute a service call to script.<script name>."""
        entity_id = ENTITY_ID_FORMAT.format(service.service)
        script = component.get_entity(entity_id)
        if script.is_on:
            _LOGGER.warning("Script %s already running.", entity_id)
            return
        await script.async_turn_on(variables=service.data,
                                   context=service.context)

    scripts = []

    for object_id, cfg in config.get(DOMAIN, {}).items():
        alias = cfg.get(CONF_ALIAS, object_id)
        script = ScriptEntity(hass, object_id, alias, cfg[CONF_SEQUENCE])
        scripts.append(script)
        hass.services.async_register(
            DOMAIN, object_id, service_handler, schema=SCRIPT_SERVICE_SCHEMA)

    await component.async_add_entities(scripts)


class ScriptEntity(ToggleEntity):
    """Representation of a script entity."""

    def __init__(self, hass, object_id, name, sequence):
        """Initialize the script."""
        self.object_id = object_id
        self.entity_id = ENTITY_ID_FORMAT.format(object_id)
        self.script = Script(hass, sequence, name, self.async_update_ha_state)

    @property
    def should_poll(self):
        """No polling needed."""
        return False

    @property
    def name(self):
        """Return the name of the entity."""
        return self.script.name

    @property
    def state_attributes(self):
        """Return the state attributes."""
        attrs = {}
        attrs[ATTR_LAST_TRIGGERED] = self.script.last_triggered
        if self.script.can_cancel:
            attrs[ATTR_CAN_CANCEL] = self.script.can_cancel
        if self.script.last_action:
            attrs[ATTR_LAST_ACTION] = self.script.last_action
        return attrs

    @property
    def is_on(self):
        """Return true if script is on."""
        return self.script.is_running

    async def async_turn_on(self, **kwargs):
        """Turn the script on."""
        context = kwargs.get('context')
        self.async_set_context(context)
        self.hass.bus.async_fire(EVENT_SCRIPT_STARTED, {
            ATTR_NAME: self.script.name,
            ATTR_ENTITY_ID: self.entity_id,
        }, context=context)
        try:
            await self.script.async_run(
                kwargs.get(ATTR_VARIABLES), context)
        except Exception as err:  # pylint: disable=broad-except
            self.script.async_log_exception(
                _LOGGER, "Error executing script {}".format(self.entity_id),
                err)
            raise err

    async def async_turn_off(self, **kwargs):
        """Turn script off."""
        self.script.async_stop()

    async def async_will_remove_from_hass(self):
        """Stop script and remove service when it will be removed from HASS."""
        if self.script.is_running:
            self.script.async_stop()

        # remove service
        self.hass.services.async_remove(DOMAIN, self.object_id)