import esphome.codegen as cg
import esphome.config_validation as cv
from esphome.components import sensor
from esphome.const import CONF_SENSOR, UNIT_OHM, ICON_FLASH, CONF_ID

resistance_ns = cg.esphome_ns.namespace('resistance')
ResistanceSensor = resistance_ns.class_('ResistanceSensor', cg.Component, sensor.Sensor)

CONF_REFERENCE_VOLTAGE = 'reference_voltage'
CONF_CONFIGURATION = 'configuration'
CONF_RESISTOR = 'resistor'

ResistanceConfiguration = resistance_ns.enum('ResistanceConfiguration')
CONFIGURATIONS = {
    'DOWNSTREAM': ResistanceConfiguration.DOWNSTREAM,
    'UPSTREAM': ResistanceConfiguration.UPSTREAM,
}

CONFIG_SCHEMA = sensor.sensor_schema(UNIT_OHM, ICON_FLASH, 1).extend({
    cv.GenerateID(): cv.declare_id(ResistanceSensor),
    cv.Required(CONF_SENSOR): cv.use_id(sensor.Sensor),
    cv.Required(CONF_CONFIGURATION): cv.enum(CONFIGURATIONS, upper=True),
    cv.Required(CONF_RESISTOR): cv.resistance,
    cv.Optional(CONF_REFERENCE_VOLTAGE, default='3.3V'): cv.voltage,
}).extend(cv.COMPONENT_SCHEMA)


def to_code(config):
    var = cg.new_Pvariable(config[CONF_ID])
    yield cg.register_component(var, config)
    yield sensor.register_sensor(var, config)

    sens = yield cg.get_variable(config[CONF_SENSOR])
    cg.add(var.set_sensor(sens))
    cg.add(var.set_configuration(config[CONF_CONFIGURATION]))
    cg.add(var.set_resistor(config[CONF_RESISTOR]))
    cg.add(var.set_reference_voltage(config[CONF_REFERENCE_VOLTAGE]))