from pyheatpump.db import DB, RowClass
from datetime import datetime

from .variable_type import VariableType
from pyheatpump.logger import logger_init
from pyheatpump.modbus import write_coil, write_holding_register

logger = logger_init()

class VariableValue(RowClass):
    type: VariableType = None
    address: int = None
    time: datetime = None
    value: int = None

    def __init__(self, **kwargs):
        if 'type' in kwargs.keys() and not isinstance(kwargs['type'], VariableType):
            kwargs['type'] = VariableType.get(kwargs['type'])


        super().__init__(**kwargs)

    def insert(self):

        try:
            old_value = VariableValue.get(
                self.type,
                self.address)
            if old_value.value == self.value:
                # last variable value is equal to current value
                # so do not insert
                return False
        except StopIteration:
            # variable value was never inserted
            pass

        try:
            params = self.__dict__.copy()
            params.update({'type': str(params['type'])})
            DB.sql(
                """INSERT INTO var_value
                (type, address, value)
                VALUES
                (:type, :address, :value)""",
                params
            )
            return True
        except Exception as e:
            logger.error('VariableValue.insert: %s', e)
            return False


    def get_value(self):
        return self.type.cast()(self.value)

    def equals(self, var_value):
        return self.get_value() == var_value.get_value()

    def set(self):
        if self.type == 'D':
            write_coil(self)
        else:
            write_holding_register(self)

        return self.insert()

    @staticmethod
    def get(var_type, address, time=datetime.now()):
        try:
            row = next(DB.sql(
            """SELECT * FROM var_value
            WHERE
                type = :type
                AND address = :address
                AND time <= :time
            ORDER BY time DESC
            LIMIT 1""", {
                'type':str(var_type), 'address':address, 'time':int(time.strftime('%s'))+1
            }))
            return VariableValue(**{ **dict(row), **{ 'type': var_type } })
        except StopIteration as e:
            raise e