"""Represent a smart water meter."""

from datetime import datetime, timedelta

from .utils import parse_iso_datetime

class SmartMeter:
    """
    A class to represent a smart water meter.
    """

    last_reading: float = 0.0
    yesterday_water_cost: float = 0.0
    yesterday_sewerage_cost: float = 0.0

    def __init__(self, serial_number):
        self.serial_number = serial_number
        self.readings = []

    def update_reading_cache(self, reads: list, costs: dict):
        """Updates the cache of meter reads for the smart meter."""
        self.readings = []
        for reading in reads:
            for meter in reading["meters"]:
                if meter["meter_serial_number"] == self.serial_number:
                    self.readings.append({**meter})
                    self.last_reading = float(meter["read"])
        self.yesterday_water_cost = costs.get("result", {}).get("water_cost", 0.0)
        self.yesterday_sewerage_cost = costs.get("result", {}).get("sewerage_cost", 0.0)

    @property
    def get_yesterday_readings(self) -> list:
        """Returns the the previous days readings for the smart meter."""
        yesterday = datetime.now() - timedelta(days=1)
        output = []
        for reading in self.readings:
            if (dt := parse_iso_datetime(reading["read_at"])) and dt.date() == yesterday.date():
                output.append(reading)
        return output

    @property
    def get_yesterday_consumption(self) -> float:
        """Returns the consumption of the previous days readings for the smart meter."""
        total = 0.0
        for reading in self.get_yesterday_readings:
            total += float(reading["consumption"])
        return total

    @property
    def latest_consumption(self) -> float:
        """Returns the latest consumption for the smart meter."""
        if len(self.readings) == 0:
            return 0.0
        return float(self.readings[-1]["consumption"])

    @property
    def latest_read(self) -> float:
        """Returns the latest read for the smart meter."""
        if len(self.readings) == 0:
            return 0.0
        return float(self.readings[-1]["read"])

    @property
    def last_updated(self) -> datetime | None:
        """Returns the last updated time for the smart meter."""
        if len(self.readings) == 0:
            return None
        return parse_iso_datetime(self.readings[-1]["read_at"])

    def to_dict(self) -> dict:
        """Returns the SmartMeter object data as a dictionary."""
        return {
            "serial_number": self.serial_number,
            "last_reading": self.last_reading,
            "readings": self.readings,
            "consumption": self.latest_consumption,
        }

    def __iter__(self):
        """Allows the object to be converted to a dictionary using dict()."""
        return iter(self.to_dict().items())