import pandas as pd
from BaseUtility import Definitions
from backend.Property import Property


class VentilationRecommendations(Definitions):
    """
    For properties that do not have ventilation, we recommend installing ventilaion
    This is particularly important for properties that have insulated walls and is also
    crucial for prevent overheating risks in warmer months
    """

    VENTILATION_DESCRIPTIONS = [
        'mechanical, extract only',
        'mechanical, supply and extract'
    ]

    # We introduce a SAP limit, to prevent over-predicting the SAP impact of mechanical ventilation
    SAP_LIMIT = 2

    def __init__(
        self,
        property_instance: Property,
        materials
    ):
        self.property = property_instance

        self.has_ventilaion = None
        self.recommendation = None
        self.materials = [part for part in materials if part["type"] == "mechanical_ventilation"]

    def identify_ventilation(self):
        self.has_ventilaion = self.property.data["mechanical-ventilation"] in self.VENTILATION_DESCRIPTIONS

    def recommend(self):
        """
        If there is no ventilation, we recommend installing ventilation

        Generally, best practice is to install controlled ventilation for insulated walls so we still recommend
        ventilation if there is natural ventilation
        :return:
        """

        self.identify_ventilation()
        if self.has_ventilaion:
            return

        if len(self.materials) != 1:
            raise NotImplementedError("Only handled the case of having one venilation option")

        # We recommend installing 2 units
        n_units = 2

        part = self.materials.copy()

        estimated_cost = n_units * part[0]["cost"]

        part[0]["total"] = estimated_cost
        part[0]["quantity"] = n_units
        part[0]["quantity_unit"] = "part"

        # We recommend installing two mechanical ventilation systems
        self.recommendation = [
            {
                "parts": part,
                "type": part[0]["type"],
                "description": f"Install {n_units} {part[0]['description']} units",
                "starting_u_value": None,
                "new_u_value": None,
                "sap_points": None,
                "total": estimated_cost,
                # We use a very simple and rough estimate of 4 hours per unit
                "labour_hours": 4 * n_units,
                "labour_days": 4 * n_units / 8.0  # Assume 8 hour day
            }
        ]