"""
Drapery module for HVAC Load Calculator.
This module provides classes and functions for handling drapery properties
and calculating their effects on window heat transfer.

Based on ASHRAE principles for drapery thermal characteristics.
"""

from typing import Dict, Any, Optional, Tuple
from enum import Enum


class DraperyOpenness(Enum):
    """Enum for drapery openness classification."""
    OPEN = "Open (>25%)"
    SEMI_OPEN = "Semi-open (7-25%)"
    CLOSED = "Closed (0-7%)"


class DraperyColor(Enum):
    """Enum for drapery color/reflectance classification."""
    DARK = "Dark (0-25%)"
    MEDIUM = "Medium (25-50%)"
    LIGHT = "Light (>50%)"


class Drapery:
    """Class for drapery properties and calculations."""
    
    def __init__(self, 
                 openness: float = 0.05, 
                 reflectance: float = 0.5, 
                 transmittance: float = 0.3, 
                 fullness: float = 1.0,
                 enabled: bool = True):
        """
        Initialize drapery object.
        
        Args:
            openness: Openness factor (0-1), fraction of fabric area that is open
            reflectance: Reflectance factor (0-1), fraction of incident radiation reflected
            transmittance: Transmittance factor (0-1), fraction of incident radiation transmitted
            fullness: Fullness factor (0-2), ratio of fabric width to covered width
            enabled: Whether the drapery is enabled/present
        """
        self.openness = max(0.0, min(1.0, openness))
        self.reflectance = max(0.0, min(1.0, reflectance))
        self.transmittance = max(0.0, min(1.0, transmittance))
        self.fullness = max(0.0, min(2.0, fullness))
        self.enabled = enabled
        
        # Calculate derived properties
        self.absorptance = 1.0 - self.reflectance - self.transmittance
        
        # Classify drapery based on openness and reflectance
        self.openness_class = self._classify_openness(self.openness)
        self.color_class = self._classify_color(self.reflectance)
    
    @staticmethod
    def _classify_openness(openness: float) -> DraperyOpenness:
        """Classify drapery based on openness factor."""
        if openness > 0.25:
            return DraperyOpenness.OPEN
        elif openness > 0.07:
            return DraperyOpenness.SEMI_OPEN
        else:
            return DraperyOpenness.CLOSED
    
    @staticmethod
    def _classify_color(reflectance: float) -> DraperyColor:
        """Classify drapery based on reflectance factor."""
        if reflectance > 0.5:
            return DraperyColor.LIGHT
        elif reflectance > 0.25:
            return DraperyColor.MEDIUM
        else:
            return DraperyColor.DARK
    
    def get_classification(self) -> str:
        """Get drapery classification string."""
        openness_map = {
            DraperyOpenness.OPEN: "I",
            DraperyOpenness.SEMI_OPEN: "II",
            DraperyOpenness.CLOSED: "III"
        }
        
        color_map = {
            DraperyColor.DARK: "D",
            DraperyColor.MEDIUM: "M",
            DraperyColor.LIGHT: "L"
        }
        
        return f"{openness_map[self.openness_class]}{color_map[self.color_class]}"
    
    def calculate_iac(self, glazing_shgc: float = 0.87) -> float:
        """
        Calculate Interior Attenuation Coefficient (IAC) for the drapery.
        
        The IAC represents the fraction of heat flow that enters the room
        after being modified by the drapery.
        
        Args:
            glazing_shgc: Solar Heat Gain Coefficient of the glazing (default: 0.87 for clear glass)
            
        Returns:
            IAC value (0-1)
        """
        if not self.enabled:
            return 1.0  # No attenuation if drapery is not enabled
        
        # Calculate base IAC for flat drapery (no fullness)
        # This is based on the principles from the Keyes Universal Chart
        # and ASHRAE's IAC calculation methods
        
        # Calculate yarn reflectance (based on openness and reflectance)
        if self.openness < 0.0001:  # Prevent division by zero
            yarn_reflectance = self.reflectance
        else:
            yarn_reflectance = self.reflectance / (1.0 - self.openness)
            yarn_reflectance = min(1.0, yarn_reflectance)  # Cap at 1.0
        
        # Base IAC calculation using fabric properties
        # This is a simplified version of the ASHWAT model calculations
        base_iac = 1.0 - (1.0 - self.openness) * (1.0 - self.transmittance / (1.0 - self.openness)) * yarn_reflectance
        
        # Adjust for fullness
        # Fullness creates multiple reflections between adjacent fabric surfaces
        if self.fullness <= 0.0:
            fullness_factor = 1.0
        else:
            # Fullness effect increases with higher fullness values
            # More fullness means more fabric area and more reflections
            fullness_factor = 1.0 - 0.15 * (self.fullness / 2.0)
            
        # Apply fullness adjustment
        adjusted_iac = base_iac * fullness_factor
        
        # Ensure IAC is within valid range
        adjusted_iac = max(0.1, min(1.0, adjusted_iac))
        
        return adjusted_iac
    
    def calculate_shading_coefficient(self, glazing_shgc: float = 0.87) -> float:
        """
        Calculate shading coefficient for the drapery.
        
        The shading coefficient is the ratio of solar heat gain through
        the window with the drapery to that of standard clear glass.
        
        Args:
            glazing_shgc: Solar Heat Gain Coefficient of the glazing (default: 0.87 for clear glass)
            
        Returns:
            Shading coefficient (0-1)
        """
        # Calculate IAC
        iac = self.calculate_iac(glazing_shgc)
        
        # Calculate shading coefficient
        # SC = IAC * SHGC / 0.87
        shading_coefficient = iac * glazing_shgc / 0.87
        
        return shading_coefficient
    
    def calculate_u_value_adjustment(self, base_u_value: float) -> float:
        """
        Calculate U-value adjustment for the drapery.
        
        The drapery adds thermal resistance to the window assembly,
        reducing the overall U-value.
        
        Args:
            base_u_value: Base U-value of the window without drapery (W/m²K)
            
        Returns:
            Adjusted U-value (W/m²K)
        """
        if not self.enabled:
            return base_u_value  # No adjustment if drapery is not enabled
        
        # Calculate additional thermal resistance based on drapery properties
        # This is a simplified approach based on ASHRAE principles
        
        # Base resistance from drapery
        # More closed fabrics provide more resistance
        base_resistance = 0.05  # m²K/W, typical for medium-weight drapery
        
        # Adjust for openness (more closed = more resistance)
        openness_factor = 1.0 - self.openness
        
        # Adjust for fullness (more fullness = more resistance due to air gaps)
        fullness_factor = 1.0 + 0.25 * self.fullness
        
        # Calculate total additional resistance
        additional_resistance = base_resistance * openness_factor * fullness_factor
        
        # Convert base U-value to resistance
        base_resistance = 1.0 / base_u_value
        
        # Add drapery resistance
        total_resistance = base_resistance + additional_resistance
        
        # Convert back to U-value
        adjusted_u_value = 1.0 / total_resistance
        
        return adjusted_u_value
    
    def to_dict(self) -> Dict[str, Any]:
        """Convert drapery object to dictionary."""
        return {
            "openness": self.openness,
            "reflectance": self.reflectance,
            "transmittance": self.transmittance,
            "fullness": self.fullness,
            "enabled": self.enabled,
            "absorptance": self.absorptance,
            "openness_class": self.openness_class.value,
            "color_class": self.color_class.value,
            "classification": self.get_classification()
        }
    
    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> 'Drapery':
        """Create drapery object from dictionary."""
        return cls(
            openness=data.get("openness", 0.05),
            reflectance=data.get("reflectance", 0.5),
            transmittance=data.get("transmittance", 0.3),
            fullness=data.get("fullness", 1.0),
            enabled=data.get("enabled", True)
        )
    
    @classmethod
    def from_classification(cls, classification: str, fullness: float = 1.0) -> 'Drapery':
        """
        Create drapery object from ASHRAE classification.
        
        Args:
            classification: ASHRAE classification (ID, IM, IL, IID, IIM, IIL, IIID, IIIM, IIIL)
            fullness: Fullness factor (0-2)
            
        Returns:
            Drapery object
        """
        # Parse classification
        if len(classification) < 2:
            raise ValueError(f"Invalid classification: {classification}")
        
        # Handle single-character openness class (I) vs two-character (II, III)
        if classification.startswith("II") or classification.startswith("III"):
            if classification.startswith("III"):
                openness_class = "III"
                color_class = classification[3] if len(classification) > 3 else ""
            else:  # II
                openness_class = "II"
                color_class = classification[2] if len(classification) > 2 else ""
        else:  # I
            openness_class = "I"
            color_class = classification[1] if len(classification) > 1 else ""
        
        # Set default values
        openness = 0.05
        reflectance = 0.5
        transmittance = 0.3
        
        # Set openness based on class
        if openness_class == "I":
            openness = 0.3  # Open (>25%)
        elif openness_class == "II":
            openness = 0.15  # Semi-open (7-25%)
        elif openness_class == "III":
            openness = 0.03  # Closed (0-7%)
        
        # Set reflectance and transmittance based on color class
        if color_class == "D":
            reflectance = 0.2  # Dark (0-25%)
            transmittance = 0.05
        elif color_class == "M":
            reflectance = 0.4  # Medium (25-50%)
            transmittance = 0.15
        elif color_class == "L":
            reflectance = 0.7  # Light (>50%)
            transmittance = 0.2
        
        return cls(
            openness=openness,
            reflectance=reflectance,
            transmittance=transmittance,
            fullness=fullness
        )


# Predefined drapery types based on ASHRAE classifications
PREDEFINED_DRAPERIES = {
    "ID": Drapery.from_classification("ID"),
    "IM": Drapery.from_classification("IM"),
    "IL": Drapery.from_classification("IL"),
    "IID": Drapery.from_classification("IID"),
    "IIM": Drapery.from_classification("IIM"),
    "IIL": Drapery.from_classification("IIL"),
    "IIID": Drapery.from_classification("IIID"),
    "IIIM": Drapery.from_classification("IIIM"),
    "IIIL": Drapery.from_classification("IIIL")
}