"""Bread ingredients model and calculation logic."""

from pydantic import BaseModel, Field, computed_field


class SourdoughRatio(BaseModel):
    """
    Represents the flour:water ratio in the sourdough starter.

    Example: 
        - Ratio(1, 1) = 50% hydration (equal parts)
        - Ratio(1, 0.8) = 44.4% hydration
        - Ratio(1, 1.2) = 54.5% hydration
    """
    flour_parts: float = Field(gt=0, description="Flour parts in starter (typically 1)")
    water_parts: float = Field(gt=0, description="Water parts in starter")

    @computed_field
    @property
    def hydration_percentage(self) -> float:
        """Calculate hydration % of the starter."""
        return (self.water_parts / self.flour_parts) * 100


class BreadRecipe(BaseModel):
    """
    Input parameters for bread recipe calculation.

    All percentages follow baker's percentage (relative to total flour weight).
    """
    # What the user provides
    total_flour: float = Field(gt=1, description="Total flour weight in grams")
    hydration: float = Field(
        ge=50, le=100, description="Total hydration % (water/flour)"
    )
    sourdough_percentage: float = Field(
        ge=10,
        le=100,
        description="Sourdough as % of total flour weight"
    )
    sourdough_ratio: SourdoughRatio = Field(
        description="Flour:water ratio in starter"
    )
    salt: float = Field(ge=0, le=2, description="Salt as % of total flour")

    # What Pydantic calculates automatically
    @computed_field
    @property
    def sourdough_weight(self) -> float:
        """Calculate total sourdough weight in grams."""
        return round(self.total_flour * (self.sourdough_percentage / 100), 2)

    @computed_field
    @property
    def water_in_sourdough(self) -> float:
        """Calculate water content in the sourdough."""
        ratio = self.sourdough_ratio
        total_parts = ratio.flour_parts + ratio.water_parts
        water_fraction = self.sourdough_ratio.water_parts / total_parts
        return round(self.sourdough_weight * water_fraction, 2)

    @computed_field
    @property
    def flour_in_sourdough(self) -> float:
        """Calculate flour content in the sourdough."""
        return round(self.sourdough_weight - self.water_in_sourdough, 2)

    @computed_field
    @property
    def total_water(self) -> float:
        """Calculate total water needed in the recipe."""
        return round(self.total_flour * (self.hydration / 100), 2)

    @computed_field
    @property
    def water_to_add(self) -> float:
        """Calculate water to add (excluding water in sourdough)."""
        return round(self.total_water - self.water_in_sourdough, 2)

    @computed_field
    @property
    def flour_to_add(self) -> float:
        """Calculate flour to add (excluding flour in sourdough)."""
        return round(self.total_flour - self.flour_in_sourdough, 2)

    @computed_field
    @property
    def salt_weight(self) -> float:
        """Calculate salt weight in grams."""
        return round(self.total_flour * (self.salt / 100), 2)