"""Pydantic request/response schemas — the API contract (spec §8.3 rule 1).

Defined separately from ORM models; services convert via from_attributes.
Validation happens here at the boundary (spec §8.1 rule 11).
"""

from datetime import date, datetime
from typing import Literal

from pydantic import BaseModel, ConfigDict, Field

UnitType = Literal["weight", "count"]
FoodSource = Literal["openfoodfacts", "manual", "meal"]
MealSlot = Literal["breakfast", "lunch", "dinner", "snack"]


class FoodCreate(BaseModel):
    name: str
    brand: str | None = None
    barcode: str | None = None
    source: FoodSource = "manual"
    unit_type: UnitType = "weight"
    calories_per_unit: float | None = Field(default=None, gt=0)
    protein_per_unit: float | None = Field(default=None, ge=0)
    carbs_per_unit: float | None = Field(default=None, ge=0)
    fat_per_unit: float | None = Field(default=None, ge=0)
    serving_size_g: float | None = Field(default=None, gt=0)
    serving_name: str | None = None


class FoodRead(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: int
    name: str
    brand: str | None
    barcode: str | None
    source: FoodSource
    is_meal: bool
    unit_type: UnitType
    calories_per_unit: float | None
    protein_per_unit: float | None
    carbs_per_unit: float | None
    fat_per_unit: float | None
    serving_size_g: float | None
    serving_name: str | None
    deleted_at: datetime | None


class LogEntryCreate(BaseModel):
    food_id: int
    quantity: float = Field(gt=0)
    meal_slot: MealSlot | None = None
    date: date  # client-supplied YYYY-MM-DD (spec §8.1 rule 8)


class LogEntryRead(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: int
    date: date
    food_id: int
    quantity: float
    meal_slot: MealSlot | None
    sort_order: int


class TargetRead(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: int
    start_date: date
    end_date: date | None
    calories: int
    protein_g: float | None
    carbs_g: float | None
    fat_g: float | None