import re

from pydantic import BaseModel, ConfigDict, Field, field_validator

from app.models.unc_thread import UncSeries

_FRACTION_RE = re.compile(r"^\d+(/\d+)?(-\d+/\d+)?$")


class UncThreadBase(BaseModel):
    diameter_fraction: str = Field(
        ...,
        description='Nominal diameter as a fractional inch string, e.g. "1/4", "3/8", "1-1/2"',
    )
    tpi: int = Field(..., gt=0, description="Threads per inch")
    series: UncSeries
    depth_in: float | None = Field(None, gt=0, description="Thread depth in inches")

    @field_validator("diameter_fraction")
    @classmethod
    def validate_fraction(cls, v: str) -> str:
        if not _FRACTION_RE.match(v):
            raise ValueError(
                'diameter_fraction must be a fractional inch string, e.g. "1/4", "3/8", "1-1/2"'
            )
        return v


class UncThreadCreate(UncThreadBase):
    pass


class UncThreadUpdate(BaseModel):
    diameter_fraction: str | None = None
    tpi: int | None = Field(None, gt=0)
    series: UncSeries | None = None
    depth_in: float | None = Field(None, gt=0)

    @field_validator("diameter_fraction")
    @classmethod
    def validate_fraction(cls, v: str | None) -> str | None:
        if v is not None and not _FRACTION_RE.match(v):
            raise ValueError(
                'diameter_fraction must be a fractional inch string, e.g. "1/4", "3/8", "1-1/2"'
            )
        return v


class UncThreadRead(UncThreadBase):
    model_config = ConfigDict(from_attributes=True)

    id: int