from dataclasses import dataclass


@dataclass
class MaskedPoissonConfig:
    """Configuration for masked Poisson solvers on irregular UV domains."""

    method: str = "sparse"  # "sparse" | "capfft"
    max_boundary: int = 96
    boundary_stride: int = 1
    max_iters: int = 3
    tol: float = 1e-4
    reg: float = 1e-8

    def __post_init__(self):
        if self.method not in ("sparse", "capfft"):
            raise ValueError("method must be one of: 'sparse', 'capfft'")
        self.max_boundary = max(0, int(self.max_boundary))
        self.boundary_stride = max(1, int(self.boundary_stride))
        self.max_iters = max(1, int(self.max_iters))
        self.tol = float(self.tol)
        self.reg = float(self.reg)

    @classmethod
    def from_kwargs(cls, kwargs):
        """Build config from PoissonSolver / nHHD constructor kwargs."""
        return cls(
            method=kwargs.get("masked_poisson_solver", "sparse"),
            max_boundary=kwargs.get("masked_poisson_max_boundary", 96),
            boundary_stride=kwargs.get("masked_poisson_boundary_stride", 1),
            max_iters=kwargs.get("masked_poisson_max_iters", 3),
            tol=kwargs.get("masked_poisson_tol", 1e-4),
            reg=kwargs.get("masked_poisson_reg", 1e-8),
        )