engine/validation.py

from typing import Dict, Any


def validate_inputs(alpha: float, beta: float, D: float, k: float, R0: float, T: float, n: int, tol: float, eps: float) -> Dict[str, Any]:
    errs = []

    def _pos(name, x):
        if x is None:
            errs.append(f"{name} is required.")
            return
        try:
            xv = float(x)
        except Exception:
            errs.append(f"{name} must be numeric.")
            return
        if xv <= 0:
            errs.append(f"{name} must be > 0.")

    # positivity where required
    _pos("alpha", alpha)
    _pos("beta", beta)
    if D is None:
        errs.append("D is required.")
    else:
        try:
            Dv = float(D)
            if Dv < 0:
                errs.append("D must be >= 0.")
        except Exception:
            errs.append("D must be numeric.")

    if k is None:
        errs.append("k is required.")
    else:
        try:
            kv = float(k)
            if kv < 0:
                errs.append("k must be >= 0.")
        except Exception:
            errs.append("k must be numeric.")

    _pos("R0", R0)
    _pos("T", T)

    if n is None:
        errs.append("n is required.")
    else:
        try:
            nv = int(n)
            if nv < 200:
                errs.append("n must be >= 200 for stable plots.")
        except Exception:
            errs.append("n must be an integer.")

    if tol is None:
        errs.append("tol is required.")
    else:
        try:
            tv = float(tol)
            if tv < 0:
                errs.append("tol must be >= 0.")
        except Exception:
            errs.append("tol must be numeric.")

    _pos("eps", eps)

    return {"ok": len(errs) == 0, "errors": errs}