"""Server-side range validation for the Framingham tabular fields.

Blank / missing fields are skipped here (they get KNN-imputed downstream).
Only *provided* values are checked: they must parse as numbers and fall inside
clinically plausible bounds. Returns a list of human-readable error strings
(empty == valid).
"""
from __future__ import annotations

from typing import Any

# Binary / categorical fields use "choices"; continuous fields use min/max.
FIELD_SPECS: dict[str, dict[str, Any]] = {
    "male":            {"choices": {0, 1}},
    "age":             {"min": 1,  "max": 120},
    "education":       {"choices": {1, 2, 3, 4}},
    "currentSmoker":   {"choices": {0, 1}},
    "cigsPerDay":      {"min": 0,  "max": 100},
    "BPMeds":          {"choices": {0, 1}},
    "prevalentStroke": {"choices": {0, 1}},
    "prevalentHyp":    {"choices": {0, 1}},
    "diabetes":        {"choices": {0, 1}},
    "totChol":         {"min": 50, "max": 700},
    "sysBP":           {"min": 50, "max": 300},
    "diaBP":           {"min": 30, "max": 200},
    "BMI":             {"min": 10, "max": 70},
    "heartRate":       {"min": 20, "max": 300},
    "glucose":         {"min": 20, "max": 700},
}


def validate_tabular(fields: dict[str, Any]) -> list[str]:
    errors: list[str] = []
    for name, spec in FIELD_SPECS.items():
        raw = fields.get(name)
        if raw is None or str(raw).strip() == "":
            continue  # blank -> imputed later, nothing to validate
        try:
            v = float(raw)
        except (TypeError, ValueError):
            errors.append(f"{name}: '{raw}' is not a number")
            continue
        if "choices" in spec and v not in spec["choices"]:
            errors.append(f"{name}: must be one of {sorted(spec['choices'])} (got {raw})")
        if "min" in spec and v < spec["min"]:
            errors.append(f"{name}: must be >= {spec['min']} (got {raw})")
        if "max" in spec and v > spec["max"]:
            errors.append(f"{name}: must be <= {spec['max']} (got {raw})")
    return errors