import { useState, type InputHTMLAttributes } from 'react';

type NativeInputProps = Omit<InputHTMLAttributes<HTMLInputElement>, 'type' | 'value' | 'onChange' | 'min' | 'max'>;

interface NumberInputProps extends NativeInputProps {
  value: number | null | undefined;
  onChange: (value: number) => void;
  min?: number;
  max?: number;
  /** Parse with parseInt (default); pass false for fields with a fractional step. */
  integer?: boolean;
  /** Committed when the field is left empty. Without it an empty field reverts to `value`. */
  fallback?: number;
}

/**
 * A number field that can be cleared and retyped (#3182).
 *
 * Clamping inside onChange rewrites the field on every keystroke: clearing a
 * "1" snaps straight back to 1, and typing the "6" of 60 into a field with a
 * minimum of 45 turns it into 45. This keeps what was typed as a draft while
 * the field is being edited, passes a value up only once the draft is a number
 * inside [min, max], and settles the field on blur — clamped into range, or
 * `fallback` when left empty.
 */
export function NumberInput({
  value,
  onChange,
  min,
  max,
  integer = true,
  fallback,
  onBlur,
  ...rest
}: NumberInputProps) {
  const [draft, setDraft] = useState<string | null>(null);

  const parse = (raw: string) => (integer ? parseInt(raw, 10) : parseFloat(raw));
  const inRange = (n: number) => (min === undefined || n >= min) && (max === undefined || n <= max);
  const clamp = (n: number) => Math.min(max ?? Infinity, Math.max(min ?? -Infinity, n));

  return (
    <input
      {...rest}
      type="number"
      min={min}
      max={max}
      value={draft ?? value ?? ''}
      onChange={(e) => {
        const raw = e.target.value;
        setDraft(raw);
        const n = parse(raw);
        if (!Number.isNaN(n) && inRange(n) && n !== value) onChange(n);
      }}
      onBlur={(e) => {
        if (draft !== null) {
          const n = parse(draft);
          const settled = Number.isNaN(n) ? fallback : n;
          if (settled !== undefined && clamp(settled) !== value) onChange(clamp(settled));
          setDraft(null);
        }
        onBlur?.(e);
      }}
    />
  );
}