import { z } from 'zod';
import { CURRENCY_DATA_SCALE } from '@repo/utils';

export const PRICE_DECIMAL_SCALE = CURRENCY_DATA_SCALE;
export const QUANTITY_DECIMAL_SCALE = 4;

function coerceDecimalInput(value: unknown) {
  if (value === '' || value === null || value === undefined) {
    return undefined;
  }
  if (typeof value === 'number') {
    return Number.isFinite(value) ? String(value) : value;
  }
  return value;
}

export function toDecimalStringValue(value: unknown): string | undefined {
  const next = coerceDecimalInput(value);
  return typeof next === 'string' ? next : undefined;
}

function decimalPattern(maxDecimals: number) {
  return new RegExp(`^\\d+(\\.\\d{1,${maxDecimals}})?$`);
}

export function decimalStringSchema(
  t: (key: string) => string,
  fieldKey = 'common:fields.price',
  maxDecimals = QUANTITY_DECIMAL_SCALE,
) {
  return z.preprocess(
    coerceDecimalInput,
    z.string().regex(decimalPattern(maxDecimals), {
      message: JSON.stringify({ key: 'validation:invalid_format', values: { field: t(fieldKey) } }),
    }),
  );
}

export function optionalDecimalStringSchema(
  t: (key: string) => string,
  fieldKey = 'common:fields.price',
  maxDecimals = PRICE_DECIMAL_SCALE,
) {
  return z.preprocess(
    coerceDecimalInput,
    z
      .string()
      .regex(decimalPattern(maxDecimals), {
        message: JSON.stringify({ key: 'validation:invalid_format', values: { field: t(fieldKey) } }),
      })
      .optional(),
  );
}