import { helper } from '@ember/component/helper';

// # Plural Helper
// Usage example: `{{plural ../pagination.total empty='No posts' singular='1 post' plural='% posts'}}`
// or for translatable themes, with (t) translation helper's subexpressions:
// `{{plural ../pagination.total empty=(t "No posts") singular=(t "1 post") plural=(t "% posts")}}`
//
// Pluralises strings depending on item count
//
// The 1st argument is the numeric variable which the helper operates on
// The 2nd argument is the string that will be output if the variable's value is 0
// The 3rd argument is the string that will be output if the variable's value is 1
// The 4th argument is the string that will be output if the variable's value is 2+
export function plural([number], hash) {
  if (hash === undefined || hash.empty === undefined ||
    hash.singular === undefined || hash.plural === undefined) {
    throw new Error("you need to define `empty`, `singular` and `plural`");
  }

  if (number === 0) {
    return hash.empty.replace('%', number);
  } else if (number === 1) {
    return hash.singular.replace('%', number);
  } else if (number >= 2) {
    return hash.plural.replace('%', number);
  }
}

export default helper(plural);
