// strings
export const str = {
  join: (arr: string[], sep: string = ',') => arr.join(sep),
  split: (str: string, sep: string = ',') => str.split(sep),
  'to-upper': (str: string) => str.toUpperCase(),
  'to-lower': (str: string) => str.toLowerCase(),
  trim: (str: string) => str.trim(),

  // predicates
  'starts-with?': (str: string, prefix: string) => str.startsWith(prefix),
  'ends-with?': (str: string, suffix: string) => str.endsWith(suffix),
  'contains?': (str: string, substr: string) => str.includes(substr),
  'empty?': (str: string) => str.length === 0,

  // inspection
  'index-of': (str: string, search: string) => str.indexOf(search),
  'last-index-of': (str: string, search: string) => str.lastIndexOf(search),

  // transformations
  replace: (str: string, search: string, replacement: string) => str.replace(search, replacement),
  'replace-all': (str: string, search: string, replacement: string) => str.replaceAll(search, replacement),
  slice: (str: string, start: number, end?: number | null) => str.slice(start, end ?? undefined),
  substring: (str: string, start: number, end?: number | null) => str.substring(start, end ?? undefined),
  repeat: (str: string, count: number) => {
    if (count < 0) throw new Error(`repeat: count must be non-negative, got ${count}`)
    if (!Number.isInteger(count)) throw new Error(`repeat: count must be an integer, got ${count}`)
    return str.repeat(count)
  },
  'pad-start': (str: string, length: number, pad: string = ' ') => str.padStart(length, pad),
  'pad-end': (str: string, length: number, pad: string = ' ') => str.padEnd(length, pad),
  lines: (str: string) => str.split('\n'),
  chars: (str: string) => str.split(''),

  // regex
  match: (str: string, regex: RegExp) => str.match(regex),
  'test?': (str: string, regex: RegExp) => regex.test(str),
}