let extendingChars = /[\u0300-\u036f\u0483-\u0489\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u065e\u0670\u06d6-\u06dc\u06de-\u06e4\u06e7\u06e8\u06ea-\u06ed\u0711\u0730-\u074a\u0b82\u0bbe\u0bc0\u0bcd\u0bd7\u0d3e\u0d41-\u0d44\u0d4d\u0d57\u0d62\u0d63\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u180b-\u180d\u18a9\u200c\u200d]/
try { extendingChars = new RegExp("\\p{Grapheme_Extend}", "u") } catch (_) {}

export function isExtendingChar(ch: string): boolean {
  let code = ch.charCodeAt(0)
  return code >= 768 && (code >= 0xdc00 && code < 0xe000 || extendingChars.test(ch))
}

const nonASCIISingleCaseWordChar = /[\u00df\u0587\u0590-\u05f4\u0600-\u06ff\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc\uac00-\ud7af]/

let wordChar: RegExp | null
try { wordChar = new RegExp("[\\p{Alphabetic}_]", "u") } catch (_) {}

// FIXME this doesn't work for astral chars yet (need different calling convention)

function isWordCharBasic(ch: string): boolean {
  if (wordChar) return wordChar.test(ch)
  return /\w/.test(ch) || ch > "\x80" &&
    (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch))
}

export function isWordChar(ch: string, wordChars?: RegExp): boolean {
  if (!wordChars) return isWordCharBasic(ch)
  if (wordChars.source.indexOf("\\w") > -1 && isWordCharBasic(ch)) return true
  return wordChars.test(ch)
}

export const enum CharType { WORD, SPACE, OTHER }

export function charType(ch: string, wordChars?: RegExp): CharType {
  return /\s/.test(ch) ? CharType.SPACE : isWordChar(ch, wordChars) ? CharType.WORD : CharType.OTHER
}