///|
/// 拼音分隔符，对齐源库 PINYIN_SEPARATOR。pub let 跨文件共享。
pub let pinyin_separator : String = ","

///|
/// 无调元音数组，对齐源库 ALL_UNMARKED_VOWEL_ARRAY。文件内私有。
let all_unmarked_vowel_array : Array[Char] = ['a', 'e', 'i', 'o', 'u', 'v']

///|
/// 带调元音数组，对齐源库 ALL_MARKED_VOWEL_ARRAY（24 个，6 元音 × 4 声调）。文件内私有。
let all_marked_vowel_array : Array[Char] = [
  'ā', 'á', 'ǎ', 'à', 'ē', 'é', 'ě', 'è', 'ī', 'í', 'ǐ', 'ì', 'ō', 'ó',
  'ǒ', 'ò', 'ū', 'ú', 'ǔ', 'ù', 'ǖ', 'ǘ', 'ǚ', 'ǜ',
]

///|
/// 在带调元音数组中查找字符索引，未找到返回 -1。对齐源库 findArrayKeyByValue。
pub fn find_array_key_by_value(ch : Char) -> Int {
  for i in 0.. Array[String] {
  let pinyin_array = str
    .split(pinyin_separator[:])
    .map(fn(x) { x.to_owned() })
    .to_array()
  for i in 0.. 'z' {
        let index_in_all_marked = find_array_key_by_value(ch)
        if index_in_all_marked >= 0 {
          let tone_number = index_in_all_marked % 4 + 1
          let replace_char = all_unmarked_vowel_array[(
              index_in_all_marked - index_in_all_marked % 4
            ) /
            4]
          original_char_array[j] = replace_char
          pinyin_array[i] = String::from_array(original_char_array[:]) +
            tone_number.to_string()
          has_marked_char = true
          break
        }
      }
    }
    if !has_marked_char {
      pinyin_array[i] = original_pinyin + "5"
    }
  }
  pinyin_array
}

///|
/// 带调拼音→无调拼音数组。对齐源库 convertWithoutTone。
/// 逐字符替换所有带调元音为对应无调元音，最后 ü 替换为 v。
pub fn convert_without_tone(str : String) -> Array[String] {
  let mut s = str
  for i in 0.. Array[String] {
  match format {
    WithToneMark =>
      str.split(pinyin_separator[:]).map(fn(x) { x.to_owned() }).to_array()
    WithToneNumber => convert_with_tone_number(str)
    WithoutTone => convert_without_tone(str)
    FirstLetter => convert_without_tone(str)
  }
}

///|
/// 单字转拼音数组（查 pinyin_table，不区分首字母特殊处理）。对齐源库 convertToPinyinArrays。
pub fn convert_to_pinyin_arrays(
  c : Char,
  format : PinyinFormat,
) -> Array[String] {
  match pinyin_table.get(c.to_string()) {
    Some(v) => format_pinyin(v, format)
    None => []
  }
}