--
-- Copyright (c) 2021-2022 Zeping Lee
-- Released under the MIT license.
-- Repository: https://github.com/zepinglee/citeproc-lua
--

-- load `slnunicode` from LuaTeX
local unicode = require("unicode")
local inspect  -- only load it when debugging


local util = {}

-- Deep copy
function util.deep_copy(obj)
  local res
  if type(obj) == "table" then
    res = {}
    for key, value in pairs(obj) do
      res[key] = util.deep_copy(value)
    end
  else
    res = obj
  end
  return res
end

-- Shallow copy
function util.clone(obj)
  if type(obj) == "table" then
    local res = {}
    for key, value in pairs(obj) do
      res[key] = value
    end
    return setmetatable(res, getmetatable(obj))
  else
    return obj
  end
end

function util.join(list, delimiter)
  local res = {}
  for i, item in ipairs(list) do
    if i > 1 then
      table.insert(res, delimiter)
    end
    table.insert(res, item)
  end
  return res
end

function util.to_boolean(str)
  if not str then
    return false
  end
  if str == "true" then
    return true
  elseif str == "false" then
    return false
  else
    util.warning(string.format('Invalid boolean string "%s"', str))
    return false
  end
end

function util.to_list(str)
  if not str then
    return nil
  end
  return util.split(str)
end

function util.to_ordinal (n)
  -- assert(type(n) == "number")
  local last_digit = n % 10
  if last_digit == 1 and n ~= 11
    then return tostring(n) .. "st"
  elseif last_digit == 2 and n ~= 12
    then return tostring(n) .. "nd"
  elseif last_digit == 3 and n ~= 13
    then return tostring(n) .. "rd"
  else
    return tostring(n) .. "th"
  end
end


function util.error(message)
  if luatexbase then
    -- The luatexbase.module_error() prints the traceback, which causes panic
    -- luatexbase.module_error("citeproc", message)

    texio.write_nl("term", "\n")
    tex.error("Module citeproc Error: " .. message)

    -- tex.print(string.format("\\PackageError{citation-style-language}{%s}{}", message))

  else
    error(message, 2)
  end
end

util.warning_enabled = true

function util.warning(message)
  if luatexbase then
    texio.write_nl("term", "\n")
    luatexbase.module_warning("citeproc", message)

    -- tex.print(string.format("\\PackageWarning{citation-style-language}{%s}{}", message))

  elseif util.warning_enabled then
    io.stderr:write("Warning: " .. message, "\n")
  end
end

local remove_all_metatables = nil

function util.debug(obj)
  if not inspect then
    inspect = require("inspect")
    remove_all_metatables = function (item, path)
      if path[#path] ~= inspect.METATABLE then
        return item
      end
    end
  end
  io.stderr:write("[")
  io.stderr:write(debug.getinfo(2, "S").source:sub(2))
  io.stderr:write(":")
  io.stderr:write(debug.getinfo(2, "l").currentline)
  io.stderr:write("] ")
  io.stderr:write(inspect(obj, {process = remove_all_metatables}))
  io.stderr:write("\n")
end

-- Similar to re.split() in Python
function util.split(str, sep, maxsplit)
  if not str then
    util.error("Invalid string.")
  end
  sep = sep or "%s+"
  if sep == "" then
    util.error("Empty separator")
  end
  if string.find(str, sep) == nil then
    return { str }
  end

  if maxsplit == nil or maxsplit < 0 then
    maxsplit = -1    -- No limit
  end
  local result = {}
  local pattern = "(.-)" .. sep .. "()"
  local num_splits = 0
  local lastPos = 1
  for part, pos in string.gmatch(str, pattern) do
    if num_splits == maxsplit then
      break
    end
    num_splits = num_splits + 1
    result[num_splits] = part
    lastPos = pos
  end
  -- Handle the last field
  result[num_splits + 1] = string.sub(str, lastPos)
  return result
end

function util.split_multiple(str, seps, include_sep)
  seps = seps or "%s+"
  if seps == "" then
    error("Empty separator")
  end
  if type(seps) == "string" then
    seps = {seps}
  end

  local splits = {}
  for _, sep_pattern in ipairs(seps) do
    for start, sep, stop in string.gmatch(str, "()(" .. sep_pattern .. ")()") do
      table.insert(splits, {start, sep, stop})
    end
  end

  if #seps > 1 then
    table.sort(splits, function (a, b) return a[1] < b[1] end)
  end

  local res = {}
  local previous = 1
  for _, sep_tuple in ipairs(splits) do
    local start, sep, stop = table.unpack(sep_tuple)
    local item = string.sub(str, previous, start - 1)
    if include_sep then
      item = {item, sep}
    end
    table.insert(res, item)
    previous = stop
  end
  local item = string.sub(str, previous, #str)
  if include_sep then
    item = {item, ""}
  end
  table.insert(res, item)
  return res
end

-- TODO: [Unicode word boundaries](https://www.unicode.org/reports/tr29/#Word_Boundaries)
-- Returns: {
--   {word, boundary},
--   {word, boundary},
-- }
function util.segment_words(str)
  return util.split_multiple(str, util.word_boundaries, true)
end

function util.slice (t, start, stop)
  start = start or 1
  stop = stop or #t
  if start < 0 then
    start = start + #t + 1
  end
  if stop < 0 then
    stop = stop + #t + 1
  end
  local new = {}
  for i, item in ipairs(t) do
    if i >= start and i <= stop then
      table.insert(new, item)
    end
  end
  return new
end

function util.concat (list, sep)
  -- This helper function omits empty strings in list, which is different from table.concat
  -- This function always returns a string, even empty.
  local res = ""
  for i = 1, #list do
    local s = list[i]
    if s and s~= "" then
      if res == "" then
        res = s
      else
        res = res .. sep .. s
      end
    end
  end
  return res
end

-- Python list.extend()
function util.extend(first, second)
  -- if not second then
  --   print(debug.traceback())
  -- end
  local l = #first
  for i, element in ipairs(second) do
    first[l + i] = element
  end
  return first
end

-- Concat two lists in place
function util.concat_list(first, second)
  local res
  for i, element in ipairs(first) do
    res[i] = element
  end
  local i = #res
  for j, element in ipairs(second) do
    res[i + j] = element
  end
  return res
end

function util.lstrip (str)
  if not str then
    error("Invalid input")
  end
  local res = string.gsub(str, "^%s*", "")
  return res
end

function util.rstrip (str)
  if not str then
    error("Invalid input")
  end
  local res = string.gsub(str, "%s*$", "")
  return res
end

function util.strip (str)
  return util.lstrip(util.rstrip(str))
end

function util.startswith(str, prefix)
  if not str or type(str) ~= "string" then
    print(debug.traceback())
  end
  return string.sub(str, 1, #prefix) == prefix
end

function util.endswith(str, suffix)
  if not str or type(str) ~= "string" then
    print(debug.traceback())
  end
  return string.sub(str, -#suffix) == suffix
end

function util.is_punct(str)
  return string.match(str, "^%p$")
end

function util.is_numeric (str)
  if str == nil or str == "" then
    return false
  end
  local res = true
  for w in string.gmatch(str, "%w+") do
    if not string.match(w, "^%a*%d+%a*$") and
        not string.match(w, "^[MDCLXVI]+$") and
        not string.match(w, "^[mdclxvi]+$") then
      -- Roman number without validation
      return false
    end
  end
  for w in string.gmatch(str, "%W+") do
    if string.match(w, "^%s*[,&-]+%s*$") == nil then
      res = false
      break
    end
  end
  return res
end

util.variable_types = {}

-- schema/schemas/styles/csl-variables.rnc
util.variables = {}

-- -- Standard variables
-- util.variables.standard = {
--   "abstract",
--   "annote",
--   "archive",
--   "archive_collection",
--   "archive_location",
--   "archive-place",
--   "authority",
--   "call-number",
--   "citation-key",
--   "citation-label",
--   "collection-title",
--   "container-title",
--   "container-title-short",
--   "dimensions",
--   "division",
--   "DOI",
--   "event",
--   "event-title",
--   "event-place",
--   "genre",
--   "ISBN",
--   "ISSN",
--   "jurisdiction",
--   "keyword",
--   "language",
--   "license",
--   "medium",
--   "note",
--   "original-publisher",
--   "original-publisher-place",
--   "original-title",
--   "part-title",
--   "PMCID",
--   "PMID",
--   "publisher",
--   "publisher-place",
--   "references",
--   "reviewed-genre",
--   "reviewed-title",
--   "scale",
--   "source",
--   "status",
--   "title",
--   "title-short",
--   "URL",
--   "volume-title",
--   "year-suffix",
-- }

-- Number variables
util.variables.number = {
  "chapter-number",
  "citation-number",
  "collection-number",
  "edition",
  "first-reference-note-number",
  "issue",
  "locator",
  "number",
  "number-of-pages",
  "number-of-volumes",
  "page",
  "page-first",
  "part-number",
  "printing-number",
  "section",
  "supplement-number",
  "version",
  "volume",
}

-- Date variables
util.variables.date = {
  "accessed",
  "available-date",
  "event-date",
  "issued",
  "original-date",
  "submitted",
}

-- Name variables
util.variables.name = {
  "author",
  "chair",
  "collection-editor",
  "compiler",
  "composer",
  "container-author",
  "contributor",
  "curator",
  "director",
  "editor",
  "editor-translator",
  "editorial-director",
  "executive-producer",
  "guest",
  "host",
  "illustrator",
  "interviewer",
  "narrator",
  "organizer",
  "original-author",
  "performer",
  "producer",
  "recipient",
  "reviewed-author",
  "script-writer",
  "series-creator",
  "translator",
}

util.variable_types = {}

for type, variables in pairs(util.variables) do
  for _, variable in ipairs(variables) do
    util.variable_types[variable] = type
  end
end

util.primary_dialects = {
  af= "af-ZA",
  ar= "ar",
  bg= "bg-BG",
  ca= "ca-AD",
  cs= "cs-CZ",
  cy= "cy-GB",
  da= "da-DK",
  de= "de-DE",
  el= "el-GR",
  en= "en-US",
  es= "es-ES",
  et= "et-EE",
  eu= "eu",
  fa= "fa-IR",
  fi= "fi-FI",
  fr= "fr-FR",
  he= "he-IL",
  hi= "hi-IN",
  hr= "hr-HR",
  hu= "hu-HU",
  id= "id-ID",
  is= "is-IS",
  it= "it-IT",
  ja= "ja-JP",
  km= "km-KH",
  ko= "ko-KR",
  la= "la",
  lt= "lt-LT",
  lv= "lv-LV",
  mn= "mn-MN",
  nb= "nb-NO",
  nl= "nl-NL",
  nn= "nn-NO",
  pl= "pl-PL",
  pt= "pt-PT",
  ro= "ro-RO",
  ru= "ru-RU",
  sk= "sk-SK",
  sl= "sl-SI",
  sr= "sr-RS",
  sv= "sv-SE",
  th= "th-TH",
  tr= "tr-TR",
  uk= "uk-UA",
  vi= "vi-VN",
  zh= "zh-CN"
}



-- Range delimiter

util.unicode = {
  ["no-break space"] = "\u{00A0}",
  ["em space"] = "\u{2003}",
  ["en dash"] = "\u{2013}",
  ["em dash"] = "\u{2014}",
  ["left single quotation mark"] = "\u{2018}",
  ["right single quotation mark"] = "\u{2019}",
  ["apostrophe"] = "\u{2019}",
  ["left double quotation mark"] = "\u{201C}",
  ["right double quotation mark"] = "\u{201D}",
  ["left-pointing double angle quotation mark"] = "\u{00AB}",
  ["right-pointing double angle quotation mark"] = "\u{00BB}",
  ["horizontal ellipsis"] = "\u{2026}",
  ["narrow no-break space"] = "\u{202F}",
}

util.word_boundaries = {
  ":",
  " ",
  "%-",
  "/",
  util.unicode["no-break space"],
  util.unicode["en dash"],
  util.unicode["em dash"],
}


-- Text-case

function util.is_lower (str)
  return unicode.utf8.lower(str) == str
end

function util.is_upper (str)
  return unicode.utf8.upper(str) == str
end

function util.capitalize(str)
  -- if not str then
  --   print(debug.traceback())
  -- end
  local res = string.gsub(str, utf8.charpattern, unicode.utf8.upper, 1)
  return res
end

function util.sentence (str)
  if util.is_upper(str) then
    return util.capitalize(str)
  else
    local output = {}
    for i, word in ipairs(util.split(str)) do
      if i == 1 and util.is_lower(word) then
        table.insert(output, util.capitalize(word))
      else
        table.insert(output, word)
      end
    end
    return table.concat(output, " ")
  end
end

-- TODO: process multiple words
util.stop_words = {
  ["a"] = true,
  ["according to"] = true,
  ["across"] = true,
  ["afore"] = true,
  ["after"] = true,
  ["against"] = true,
  ["ahead of"] = true,
  ["along"] = true,
  ["alongside"] = true,
  ["amid"] = true,
  ["amidst"] = true,
  ["among"] = true,
  ["amongst"] = true,
  ["an"] = true,
  ["and"] = true,
  ["anenst"] = true,
  ["apart from"] = true,
  ["apropos"] = true,
  ["apud"] = true,
  ["around"] = true,
  ["as"] = true,
  ["as regards"] = true,
  ["aside"] = true,
  ["astride"] = true,
  ["at"] = true,
  ["athwart"] = true,
  ["atop"] = true,
  ["back to"] = true,
  ["barring"] = true,
  ["because of"] = true,
  ["before"] = true,
  ["behind"] = true,
  ["below"] = true,
  ["beneath"] = true,
  ["beside"] = true,
  ["besides"] = true,
  ["between"] = true,
  ["beyond"] = true,
  ["but"] = true,
  ["by"] = true,
  ["c"] = true,
  ["ca"] = true,
  ["circa"] = true,
  ["close to"] = true,
  ["d'"] = true,
  ["de"] = true,
  ["despite"] = true,
  ["down"] = true,
  ["due to"] = true,
  ["during"] = true,
  ["et"] = true,
  ["except"] = true,
  ["far from"] = true,
  ["for"] = true,
  ["forenenst"] = true,
  ["from"] = true,
  ["given"] = true,
  ["in"] = true,
  ["inside"] = true,
  ["instead of"] = true,
  ["into"] = true,
  ["lest"] = true,
  ["like"] = true,
  ["modulo"] = true,
  ["near"] = true,
  ["next"] = true,
  ["nor"] = true,
  ["notwithstanding"] = true,
  ["of"] = true,
  ["off"] = true,
  ["on"] = true,
  ["onto"] = true,
  ["or"] = true,
  ["out"] = true,
  ["outside of"] = true,
  ["over"] = true,
  ["per"] = true,
  ["plus"] = true,
  ["prior to"] = true,
  ["pro"] = true,
  ["pursuant to"] = true,
  ["qua"] = true,
  ["rather than"] = true,
  ["regardless of"] = true,
  ["sans"] = true,
  ["since"] = true,
  ["so"] = true,
  ["such as"] = true,
  ["than"] = true,
  ["that of"] = true,
  ["the"] = true,
  ["through"] = true,
  ["throughout"] = true,
  ["thru"] = true,
  ["thruout"] = true,
  ["till"] = true,
  ["to"] = true,
  ["toward"] = true,
  ["towards"] = true,
  ["under"] = true,
  ["underneath"] = true,
  ["until"] = true,
  ["unto"] = true,
  ["up"] = true,
  ["upon"] = true,
  ["v."] = true,
  ["van"] = true,
  ["versus"] = true,
  ["via"] = true,
  ["vis-à-vis"] = true,
  ["von"] = true,
  ["vs."] = true,
  ["where as"] = true,
  ["with"] = true,
  ["within"] = true,
  ["without"] = true,
  ["yet"] = true,
}

function util.title (str)
  local output = {}
  local previous = ":"
  for i, word in ipairs(util.split(str)) do
    local lower = unicode.utf8.lower(word)
    if previous ~= ":" and util.stop_words[string.match(lower, "%w+")] then
      table.insert(output, lower)
    elseif util.is_lower(word) or util.is_upper(word) then
      table.insert(output, util.capitalize(word))
    else
      table.insert(output, word)
    end
  end
  local res = table.concat(output, " ")
  return res
end

function util.all (t)
  for _, item in ipairs(t) do
    if not item then
      return false
    end
  end
  return true
end

function util.any (t)
  for _, item in ipairs(t) do
    if item then
      return true
    end
  end
  return false
end

-- ROMANESQUE_REGEXP = "-0-9a-zA-Z\u0e01-\u0e5b\u00c0-\u017f\u0370-\u03ff\u0400-\u052f\u0590-\u05d4\u05d6-\u05ff\u1f00-\u1fff\u0600-\u06ff\u200c\u200d\u200e\u0218\u0219\u021a\u021b\u202a-\u202e"

util.romanesque_ranges = {
  {0x0030, 0x0039},  -- 0-9
  {0x0041, 0x005A},  -- A-Z
  {0x0061, 0x007A},  -- a-z
  {0x0E01, 0x0E5B},  -- Thai
  {0x0E01, 0x0E5B},  -- Thai
  {0x00C0, 0x017F},  -- Latin-1 Supplement
  {0x0370, 0x03FF},  -- Greek and Coptic
  {0x0400, 0x052F},  -- Cyrillic
  {0x0590, 0x05D4},  -- Hebrew
  {0x05D6, 0x05FF},  -- Hebrew
  {0x1F00, 0x1FFF},  -- Greek Extended
  {0x0600, 0x06FF},  -- Arabic
  {0x202A, 0x202E},  -- Writing directions in General Punctuation
}

util.romanesque_chars = {
  0x200c,
  0x200d,
  0x200e,
  0x0218,
  0x0219,
  0x021a,
  0x021b,
}

util.CJK_ranges = {
  {0x4E00, 0x9FFF},  -- CJK Unified Ideographs
  {0x3400, 0x4DBF},  -- CJK Unified Ideographs Extension A
  {0x3040, 0x309F},  -- Hiragana
  {0x30A0, 0x30FF},  -- Katakana
  {0xF900, 0xFAFF},  -- CJK Compatibility Ideographs
  {0x20000, 0x2A6DF},  -- CJK Unified Ideographs Extension B
  {0x2A700, 0x2B73F},  -- CJK Unified Ideographs Extension C
  {0x2B740, 0x2B81F},  -- CJK Unified Ideographs Extension D
  {0x2B820, 0x2CEAF},  -- CJK Unified Ideographs Extension E
  {0x2CEB0, 0x2EBEF},  -- CJK Unified Ideographs Extension F
  {0x30000, 0x3134F},  -- CJK Unified Ideographs Extension G
  {0x2F800, 0x2FA1F},  -- CJK Compatibility Ideographs Supplement
}

function util.in_list (value, list)
  for _, v in ipairs(list) do
    if value == v then
      return true
    end
  end
  return false
end

function util.in_ranges (value, ranges)
  for _, range in ipairs(ranges) do
    if value >= range[1] and value <= range[2] then
      return true
    end
  end
  return false
end

function util.is_romanesque(code_point)
  if not code_point then
    return false
  end
  if util.in_ranges(code_point, util.romanesque_ranges) then
    return true
  end
  if util.in_list(code_point, util.romanesque_chars) then
    return true
  end
  return false
end

function util.has_romanesque_char(s)
  -- has romanesque char but not necessarily pure romanesque
  if not s then
    return false
  end
  for _, code_point in utf8.codes(s) do
    if util.is_romanesque(code_point) then
      return true
    end
  end
  return false
end

function util.is_cjk_char(code_point)
  if not code_point then
    return false
  end
  if util.in_ranges(code_point, util.CJK_ranges) then
    return true
  end
  return false
end

function util.has_cjk_char(s)
  -- has romanesque char but not necessarily pure romanesque
  if not s then
    return false
  end
  for _, code_point in utf8.codes(s) do
    if util.is_cjk_char(code_point) then
      return true
    end
  end
  return false
end

function util.convert_roman (number)
  -- assert(type(number) == "number")
  local output = {}
  for _, tuple in ipairs(util.roman_numerals) do
    local letter, value = table.unpack(tuple)
    table.insert(output, string.rep(letter, math.floor(number / value)))
    number = number % value
  end
  return table.concat(output, "")
end

util.roman_numerals = {
  {"m",  1000},
  {"cm", 900},
  {"d",  500},
  {"cd", 400},
  {"c",  100},
  {"xc", 90},
  {"l",  50},
  {"xl", 40},
  {"x",  10},
  {"ix", 9},
  {"v",  5},
  {"iv", 4},
  {"i",  1},
};


-- Choose

util.position_map = {
  ["first"] = 0,
  ["subsequent"] = 1,
  ["ibid"] = 2,
  ["ibid-with-locator"] = 3,
  ["container-subsequent"] = 4,
}


-- Output

util.superscripts = {
  ["\u{00AA}"] = "\u{0061}",
  ["\u{00B2}"] = "\u{0032}",
  ["\u{00B3}"] = "\u{0033}",
  ["\u{00B9}"] = "\u{0031}",
  ["\u{00BA}"] = "\u{006F}",
  ["\u{02B0}"] = "\u{0068}",
  ["\u{02B1}"] = "\u{0266}",
  ["\u{02B2}"] = "\u{006A}",
  ["\u{02B3}"] = "\u{0072}",
  ["\u{02B4}"] = "\u{0279}",
  ["\u{02B5}"] = "\u{027B}",
  ["\u{02B6}"] = "\u{0281}",
  ["\u{02B7}"] = "\u{0077}",
  ["\u{02B8}"] = "\u{0079}",
  ["\u{02E0}"] = "\u{0263}",
  ["\u{02E1}"] = "\u{006C}",
  ["\u{02E2}"] = "\u{0073}",
  ["\u{02E3}"] = "\u{0078}",
  ["\u{02E4}"] = "\u{0295}",
  ["\u{1D2C}"] = "\u{0041}",
  ["\u{1D2D}"] = "\u{00C6}",
  ["\u{1D2E}"] = "\u{0042}",
  ["\u{1D30}"] = "\u{0044}",
  ["\u{1D31}"] = "\u{0045}",
  ["\u{1D32}"] = "\u{018E}",
  ["\u{1D33}"] = "\u{0047}",
  ["\u{1D34}"] = "\u{0048}",
  ["\u{1D35}"] = "\u{0049}",
  ["\u{1D36}"] = "\u{004A}",
  ["\u{1D37}"] = "\u{004B}",
  ["\u{1D38}"] = "\u{004C}",
  ["\u{1D39}"] = "\u{004D}",
  ["\u{1D3A}"] = "\u{004E}",
  ["\u{1D3C}"] = "\u{004F}",
  ["\u{1D3D}"] = "\u{0222}",
  ["\u{1D3E}"] = "\u{0050}",
  ["\u{1D3F}"] = "\u{0052}",
  ["\u{1D40}"] = "\u{0054}",
  ["\u{1D41}"] = "\u{0055}",
  ["\u{1D42}"] = "\u{0057}",
  ["\u{1D43}"] = "\u{0061}",
  ["\u{1D44}"] = "\u{0250}",
  ["\u{1D45}"] = "\u{0251}",
  ["\u{1D46}"] = "\u{1D02}",
  ["\u{1D47}"] = "\u{0062}",
  ["\u{1D48}"] = "\u{0064}",
  ["\u{1D49}"] = "\u{0065}",
  ["\u{1D4A}"] = "\u{0259}",
  ["\u{1D4B}"] = "\u{025B}",
  ["\u{1D4C}"] = "\u{025C}",
  ["\u{1D4D}"] = "\u{0067}",
  ["\u{1D4F}"] = "\u{006B}",
  ["\u{1D50}"] = "\u{006D}",
  ["\u{1D51}"] = "\u{014B}",
  ["\u{1D52}"] = "\u{006F}",
  ["\u{1D53}"] = "\u{0254}",
  ["\u{1D54}"] = "\u{1D16}",
  ["\u{1D55}"] = "\u{1D17}",
  ["\u{1D56}"] = "\u{0070}",
  ["\u{1D57}"] = "\u{0074}",
  ["\u{1D58}"] = "\u{0075}",
  ["\u{1D59}"] = "\u{1D1D}",
  ["\u{1D5A}"] = "\u{026F}",
  ["\u{1D5B}"] = "\u{0076}",
  ["\u{1D5C}"] = "\u{1D25}",
  ["\u{1D5D}"] = "\u{03B2}",
  ["\u{1D5E}"] = "\u{03B3}",
  ["\u{1D5F}"] = "\u{03B4}",
  ["\u{1D60}"] = "\u{03C6}",
  ["\u{1D61}"] = "\u{03C7}",
  ["\u{2070}"] = "\u{0030}",
  ["\u{2071}"] = "\u{0069}",
  ["\u{2074}"] = "\u{0034}",
  ["\u{2075}"] = "\u{0035}",
  ["\u{2076}"] = "\u{0036}",
  ["\u{2077}"] = "\u{0037}",
  ["\u{2078}"] = "\u{0038}",
  ["\u{2079}"] = "\u{0039}",
  ["\u{207A}"] = "\u{002B}",
  ["\u{207B}"] = "\u{2212}",
  ["\u{207C}"] = "\u{003D}",
  ["\u{207D}"] = "\u{0028}",
  ["\u{207E}"] = "\u{0029}",
  ["\u{207F}"] = "\u{006E}",
  ["\u{2120}"] = "\u{0053}\u{004D}",
  ["\u{2122}"] = "\u{0054}\u{004D}",
  ["\u{3192}"] = "\u{4E00}",
  ["\u{3193}"] = "\u{4E8C}",
  ["\u{3194}"] = "\u{4E09}",
  ["\u{3195}"] = "\u{56DB}",
  ["\u{3196}"] = "\u{4E0A}",
  ["\u{3197}"] = "\u{4E2D}",
  ["\u{3198}"] = "\u{4E0B}",
  ["\u{3199}"] = "\u{7532}",
  ["\u{319A}"] = "\u{4E59}",
  ["\u{319B}"] = "\u{4E19}",
  ["\u{319C}"] = "\u{4E01}",
  ["\u{319D}"] = "\u{5929}",
  ["\u{319E}"] = "\u{5730}",
  ["\u{319F}"] = "\u{4EBA}",
  ["\u{02C0}"] = "\u{0294}",
  ["\u{02C1}"] = "\u{0295}",
  ["\u{06E5}"] = "\u{0648}",
  ["\u{06E6}"] = "\u{064A}",
}


-- File IO

function util.read_file(path)
  -- if not path then
  --   print(debug.traceback())
  -- end
  local file = io.open(path, "r")
  if not file then
    -- util.error(string.format('Cannot read file "%s".', path))
    return nil
  end
  local content = file:read("*a")
  file:close()
  return content
end


function util.parse_iso_date(str)
  local date
  local date_parts = util.split(str, "/")
  if #date_parts <= 2 then
    date = {["date-parts"] = {}}
    for _, date_part in ipairs(date_parts) do
      table.insert(date["date-parts"], util.split(date_part, "%-"))
    end
  end
  if not date then
    date = {literal = str}
  end
  return date
end


function util.parse_extra_name(str)
  local name
  local name_parts = util.split(str, "%s*||%s*")
  if #name_parts == 2 then
    name = {
      family = name_parts[1],
      given = name_parts[2],
    }
  else
    name = {literal = str}
  end
  return name
end


return util
