#!/usr/bin/env texlua
--------------------------------------------------------------------------------
--         FILE:  cyrillicnumbers.lua
--        USAGE:  called by t-cyrillicnumbers.mkiv
--  DESCRIPTION:  part of the Cyrillic Numbers module for ConTeXt
-- REQUIREMENTS:  recent ConTeXt MkIV and LuaTeX
--       AUTHOR:  Philipp Gesang (phg), <gesang at stud dot uni-heidelberg dot de>
--      VERSION:  hg tip
--      CREATED:  2011-11-29 10:06:00+0100
--------------------------------------------------------------------------------
--

--- read this first:
---
--- Жолобов, О. Ф.: *Числительные*. In: *Историческая грамматика древнерусского
---                 языка*, vol. 4, Moskva 2006, pp. 58--63
---
--- Trunte, Nikolaos H.: *Altkirchenslavisch*. In: *Словѣньскъи ѩꙁъікъ.
---                      Ein praktisches Lehrbuch des Kirchenslavischen in 30
---                      Lektionen. Zugleich eine Einführung in die slavische
---                      Philologie*, vol. 1, München ⁵2005, pp. 161ff.

--- or have a glance at these:
--- http://www.pravpiter.ru/zads/n018/ta013.htm
--- http://www.uni-giessen.de/partosch/eurotex99/berdnikov2.pdf
--- <http://ru.wikipedia.org/wiki/Кириллическая_система_счисления>

local iowrite     = io.write
local mathceil    = math.ceil
local mathfloor   = math.floor
local tableconcat = table.concat
local tablemaxn   = table.maxn
local tableinsert = table.insert
local utf8char    = unicode.utf8.char
local utf8len     = unicode.utf8.len
local utfupper    = unicode.utf8.upper

local cyrnum     = {
  placetitlo    = "font",
  titlolocation = "final", -- above final digit
  titlospan     = 3,       -- only with mp
  drawdots      = true,
  debug         = false,
}

thirddata        = thirddata or { }
thirddata.cyrnum = cyrnum

local dbgpfx = "[cyrnum]"
local dbg = function (...)
  if cyrnum.debug then
    local args = {...}
    if type(args[1]) == "table" then args = args[1] end
    iowrite(dbgpfx)
    for i=1, #args do
      local this = args[i]
      local tthis = type(this)
      iowrite" "
      if tthis == "number" or tthis == "string" then
        iowrite(this)
      else
        iowrite(tostring(this))
      end
    end
    iowrite"\n"
  end
end

local cyrillic_numerals = {
  { "а", "в", "г", "д", "е", "ѕ", "з", "и", "ѳ", },
  { "і", "к", "л", "м", "н", "ѯ", "о", "п", "ч", },
  { "р", "с", "т", "у", "ф", "х", "ѱ", "ѡ", "ц", },
}
local cyrillic_1k    = "҂"
local cyrillic_100k  = utf8char(0x488) -- combining hundred thousands sign
local cyrillic_1m    = utf8char(0x489) -- combining million sign
local cyrillic_titlo = utf8char(0x483) -- combining titlo


--local concat_cyrillic_nums = function (chars, upper)
--  dbg(chars)
--  local nchars, result = tablemaxn(chars), ""
--  --if cyrnum.placetitlo and cyrnum.titlomode == "fm" then -- above central char
--  --  dbg("char cnt", nchars)
--  --  dbg("insert pos", mathceil(nchars/2))
--  --  tableinsert(chars, mathceil(nchars/2), cyrillic_titlo)
--  --end
--  for i=#chars, 1, -1 do
--    local this = chars[i]
--    if this then
--      if upper then this = utfupper(this) end
--      if i > 3 then
--        result = result .. cyrillic_1k .. this
--      else
--        result = result .. this
--      end
--    end
--  end
--  if cyrnum.placetitlo and cyrnum.titlomode == "fl" then -- take titlo from font, place it after / above last char
--    result = result .. cyrillic_titlo
--  end
--  return result
--end

local digits_only = function (list)
  local result = { }
  for i=1, tablemaxn(list) do
    local elm = list[i]
    if type(elm) == "string" then
      result[#result+1] = elm
    end
  end
  return result
end

local lreverse = function(list)local r={}for i=tablemaxn(list),1,-1 do r[#r+1]=list[i]end return r end

local start_titlo, stop_titlo = [[\cyrnumdrawtitlo{]], "}"

local titlofuncs = {
  font = function (list)
    if cyrnum.titlolocation == "final" then
      list[#list+1] = cyrillic_titlo
    else -- “middle” or whatever
      local pos = mathceil(tablemaxn(list)/2)
      tableinsert(list, mathceil(tablemaxn(list)/2), cyrillic_titlo)
    end
    return lreverse(list)
  end,
  mp = function (list)
    local result = { start_titlo }
    for i=tablemaxn(list), 1, -1 do
      result[#result+1] = list[i]
    end
    result[#result+1] = stop_titlo
    return result
  end,
  no = function (x) return x end,
}

local concat_cyrillic_nums = function (list, upper)
  local result         = ""
  local digits         = digits_only(list) -- strip placeholders
  local nlist, ndigits = tablemaxn(list), tablemaxn(digits)
  dbg(list)
  dbg(digits)
  local titlo = titlofuncs[cyrnum.placetitlo]
  if titlo then
    result = tableconcat(titlo(digits))
    if cyrnum.drawdots then
      local sym = cyrnum.dotsymbol
      result = sym .. result .. sym
    end
  end
  dbg(result)
  return result
end

local do_tocyrillic do_tocyrillic = function (n, result)
  if n < 1000 then
    local mod100 = n % 100
    if #result == 0 and  mod100 > 10 and mod100 < 20 then
      result[#result+1] = "і"
      result[#result+1] = cyrillic_numerals[1][mod100%10]             or false
    else
      result[#result+1] = cyrillic_numerals[1][mathfloor(n%10)]       or false
      result[#result+1] = cyrillic_numerals[2][mathfloor((n%100)/10)] or false
    end
    result[#result+1] = cyrillic_numerals[3][mathfloor((n%1000)/100)] or false
  else
    result = do_tocyrillic(n%1000, result)
    result = do_tocyrillic(mathfloor(n/1000), result)
  end
  return result
end

local tocyrillic = function (n)
  local chars = do_tocyrillic(n, { })
  return concat_cyrillic_nums(chars)
end

local Tocyrillic = function (n)
  local chars = do_tocyrillic(n, { })
  return concat_cyrillic_nums(chars, true)
end

converters.tocyrillic       = tocyrillic
converters.cyrillicnumerals = tocyrillic
converters.Cyrillicnumerals = Tocyrillic

function commands.cyrillicnumerals (n) context(tocyrillic(n)) end
function commands.Cyrillicnumerals (n) context(Tocyrillic(n)) end