-- (obligatory) language code
-- (obligatory) word class
-- (optional) base form
-- (optional) "text=" base form with diacrit
-- (optional) "host=" host page, special value "#" for same

local exporttbl = {}

local import_h3    = require ("Modul:h3")
local import_lang  = require ("Modul:lang")
local import_param = require ("Modul:param")
local import_sort  = require ("Modul:sort")

local cbo        = "b" .. string.char(195,182) .. "jning"
local cbform     = cbo .. "sform av"
local name_short = cbo
local name_long  = '"Mall:' .. name_short .. '"'

local function expandTwo (control_string, insert_m_string, insert_v_string)

  local temp_string = ''
  local expanded_string = ''
  local x_length = 0
  local x_index = 0
  local chark = 0
  local charl = 0

  x_length = string.len (control_string)
  while true do
    if (x_index==x_length) then
      break
    end--if
    chark = string.byte (control_string,(x_index+1),(x_index+1))
    x_index = x_index + 1
    charl = 0
    if (x_index<x_length) then
      charl = string.byte (control_string,(x_index+1),(x_index+1))
    end--if
    if ((chark==64) and (charl==77)) then -- @M cannot be empty
      temp_string = insert_m_string
      x_index = x_index + 1
    else
      if ((chark==64) and (charl==86)) then -- @V can be empty
        temp_string = insert_v_string
        x_index = x_index + 1
      else
        temp_string = string.char (chark)
      end--if
    end--if
    expanded_string = expanded_string .. temp_string
  end--while

  return expanded_string

end--function expandTwo

function exporttbl.go (arxframent)

  local arxsomons = 0

  local legal_params = {}
  local many_complaints = {}

  local list_bad_params = ''
  local violating_string = ''
  local problem_1_main = ''
  local problem_2_desc = ''
  local problem_3_hint = ''
  local p_2_desc_expanded = ''

  local pagename = ''
  local link_target = ''
  local taget_section = ''
  local link_right_part = ''

  local error_visible = ''
  local error_cat = ''
  local good_visible = ''
  local good_cat = ''
  local final_result = ''

  local error_code = 0

  local boo_no_cat_true = false
  local boo_no_cat_false = false

  arxsomons = arxframent.args -- "args" from our own "frame"
  if (arxsomons=="true") then
    arxsomons = arxframent:getParent().args -- "args" from caller's "frame"
  end--if

  legal_params = {=3,"text","host","nocat","pagenameoverridetestonly"}
  list_bad_params = import_param.go (arxsomons,legal_params)

  local lang_code  = mw.text.trim (arxsomons or "")
  local word_class = mw.text.trim (arxsomons or "")
  local base_form  = mw.text.trim (arxsomons or "")
  local base_text  = arxsomons or "" -- diacrit will get removed later
  local page_host  = arxsomons or "" -- special value "#" defined

  pagename = arxsomons or mw.title.getCurrentTitle().prefixedText
  boo_no_cat_true  = (arxsomons=="true")
  boo_no_cat_false = (arxsomons=="false")

  local h3_singular = import_h3.getLongSingUCFirst(word_class) -- returns empty for unknown

  many_complaints = {'Ogiltiga parametrar','@M använder inte @V'}
  many_complaints = {'Mallsyntax','Obligatorisk parameter saknas i @M','Språkkod, ordklass och grundform krävs alltid.'}
  many_complaints = {'Uppenbarligen ogiltig språkkod','Kod @V skickades in i @M'}
  many_complaints = {'Okänd språkkod','Kod @V skickades in i @M'}
  many_complaints = {'Mallsyntax','Okänd ordklass @V skickades in i @M'}
  many_complaints = {'Mallsyntax','Grundformen har angetts dubbelt för @M'}

  while true do
    if list_bad_params ~= '' then
      error_code = 1
      violating_string = list_bad_params
      break
    end--if
    if ((lang_code=="") or (word_class=="") or (base_form=="") and (base_text=="")) then
      error_code = 2 -- no string here
      break
    end--if
    if import_lang.isObviouslyInvalid(lang_code) then
      error_code = 3
      violating_string = '"' .. lang_code .. '"'
      break
    end--if
    if not import_lang.hasLanguage(lang_code) then
      error_code = 4
      violating_string = '"' .. lang_code .. '"'
      break
    end--if
    if (h3_singular=="") then
      error_code = 5
      violating_string = '"' .. word_class .. '"'
      break
    end--if
    if ((base_form~="") and (base_text~="")) then
      error_code = 6 -- no string here
    end--if
    break
  end--while

  if (error_code~=0) then
    problem_1_main = many_complaints
    problem_2_desc = many_complaints -- @M cannot be empty, @V can be empty
    problem_3_hint = many_complaints or '' -- optional, can be empty
    p_2_desc_expanded = expandTwo (problem_2_desc, name_long, violating_string)
    error_cat = ']]'
    error_visible = '<br><span class="error"><b>' .. problem_1_main .. ' -- ' .. p_2_desc_expanded .. '.</b></span></br>'
    if (problem_3_hint~='') then
      error_visible = error_visible .. problem_3_hint
    end--if
  end--if

  if (error_code==0) then

    local language_ucf = import_lang.getLanguageUCFirst(lang_code) -- use "hasLanguage" for validation
    local sort_key = import_sort.getSortKey(lang_code, pagename)

    if (base_text~="") then
      link_target = import_lang.getEntryName(lang_code, base_text) -- remove diacrit
      link_right_part = base_text -- with diacrit
    else
      link_target = base_form -- keep diacrit
      link_right_part = base_form -- with possible diacrit
    end--if

    if (page_host~="") then -- neither word class nor language as section
      taget_section = link_target
      if (page_host=="#") then
        link_target = pagename
      else
        link_target = page_host
      end--if
    else
      if (lang_code=="sv") then
        taget_section = h3_singular -- word class as section
      else
        taget_section = language_ucf -- language name as section
      end--if
    end--if

    if (h3_singular=="Räkneord") then
      h3_singular = h3_singular .. "s" -- absurdities of the Swedish language "Räkneordsformer"
    end--if

    good_visible = '<i style="color:#6B5A40">' .. cbform .. '</i> ]'
    good_cat = "]"

  end--if (error_code==0) then

  if (error_code==0) then
    final_result = good_visible
  else
    if ((arxframent:preprocess ("{{REVISIONID}}") == '') or boo_no_cat_true or boo_no_cat_false) then
      mw.addWarning (error_visible)
      final_result = error_visible
    else
      final_result = "<i>" .. name_short .. "</i>"
    end--if
  end--if
  if (not boo_no_cat_true) then
    if (error_code==0) then
      final_result = final_result .. good_cat
    else
      final_result = final_result .. error_cat
    end--if
  end--if

  return final_result

end--function

return exporttbl