local util = require("itteutil")

-- Default settings
local folia = {
  foils_dir = "",
  debug = false,
}


util.docs.get_foils = [[  (directory_str)
  Given the full path to a directory of foils, return the foil contents as a
  table.
  ]]
function folia.get_foils(str)
  local foil_list_str = io.popen("ls " .. str)
  local foils = {}
  if foil_list_str then
    local foil_list = util.split_str(foil_list_str:read("*a"))
    for i = 1, #foil_list do
      local key = string.gsub(foil_list[i], ".lua", "")
      local func, err = loadfile(str .. "/" .. foil_list[i])
      if func then
        func()
        foils[key] = grammar
      end
    end
    -- Unset global variables
    func = nil
    grammar = nil
  end
  return foils
end


util.docs.output = [[  (key_str)
  Given a foil name or foils table key, output a random expanded string.
  ]]
function folia.output(key)
  local foils = folia.get_foils(folia.foils_dir)
  if table.concat(util.table_keys(foils), "") == "" then
    util.debug("output", "Error: cannot retrieve foils." ..
      " Please make sure the full directory path is correct.", folia.debug)
    do return end
  elseif not util.has_key(foils, key) then
    util.debug("output", "Error: the key `" .. key ..
      "` is not in the foils table.", folia.debug)
    do return end
  elseif not util.has_key(foils[key], "origin") then
    util.debug("output", "Error: no origin found in the foil.", folia.debug)
    do return end
  elseif foils[key]["origin"] == {} then
    util.debug("output", "Error: empty origin.", folia.debug)
    do return end
  end

  local output_str = util.pick(foils[key]["origin"])[1]
  local pattern = "#(%w+_*%-*%w+)#"
  util.debug("output", "level 1: " .. output_str, folia.debug)
  -- Check for expansion objects and replace them until none are found
  while string.find(output_str, pattern) ~= nil do
    local hash = output_str:sub(string.find(output_str, pattern))
    local obj = hash:sub(2, #hash - 1)
    -- Check the object key is in the foil grammar, and replace one instance
    -- at a time.
    if util.has_key(foils[key], obj) then
      local expand_str = util.pick(foils[key][obj])[1]
      output_str = string.gsub(output_str, hash, expand_str, 1)
      util.debug("output", "level n: " .. output_str, folia.debug)
    -- If the object key is not in the grammar, replace references with a
    -- placeholder.
    else
      output_str = string.gsub(output_str, hash, "[" .. obj .. "]")
    end
  end
  return output_str
end


return folia