-- ---------------------------------------------------------------------------
-- Itte Util
-- ---------------------------------------------------------------------------

--[[
-- A collection of helper functions used by Itte.
--]]

local itteutil = {}
itteutil.docs = {}


itteutil.docs.get_docs = [===[  (docstring_table [, func_str [, printd_bool]])
  Given a table of docstrings and a function name, return the description for
  the function name. If `name` is unspecified, return descriptions for all
  functions. If `printd` is unspecified, print to stdout, or if set to false,
  return results as a string.
  ]===]
function itteutil.get_docs(docstr, name, printd)
  local docs = ""
  if name ~= nil then
    -- 2nd-level nested objects, e.g. x.y.func()
    if itteutil.is_substr(name, "%.") then
      local sep, _ = string.find(name, "%.")
      local dk = name:sub(1, sep - 1)
      local nk = name:sub(sep + 1)
      docs = "\n" .. name .. " " .. string.gsub(docstr[dk][nk]:sub(3),
        "  ", "") .. "\n"
    else
      docs = "\n" .. name .. " " .. string.gsub(docstr[name]:sub(3), "  ", "")
        .. "\n"
    end
  else
    -- Sort on-site since associative arrays have no fixed order
    local dk = itteutil.table_keys(docstr)
    docs = "\n"
    for c = 1, #dk do
      -- 2nd-level nested objects, e.g. x.y.func()
      if type(docstr[dk[c]]) == "table" then
        local n_dk = itteutil.table_keys(docstr[dk[c]])
        for nc = 1, #n_dk do
          docs = docs .. dk[c] .. "." .. n_dk[nc] .. " " ..
            string.gsub(docstr[dk[c]][n_dk[nc]]:sub(3), "  ", "") .. "\n"
        end
      else
        docs = docs .. dk[c] .. " " .. string.gsub(docstr[dk[c]]:sub(3),
          "  ", "") .. "\n"
      end
    end
  end

  if printd == false then
    return docs
  else
    print(docs)
  end
end



itteutil.docs.help = [[  ([func_str])
  Given a function name, print a corresponding description.
]]
function itteutil.help(name)
  itteutil.get_docs(itteutil.docs, name)
end


itteutil.docs.is_substr = [[  (str, find_str)
  Check if a string is a substring of another string. Return true if it is a
  substring, or false otherwise.
  ]]
function itteutil.is_substr(str, search)
  if (string.find(str, search) ~= nil) then
    return true
  else
    return false
  end
end


itteutil.docs.first_upper = [[  (str)
  Return a string with the first character in uppercase.
  ]]
function itteutil.first_upper(str)
  return str:sub(1, 1):upper() .. str:sub(2)
end


itteutil.docs.first_lower = [[  (str)
  Return a string with the first character in lowercase.
  ]]
function itteutil.first_lower(str)
  return str:sub(1, 1):lower() .. str:sub(2)
end


itteutil.docs.split_str = [[  (str, [, pattern_str])
  Split a string on a pattern separator and return a table of string values,
  e.g. split_str("Hello world", "%S+"). If no pattern is specified, split
  string on the space character.
  ]]
function itteutil.split_str(str, sep)
  local tbl = {}
  local n = 0
  -- Other patterns: https://www.lua.org/pil/20.2.html
  if sep == nil then sep = "%S+" end
  for sub in string.gmatch(str, sep) do
    n = n + 1
    tbl[n] = sub
  end
  return tbl
end


itteutil.docs.a_or_an = [[  (str)
  Return the corresponding indefinite article for a word.
  Does *not* apply to acronyms, e.g. FTP.
  ]]
function itteutil.a_or_an(str)
  local article = "a"
  if itteutil.is_substr("a e i o u", str:sub(1, 1)) or
    itteutil.is_substr("ho", str:sub(1, 2)) then
    article = "an"
  end
  if (str == "one") or (itteutil.is_substr("eu", str:sub(1, 2))) or
    (itteutil.is_substr("uni usa use usi usu", str:sub(1, 3))) then
    article = "a"
  end
  return article
end


itteutil.docs.table_keys = [[  (table)
  Return a sorted table of keys for an associative table.
  ]]
function itteutil.table_keys(tbl)
  local keys = {}
  local n = 0
  for k, v in pairs(tbl) do
    n = n + 1
    keys[n] = k
  end
  table.sort(keys)
  return keys
end


itteutil.docs.has_key = [[  (table, find_str)
  Given a table and string, check whether the string is a key in the table.
  Return true if found, or false otherwise.
  ]]
function itteutil.has_key(tbl, str)
  local keys = itteutil.table_keys(tbl)
  -- Primitive check for array-like table with numerical keys
  if (keys[1] == 1) and (keys[#keys] == #keys) then
    for k = 1, #keys do
      if str == tbl[k] then
        do return true end
      end
    end
  -- Associative table
  else
    for k = 1, #keys do
      if str == keys[k] then
        do return true end
      end
    end
  end
  return false
end


itteutil.docs.find_key = [[  (table, find_str)
  Given a table and string, check whether the string is a key in the table.
  Return the key if found, or nil otherwise.
  ]]
function itteutil.find_key(tbl, str)
  local keys = itteutil.table_keys(tbl)
  -- Primitive check for array-like table with numerical keys
  if (keys[1] == 1) and (keys[#keys] == #keys) then
    for k = 1, #keys do
      if str == tbl[k] then
        do return k end
      end
    end
  -- Associative table
  else
    for k = 1, #keys do
      if str == keys[k] then
        do return k end
      end
    end
  end
  return nil
end



itteutil.docs.is_entry = [[  (table, key_str, val_str)
  Given an associative table, a key and value pair as strings, check whether
  the pair is in the table. Return true if it exists in the table, or false
  otherwise.
  ]]
function itteutil.is_entry(tbl, key, val)
  for k, v in pairs(tbl) do
    if (key == k) and (val == v) then
      do return true end
    end
  end
  return false
end


itteutil.docs.pick = [===[  (table [, num_int [, unique_bool ]])
  Pseudo-randomly pick entries from a non-associative table and return the
  entries in a table. If `num` is unspecified, it will return one entry.
  If `unique` is unspecified, it will return non-recurring values.
  ]===]
function itteutil.pick(tbl, num, unique)
  local picks = {}
  if num == nil then num = 1 end
  if unique == nil then unique = true end
  picks[1] = tbl[math.random(1, #tbl)]

  if (num > 1) and (num <= #tbl) then
    for n = 2, num do
      local p = tbl[math.random(1, #tbl)]
      -- Check for duplicate
      if unique then
        local c = 1
        -- Avoid endless loop if all values in the table are identical
        while (itteutil.has_key(picks, p)) and (c <= #tbl) do
          p = tbl[math.random(1, #tbl)]
          c = c + 1
        end
      end
      picks[n] = p
    end
  end
  return picks
end


itteutil.docs.sleep = [[  (seconds_int)
  Set a delay in seconds.
  ]]
function itteutil.sleep(s)
  local timer = os.clock()
  while (os.clock() - timer < s) do end
end


itteutil.docs.debug = [[  (tag_str, debug_str [, enabled_bool])
  Format and print debug output if `enabled` is true.
  ]]
function itteutil.debug(tag, str, enabled)
  if enabled then
    local ts = os.date("%Y-%m-%d %H:%M:%S", os.time())
    print("[" .. ts .. "][" .. tag .. "] " .. str)
  end
end


itteutil.docs.source_file = [[  (filename_str)
  Load a source file.
  ]]
function itteutil.source_file(str)
  local func, err = loadfile(str)
  if func then
    return func()
  else
    itteutil.debug("source_file", "Error: " .. err, true)
    do return end
  end
end



itteutil.docs.read_file = [[  (filename_str)
  Open a file and return the contents as a string.
  ]]
function itteutil.read_file(str)
  local file = io.open(str)
  if io.type(file) == "file" then
    local contents = file:read("*a")
    file:close()
    return contents
  else
    itteutil.debug("read_file", "Error: cannot read file.", true)
  end
end


return itteutil