Module:User:Chernorizets/bg-orthography

local export = {}

local umatch = mw.ustring.match
local ufind = mw.ustring.find
local ulower = mw.ustring.lower

local vowels_lower = "аъоуеиюяѝ"
local vowels_upper = "АЪОУЕИЮЯ"

export.vowels_lower_c = ""
export.vowels_upper_c = ""
export.vowels_c = ""

local consonants_lower = "бвгджзйклмнпрстфхцчшщь"
local consonants_upper = "БВГДЖЗЙКЛМНПРСТФХЦЧШЩЬ"

export.cons_lower_c = ""
export.cons_upper_c = ""
export.cons_c = ""

local alpha_lower = vowels_lower .. consonants_lower
local alpha_upper = vowels_upper .. consonants_upper

export.alpha_lower_c = ""
export.alpha_upper_c = ""
export.alphabet_c = ""
export.non_bulgarian_c = ""

local function get_opt(validation_opts, key)
	if validation_opts and type(validation_opts) == "table" then
		return validation_opts
	else
		return nil
	end
end

local orthographic_rules = {}

orthographic_rules = function(word, opts)
	-- All uppercase, all lowercase, or capitalized
	return umatch(word, "^%u+$") or umatch(word, "^%l+$") or umatch(word, "^%u%l*$")
end

orthographic_rules = function(word, opts)
	if ufind(word, "") then
		local lowered = ulower(word)
		return umatch(lowered, export.cons_lower_c .. "ьо") ~= nil
	end
	
	return true
end

orthographic_rules = function(word, opts)
	return umatch(word, "^" .. export.alphabet_c .. "+$") or
			umatch(word, "^" .. export.non_bulgarian_c .. "+$")
end

--[==[
Checks whether the provided word is valid according to Bulgarian orthographic rules.

===Parameters===

* word: a {string} representing a Bulgarian word.
*: The empty string is considered valid. {nil} is invalid by default, but that can be overriden via an option.
* validation_opts: a {table} of Boolean validation options
*: |nil_is_valid=: treats {nil} as valid input

===Errors===

If `word` is not a {string}, the function raises the error {"Input must be a string!"}.

===Return values===

The function returns two values: `result` and `message`:
* `result`: {true} if the word is orthographically valid, {false} otherwise
* `message`: {nil} if {result == true}, otherwise identifies the first failing orthographic rule
]==]
function export.is_valid(word, validation_opts)
	if not word then
		if get_opt(validation_opts, "nil_is_valid") then
			return true, nil
		else
			return false, "no input"
		end
	end
	
	if type(word) ~= "string" then error("Input must be a string!") end
	
	if word == "" then return true, nil end
	
	for rule_name, rule in pairs(orthographic_rules) do
		if not rule(word, validation_opts) then
			return false, rule_name
		end
	end
	
	return true, nil
end

return export