local p = {}
local find = mw.ustring.find
local hanja_ranges = "[〇㐀-䶿一-鿿﨎﨏﨑﨓﨔﨟﨡﨣﨤﨧-﨩𠀀-𪛟𪜀-𮹟𰀀-𲎯]"

-- Iteratively applies gsub text replacements to a given piece of text 
-- table should contain pairs of search patterns and replacements
function p.gsub_iterate(text, table)
	for _, entry in ipairs(table) do
		text = mw.ustring.gsub(text, entry[1], entry[2])
	end
	return text
end

-- Decomposes Hangul into jamo (e.g. 한 (U+D55C) → ᄒ (U+1112), ᅡ (U+1161), ᆫ (U+11AB))
function p.decompose_hangul(text)
	return mw.ustring.gsub(text, "[가-힣]", mw.ustring.toNFD)
end

-- Returns boolean on whether input contains any Hangul text at all
function p.contains_hangul(text)
	local hangul_ranges = "[ᄀ-ᇿ〮〯ㄱ-ㆎ㈀-㈞㉠-㉾ꥠ-꥿가-힣ힰ-퟿]"
	return text ~= nil and text ~= "" and find(text, hangul_ranges)
end

-- Returns boolean on whether input Hangul contains any special chars used by Module:Ko-translit
function p.hangul_contains_syntax(text)
	-- check if string empty
	if text == nil or text == "" then
		return false
	end
	-- check if first char of string is a special char
	if mw.ustring.match(mw.ustring.sub(text, 1, 1), "[%$%%%*@%^_`]") then
		return true
	end
	-- check if the rest of the chars are special
	return find(text, "[^\\][%$%%%*@%^_`]")
end

-- Returns boolean on whether input contains any Hanja text at all
function p.contains_hanja(text)
	return text ~= nil and text ~= "" and find(text, hanja_ranges)
end

-- Returns boolean on whether input only contains Hanja text
function p.all_hanja(text)
    for i = 1, #text do
        local c = text:sub(i, i)
        if not find(c, hanja_ranges) then
            return false
        end
    end
    return true
end

-- Returns boolean on whether input directly contains a Wikipedia reference
function p.contains_reference(text)
	return find(text, "'\"`UNIQ--") or find(text, "-QINU`\"'")
end

return p