Mô đun:zu-common

local export = {}

local u = mw.ustring.char

local ACUTE     = u(0x0301)
local CIRC      = u(0x0302)
local MACRON    = u(0x0304)
local SYLL      = u(0x0324)

export.diacritic = MACRON .. ACUTE .. CIRC
export.toneless_vowel = "aeiouāēīōūAEIOUĀĒĪŌŪ." .. SYLL
export.vowel = export.toneless_vowel .. "áéíóúâêîôûḗṓÁÉÍÓÚÂÊÎÔÛḖṒ" .. export.diacritic


-- Use '.' to denote syllabic m. e.g. um.ndeni
function export.split_syllables(word)
	local syllables = {}
	
	for syll in mw.ustring.gmatch(word, "[^" .. export.vowel .. "]*[" .. export.vowel .. "%.]+") do
		table.insert(syllables, syll)
	end
	
	syllables[#syllables] = syllables[#syllables] .. mw.ustring.match(word, "[^" .. export.vowel .. "]*$")
	
	return syllables
end

local function depressor_shift(syllables, pattern)
	if #pattern ~= #syllables then
		error("Number of syllables and number of tones do not match.")
	end
	
	local depressor_consonant = {"bh", "d", "dl", "g", "gc", "gq", "gx", "hh", "j", "mb", "mv", "nd", "ndl", "ng", "ngc", "ngq", "ngx", "nj", "nz", "v", "z"}
	local dep_table = {}
	for _, consonant in ipairs(depressor_consonant) do
		dep_table[consonant] = true
		dep_table[consonant .. "w"] = true
	end
	
	consonants = {}
	for _, syll in ipairs(syllables) do
		consonant = mw.ustring.sub(syll, 1, #syll-1)
		table.insert(consonants, consonant)
	end
	
	for i, cons in ipairs(consonants) do
		 --If the syllable is H and has a depressor consonant, and next syllable does not have a depressor consonant
		if pattern[i] == "H" and dep_table[cons] and not dep_table[consonants[i+1]] then
			if #consonants - i > 2 then --next syllable is before the penult
				pattern[i] = "L"
				if pattern[i+1] == "L" then
					pattern[i+1] = "H"
				end
			elseif #consonants - i == 2 then --next syllable is penultimate
				pattern[i] = "L"
				if pattern[i+1] == "L" then
					pattern[i+1] = "F"
				end
			end
		end
	end
	
	return pattern
end

function export.apply_tone(word, pattern, shift)
	if shift == nil then
		shift = true
	end
	word = export.split_syllables(word)
	pattern = mw.text.split(pattern or mw.ustring.rep("L", #word), "")
	
	if #word ~= #pattern then
		error("The word \"" .. table.concat(word) .. "\" and the tone pattern " .. table.concat(pattern) .. " have different numbers of syllables.")
	end
	
	if shift then
		pattern = depressor_shift(word, pattern)
	end
	
	for i, tone in ipairs(pattern) do
		if tone == "F" then
			word[i] = mw.ustring.gsub(word[i], "([" .. export.toneless_vowel .. "])", "%1" .. CIRC)
			-- Delete macron under circumflex
			word[i] = mw.ustring.toNFC(mw.ustring.gsub(mw.ustring.toNFD(word[i]), MACRON, ""))
		elseif tone == "H" then
			word[i] = mw.ustring.gsub(word[i], "([" .. export.toneless_vowel .. "])", "%1" .. ACUTE)
		elseif tone ~= "L" then
			error("Invalid character \"" .. tone .. "\" in tone pattern string.")
		end
	end
	
	return (mw.ustring.gsub(mw.ustring.toNFC(table.concat(word)), "̩", ""))
end

-- Strip the tone diacritics from a word.
-- Returns the stripped word and a tone pattern consisting of H, L, and F.
function export.split_tone(word)
	local syllables = export.split_syllables(word)
	local tones = ""
	local stripped = ""
	
	for _, syll in ipairs(syllables) do
		-- remove any '.' char and convert to NFD
		syll = mw.ustring.toNFD(mw.ustring.gsub(syll, "%.", ""))
		local endChar = mw.ustring.sub(syll, mw.ustring.len(syll))
    	if endChar == ACUTE then
    		tones = tones .. "H"
    		stripped = stripped .. mw.ustring.sub(syll, 1, mw.ustring.len(syll)-1)
    	elseif endChar == CIRC then
    		tones = tones .. "F"
    		stripped = stripped .. mw.ustring.sub(syll, 1, mw.ustring.len(syll)-1)
    	else
    		tones = tones .. "L"
			stripped = stripped .. syll
		end
	end
	
	return {mw.ustring.toNFC(stripped), tones}
end

return export