local lang = require("Module:languages").getByCode("cy")

local export = {}

local rfind = mw.ustring.find
local usub = mw.ustring.sub
local ulower = mw.ustring.lower

local PAGENAME = mw.title.getCurrentTitle().text
local IRREGMARKER = "<sup>△</sup>"

local mutation_rules = {
	['b'] = {"f", "m",},
	['c'] = {"g", "ngh", "ch",},
	['ch'] = {},
	['d'] = {"dd", "n",},
	['f'] = {},
	['g'] = {"", "ng"},
	['h'] = {},
	['l'] = {},
	['ll'] = {"l",},
	['m'] = {"f",},
	['n'] = {},
	['p'] = {"b", "mh", "ph",},
	['r'] = {},
	['rh'] = {"r",},
	['s'] = {},
	['t'] = {"d", "nh", "th",},
}

function export.get_mutation_data(term)
	local data = {}
	data.radical = term
	data.initial = usub(term, 1, 1)
	data.is_uppercase = ulower(data.initial) ~= data.initial
	data.initial = ulower(data.initial)
	data.final = usub(term, 2, -1)
	
	data.first_two = data.initial .. usub(data.final, 1, 1)
	if data.first_two == 'll' or data.first_two == 'rh' or data.first_two == 'ch' then
		data.initial = data.first_two
		data.final = usub(data.final, 2, -1)
	end
	data.vowel = false
	
	data.mut1 = nil
	data.mut2 = nil
	data.mut3 = nil
	
	if rfind(data.initial, "[aâàeêèiîìoôòuûùwŵẁyŷỳ]") then
		data.vowel = true
		data.mut3 = "h" .. data.initial
	elseif mutation_rules[data.initial] then
		data.mut1 = mutation_rules[data.initial][1]
		data.mut2 = mutation_rules[data.initial][2]
		data.mut3 = mutation_rules[data.initial][3]
	else
		error("no mutation rule found for this term: " .. term)
	end

	return data
end

function export.show(frame)
	args = frame:getParent().args
	radical = args[1] or PAGENAME
	initial = mw.ustring.sub(radical,1,1)
	is_uppercase = mw.ustring.lower(initial) ~= initial
	initial = mw.ustring.lower(initial)
	final = mw.ustring.sub(radical,2,-1)
	
	first_two = initial .. mw.ustring.sub(final,1,1)
	if first_two=='ll' or first_two=='rh' or first_two=='ch' then
		initial = first_two
		final = mw.ustring.sub(final,2,-1)
	end
	vowel = false
	
	local mut1 = nil
	local mut2 = nil
	local mut3 = nil
	
	if mw.ustring.match(initial,'[aâeêiîoôuûwŵyŷ]') then
		vowel = true
		mut3 = "h" .. initial
	elseif mutation_rules[initial] then
		mut1 = mutation_rules[initial][1]
		mut2 = mutation_rules[initial][2]
		mut3 = mutation_rules[initial][3]
	else
		error('rule not specified for this word:'..radical)
	end
	
	local function link(target, accel)
		target = target .. final
		if is_uppercase then
			target = mw.ustring.upper(mw.ustring.sub(target,1,1)) .. mw.ustring.sub(target,2,-1)
		end
		return require("Module:links").full_link({lang = lang, accel = {form = accel, lemma = radical}, term = target})
	end
	
	mut1 = mut1 and link(mut1, 'soft')
	mut2 = mut2 and link(mut2, 'nasal')
	mut3 = mut3 and link(mut3, vowel and 'h-prothesis' or 'aspirate')

	radical = radical == PAGENAME and "'''"..radical.."'''" or '[['..radical..'#威爾士語|'..radical..']]'
	result = '{| border="1" cellpadding="4" cellspacing="0" class="inflection-table" style="align: left; margin: 0.5em 0 0 0; border-style: solid; border: 1px solid #7f7f7f; border-right-width: 2px; border-bottom-width: 2px; border-collapse: collapse; background-color: #F8F8F8; font-size: 95%;"'
	result = result .. '\n|-'
	result = result .. '\n! colspan=4 | [[Appendix:威爾士語輔音變化|輔音變化]]'
	result = result .. '\n|-'
	result = result .. '\n! 原型 !! 濁化 !! 鼻音化 !! ' .. (vowel and 'h-音化' or '清音化')
	result = result .. '\n|-'
	result = result .. '\n| ' .. radical
	result = result .. '\n| ' .. (mut1 or "無變化")
	result = result .. '\n| ' .. (mut2 or "無變化")
	result = result .. '\n| ' .. (mut3 or "無變化")
	result = result .. '\n|-'
	result = result .. "\n| colspan=4 | <small style=\"font-size:85%;\">注意:有些形式僅是推測,不是每種形式都一定存在。</small>"
	result = result .. '\n|}'
	return result
end

return export