モジュール:Wd

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local p = {}

local aliasesP = {
	author          = "P50",
	publisher       = "P123",
	importedFrom    = "P143",
	statedIn        = "P248",
	coord           = "P625",
	publicationDate = "P577",
	startTime       = "P580",
	endTime         = "P582",
	retrieved       = "P813",
	referenceURL    = "P854",
	archiveURL      = "P1065",
	title           = "P1476",
	quote           = "P1683",
	shortName       = "P1813",
	language        = "P2439",
	archiveDate     = "P2960"
}

local aliasesQ = {
	percentage              = "Q11229",
	prolepticJulianCalendar = "Q1985786"
}

local State = {}
State.__index = State

-- allows for recursive calls
function State.new()
	local stt = {}
	setmetatable(stt, State)
	
	stt.outPreferred = {}
	stt.outNormal = {}
	stt.outDeprecated = {}
	
	stt.bestRank = true
	stt.foundRank = 3
	stt.maxRank = nil
	stt.minRank = nil
	
	stt.period = 0
	
	stt.propertyWithQualifier = false
	stt.pageTitle = false
	
	stt.linked = false
	stt.rawValue = false
	stt.shortName = false
	stt.singleValue = false
	stt.mdyDate = false
	stt.withRefs = false
	
	stt.langCode = mw.language.getContentLanguage().code
	stt.langName = mw.language.fetchLanguageName(stt.langCode, stt.langCode)
	stt.langObj = mw.language.new(stt.langCode)
	
	stt:setRankBoundaries("best")
	
	return stt
end

function State:unknownDatatypeError(type)
	return "<strong class=\"error\">'" .. type .. "'は不明もしくは未対応のデータタイプです。</strong>"
end

function State:parseWikidataURL(url)
	local i, j
	
	if url:match('^http[s]?://') then
		i, j = url:find("Q")
		
		if i then
			return url:sub(i)
		end
	end
	
	return nil
end

function State:parseDate(dateStr, precision)
	precision = precision or "d"
	local i, j, index, ptr
	local parts = {nil, nil, nil}
	
	if dateStr == nil then
		return parts[1], parts[2], parts[3]  -- year, month, day
	end
	
	-- 'T' for snak values, '/' for outputs with '/Julian' attached
	i, j = dateStr:find("[T/]")
	
	if i then
		dateStr = dateStr:sub(1, i-1)
	end
	
	local from = 1
	
	if dateStr:sub(1,1) == "-" then
		-- this is a negative number, look further ahead
		from = 2
	end
	
	index = 1
	ptr = 1
	
	i, j = dateStr:find("-", from)
	
	if i then
		-- year
		parts[index] = tonumber(mw.ustring.gsub(dateStr:sub(ptr, i-1), "^\+(.+)$", "%1"), 10)  -- remove + sign
		
		if parts[index] == -0 then
			parts[index] = 0
		end
		
		if precision == "y" then
			-- we're done
			return parts[1], parts[2], parts[3]  -- year, month, day
		end
		
		index = index + 1
		ptr = i + 1
		
		i, j = dateStr:find("-", ptr)
		
		if i then
			-- month
			parts[index] = tonumber(dateStr:sub(ptr, i-1), 10)
			
			if precision == "m" then
				-- we're done
				return parts[1], parts[2], parts[3]  -- year, month, day
			end
			
			index = index + 1
			ptr = i + 1
		end
	end
	
	if dateStr:sub(ptr) ~= "" then
		-- day if we have month, month if we have year, or year
		parts[index] = tonumber(dateStr:sub(ptr), 10)
	end
	
	return parts[1], parts[2], parts[3]  -- year, month, day
end

function State:convertUnit(unit, link)
	link = link or false
	local itemID, label, title
	
	if unit == "" or unit == "1" then
		return nil
	end
	
	itemID = self:parseWikidataURL(unit)
	
	if itemID then
		if itemID == aliasesQ.percentage then
			return "%"
		else
			label = mw.wikibase.label(itemID)
			title = nil
			
			if link or label == nil then
				title = mw.wikibase.sitelink(itemID)
			end
			
			if link then
				if title then
					return " " .. "[[" .. title .. "|" .. (label or title) .. "]]"
				end
				
				if not label then
					return " " .. "[[d:" .. itemID .. "|" .. itemID .. "]]"
				end
			end
			
			return " " .. (label or title or itemID)
		end
	end
	
	return " " .. unit
end

function State:getShortName(itemID)
	return p._property({"single", itemID, aliasesP.shortName})
end

function State:getLabel(ID)
	return p._label({ID})
end

function State:getOrdinalSuffix(num)
	if tostring(num):sub(-2,-2) == '1' then
		return "th"  -- 10th, 11th, 12th, 13th, ... 19th
	end
	
	num = tostring(num):sub(-1)
	
	if num == '1' then
		return ""
	elseif num == '2' then
		return ""
	elseif num == '3' then
		return ""
	else
		return ""
	end
end

function State:addDecimalMarks(n)
	local left,num,right = string.match(n,'^([^%d]*%d)(%d*)(.-)$')
	return left..(num:reverse():gsub('(%d%d%d)','%1,'):reverse())..right
end

function State:getValue(snak, raw, link, anyLang)
	raw = raw or false
	link = link or false
	anyLang = anyLang or false
	
	if snak.snaktype == 'value' then
		if snak.datavalue.type == 'string' then
			return snak.datavalue.value
		elseif snak.datavalue.type == 'monolingualtext' then
			if anyLang then
				return snak.datavalue.value['text'], snak.datavalue.value['language']
			elseif snak.datavalue.value['language'] == self.langCode then
				return snak.datavalue.value['text']
			else
				return nil
			end
		elseif snak.datavalue.type == 'quantity' then
			-- strip + signs from front
			local value = mw.ustring.gsub(snak.datavalue.value['amount'], "^\+(.+)$", "%1")
			
			if not raw then
				value = self:addDecimalMarks(value)
				local unit = self:convertUnit(snak.datavalue.value['unit'], link)
				if unit then
					value = value .. unit
				end
			end
			
			return value
		elseif snak.datavalue.type == 'time' then
			local y, m, d, p, yDiv, yRound, yFull, value, calendarID, dateStr
			local yFactor = 1
			local sign = 1
			local suffix = ""
			local mayAddCalendar = false
			local calendar = ""
			local precision = snak.datavalue.value['precision']
			
			if precision == 11 then
				p = "d"
			elseif precision == 10 then
				p = "m"
			else
				p = "y"
				yFactor = 10^(9-precision)
			end
			
			y, m, d = self:parseDate(snak.datavalue.value['time'], p)
			
			if y < 0 then
				sign = -1
				y = y * sign
			end
			
			-- if precision is tens/hundreds/thousands/millions/billions of years
			if precision <= 8 then
				yDiv = y / yFactor
				
				-- if precision is tens/hundreds/thousands of years
				if precision >= 6 then
					mayAddCalendar = true
					
					if precision <= 7 then
						-- round centuries/millenniums up (e.g. 20th century or 3rd millennium)
						yRound = math.ceil(yDiv)
						
						if not raw then
							if precision == 6 then
								suffix = " millennium"
							else
								suffix = " century"
							end
							
							suffix = self:getOrdinalSuffix(yRound) .. suffix
						else
							-- if not verbose, take the first year of the century/millennium
							-- (e.g. 1901 for 20th century or 2001 for 3rd millennium)
							yRound = (yRound - 1) * yFactor + 1
						end
					else
						-- precision == 8
						-- round decades down (e.g. 2010s)
						yRound = math.floor(yDiv) * yFactor
						
						if not raw then
							suffix = "s"
						end
					end
					
					if raw and sign < 0 then
						-- if BCE then compensate for "counting backwards"
						-- (e.g. -2019 for 2010s BCE, -2000 for 20th century BCE or -3000 for 3rd millennium BCE)
						yRound = yRound + yFactor - 1
					end
				else
					local yReFactor, yReDiv, yReRound
					
					-- round to nearest for tens of thousands of years or more
					yRound = math.floor(yDiv + 0.5)
					
					if yRound == 0 then
						if precision <= 2 and y ~= 0 then
							yReFactor = 1e6
							yReDiv = y / yReFactor
							yReRound = math.floor(yReDiv + 0.5)
							
							if yReDiv == yReRound then
								-- change precision to millions of years only if we have a whole number of them
								precision = 3
								yFactor = yReFactor
								yRound = yReRound
							end
						end
						
						if yRound == 0 then
							-- otherwise, take the unrounded (original) number of years
							precision = 5
							yFactor = 1
							yRound = y
							mayAddCalendar = true
						end
					end
					
					if precision >= 1 and y ~= 0 then
						yFull = yRound * yFactor
						
						yReFactor = 1e9
						yReDiv = yFull / yReFactor
						yReRound = math.floor(yReDiv + 0.5)
						
						if yReDiv == yReRound then
							-- change precision to billions of years if we're in that range
							precision = 0
							yFactor = yReFactor
							yRound = yReRound
						else
							yReFactor = 1e6
							yReDiv = yFull / yReFactor
							yReRound = math.floor(yReDiv + 0.5)
							
							if yReDiv == yReRound then
								-- change precision to millions of years if we're in that range
								precision = 3
								yFactor = yReFactor
								yRound = yReRound
							end
						end
					end
					
					if addUnit then
						if precision == 3 then
							suffix = "百万年"
						elseif precision == 0 then
							suffix = "億年"
						else
							yRound = yRound * yFactor
							if yRound == 1 then
								suffix = "年"
							else
								suffix = "年"
							end
						end
					else
						yRound = yRound * yFactor
					end
				end
			else
				yRound = y
				mayAddCalendar = true
			end
			
			if mayAddCalendar then
				calendarID = self:parseWikidataURL(snak.datavalue.value['calendarmodel'])
				
				if calendarID and calendarID == aliasesQ.prolepticJulianCalendar then
					if addUnit then
						if addLink then
							calendar = " ([[ユリウス暦]])"
						else
							calendar = " (ユリウス暦)"
						end
					else
						calendar = "/ユリウス暦"
					end
				end
			end
			
			if not raw then
				local ce = nil
				
				if sign < 0 then
					ce = "BCE"
				elseif precision <= 5 then
					ce = "CE"
				end
				
				if ce then
					if link then
						ce = "[[:en:Common Era|" .. ce .. "]]"
					end
					suffix = suffix .. " " .. ce
				end
				
				value = tostring(yRound)
				
				if m then
					dateStr = self.langObj:formatDate("F", "1-"..m.."-1")
					
					if d then
						if self.mdyDate then
							dateStr = dateStr .. " " .. d .. ","
						else
							dateStr = d .. " " .. dateStr
						end
					end
					
					value = dateStr .. " " .. value
				end
				
				value = value .. suffix .. calendar
			else
				value = tostring(yRound * sign)
				
				if m then
					value = value .. "-" .. m
					
					if d then
						value = value .. "-" .. d
					end
				end
				
				value = value .. calendar
			end
			
			return value
		elseif snak.datavalue.type == 'globecoordinate' then
			local precision, numDigits, strFormat, value, globe
			local latValue, latitude, latDegrees, latMinutes, latSeconds
			local latDirection = "N"
			local lonValue, longitude, lonDegrees, lonMinutes, lonSeconds
			local lonDirection = "E"
			
			local degSymbol = "°"
			local minSymbol = "'"
			local secSymbol = '"'
			local partsGlue = ", "
			
			if raw then
				degSymbol = "/"
				minSymbol = "/"
				secSymbol = "/"
				partsGlue = "/"
			end
			
			latitude = snak.datavalue.value['latitude']
			longitude = snak.datavalue.value['longitude']
			
			if latitude < 0 then
				latDirection = "S"
				latitude = math.abs(latitude)
			end
			if longitude < 0 then
				lonDirection = "W"
				longitude = math.abs(longitude)
			end
			
			precision = snak.datavalue.value['precision']
			
			latitude = math.floor(latitude / precision + 0.5) * precision
			longitude = math.floor(longitude / precision + 0.5) * precision
			
			latDegrees = math.floor(latitude)
			lonDegrees = math.floor(longitude)
			
			latMinutes = math.floor((latitude - latDegrees) * 60)
			lonMinutes = math.floor((longitude - lonDegrees) * 60)
			
			latSeconds = (latitude - (latDegrees + latMinutes / 60)) * 3600
			lonSeconds = (longitude - (lonDegrees + lonMinutes / 60)) * 3600
			
			latValue = latDegrees .. degSymbol
			lonValue = lonDegrees .. degSymbol
			
			if precision < 1 then
				latValue = latValue .. latMinutes .. minSymbol
				lonValue = lonValue .. lonMinutes .. minSymbol
			end
			
			if precision < (1 / 60) then
				numDigits = math.ceil(-math.log10(3600 * precision))
				
				if numDigits < 0 or numDigits == -0 then
					numDigits = 0
				end
				
				strFormat = "%." .. numDigits .. "f"
				
				latSeconds = string.format(strFormat, latSeconds)
				lonSeconds = string.format(strFormat, lonSeconds)
				
				latValue = latValue .. latSeconds .. secSymbol
				lonValue = lonValue .. lonSeconds .. secSymbol
			end
			
			latValue = latValue .. latDirection
			lonValue = lonValue .. lonDirection
			
			value = latValue .. partsGlue .. lonValue
			
			if link then
				globe = self:parseWikidataURL(snak.datavalue.value['globe'])
				
				if globe then
					globe = mw.wikibase.label(globe):lower()
				else
					globe = "earth"
				end
				
				value = "[https://tools.wmflabs.org/geohack/geohack.php?language="..self.langCode.."&params="..latitude.."_"..latDirection.."_"..longitude.."_"..lonDirection.."_globe:"..globe.." "..value.."]"
			end
			
			return value
		elseif snak.datavalue.type == 'wikibase-entityid' then
			local value = ""
			local title = nil
			local itemID = "Q" .. snak.datavalue.value['numeric-id']
			
			if raw then
				if link then
					return "[[d:" .. itemID .. "|" .. itemID .. "]]"
				else
					return itemID
				end
			end
			
			if self.shortName then
				value = self:getShortName(itemID)
			end
			
			if value == "" then
				value = mw.wikibase.label(itemID)
			end
			
			if link or value == nil then
				title = mw.wikibase.sitelink(itemID)
			end
			
			if link then
				if title then
					value = "[[" .. title .. "|" .. (value or title) .. "]]"
				elseif not value then
					value = "[[d:" .. itemID .. "|" .. itemID .. "]]"
				end
			elseif not value then
				value = (title or itemID)
			end
			
			return value
		else
			return self:unknownDatatypeError(snak.datavalue.type)
		end
	elseif snak.snaktype == 'somevalue' then
		if raw then
			return " "  -- single space represents 'somevalue'
		else
			return "unknown"
		end
	elseif snak.snaktype == 'novalue' then
		if raw then
			return ""  -- empty value represents 'novalue'
		else
			return "none"
		end
	else
		return nil
	end
end

function State:getSingleRawQualifier(claim, qualifierID)
	local qualifiers
	
	if claim.qualifiers then qualifiers = claim.qualifiers[qualifierID] end
	
	if qualifiers and qualifiers[1] then
		return self:getValue(qualifiers[1], true)  -- raw = true
	else
		return nil
	end
end

function State:snakEqualsValue(snak, value)
	local snakValue = self:getValue(snak, true)  -- raw = true
	
	if snakValue and snak.snaktype == 'value' and snak.datavalue.type == 'wikibase-entityid' then value = value:upper() end
	
	return snakValue == value
end

function State:setRankBoundaries(rank)
	local rankPos
	
	if (rank == "best") then
		self.bestRank = true
		self.foundRank = 3
		return
	else
		self.bestRank = false
	end
	
	if (rank:sub(1,9) == "preferred") then
		rankPos = 1
	elseif (rank:sub(1,6) == "normal") then
		rankPos = 2
	elseif (rank:sub(1,10) == "deprecated") then
		rankPos = 3
	end
	
	if (rank:sub(-1) == "+") then
		self.maxRank = 1
		self.minRank = rankPos
	elseif (rank:sub(-1) == "-") then
		self.maxRank = rankPos
		self.minRank = 3
	else
		self.maxRank = rankPos
		self.minRank = rankPos
	end
end

function State:convertRank(rank)
	if (rank == "preferred") then
		return 1
	elseif (rank == "normal") then
		return 2
	elseif (rank == "deprecated") then
		return 3
	else
		return 4  -- default (in its literal sense)
	end
end

function State:rankMatches(rankPos)
	if self.bestRank then
		if self.foundRank > rankPos then
			self.foundRank = rankPos
			
			-- found a better rank, reset worse rank outputs
			if self.foundRank == 1 then
				self.outNormal = {}
				self.outDeprecated = {}
			elseif self.foundRank == 2 then
				self.outDeprecated = {}
			end
		end
		
		return self.foundRank >= rankPos  -- == would also work here
	else
		return (self.maxRank <= rankPos and rankPos <= self.minRank)
	end
end

function State:datePrecedesDate(aY, aM, aD, bY, bM, bD)
	if aY == nil or bY == nil then
		return nil
	end
	aM = aM or 1
	aD = aD or 1
	bM = bM or 1
	bD = bD or 1
	
	if aY < bY then
		return true
	end
	
	if aY > bY then
		return false
	end
	
	if aM < bM then
		return true
	end
	
	if aM > bM then
		return false
	end
	
	if aD < bD then
		return true
	end
	
	return false
end

function State:timeMatches(claim)
	local startTime = nil
	local startTimeY = nil
	local startTimeM = nil
	local startTimeD = nil
	local endTime = nil
	local endTimeY = nil
	local endTimeM = nil
	local endTimeD = nil
	
	if self.period == 0 then
		-- any time
		return true
	end
	
	local now = os.date('!*t')
	
	startTime = self:getSingleRawQualifier(claim, aliasesP.startTime)
	if startTime and startTime ~= "" and startTime ~= " " then
		startTimeY, startTimeM, startTimeD = self:parseDate(startTime)
	end
	
	endTime = self:getSingleRawQualifier(claim, aliasesP.endTime)
	if endTime and endTime ~= "" and endTime ~= " " then
		endTimeY, endTimeM, endTimeD = self:parseDate(endTime)
	elseif endTime == " " then
		-- end time is 'unknown', assume it is somewhere in the past;
		-- we can do this by taking the current date as a placeholder for the end time
		endTimeY = now['year']
		endTimeM = now['month']
		endTimeD = now['day']
	end
	
	if startTimeY ~= nil and endTimeY ~= nil and self:datePrecedesDate(endTimeY, endTimeM, endTimeD, startTimeY, startTimeM, startTimeD) then
		-- invalidate end time if it precedes start time
		endTimeY = nil
		endTimeM = nil
		endTimeD = nil
	end
	
	if self.period == 1 then
		-- future
		if startTimeY == nil or not self:datePrecedesDate(now['year'], now['month'], now['day'], startTimeY, startTimeM, startTimeD) then
			return false
		else
			return true
		end
	elseif self.period == 2 then
		-- current
		if (startTimeY ~= nil and self:datePrecedesDate(now['year'], now['month'], now['day'], startTimeY, startTimeM, startTimeD)) or
		   (endTimeY ~= nil and not self:datePrecedesDate(now['year'], now['month'], now['day'], endTimeY, endTimeM, endTimeD)) then
		    return false
		else
		   	return true
		end
	elseif self.period == 3 then
		-- former
		if endTimeY == nil or self:datePrecedesDate(now['year'], now['month'], now['day'], endTimeY, endTimeM, endTimeD) then
			return false
		else
			return true
		end
	end
end

function State:appendOutput(value, rankPos)
	local done = false
	
	if rankPos == 1 then
		self.outPreferred[#self.outPreferred + 1] = value
		
		if self.singleValue then
			done = true
		end
	elseif rankPos == 2 then
		self.outNormal[#self.outNormal + 1] = value
		
		if self.singleValue and not self.bestRank and self.maxRank == 2 then
			done = true
		end
	elseif rankPos == 3 then
		self.outDeprecated[#self.outDeprecated + 1] = value
		
		if self.singleValue and not self.bestRank and self.maxRank == 3 then
			done = true
		end
	end
	
	return done
end

function State:out()
	local out = ""
	
	if self.outDeprecated[1] then
		if self.singleValue then
			out = self.outDeprecated[1]
		else
			out = table.concat(self.outDeprecated, ", ")
		end
	end
	
	if self.outNormal[1] then
		if self.singleValue then
			out = self.outNormal[1]
		else
			if out ~= "" then
				out = "; " .. out
			end
			
			out = table.concat(self.outNormal, ", ") .. out
		end
	end
	
	if self.outPreferred[1] then
		if self.singleValue then
			out = self.outPreferred[1]
		else
			if out ~= "" then
				out = "; " .. out
			end
			
			out = table.concat(self.outPreferred, ", ") .. out
		end
	end
	
	return out
end

-- logic based on https://www.wikidata.org/wiki/Help:Sources
function State:getReferences(claim)
	local snaks, snakValue, lang, params, leadParams, property, ref
	local value = ""
	
	if not claim.references then
		return ""
	end
	
	for i, v in ipairs(claim.references) do
		if v.snaks then
			ref = ""
			snaks = {}
			params = {}
			leadParams = {}
			
			for i2, v2 in pairs(v.snaks) do
				if v2[1] then
					snaks[i2] = v2[1]
				end
			end
			
			if snaks[aliasesP.importedFrom] then
				snaks[aliasesP.importedFrom] = nil
			end
			
			if snaks[aliasesP.referenceURL] and snaks[aliasesP.title] then
				params["url"] = self:getValue(snaks[aliasesP.referenceURL])
				params["title"] = self:getValue(snaks[aliasesP.title], false, false, true)
				
				if snaks[aliasesP.publicationDate] then params["date"]         = self:getValue(snaks[aliasesP.publicationDate])           end
				if snaks[aliasesP.retrieved]       then params["access-date"]  = self:getValue(snaks[aliasesP.retrieved])                 end
				if snaks[aliasesP.archiveURL]      then params["archive-url"]  = self:getValue(snaks[aliasesP.archiveURL])                end
				if snaks[aliasesP.archiveDate]     then params["archive-date"] = self:getValue(snaks[aliasesP.archiveDate])               end
				if snaks[aliasesP.author]          then params["author"]       = self:getValue(snaks[aliasesP.author])                    end
				if snaks[aliasesP.publisher]       then params["publisher"]    = self:getValue(snaks[aliasesP.publisher])                 end
				if snaks[aliasesP.quote]           then params["quote"]        = self:getValue(snaks[aliasesP.quote], false, false, true) end
				
				if snaks[aliasesP.language] then
					snakValue = self:getValue(snaks[aliasesP.language])
					
					if self.langName ~= snakValue then
						params["language"] = snakValue
					end
				end
				
				ref = mw.getCurrentFrame():expandTemplate{title="cite_web", args=params}
			else
				for i2, v2 in pairs(snaks) do
					property = self:getLabel(i2)
					
					if property ~= "" then
						snakValue, lang = self:getValue(v2, false, (i2 == aliasesP.statedIn), true)
						
						if lang and lang ~= self.langCode then
							snakValue = "''" .. snakValue .. "'' (" .. mw.language.fetchLanguageName(lang, self.langCode) .. ")"
						end
						
						if i2 == aliasesP.referenceURL or i2 == aliasesP.statedIn then
							leadParams[#leadParams + 1] = snakValue
						elseif i2 ~= aliasesP.language or self.langName ~= snakValue then
							params[#params + 1] = property .. ": " .. snakValue
						end
					end
				end
				
				ref = table.concat(leadParams, "; ")
				params = table.concat(params, "; ")
				
				if params ~= "" then
					if ref ~= "" then
						ref = ref .. "; "
					end
					ref = ref .. params
				end
				
				if ref ~= "" then
					ref = ref .. "."
				end
			end
			
			if ref ~= "" then
				value = value .. mw.getCurrentFrame():extensionTag("ref", ref)
			end
		end
	end
	
	return value
end

function State:processFlag(flag)
	if flag == "linked" then
		self.linked = true
		return true
	elseif flag == "raw" then
		self.rawValue = true
		return true
	elseif flag == "short" then
		self.shortName = true
		return true
	elseif flag == "single" then
		self.singleValue = true
		return true
	elseif flag == "mdy" then
		self.mdyDate = true
		return true
	elseif flag == "refs" then
		self.withRefs = true
		return true
	elseif flag == "best" or flag:match('^preferred[+-]?$') or flag:match('^normal[+-]?$') or flag:match('^deprecated[+-]?$') then
		self:setRankBoundaries(flag)
		return true
	elseif flag == "future" then
		self.period = 1
		return true
	elseif flag == "current" then
		self.period = 2
		return true
	elseif flag == "former" then
		self.period = 3
		return true
	else
		return false
	end
end

function p.property(frame)
	return p._property(frame.args)
end

function p._property(args, _)
	_ = _ or State.new()
	
	local entity, propertyID, claims, rankPos, value, done
	local nextArg = mw.text.trim(args[1] or "")
	local nextIndex = 2
	
	while _:processFlag(nextArg) do
		nextArg = mw.text.trim(args[nextIndex] or "")
		nextIndex = nextIndex + 1
	end
	
	if nextArg:sub(1,1):upper() == "Q" then
		entity = mw.wikibase.getEntity(nextArg)
		propertyID = mw.text.trim(args[nextIndex] or "")
	else
		entity = mw.wikibase.getEntity()
		propertyID = nextArg
	end
	
	if aliasesP[propertyID] then
		propertyID = aliasesP[propertyID]
	end
	
	propertyID = propertyID:upper()
	
	if entity and entity.claims then claims = entity.claims[propertyID] end
	if claims then
		for i, v in ipairs(claims) do
			rankPos = _:convertRank(v.rank)
			if _:rankMatches(rankPos) and _:timeMatches(v) then
				value = _:getValue(v.mainsnak, _.rawValue, _.linked)
				if value then
					if _.withRefs then
						value = value .. _:getReferences(v)
					end
					done = _:appendOutput(value, rankPos)
					if done then
						break
					end
				end
			end
		end
		return _:out()
	else
		return ""
	end
end

function p.qualifier(frame)
	return p._qualifier(frame.args)
end

function p._qualifier(args, _)
	_ = _ or State.new()
	
	local entity, propertyID, propertyValue, qualifierID, claims, qualifiers, rankPos, outValue, outInter, outQualifiers
	local done = false
	
	local nextArg = mw.text.trim(args[1] or "")
	local nextIndex = 2
	
	while _:processFlag(nextArg) do
		nextArg = mw.text.trim(args[nextIndex] or "")
		nextIndex = nextIndex + 1
	end
	
	if nextArg:sub(1,1):upper() == "Q" then
		entity = mw.wikibase.getEntity(nextArg)
		propertyID = mw.text.trim(args[nextIndex] or "")
		nextIndex = nextIndex + 1
	else
		entity = mw.wikibase.getEntity()
		propertyID = nextArg
	end
	
	if aliasesP[propertyID] then
		propertyID = aliasesP[propertyID]
	end
	
	propertyID = propertyID:upper()
	
	nextArg = args[nextIndex]
	nextIndex = nextIndex + 1
	
	qualifierID = nextArg
	
	nextArg = mw.text.trim(args[nextIndex] or "")
	nextIndex = nextIndex + 1
	
	if nextArg == "" then
		-- claim ID or literal value has NOT been given
		propertyValue = nil
		qualifierID = mw.text.trim(qualifierID or "")
	else
		-- claim ID or literal value has been given
		propertyValue = qualifierID  -- cannot be nil when reached; empty value represents 'novalue'
		if propertyValue ~= "" and mw.text.trim(propertyValue) == "" then
			propertyValue = " "  -- single space represents 'somevalue'
		else
			propertyValue = mw.text.trim(propertyValue)
		end
		qualifierID = nextArg
	end
	
	if aliasesP[qualifierID] then
		qualifierID = aliasesP[qualifierID]
	end
	
	qualifierID = qualifierID:upper()
	
	if entity and entity.claims then claims = entity.claims[propertyID] end
	if claims then
		for i, v in ipairs(claims) do
			rankPos = _:convertRank(v.rank)
			if propertyValue == nil or _:snakEqualsValue(v.mainsnak, propertyValue) then
				if _:rankMatches(rankPos) and _:timeMatches(v) then
					outValue = nil
					outInter = nil
					outQualifiers = {}
					
					if _.propertyWithQualifier then
						-- get the property value first
						outValue = _:getValue(v.mainsnak, _.rawValue, _.linked)
						
						if outValue and _.withRefs then
							outValue = outValue .. _:getReferences(v)
						end
					end
					
					if v.qualifiers then qualifiers = v.qualifiers[qualifierID] end
					if (not _.propertyWithQualifier or outValue) and qualifiers then
						-- get a bare qualifier, or the qualifiers connected to the property if it had a value
						for i2, v2 in ipairs(qualifiers) do
							outInter = _:getValue(v2, _.rawValue, _.linked)
							if outInter then
								if not _.propertyWithQualifier then
									done = _:appendOutput(outInter, rankPos)
									if done then
										break
									end
								else
									outQualifiers[#outQualifiers + 1] = outInter
								end
							end
						end
					end
					
					if _.propertyWithQualifier and outValue then
						outQualifiers = table.concat(outQualifiers, ", ")
						
						if outQualifiers ~= "" then
							outQualifiers = " <span style=\"font-size:smaller\">(" .. outQualifiers .. ")</span>"
							outValue = outValue .. outQualifiers
						end
						
						done = _:appendOutput(outValue, rankPos)
					end
					
					if done then
						break
					end
				end
			end
		end
		return _:out()
	else
		return ""
	end
end

function p.propertyWithQualifier(frame)
	return p._propertyWithQualifier(frame.args)
end

function p._propertyWithQualifier(args, _)
	_ = _ or State.new()
	_.propertyWithQualifier = true
	return p._qualifier(args, _)
end

function p.label(frame)
	return p._label(frame.args)
end

function p._label(args, _)
	_ = _ or State.new()
	
	local ID
	local label = ""
	local title = nil
	
	local nextArg = mw.text.trim(args[1] or "")
	local nextIndex = 2
	
	while _:processFlag(nextArg) do
		nextArg = mw.text.trim(args[nextIndex] or "")
		nextIndex = nextIndex + 1
	end
	
	ID = nextArg
	
	if ID ~= "" then
		if aliasesP[ID] then
			ID = aliasesP[ID]
		end
		
		ID = ID:upper()
		
		-- check if this is a valid ID, and if the number is not larger than max int (to prevent error)
		if not string.match(ID, '^[QP]%d+$') or tonumber(string.match(ID, '%d+')) > 2147483647 then
			return ""
		end
		
		if _.rawValue then
			if mw.wikibase.getEntity(ID) or mw.wikibase.resolvePropertyId(ID) then
				if _.linked then
					if ID:sub(1,1) == "P" then
						label = "[[d:Property:" .. ID .. "|" .. ID .. "]]"
					else
						label = "[[d:" .. ID .. "|" .. ID .. "]]"
					end
				else
					label = ID
				end
			end
		else
			if ID:sub(1,1) == "P" then
				if not _.pageTitle then
					label = mw.wikibase.label(ID) or ""
					
					if _.linked and label ~= "" then
						label = "[[d:Property:" .. ID .. "|" .. label .. "]]"
					end
				end
			else
				if not _.pageTitle then
					if _.shortName then
						label = _:getShortName(ID)
					end
					
					-- at this point, 'label' will be a string and not nil
					
					if label == "" then
						label = mw.wikibase.label(ID)
					end
				else
					-- set 'label' to nil so 'title' will always prevail
					label = nil
				end
				
				-- at this point, 'label' will be nil or a non-empty string
				
				if _.linked or label == nil then
					title = mw.wikibase.sitelink(ID)
				end
				
				if _.linked and title then
					label = "[[" .. title .. "|" .. (label or title) .. "]]"
				else
					label = label or title or ""
				end
			end
		end
	else
		if _.rawValue then
			label = mw.wikibase.getEntityIdForCurrentPage() or ""
			
			if _.linked and label ~= "" then
				label = "[[d:" .. label .. "|" .. label .. "]]"
			end
		else
			if not _.pageTitle then
				label = mw.wikibase.label()
			else
				-- set 'label' to nil so 'title' will always prevail
				label = nil
			end
			
			if _.linked or label == nil then
				title = mw.title.getCurrentTitle().prefixedText
			end
			
			if _.linked then
				label = "[[" .. title .. "|" .. (label or title) .. "]]"  -- not much use since it links to the current page, but does add wiki mark-up
			else
				label = label or title
			end
		end
	end
	
	return label
end

function p.title(frame)
	return p._title(frame.args)
end

function p._title(args, _)
	_ = _ or State.new()
	_.pageTitle = true
	return p._label(args, _)
end

-- main function that may be used by wrapper templates
function p.main(frame)
	local f, args, i, v
	
	frame = frame:getParent() or frame
	f = mw.text.trim(frame.args[1] or "")
	assert(p[f], 'The function "' .. f .. '" does not exist')
	
    args = {}
    for i, v in ipairs(frame.args) do
    	if i > 1 then
        	args[i-1] = v
        end
    end
	frame.args = args
	
	return p[f](frame)
end

return p