Módulo:Wikidata

Xablón:Module rating This module is a modification of the original at Module:Sandbox/Tom Morris which was created 19 May 2013.

Methods

The module "Wikidata" contains the following methods, that allow the calling script to retrieve the value for any property from Wikidata by supplying the property ID as the first parameter:

• getValue: Returns wiki-linked values, if applicable. All other values will be output similar to {{#property:}}, except that if values with preferred rank exist, then only they are returned. Unlike formatStatements from ru:Модуль:Wikidata, getValue does not yet pick up any references (see en:Module talk:Wikidata#Why the references from Wikidata get dropped?).
• getRawValue: Returns non-linked property values and numbers with the thousand separator. It also returns the plain numeric value of a property which is a quantity. All other values will be output similar to {{#property:}}, including normal values, even if preferred values exist.
• getDateValue: Special method to return formatted dates. The default date format is [day month year]; an optional third parameter can be added for other date formats: for [month day, year], add "mdy"; for [month year], add "my"; for year only, add "y". A further optional parameter, which must be fourth, such as "BCE", may be added to override the default "BC" that is suffixed for dates BC.
• getImages: Returns all of the images of a particular property, e.g. image (P18), Gene Atlas Image (P692), etc. Parameters are | propertyID | value / FETCH_WIKIDATA / nil | separator (default=space) | size (default=220px). The returned text will be in the format [[File:Filename | size]] for each image with a selectable size and separator (which may be html). If a property is supplied that is not of type "commonsMedia", it will return empty text.
• getUnits This takes a propertyID which is a quantity as the first parameter, and returns the name of the units that the property is using on the current page. It returns empty if the property is not a quantity type or if the value is not set. The second parameter may be used to override fetching from Wikidata, if it is anything other than "FETCH_WIKIDATA".
• getUnitID This takes a propertyID which is a quantity as the first parameter, and returns the QID of the units that the property is using on the current page. It returns empty if the property is not a quantity type or if the value is not set. The second parameter may be used to override fetching from Wikidata, if it is anything other than "FETCH_WIKIDATA".

Wikidata qualifier values (if present) can be retrieved by the following methods:

• getQualifierValue: returns only wiki-linked values, if applicable.
• getRawQualifierValue: returns non-linked values
• getQualifierDateValue: returns formatted dates

If the property is not defined in Wikidata for the article that invokes this code, then an empty string ("") is returned.

Other methods:

• pageId: returns the Wikidata id (Q…) of the current page or nothing if the page is not connected to Wikidata
• getTAValue: gets the TA98 (Terminologia Anatomica first edition 1998) values for property P1323. It takes no parameters and constructs its output as a list, with each value linked to an external resource. This is an exemplar for writing calls that need to return external links.
• ViewSomething: gets anything in the structured data, including labels, descriptions, references and interwiki links. See [1]
• getSiteLink: gets name of a page in given in argument wiki (like enwikiquote for English Wikiquote).
• Dump: {{#invoke:Wikidata|Dump|claims}} spies the structured data. It uses the same arguments as ViewSomething. Try this with preview only to see results. That helps you a lot in developing Lua scripts that access the data. If used without arguments, it dumps everything including labels, descriptions, references and interwiki links. See [2]
• getImageLegend: returns an image legend (image is property P18; image legend is property P2096).

  Call as {{#invoke:Wikidata |getImageLegend | <PARAMETER> | lang=<ISO-639code> |id=<QID>}}

  Returns PARAMETER, unless it is equal to "FETCH_WIKIDATA", from Item QID (expensive call). If QID is omitted or blank, the current article is used (not an expensive call). If lang is omitted, it uses the local wiki language, otherwise it uses the provided ISO-639 language code.

  The label is returned from the first image with 'preferred' rank; or from the first image with 'normal' rank if no image has preferred rank.

• getValueShortName: returns the same data as getValue, but utilizes the property short name as the label, if available. This allows for piped links to use a shorter label where preferred. If short name is not set on the item, the normal label is used.

Arbitrary Access

As of 16 September 2015, it is now possible to fetch data from other articles by using their QID. The following call:

• {{#invoke:Wikidata|getValueFromID|<QID>|<Property>|FETCH_WIKIDATA}}

will do the same as getValue, but takes an extra parameter, which is the QID of the Wikidata item that you want to get the property value from. For example:

• {{#invoke:Wikidata|getValueFromID|Q151973|P26|FETCH_WIKIDATA}}

will fetch a list of the linked values for 'spouse' (P26) from 'Richard Burton' (Q151973) from anywhere in the English Wikipedia.

This means that testing environments may be set up in user space, but remember that these calls are classed as expensive, so please use them as sparingly as possible.

Parameters

• For the generalized case (getValue), two unnamed parameters are supplied. The first is the ID of the property that is to be retrieved (e.g. P19 for birthplace or P26 for spouse). The second may be null, "FETCH_WIKIDATA", or any other string, which becomes the returned value.
• For the generalized unlinked case (getRawValue), two unnamed parameters are supplied. The first is the ID of the property that is to be retrieved (e.g. P21 for gender). The second may be null, "FETCH_WIKIDATA", or any other string, which becomes the returned value.
• For the generalized date case (getDateValue), three unnamed parameters are supplied. The first is the ID of the property that is to be retrieved (e.g. P569 for date of birth). The second may be null, "FETCH_WIKIDATA", or any other string, which becomes the returned value. The third is the format that the date should be returned in, either dmy, mdy, my, or y.

Please note that lower-case parameters are no longer supported by the wikibase call: p123, so please check that upper-case, like P123, is used if problems should arise.

Usage

Example: spouse (P26)

• {{#invoke:Wikidata|getValue|P26|}} = returns nothing, so suppresses the display of spouse in an infobox
• {{#invoke:Wikidata|getValue|P26|FETCH_WIKIDATA}} = returns the linked value(s) of property P26 (spouse) stored in wikidata for the corresponding article (e.g. for article Bill Clinton, it returns Hillary Clinton)
• {{#invoke:Wikidata|getValue|P26|[[Hillary Rodham Clinton]]}} = returns Hillary Rodham Clinton, allowing an infobox to use a local value rather than the value stored in Wikidata.

Example in Infobox template

Inside an infobox definition, it may be called like this:

• | data55 = {{#invoke:Wikidata|getValue|P26|{{{spouse|FETCH_WIKIDATA}}} }}

which causes the infobox to:

1. not display spouse if the infobox parameter |spouse is set to be blank (as "| spouse ="}
2. display the linked value(s) from Wikidata if the infobox parameter |spouse is not supplied
3. display the local infobox parameter |spouse if it is supplied (e.g. "|spouse = Hillary Rodham Clinton")

Optionally, it could be called as:

• | data55 = {{#invoke:Wikidata|getValue|P26|{{{spouse|}}} }}

which causes the infobox to:

1. not display spouse if the infobox parameter |spouse is set to be blank (as "| spouse ="}
2. not display spouse if the infobox parameter |spouse is not supplied
3. display the local infobox parameter |spouse if it is supplied (e.g. "|spouse = Hillary Rodham Clinton")
4. display the linked value(s) from Wikidata if the infobox parameter is locally set to FETCH_WIKIDATA

See Module:WikidataIB for a modification that allows fields, on a per article basis, to be blacklisted so that they never display. It also allows the editor to specify, on a per article basis, which fields may be automatically fetched from Wikidata when local parameter is supplied; the default is none, allowing an infobox to be modified to accept Wikidata without any change in the articles using the infobox until the functionality is enabled in the article.

Example:birth place

This works in just the same way as the calls above:

• {{#invoke:Wikidata|getValue|P19|}} = returns nothing, so suppresses the display of birth place in an infobox
• {{#invoke:Wikidata|getValue|P19|FETCH_WIKIDATA}} = returns the linked value(s) of property P19 (place of birth) stored in wikidata for the corresponding article (e.g. for article Bill Clinton, it returns Hope, Arkansas)
• {{#invoke:Wikidata|getValue|P19|[[Hope, Arkansas|Hope]]}} = returns Hope, allowing an infobox to use a local value rather than the value stored in Wikidata.

Example:gender

We don't want the returned value linked, so use:

• - {{#invoke:Wikidata|getRawValue|P21|FETCH_WIKIDATA}}

Example:date of birth

If we want the date of birth in dmy format, we use:

• - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|dmy}}

If we want the date of birth in mdy format, we use:

• - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|mdy}}

If we want a year of birth, we use:

• - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|y}}

If we want a year of birth that may be BC, but should read "BCE", we use:

• - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|y|BCE}}

Example: Linking to Wikidata item

Use the following code to just retrieve the Q-ID:

• - {{#invoke:Wikidata|pageId}}

Linking to Wikidata used the usual Wiki markup:

• - [[d:{{#invoke:Wikidata|pageId}}|Name of Link]]

Example: Linking to another wiki page

Use code like this to link to another wiki. English Wikivoyage in the example:

• - [[voy:{{#invoke:Wikidata|getSiteLink|enwikivoyage}}|Name of Link]]

Testing

Testing spouse

Copy and paste the following into any article and preview it (please don't save!):

* - {{#invoke:Wikidata|getValue|P26|}}
* - {{#invoke:Wikidata|getValue|P26|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getValue|P26|[[Hillary Rodham Clinton]]}}

In Bill Clinton you should get:

• -
• - Hillary Clinton
• - Hillary Rodham Clinton

In Barack Obama you should get:

• -
• - Michelle Obama
• - Hillary Rodham Clinton

In Richard Burton you should get:

• -
• - Elizabeth Taylor, Sally Burton, Sybil Christopher, Suzy Miller, Elizabeth Taylor
• - Hillary Rodham Clinton

In Franz Kafka you should get:

• -
• -
• - Hillary Rodham Clinton

Testing birthplace

Copy and paste the following into any article and preview it (please don't save!):

* - {{#invoke:Wikidata|getValue|P19|}}
* - {{#invoke:Wikidata|getValue|P19|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getValue|P19|[[Newport]]}}

Try William Ellery and check that the Wikidata call correctly disambiguates.

Testing getValue, getRawValue and getDateValue

Copy and paste the following into any article and preview it (please don't save!):

* - {{#invoke:Wikidata|getValue|P19|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getValue|P26|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getValue|P27|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getValue|P140|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getRawValue|P21|FETCH_WIKIDATA}}
* - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|dmy}}
* - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|mdy}}
* - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|y}}

This should return the Wikidata values for birthplace, spouse, citizenship, religion, gender, date of birth (twice) and year of birth, if they exist. The dob is first in dmy format and then in mdy.

Testing dates BC/BCE

Copy and paste the following into a short section of article such as Horace #See also and preview it (please don't save!):

* - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|y}}
* - {{#invoke:Wikidata|getDateValue|P569|FETCH_WIKIDATA|y|BCE}}

This should return 65 BC and 65 BCE, respectively.

See also

• Module:WikidataIB, for handling Wikidata in infoboxes

---

-- module local variables
local wiki = 
{
	langcode = mw.language.getContentLanguage().code
}

-- internationalisation
local i18n = {
    ["errors"] = {
        ["property-not-found"] = "המאפיין לא נמצא.",
        ["entity-not-found"] = "היישות לא נמצאה",
        ["unknown-claim-type"] = "מאפיין לא מוכר",
        ["unknown-snak-type"] = "Unbekannter Snak-Typ.",
        ["unknown-datavalue-type"] = "סוג נתון לא ידוע",
        ["unknown-entity-type"] = "סוג יישות לא ידוע",
        ["qualifier-not-found"] = "המבחין לא נמצא.",
        ["site-not-found"] = "האתר לא נמצא.",
    },
    ["somevalue"] = "Unbekannter Wert",
    ["novalue"] = "Kein Wert",
    ["datetime"] =
	{
		-- $1 is a placeholder for the actual number
		[0] = "$1 מיליארד שנים",		-- precision: billion years
		[1] = "$100 מיליון שנים",	-- precision: hundred million years
		[2] = "$10 מיליון שנים",	-- precision: ten million years
		[3] = "$1 מיליון שנים",		-- precision: million years
		[4] = "$100,000 שנים",	-- precision: hundred thousand years
		[5] = "$10,000 שנים",		-- precision: ten thousand years
		[6] = "המילוניום ה-$1", 	-- precision: millenium
		[7] = "המאה ה-$1",	-- precision: century
		[8] = "$1er",				-- precision: decade
		-- the following use the format of #time parser function
		[9]  = "Y",					-- precision: year, 
		[10] = "F Y",				-- precision: month
		[11] = "j xg Y",			-- precision: day
		[12] = 'j xg Y, G "Uhr"',	-- precision: hour
		[13] = "j xg Y G:i",		-- precision: minute
		[14] = "j xg Y G:i:s",		-- precision: second
		["beforenow"] = "vor $1",	-- how to format negative numbers for precisions 0 to 5
		["afternow"] = "in $1",		-- how to format positive numbers for precisions 0 to 5
		["bc"] = '$1 לפנה"ס',		-- how print negative years
		["ad"] = "$1"				-- how print positive years
	},
	["monolingualtext"] = '<span lang="%language">%text</span>'
}

local p = { }

local function printError(code)
	return '<span class="error">' .. i18n.errors[code] .. '</span>[[קטגוריה:שגיאת קריאת ויקינתונים]]'
end

-- the "qualifiers" and "snaks" field have a respective "qualifiers-order" and "snaks-order" field
-- use these as the second parameter and this function instead of the built-in "pairs" function
-- to iterate over all qualifiers and snaks in the intended order.
local function orderedpairs(array, order)
	if not order then return pairs(array) end
	
	-- return iterator function
    local i = 0
    return function()
        i = i + 1
        if order[i] then
            return order[i], array[order[i]]
        end
    end	
end

function p.descriptionIn(frame)
	local langcode = frame.args[1]
	local id = frame.args[2]	-- "id" must be nil, as access to other Wikidata objects is disabled in Mediawiki configuration
	-- return description of a Wikidata entity in the given language or the default language of this Wikipedia site
	return mw.wikibase.getEntityObject(id).descriptions[langcode or wiki.langcode].value
end

function p.labelIn(frame)
	local langcode = frame.args[1]
	local id = frame.args[2]	-- "id" must be nil, as access to other Wikidata objects is disabled in Mediawiki configuration
	-- return label of a Wikidata entity in the given language or the default language of this Wikipedia site
	return mw.wikibase.getEntityObject(id).labels[langcode or wiki.langcode].value
end

local function printDatavalueCoordinate(data, parameter)
	-- data fields: latitude [double], longitude [double], altitude [double], precision [double], globe [wikidata URI, usually http://www.wikidata.org/entity/Q2 [earth]]
	if parameter then
		if parameter == "globe" then data.globe = mw.ustring.match(data.globe, "Q%d+") end -- extract entity id from the globe URI
		return data[parameter]
	else
		return data.latitude .. "/" .. data.longitude -- combine latitude and longitude, which can be decomposed using the #titleparts wiki function
	end
end

local function printDatavalueQuantity(data, parameter)
	-- data fields: amount [number], unit [string], upperBound [number], lowerBound [number]
	if parameter then
		return data[paramater]
	else
		return tonumber(data.amount)
	end
end

-- precision: 0 - billion years, 1 - hundred million years, ..., 6 - millenia, 7 - century, 8 - decade, 9 - year, 10 - month, 11 - day, 12 - hour, 13 - minute, 14 - second
local function normalizeDate(date)
	date = mw.text.trim(date, "+")
	-- extract year
	local yearstr = mw.ustring.match(date, "^\-?%d+")
	local year = tonumber(yearstr)
	-- remove leading zeros of year
	return year .. mw.ustring.sub(date, #yearstr + 1), year
end

function formatDate(date, precision, timezone)
	precision = precision or 11
	date, year = normalizeDate(date)
	if year == 0 and precision <= 9 then return "" end
 
 	-- precision is 10000 years or more
	if precision <= 5 then
		local factor = 10 ^ ((5 - precision) + 4)
		local y2 = math.ceil(math.abs(year) / factor)
		local relative = mw.ustring.gsub(i18n.datetime[precision], "$1", tostring(y2))
		if year < 0 then
			relative = mw.ustring.gsub(i18n.datetime.beforenow, "$1", relative)
		else
			relative = mw.ustring.gsub(i18n.datetime.afternow, "$1", relative)
		end			
		return relative
	end
 
 	-- precision is decades, centuries and millenia
	local era
	if precision == 6 then era = mw.ustring.gsub(i18n.datetime[6], "$1", tostring(math.floor((math.abs(year) - 1) / 1000) + 1)) end
	if precision == 7 then era = mw.ustring.gsub(i18n.datetime[7], "$1", tostring(math.floor((math.abs(year) - 1) / 100) + 1)) end
	if precision == 8 then era = mw.ustring.gsub(i18n.datetime[8], "$1", tostring(math.floor(math.abs(year) / 10) * 10)) end
	if era then
		if year < 0 then era = mw.ustring.gsub(mw.ustring.gsub(i18n.datetime.bc, '"', ""), "$1", era)
		elseif year > 0 then era = mw.ustring.gsub(mw.ustring.gsub(i18n.datetime.ad, '"', ""), "$1", era) end
		return era
	end
	
	-- precision is year
	if precision == 9 then
		return year
	end	
	
	-- precision is less than years
	if precision >= 9 then
		--[[ the following code replaces the UTC suffix with the given negated timezone to convert the global time to the given local time
		timezone = tonumber(timezone)
		if timezone and timezone ~= 0 then
			timezone = -timezone
			timezone = string.format("%.2d%.2d", timezone / 60, timezone % 60)
			if timezone[1] ~= '-' then timezone = "+" .. timezone end
			date = mw.text.trim(date, "Z") .. " " .. timezone
		end
		]]--
		
		local formatstr = i18n.datetime[precision]
		if year == 0 then formatstr = mw.ustring.gsub(formatstr, i18n.datetime[9], "")
		elseif year < 0 then
			-- Mediawiki formatDate doesn't support negative years
			date = mw.ustring.sub(date, 2)
			formatstr = mw.ustring.gsub(formatstr, i18n.datetime[9], mw.ustring.gsub(i18n.datetime.bc, "$1", i18n.datetime[9]))
		elseif year > 0 and i18n.datetime.ad ~= "$1" then
			formatstr = mw.ustring.gsub(formatstr, i18n.datetime[9], mw.ustring.gsub(i18n.datetime.ad, "$1", i18n.datetime[9]))
		end
		return mw.language.new(wiki.langcode):formatDate(formatstr, date)
	end
end

-- This is used to get a value, or a comma separated list of them if multiple values exist
-- from an arbitrary entry by using its QID.
-- Use : {{#invoke:Wikidata|getValueFromID|<ID>|<Property>|FETCH_WIKIDATA}}
-- E.g.: {{#invoke:Wikidata|getValueFromID|Q151973|P26|FETCH_WIKIDATA}} - to fetch value of 'spouse' (P26) from 'Richard Burton' (Q151973)
-- Please use sparingly - this is an *expensive call*.
p.getValueFromID = function(frame)
	local itemID = mw.text.trim(frame.args[1] or "")
	local propertyID = mw.text.trim(frame.args[2] or "")
	local input_parm = mw.text.trim(frame.args[3] or "")
	if input_parm == "FETCH_WIKIDATA" then
		local entity = mw.wikibase.getEntity(itemID)
		local claims
		if entity and entity.claims then
			claims = entity.claims[propertyID]
		end
		if claims then
			-- if wiki-linked value output as link if possible
			if (claims[1] and claims[1].mainsnak.snaktype == "value" and claims[1].mainsnak.datavalue.type == "wikibase-entityid") then
				local out = {}
				for k, v in pairs(claims) do
					local sitelink = mw.wikibase.sitelink("Q" .. v.mainsnak.datavalue.value["numeric-id"])
					local label = mw.wikibase.label("Q" .. v.mainsnak.datavalue.value["numeric-id"])
					if label == nil then label = "Q" .. v.mainsnak.datavalue.value["numeric-id"] end

					if sitelink then
						out[#out + 1] = "[[" .. sitelink .. "|" .. label .. "]]"
					else
						out[#out + 1] = "[[:d:Q" .. v.mainsnak.datavalue.value["numeric-id"] .. "|" .. label .. "]]<abbr title='" .. i18n["errors"]["local-article-not-found"] .. "'>[*]</abbr>"
					end
				end
				return table.concat(out, ", ")
			else
				return entity:formatPropertyValues(propertyID).value
			end
		else
			return ""
		end
	else
		return input_parm
	end
end

local function printDatavalueTime(data, parameter)
	-- data fields: time [ISO 8601 time], timezone [int in minutes], before [int], after [int], precision [int], calendarmodel [wikidata URI]
	--   precision: 0 - billion years, 1 - hundred million years, ..., 6 - millenia, 7 - century, 8 - decade, 9 - year, 10 - month, 11 - day, 12 - hour, 13 - minute, 14 - second
	--   calendarmodel: e.g. http://www.wikidata.org/entity/Q1985727 for the proleptic Gregorian calendar or http://www.wikidata.org/wiki/Q11184 for the Julian calendar]
	if parameter then
		if parameter == "calendarmodel" then data.calendarmodel = mw.ustring.match(data.calendarmodel, "Q%d+") -- extract entity id from the calendar model URI
		elseif parameter == "time" then data.time = normalizeDate(data.time) end
		return data[parameter]
	else
		return formatDate(data.time, data.precision, data.timezone)
	end
end

local function printDatavalueEntity(data, parameter)
	-- data fields: entity-type [string], numeric-id [int, Wikidata id]
	local id = "Q" .. data["numeric-id"]
	if parameter then
		if parameter == "link" then
			return "[[" .. (mw.wikibase.sitelink(id) or (":d:" .. id))  .. "|" ..  (mw.wikibase.label(id) or id)  .. "]]"
		else
			return data[parameter]
		end
	else
		if data["entity-type"] == "item" then return mw.wikibase.label("Q" .. data["numeric-id"]) or mw.ustring.format('%s%s', id, '[[קטגוריה:ויקינתונים:ערכים_חסרי_תווית_בעברית]]') else printError("unknown-entity-type") end
	end
end

local function printDatavalueMonolingualText(data, parameter)
	-- data fields: language [string], text [string]
	if parameter then
		return data[parameter]
	else
		return mw.ustring.gsub(mw.ustring.gsub(i18n.monolingualtext, "%%language", data["language"]), "%%text", data["text"])
	end
end

function findClaims(entity, property)
	if not property or not entity or not entity.claims then return end
	
	if mw.ustring.match(property, "^P%d+$") then
		-- if the property is given by an id (P..) access the claim list by this id
		return entity.claims[property]
	else
		property = mw.wikibase.resolvePropertyId(property)
		if not property then return end

		return entity.claims[property]
	end
end

function getSnakValue(snak, parameter)
	-- snaks have three types: "novalue" for null/nil, "somevalue" for not null/not nil, or "value" for actual data
	if snak.snaktype == "novalue" then return i18n["novalue"]
	elseif snak.snaktype == "somevalue" then return i18n["somevalue"]
	elseif snak.snaktype ~= "value" then return nil, printError("unknown-snak-type")
	end
		
	-- call the respective snak parser
	if snak.datavalue.type == "string" then return snak.datavalue.value
	elseif snak.datavalue.type == "globecoordinate" then return printDatavalueCoordinate(snak.datavalue.value, parameter)
	elseif snak.datavalue.type == "quantity" then return printDatavalueQuantity(snak.datavalue.value, parameter)
	elseif snak.datavalue.type == "time" then return printDatavalueTime(snak.datavalue.value, parameter)
	elseif snak.datavalue.type == "wikibase-entityid" then return printDatavalueEntity(snak.datavalue.value, parameter)
	elseif snak.datavalue.type == "monolingualtext" then return printDatavalueMonolingualText(snak.datavalue.value, parameter)
	else return nil, printError("unknown-datavalue-type")
	end
end

function getQualifierSnak(claim, qualifierId)
	-- a "snak" is Wikidata terminology for a typed key/value pair
	-- a claim consists of a main snak holding the main information of this claim,
	-- as well as a list of attribute snaks and a list of references snaks
	if qualifierId then
		-- search the attribute snak with the given qualifier as key
		if claim.qualifiers then
			local qualifier = claim.qualifiers[qualifierId]
			if qualifier then return qualifier[1] end
		end
		return nil, printError("qualifier-not-found")
	else
		-- otherwise return the main snak
		return claim.mainsnak
	end
end

function getValueOfClaim(claim, qualifierId, parameter)
	local error
	local snak
	snak, error = getQualifierSnak(claim, qualifierId)
	if snak then

		return getSnakValue(snak, parameter)
	else
		return nil, error
	end
end

function getReferences(frame, claim)
	local result = ""
	-- traverse through all references
	for ref in pairs(claim.references or {}) do
		local refparts
		-- traverse through all parts of the current reference
		for snakkey, snakval in orderedpairs(claim.references[ref].snaks or {}, claim.references[ref]["snaks-order"]) do
			if refparts then refparts = refparts .. ", " else refparts = "" end
			-- output the label of the property of the reference part, e.g. "imported from" for P143
			refparts = refparts .. tostring(mw.wikibase.label(snakkey)) .. ": " 
			-- output all values of this reference part, e.g. "German Wikipedia" and "English Wikipedia" if the referenced claim was imported from both sites
			for snakidx = 1, #snakval do
				if snakidx > 1 then refparts = refparts .. ", " end
				refparts = refparts .. getSnakValue(snakval[snakidx])
			end
		end
		if refparts then result = result .. frame:extensionTag("ref", refparts) end
	end
	return result
end

function p.claim(frame)
	local property = frame.args[1] or ""
	local id = frame.args["id"]	-- "id" must be nil, as access to other Wikidata objects is disabled in Mediawiki configuration
	local qualifierId = frame.args["qualifier"]
	local parameter = frame.args["parameter"]
	local list = frame.args["list"]
	local references = frame.args["references"]
	local showerrors = frame.args["showerrors"]
	local default = frame.args["default"]
	if default then showerrors = nil end

	-- get wikidata entity
	local entity = mw.wikibase.getEntityObject(id)
	if not entity then
		if showerrors then return printError("entity-not-found") else return default end
	end
	-- fetch the first claim of satisfying the given property
	local claims = findClaims(entity, property)
	if not claims or not claims[1] then
		if showerrors then return printError("property-not-found") else return default end
	end
		
	-- get initial sort indices
	local sortindices = {}
	for idx in pairs(claims) do
		sortindices[#sortindices + 1] = idx
	end
	-- sort by claim rank
	local comparator = function(a, b)
		local rankmap = { deprecated = 2, normal = 1, preferred = 0 }
		local ranka = rankmap[claims[a].rank or "normal"] ..  string.format("%08d", a)
		local rankb = rankmap[claims[b].rank or "normal"] ..  string.format("%08d", b)
		return ranka < rankb
 	end
	table.sort(sortindices, comparator)

	local result
	local error
	if list then
		local value
		-- iterate over all elements and return their value (if existing)
		result = {}
		for idx in pairs(claims) do
			local claim = claims[sortindices[idx]]
			value, error =  getValueOfClaim(claim, qualifierId, parameter)
			if not value and showerrors then value = error end
			if value and references then value = value .. getReferences(frame, claim) end
			result[#result + 1] = value
		end
		result = table.concat(result, list)
	else
		-- return first element	
		local claim = claims[sortindices[1]]
		result, error = getValueOfClaim(claim, qualifierId, parameter)
		if result and references then result = result .. getReferences(frame, claim) end
	end
	
	if result then return result else
		if showerrors then return error else return default end
	end
end

function p.getValue(frame)
	local param = frame.args[2]
	if param == "FETCH_WIKIDATA" then return p.claim(frame) else return param end
end

-- This is used to get a value like 'male' (for property p21) which won't be linked and numbers without the thousand separators
p.getRawValue = function(frame)
	local propertyID = mw.text.trim(frame.args[1] or "")
	local input_parm = mw.text.trim(frame.args[2] or "")
	local qid = frame.args.qid
	if qid and (#qid == 0) then qid = nil end
	if input_parm == "FETCH_WIKIDATA" then
		local entity = mw.wikibase.getEntityObject(qid)
		local claims
		if entity and entity.claims then claims = entity.claims[propertyID] end
		if claims then
			local result = entity:formatPropertyValues(propertyID, mw.wikibase.entity.claimRanks).value

			-- if number type: remove thousand separators, bounds and units
			if (claims[1] and claims[1].mainsnak.snaktype == "value" and claims[1].mainsnak.datavalue.type == "quantity") then
				result = mw.ustring.gsub(result, "(%d),(%d)", "%1%2")
				result = mw.ustring.gsub(result, "(%d)±.*", "%1")
			end
			return result
		else
			return ""
		end
	else
		return input_parm
	end
end

function p.pageId(frame)
	local entity = mw.wikibase.getEntityObject()
	if not entity then return nil else return entity.id end
end

function p.labelOf(frame)
	local id = frame.args[1]
	-- returns the label of the given entity/property id
	-- if no id is given, the one from the entity associated with the calling Wikipedia article is used
	if not id then
		local entity = mw.wikibase.getEntityObject()
		if not entity then return printError("entity-not-found") end
		id = entity.id
	end
	return mw.wikibase.label(id)
end

function p.sitelinkOf(frame)
	local id = frame.args[1]
	-- returns the Wikipedia article name of the given entity
	-- if no id is given, the one from the entity associated with the calling Wikipedia article is used
	if not id then
		local entity = mw.wikibase.getEntityObject()
		if not entity then return printError("entity-not-found") end
		id = entity.id
	end
	return mw.wikibase.sitelink(id)
end

function p.badges(frame)
	local site = frame.args[1]
	local id = frame.args[2]	-- "id" must be nil, as access to other Wikidata objects is disabled in Mediawiki configuration
	if not site then return printError("site-not-found") end
	local entity = mw.wikibase.getEntityObject(id)
	if not entity then return printError("entity-not-found") end
	local badges = entity.sitelinks[site].badges
	if badges then
		local result
		for idx = 1, #badges do
			if result then result = result .. "/" .. badges[idx] else result = badges[idx] end
		end
		return result
	end
end

-- call this in cases of script errors within a function instead of {{#invoke:Wikidata|<method>|...}} call {{#invoke:Wikidata|debug|<method>|...}}
function p.debug(frame)
	local func = frame.args[1]
	if func then
		-- create new parameter set, where the first parameter with the function name is removed
		local newargs = {}
		for key, val in pairs(frame.args) do
			if type(key) == "number" then
				if key > 1 then newargs[key - 1] = val end
			else
				newargs[key] = val
			end
		end
		frame.args = newargs
		local status, result = pcall(p[func], frame)
		if status then return result else return '<span class="error">' .. result .. '</span>' end
	else
		return '<span class="error">invalid parameters</span>'
	end
end

function printTable(data, level)
	level = tonumber(level) or 0
	local result = ""
	local prefix = ""
	for idx = 1, level do prefix = prefix .. "　" end
	
	if type(data) == "table" then
		for key, val in pairs(data) do
			result = result .. prefix .. key .. ": "
			if type(val) == "table" then result = result .. "\n" .. printTable(val, level + 1) else result = result .. tostring(val) .. "\n" end
		end
	else
		result = prefix .. tostring(data)
	end
	if level == 0 then result = "<pre>" .. mw.text.encode(result) .. "</pre>" end
	return result
end

-- look into entity object
function p.ViewSomething(frame)
	local data = mw.wikibase.getEntityObject()
	if not data then
		return nil
	end

	local f = frame.args[1] and frame or frame:getParent()

	local i = 1
	while true do
		local index = f.args[i]
		if not index then
			if type(data) == "table" then
				return mw.text.jsonEncode(data, mw.text.JSON_PRESERVE_KEYS + mw.text.JSON_PRETTY)
			else
				return tostring(data)
			end
		end
		
		data = data[index] or data[tonumber(index)]
		if not data then
			return
		end
		
		i = i + 1
	end
end

function p.printEntity(frame)
	local id = frame.args[1] -- "id" must be nil, as access to other Wikidata objects is disabled in Mediawiki configuration
	local entity = mw.wikibase.getEntityObject(id)
	return printTable(entity)
end

local function computeLinkToItem(entityId, capitalize, callFunction)
	local sitelink = mw.wikibase.sitelink(StringUtils._prependIfMissing({tostring(entityId), 'Q'}))
	local label = nil
	local object = mw.wikibase.getEntityObject(StringUtils._prependIfMissing({tostring(entityId), 'Q'}))
	if callFunction and type(callFunction) == 'function' then
		label = callFunction(object)
	end
	if label == nil then label = mw.wikibase.label(StringUtils._prependIfMissing({tostring(entityId), 'Q'})) end
	if label == nil and object ~= nil then label = object:getLabel('en') end
	if label == nil then label = StringUtils._prependIfMissing({tostring(entityId), 'Q'}) end

	if capitalize then
		label = lang:ucfirst(label)
	end
	if sitelink then
		return "[[:" .. sitelink .. "|" .. label .. "]]"
	else
		return "[[:d:" .. StringUtils._prependIfMissing({tostring(entityId), 'Q'}) .. "|" .. label .. "]]<abbr title='הערך אינו קיים בויקי זה'>[*]</abbr>"
	end
end

p.findLinkToItem = function(entityId, capitalize, feminine, shortestAlias)
	if capitalize == nil then capitalize = false end
	local callFunction = nil
	if shortestAlias then
		callFunction = function(object)
			local returnedAlias = nil
			if object then
				if object.claims and object.claims['P1813'] then
					local shortNameEn = nil
					for shortNameIdx,shortNameClaim in pairs(object.claims['P1813']) do
						if shortNameClaim.mainsnak.datavalue.value.language == 'en' then shortNameEn = shortNameClaim.mainsnak.datavalue.value.text end
						if shortNameClaim.mainsnak.datavalue.value.language == 'ro' then returnedAlias = shortNameClaim.mainsnak.datavalue.value.text end
					end
					returnedAlias = returnedAlias or shortNameEn
				end
			end
			return returnedAlias
		end
	end
	if feminine then
		callFunction = function(object)
			if object then
				local feminineForms = object:getBestStatements('P2521')
				if feminineForms then
					for _idx, eachFForm in pairs(feminineForms) do
						if eachFForm.type == 'statement' and eachFForm.mainsnak.datatype == 'monolingualtext' and eachFForm.mainsnak.datavalue.type == 'monolingualtext' and eachFForm.mainsnak.datavalue.value and eachFForm.mainsnak.datavalue.value.language == 'he' then
							return eachFForm.mainsnak.datavalue.value.text
						end
					end
				end
			end
		end
	end
	return computeLinkToItem(entityId, capitalize, callFunction)
end
p.getValueOfClaim = getValueOfClaim
return p