Module:LangSwitcher

Documentation for this module may be created at Module:LangSwitcher/doc

local p = {}

local function trim(s) return (s or ""):gsub("^%s+",""):gsub("%s+$","") end

local function getTitleParts(link)
    local title = mw.title.getCurrentTitle()

    if link then
        local link = trim(link) or ""
        if link ~= "" then
            local name, code = link:match("^(.*)/([A-Za-z%-][A-Za-z%-][A-Za-z%-]*)$")
            if name and code then
                return name, code:lower(), title
            end
        end
    end

    if title.subpageText ~= title.text then
        local last = title.subpageText
        local code = last:match("^([A-Za-z%-][A-Za-z%-][A-Za-z%-]*)$")
        if code then
            local baseTitle = mw.title.new(title.baseText, title.namespace)
            if baseTitle then
                return baseTitle.fullText, code:lower(), title
            end
        end
    end
    local full = title.fullText
    local base, code = full:match("^(.*)/([A-Za-z%-][A-Za-z%-][A-Za-z%-]*)$")
    if base and code then
        local baseTitle = mw.title.new(base, title.namespace)
        if baseTitle then
            return baseTitle.fullText, code:lower(), title
        end
    end
    return title.fullText, nil, title
end

local function makeTarget(baseFullText, code, defaultLang)
    code = (code or ""):lower()
    if code == defaultLang then
        return baseFullText
    end
    local baseTitle = mw.title.new(baseFullText)
    if not baseTitle then
        return baseFullText .. "/" .. code
    end
    local targetTitle = mw.title.new(baseTitle.fullText .. "/" .. code, baseTitle.namespace)
    return (targetTitle and targetTitle.fullText) or (baseFullText .. "/" .. code)
end

local function wikilink(page, label)
    return string.format('[[%s|%s]]', page, label)
end

local builtinNames = {
    en="English",
	es="Español",
	it="Italiano",
	fr="Français",
	de="Deutsch",
	["pt-br"]="Português (Brasil)",
	ja="日本語",
	ko="한국어",
	pl="Polski",
	cs="Čeština",
	nl="Nederlands",
	uk="Українська",
	da="Dansk",
	sv="Svenska",
	tr="Türkçe",
	hu="Magyar",
	ru="Русский",
	["zh-hans"]="中文（简体）",
	["zh-hant"]="中文（繁體）",
}

function p.render(frame)
    local args = frame:getParent() and frame:getParent().args or frame.args

    local defaultLang = "en" -- fixed to English
    local icon = args.icon or ""

    local base, currentLang = getTitleParts(frame.args[1])

    -- Edit this list to control which languages always appear, in desired order.
    local candidates = {
        "en","pl","ru","fr","ja","zh-hans"
    }

    -- Order: default first, then listed candidates (excluding duplicate default)
    local seen, ordered = {}, {}
    local function add(code)
        code = (code or ""):lower()
        if code ~= "" and not seen[code] then
            table.insert(ordered, code)
            seen[code] = true
        end
    end
    add(defaultLang)
    for _, code in ipairs(candidates) do
        if code:lower() ~= defaultLang then
            add(code)
        end
    end

    local links = {}
    for _, code in ipairs(ordered) do
        local target = makeTarget(base, code, defaultLang)
        local label = builtinNames[code] or code
        local link = wikilink(target, label)
        local isActive = (currentLang and (currentLang == code)) or (code == defaultLang and not currentLang)
        if isActive then
            link = "'''" .. link .. "'''"
        end
        table.insert(links, link)
    end

    if #links == 0 then
        return ""
    end

    local out = {}
    if icon ~= "" then
        table.insert(out, "''" .. icon .. "'' ")
    end
    table.insert(out, table.concat(links, " • "))
    return '<div style="text-align:center; font-size:0.9em; margin-top:0.5em; margin-bottom:1em">' .. table.concat(out) .. '</div>'
end

return p