模块:Documentation

This module displays a blue box containing documentation for templates, Lua modules, or other pages. The {{documentation}} template invokes it.

Normal usage

For most uses, you should use the {{documentation}} template; please see that template's page for its usage instructions and parameters.

Use in other modules

To use this module from another Lua module, first load it with require:

local documentation = require('Module:Documentation').main

Then you can simply call it using a table of arguments.

documentation{content = 'Some documentation', ['link box'] = 'My custom link box'}

Please refer to the template documentation for usage instructions and a list of parameters.

Porting to other wikis

The module has a configuration file at Module:Documentation/config which is intended to allow easy translation and porting to other wikis. Please see the code comments in the config page for instructions. If you have any questions, or you need a feature which is not currently implemented, please leave a message at Template talk:Documentation to get the attention of a developer.

The messages that need to be customized to display a documentation template/module at the top of module pages are MediaWiki:Scribunto-doc-page-show and MediaWiki:Scribunto-doc-page-does-not-exist.

---

-- This module implements {{documentation}}.
-- Get required modules.
local getArgs = require('Module:Arguments').getArgs
local dependencyList = require( 'Module:DependencyList' )
local yn = require( 'Module:Yesno' )
local hatnote = require( 'Module:Hatnote' )._hatnote
local mbox = require( 'Module:Mbox' )._mbox
local lang = mw.getContentLanguage()
-- Get the config table.
local cfg = mw.loadData('Module:Documentation/config')
local p = {}

function p.doc( frame )
    local title = mw.title.getCurrentTitle()
    local args = frame:getParent().args
    local page = args[1] or mw.ustring.gsub( title.fullText, '/doc$', '' )
    local ret, cats, ret1, ret2, ret3
    local pageType = title.namespace == 828 and 'module' or 'template'

    local opts = frame.args;

    -- subpage header
    if title.subpageText == 'doc' then
        ret = mbox(
                'This is a documentation subpage for ' .. page .. '.',
                string.format(
                        'It contains usage information, categories, and other content that is not part of the [[' .. page .. '|original %s page]].',
                        pageType
                ),
                { icon = 'WikimediaUI-Notice.svg' }
        )

        if title.namespace == 10 then -- Template namespace
            cats = '[[Category:Template documentation|' .. title.baseText .. ']]'
            ret2 = dependencyList._main()
        elseif title.namespace == 828 then -- Module namespace
            cats = '[[Category:Module documentation|' .. title.baseText .. ']]'
            ret2 = dependencyList._main()
            ret2 = ret2 .. require('Module:Module toc').main()
        else
            cats = ''
            ret2 = ''
        end

        return tostring( ret ) .. ret2 .. cats
    end

    -- template header
    -- don't use mw.html as we aren't closing the main div tag
    ret1 = '<div class="documentation">'

    ret2 = mw.html.create( nil )
             :tag( 'div' )
             :addClass( 'documentation-header' )
             :tag( 'span' )
             :addClass( 'documentation-title' )
             :wikitext( lang:ucfirst( string.format('%s documentation', pageType) ) )
             :done()
             :tag( 'span' )
             :addClass( 'documentation-links plainlinks' )
             :wikitext(
            '[[' .. tostring( mw.uri.fullUrl( page .. '/doc', {action='view'} ) ) .. ' view]]' ..
                    '[[' .. tostring( mw.uri.fullUrl( page .. '/doc', {action='edit'} ) ) .. ' edit]]' ..
                    '[[' .. tostring( mw.uri.fullUrl( page .. '/doc', {action='history'} ) ) .. ' history]]' ..
                    '[<span class="jsPurgeLink">[' .. tostring( mw.uri.fullUrl( title.fullText, {action='purge'} ) ) .. ' purge]</span>]'
    )
             :done()
             :done()
             :tag( 'div' )
             :addClass( 'documentation-subheader' )
             :tag( 'span' )
             :addClass( 'documentation-documentation' )
             :wikitext( 'This documentation is transcluded from [[' .. page .. '/doc]]. Changes can be proposed in the talk page.' )
             :done()
             :wikitext(frame:extensionTag{ name = 'templatestyles', args = { src = 'Documentation/styles.css'} })
             :done()

    ret3 = {}

    if args.scwShared then
        --- Message box
        table.insert( ret3,
                mbox(
                        string.format(
                                "'''%s''' is [%s%s shared across] the Star Citizen Wikis.",
                                title.fullText,
                                'https://github.com/The-Star-Citizen-Wikis/SharedModules/tree/master/',
                                mw.uri.encode( title.rootText, 'PATH' )
                        ),
                        string.format(
                                'This %s is shared across the Star Citizen Wikis. Any changes should also be relayed to the GitHub repository.',
                                pageType
                        ),
                        { icon = 'WikimediaUI-ArticleDisambiguation-ltr.svg' }
                )
        )
        --- Set category
        table.insert( ret3, string.format( '[[Category:%s shared by the Star Citizen Wikis]]', lang:ucfirst( pageType )  .. 's' ) )
        --- Interlanguage link
        --- TODO: Make this into a for loop when there are more wikis
        table.insert( ret3, string.format( '[[%s:%s]]', 'de', title.fullText ) )
    end

    if args.fromWikipedia then
        table.insert( ret3,
                mbox(
                        string.format(
                                "'''%s''' is imported from [https://en.wikipedia.org/wiki/%s %s] on Wikipedia.",
                                title.fullText,
                                page,
                                page
                        ),
                        string.format(
                                'This %s is imported from the English Wikipedia. Although the visual appearance might be different, the functionality is identical. Please refer to the Wikipedia page for detailed documentation.',
                                pageType
                        ),
                        { icon = 'WikimediaUI-Logo-Wikipedia.svg' }
                )
        )
        --- Set category
        table.insert( ret3, string.format( '[[Category:%s imported from Wikipedia]]', lang:ucfirst( pageType ) .. 's' ) )
    end

    if title.namespace == 828 then
        -- Has config
        if mw.title.new( title.fullText .. '/config.json', 'Module' ).exists then
            table.insert( ret3,
                    mbox(
                            string.format(
                                    "'''%s''' loads configuration from [[%s/config.json]].",
                                    title.fullText,
                                    title.fullText
                            ),
                            'This module can be configurated from the config.json subpage.',
                            { icon='WikimediaUI-Settings.svg' }
                    )
            )
        end

        -- Has localization
        if mw.title.new( title.fullText .. '/i18n.json', 'Module' ).exists then
            table.insert( ret3,
                    mbox(
                            string.format(
                                    "'''%s''' loads messages from [[%s/i18n.json]].",
                                    title.fullText,
                                    title.fullText
                            ),
                            'This module is designed to be language-neutral. All of the messages are saved in the i18n.json subpage.',
                            { icon='WikimediaUI-Language.svg' }
                    )
            )
        end

        -- Testcase page
        if title.subpageText == 'testcases' then
            table.insert( ret3,
                    hatnote(
                            string.format( 'This is the test cases page for the module [[Module:%s]].', title.baseText ),
                            { icon='WikimediaUI-LabFlask.svg' }
                    )
            )
        end
    end

    --- Dependency list
    table.insert( ret3, dependencyList._main( nil, args.category, args.isUsed ) )

    -- Has templatestyles
    if mw.title.new( title.fullText .. '/styles.css' ).exists then
        table.insert( ret3,
                hatnote(
                        string.format(
                                "'''%s''' loads styles from [[%s/styles.css]].",
                                title.fullText,
                                title.fullText
                        ),
                        { icon='WikimediaUI-Palette.svg' }
                )
        )
    end

    --- Module stats bar
    if title.namespace == 828 then
        table.insert( ret3, '<div class="documentation-modulestats">' )

        -- Function list
        table.insert( ret3, require( 'Module:Module toc' ).main() )

        -- Unit tests
        local testcaseTitle = title.baseText .. '/testcases'
        if mw.title.new( testcaseTitle, 'Module' ).exists then
            -- There is probably a better way :P
            table.insert( ret3, frame:preprocess( '{{#invoke:' .. testcaseTitle .. '|run}}' ) )
        end

        table.insert( ret3, '</div>' )
    end

    return ret1 .. tostring( ret2 ) .. '<div class="documentation-content">' .. table.concat( ret3 )
end

-- Often-used functions.
local ugsub = mw.ustring.gsub
local format = mw.ustring.format

----------------------------------------------------------------------------
-- Helper functions
--
-- These are defined as local functions, but are made available in the p
-- table for testing purposes.
----------------------------------------------------------------------------

local function message(cfgKey, valArray, expectType)
    --[[
    -- Gets a message from the cfg table and formats it if appropriate.
    -- The function raises an error if the value from the cfg table is not
    -- of the type expectType. The default type for expectType is 'string'.
    -- If the table valArray is present, strings such as $1, $2 etc. in the
    -- message are substituted with values from the table keys [1], [2] etc.
    -- For example, if the message "foo-message" had the value 'Foo $2 bar $1.',
    -- message('foo-message', {'baz', 'qux'}) would return "Foo qux bar baz."
    --]]
    local msg = cfg[cfgKey]
    expectType = expectType or 'string'
    if type(msg) ~= expectType then
        error('message: type error in message cfg.' .. cfgKey .. ' (' .. expectType .. ' expected, got ' .. type(msg) .. ')', 2)
    end
    if not valArray then
        return msg
    end

    local function getMessageVal(match)
        match = tonumber(match)
        return valArray[match] or error('message: no value found for key $' .. match .. ' in message cfg.' .. cfgKey, 4)
    end

    return ugsub(msg, '$([1-9][0-9]*)', getMessageVal)
end

p.message = message

local function makeWikilink(page, display)
    if display then
        return format('[[%s|%s]]', page, display)
    else
        return format('[[%s]]', page)
    end
end

p.makeWikilink = makeWikilink

local function makeCategoryLink(cat, sort)
    local catns = mw.site.namespaces[14].name
    return makeWikilink(catns .. ':' .. cat, sort)
end

p.makeCategoryLink = makeCategoryLink

local function makeUrlLink(url, display)
    return format('[%s %s]', url, display)
end

p.makeUrlLink = makeUrlLink

local function makeToolbar(...)
    local ret = {}
    local lim = select('#', ...)
    if lim < 1 then
        return nil
    end
    for i = 1, lim do
        ret[#ret + 1] = select(i, ...)
    end
    -- 'documentation-toolbar'
    return format(
            '<span class="%s">(%s)</span>',
            message('toolbar-class'),
            table.concat(ret, ' &#124; ')
    )
end

p.makeToolbar = makeToolbar

----------------------------------------------------------------------------
-- Argument processing
----------------------------------------------------------------------------

local function makeInvokeFunc(funcName)
    return function (frame)
        local args = getArgs(frame, {
            valueFunc = function (key, value)
                if type(value) == 'string' then
                    value = value:match('^%s*(.-)%s*$') -- Remove whitespace.
                    if key == 'heading' or value ~= '' then
                        return value
                    else
                        return nil
                    end
                else
                    return value
                end
            end
        })
        return p[funcName](args)
    end
end

----------------------------------------------------------------------------
-- Entry points
----------------------------------------------------------------------------

function p.nonexistent(frame)
    if mw.title.getCurrentTitle().subpageText == 'testcases' then
        return frame:expandTemplate{title = 'module test cases notice'}
    else
        return p.main(frame)
    end
end

p.main = makeInvokeFunc('_main')

function p._main(args)
    --[[
    -- This function defines logic flow for the module.
    -- @args - table of arguments passed by the user
    --]]
    local env = p.getEnvironment(args)
    local root = mw.html.create()
    root
            :wikitext(p._getModuleWikitext(args, env))
            :wikitext(p.protectionTemplate(env))
            :wikitext(p.sandboxNotice(args, env))
            :tag('div')
    -- 'documentation-container'
            :addClass(message('container'))
            :attr('role', 'complementary')
            :attr('aria-labelledby', args.heading ~= '' and 'documentation-heading' or nil)
            :attr('aria-label', args.heading == '' and 'Documentation' or nil)
            :newline()
            :tag('div')
    -- 'documentation'
            :addClass(message('main-div-classes'))
            :newline()
            :wikitext(p._startBox(args, env))
            :wikitext(p._content(args, env))
            :tag('div')
    -- 'documentation-clear'
            :addClass(message('clear'))
            :done()
            :newline()
            :done()
            :wikitext(p._endBox(args, env))
            :done()
            :wikitext(p.addTrackingCategories(env))
    -- 'Module:Documentation/styles.css'
    return mw.getCurrentFrame():extensionTag (
            'templatestyles', '', {src=cfg['templatestyles']
            }) .. tostring(root)
end

----------------------------------------------------------------------------
-- Environment settings
----------------------------------------------------------------------------

function p.getEnvironment(args)
    --[[
    -- Returns a table with information about the environment, including title
    -- objects and other namespace- or path-related data.
    -- @args - table of arguments passed by the user
    --
    -- Title objects include:
    -- env.title - the page we are making documentation for (usually the current title)
    -- env.templateTitle - the template (or module, file, etc.)
    -- env.docTitle - the /doc subpage.
    -- env.sandboxTitle - the /sandbox subpage.
    -- env.testcasesTitle - the /testcases subpage.
    --
    -- Data includes:
    -- env.protectionLevels - the protection levels table of the title object.
    -- env.subjectSpace - the number of the title's subject namespace.
    -- env.docSpace - the number of the namespace the title puts its documentation in.
    -- env.docpageBase - the text of the base page of the /doc, /sandbox and /testcases pages, with namespace.
    -- env.compareUrl - URL of the Special:ComparePages page comparing the sandbox with the template.
    --
    -- All table lookups are passed through pcall so that errors are caught. If an error occurs, the value
    -- returned will be nil.
    --]]

    local env, envFuncs = {}, {}

    -- Set up the metatable. If triggered we call the corresponding function in the envFuncs table. The value
    -- returned by that function is memoized in the env table so that we don't call any of the functions
    -- more than once. (Nils won't be memoized.)
    setmetatable(env, {
        __index = function (t, key)
            local envFunc = envFuncs[key]
            if envFunc then
                local success, val = pcall(envFunc)
                if success then
                    env[key] = val -- Memoise the value.
                    return val
                end
            end
            return nil
        end
    })

    function envFuncs.title()
        -- The title object for the current page, or a test page passed with args.page.
        local title
        local titleArg = args.page
        if titleArg then
            title = mw.title.new(titleArg)
        else
            title = mw.title.getCurrentTitle()
        end
        return title
    end

    function envFuncs.templateTitle()
        --[[
        -- The template (or module, etc.) title object.
        -- Messages:
        -- 'sandbox-subpage' --> 'sandbox'
        -- 'testcases-subpage' --> 'testcases'
        --]]
        local subjectSpace = env.subjectSpace
        local title = env.title
        local subpage = title.subpageText
        if subpage == message('sandbox-subpage') or subpage == message('testcases-subpage') then
            return mw.title.makeTitle(subjectSpace, title.baseText)
        else
            return mw.title.makeTitle(subjectSpace, title.text)
        end
    end

    function envFuncs.docTitle()
        --[[
        -- Title object of the /doc subpage.
        -- Messages:
        -- 'doc-subpage' --> 'doc'
        --]]
        local title = env.title
        local docname = args[1] -- User-specified doc page.
        local docpage
        if docname then
            docpage = docname
        else
            docpage = env.docpageBase .. '/' .. message('doc-subpage')
        end
        return mw.title.new(docpage)
    end

    function envFuncs.sandboxTitle()
        --[[
        -- Title object for the /sandbox subpage.
        -- Messages:
        -- 'sandbox-subpage' --> 'sandbox'
        --]]
        return mw.title.new(env.docpageBase .. '/' .. message('sandbox-subpage'))
    end

    function envFuncs.testcasesTitle()
        --[[
        -- Title object for the /testcases subpage.
        -- Messages:
        -- 'testcases-subpage' --> 'testcases'
        --]]
        return mw.title.new(env.docpageBase .. '/' .. message('testcases-subpage'))
    end

    function envFuncs.protectionLevels()
        -- The protection levels table of the title object.
        return env.title.protectionLevels
    end

    function envFuncs.subjectSpace()
        -- The subject namespace number.
        return mw.site.namespaces[env.title.namespace].subject.id
    end

    function envFuncs.docSpace()
        -- The documentation namespace number. For most namespaces this is the
        -- same as the subject namespace. However, pages in the Article, File,
        -- MediaWiki or Category namespaces must have their /doc, /sandbox and
        -- /testcases pages in talk space.
        local subjectSpace = env.subjectSpace
        if subjectSpace == 0 or subjectSpace == 6 or subjectSpace == 8 or subjectSpace == 14 then
            return subjectSpace + 1
        else
            return subjectSpace
        end
    end

    function envFuncs.docpageBase()
        -- The base page of the /doc, /sandbox, and /testcases subpages.
        -- For some namespaces this is the talk page, rather than the template page.
        local templateTitle = env.templateTitle
        local docSpace = env.docSpace
        local docSpaceText = mw.site.namespaces[docSpace].name
        -- Assemble the link. docSpace is never the main namespace, so we can hardcode the colon.
        return docSpaceText .. ':' .. templateTitle.text
    end

    function envFuncs.compareUrl()
        -- Diff link between the sandbox and the main template using [[Special:ComparePages]].
        local templateTitle = env.templateTitle
        local sandboxTitle = env.sandboxTitle
        if templateTitle.exists and sandboxTitle.exists then
            local compareUrl = mw.uri.canonicalUrl(
                    'Special:ComparePages',
                    { page1 = templateTitle.prefixedText, page2 = sandboxTitle.prefixedText}
            )
            return tostring(compareUrl)
        else
            return nil
        end
    end

    return env
end

----------------------------------------------------------------------------
-- Auxiliary templates
----------------------------------------------------------------------------

p.getModuleWikitext = makeInvokeFunc('_getModuleWikitext')

function p._getModuleWikitext(args, env)
    local currentTitle = mw.title.getCurrentTitle()
    if currentTitle.contentModel ~= 'Scribunto' then return end
    pcall(require, currentTitle.prefixedText) -- if it fails, we don't care
    local moduleWikitext =  package.loaded["Module:Module wikitext"]
    if moduleWikitext then
        return moduleWikitext.main()
    end
end

function p.sandboxNotice(args, env)
    --[=[
    -- Generates a sandbox notice for display above sandbox pages.
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    -- Messages:
    -- 'sandbox-notice-image' --> '[[File:Sandbox.svg|50px|alt=|link=]]'
    -- 'sandbox-notice-blurb' --> 'This is the $1 for $2.'
    -- 'sandbox-notice-diff-blurb' --> 'This is the $1 for $2 ($3).'
    -- 'sandbox-notice-pagetype-template' --> '[[Wikipedia:Template test cases|template sandbox]] page'
    -- 'sandbox-notice-pagetype-module' --> '[[Wikipedia:Template test cases|module sandbox]] page'
    -- 'sandbox-notice-pagetype-other' --> 'sandbox page'
    -- 'sandbox-notice-compare-link-display' --> 'diff'
    -- 'sandbox-notice-testcases-blurb' --> 'See also the companion subpage for $1.'
    -- 'sandbox-notice-testcases-link-display' --> 'test cases'
    -- 'sandbox-category' --> 'Template sandboxes'
    -- 'module-sandbox-category' --> 'Module sandboxes'
    -- 'other-sandbox-category' --> 'Sandboxes outside of template or module namespace'
    --]=]
    local title = env.title
    local sandboxTitle = env.sandboxTitle
    local templateTitle = env.templateTitle
    local subjectSpace = env.subjectSpace
    if not (subjectSpace and title and sandboxTitle and templateTitle
            and mw.title.equals(title, sandboxTitle)) then
        return nil
    end
    -- Build the table of arguments to pass to {{ombox}}. We need just two fields, "image" and "text".
    local omargs = {}
    omargs.image = message('sandbox-notice-image')
    -- Get the text. We start with the opening blurb, which is something like
    -- "This is the template sandbox for [[Template:Foo]] (diff)."
    local text = ''
    local pagetype, sandboxCat
    if subjectSpace == 10 then
        pagetype = message('sandbox-notice-pagetype-template')
        sandboxCat = message('sandbox-category')
    elseif subjectSpace == 828 then
        pagetype = message('sandbox-notice-pagetype-module')
        sandboxCat = message('module-sandbox-category')
    else
        pagetype = message('sandbox-notice-pagetype-other')
        sandboxCat = message('other-sandbox-category')
    end
    local templateLink = makeWikilink(templateTitle.prefixedText)
    local compareUrl = env.compareUrl
    if compareUrl then
        local compareDisplay = message('sandbox-notice-compare-link-display')
        local compareLink = makeUrlLink(compareUrl, compareDisplay)
        text = text .. message('sandbox-notice-diff-blurb', {pagetype, templateLink, compareLink})
    else
        text = text .. message('sandbox-notice-blurb', {pagetype, templateLink})
    end
    -- Get the test cases page blurb if the page exists. This is something like
    -- "See also the companion subpage for [[Template:Foo/testcases|test cases]]."
    local testcasesTitle = env.testcasesTitle
    if testcasesTitle and testcasesTitle.exists then
        if testcasesTitle.contentModel == "Scribunto" then
            local testcasesLinkDisplay = message('sandbox-notice-testcases-link-display')
            local testcasesRunLinkDisplay = message('sandbox-notice-testcases-run-link-display')
            local testcasesLink = makeWikilink(testcasesTitle.prefixedText, testcasesLinkDisplay)
            local testcasesRunLink = makeWikilink(testcasesTitle.talkPageTitle.prefixedText, testcasesRunLinkDisplay)
            text = text .. '<br />' .. message('sandbox-notice-testcases-run-blurb', {testcasesLink, testcasesRunLink})
        else
            local testcasesLinkDisplay = message('sandbox-notice-testcases-link-display')
            local testcasesLink = makeWikilink(testcasesTitle.prefixedText, testcasesLinkDisplay)
            text = text .. '<br />' .. message('sandbox-notice-testcases-blurb', {testcasesLink})
        end
    end

    -- Add the sandbox to the sandbox category.
    omargs.text = text .. makeCategoryLink(sandboxCat)

    -- 'documentation-clear'
    return '<div class="' .. message('clear') .. '"></div>'
            .. require('Module:Message box').main('ombox', omargs)
end

function p.protectionTemplate(env)
    -- Generates the padlock icon in the top right.
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    -- Messages:
    -- 'protection-template' --> 'pp-template'
    -- 'protection-template-args' --> {docusage = 'yes'}
    local protectionLevels = env.protectionLevels
    if not protectionLevels then
        return nil
    end
    local editProt = protectionLevels.edit and protectionLevels.edit[1]
    local moveProt = protectionLevels.move and protectionLevels.move[1]
    if editProt then
        -- The page is edit-protected.
        return require('Module:Protection banner')._main{
            message('protection-reason-edit'), small = true
        }
    elseif moveProt and moveProt ~= 'autoconfirmed' then
        -- The page is move-protected but not edit-protected. Exclude move
        -- protection with the level "autoconfirmed", as this is equivalent to
        -- no move protection at all.
        return require('Module:Protection banner')._main{
            action = 'move', small = true
        }
    else
        return nil
    end
end

----------------------------------------------------------------------------
-- Start box
----------------------------------------------------------------------------

p.startBox = makeInvokeFunc('_startBox')

function p._startBox(args, env)
    --[[
    -- This function generates the start box.
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    -- The actual work is done by p.makeStartBoxLinksData and p.renderStartBoxLinks which make
    -- the [view] [edit] [history] [purge] links, and by p.makeStartBoxData and p.renderStartBox
    -- which generate the box HTML.
    --]]
    env = env or p.getEnvironment(args)
    local links
    local content = args.content
    if not content or args[1] then
        -- No need to include the links if the documentation is on the template page itself.
        local linksData = p.makeStartBoxLinksData(args, env)
        if linksData then
            links = p.renderStartBoxLinks(linksData)
        end
    end
    -- Generate the start box html.
    local data = p.makeStartBoxData(args, env, links)
    if data then
        return p.renderStartBox(data)
    else
        -- User specified no heading.
        return nil
    end
end

function p.makeStartBoxLinksData(args, env)
    --[[
    -- Does initial processing of data to make the [view] [edit] [history] [purge] links.
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    -- Messages:
    -- 'view-link-display' --> 'view'
    -- 'edit-link-display' --> 'edit'
    -- 'history-link-display' --> 'history'
    -- 'purge-link-display' --> 'purge'
    -- 'module-preload' --> 'Template:Documentation/preload-module-doc'
    -- 'docpage-preload' --> 'Template:Documentation/preload'
    -- 'create-link-display' --> 'create'
    --]]
    local subjectSpace = env.subjectSpace
    local title = env.title
    local docTitle = env.docTitle
    if not title or not docTitle then
        return nil
    end
    if docTitle.isRedirect then
        docTitle = docTitle.redirectTarget
    end

    -- Create link if /doc doesn't exist.
    local preload = args.preload
    if not preload then
        if subjectSpace == 828 then -- Module namespace
            preload = message('module-preload')
        else
            preload = message('docpage-preload')
        end
    end

    return {
        title = title,
        docTitle = docTitle,
        -- View, display, edit, and purge links if /doc exists.
        viewLinkDisplay = message('view-link-display'),
        editLinkDisplay = message('edit-link-display'),
        historyLinkDisplay = message('history-link-display'),
        purgeLinkDisplay = message('purge-link-display'),
        preload = preload,
        createLinkDisplay = message('create-link-display')
    }
end

function p.renderStartBoxLinks(data)
    --[[
    -- Generates the [view][edit][history][purge] or [create][purge] links from the data table.
    -- @data - a table of data generated by p.makeStartBoxLinksData
    --]]
    local docTitle = data.docTitle
    -- yes, we do intend to purge the template page on which the documentation appears
    local purgeLink = makeWikilink("Special:Purge/" .. data.title.prefixedText, data.purgeLinkDisplay)

    if docTitle.exists then
        local viewLink = makeWikilink(docTitle.prefixedText, data.viewLinkDisplay)
        local editLink = makeWikilink("Special:EditPage/" .. docTitle.prefixedText, data.editLinkDisplay)
        local historyLink = makeWikilink("Special:PageHistory/" .. docTitle.prefixedText, data.historyLinkDisplay)
        return "&#91;" .. viewLink .. "&#93; &#91;" .. editLink .. "&#93; &#91;" .. historyLink .. "&#93; &#91;" .. purgeLink .. "&#93;"
    else
        local createLink = makeUrlLink(docTitle:canonicalUrl{action = 'edit', preload = data.preload}, data.createLinkDisplay)
        return  "&#91;" .. createLink .. "&#93; &#91;" .. purgeLink .. "&#93;"
    end
    return ret
end

function p.makeStartBoxData(args, env, links)
    --[=[
    -- Does initial processing of data to pass to the start-box render function, p.renderStartBox.
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    -- @links - a string containing the [view][edit][history][purge] links - could be nil if there's an error.
    --
    -- Messages:
    -- 'documentation-icon-wikitext' --> '[[File:Test Template Info-Icon - Version (2).svg|50px|link=|alt=]]'
    -- 'template-namespace-heading' --> 'Template documentation'
    -- 'module-namespace-heading' --> 'Module documentation'
    -- 'file-namespace-heading' --> 'Summary'
    -- 'other-namespaces-heading' --> 'Documentation'
    -- 'testcases-create-link-display' --> 'create'
    --]=]
    local subjectSpace = env.subjectSpace
    if not subjectSpace then
        -- Default to an "other namespaces" namespace, so that we get at least some output
        -- if an error occurs.
        subjectSpace = 2
    end
    local data = {}

    -- Heading
    local heading = args.heading -- Blank values are not removed.
    if heading == '' then
        -- Don't display the start box if the heading arg is defined but blank.
        return nil
    end
    if heading then
        data.heading = heading
    elseif subjectSpace == 10 then -- Template namespace
        data.heading = message('documentation-icon-wikitext') .. ' ' .. message('template-namespace-heading')
    elseif subjectSpace == 828 then -- Module namespace
        data.heading = message('documentation-icon-wikitext') .. ' ' .. message('module-namespace-heading')
    elseif subjectSpace == 6 then -- File namespace
        data.heading = message('file-namespace-heading')
    else
        data.heading = message('other-namespaces-heading')
    end

    -- Heading CSS
    local headingStyle = args['heading-style']
    if headingStyle then
        data.headingStyleText = headingStyle
    else
        -- 'documentation-heading'
        data.headingClass = message('main-div-heading-class')
    end

    -- Data for the [view][edit][history][purge] or [create] links.
    if links then
        -- 'mw-editsection-like plainlinks'
        data.linksClass = message('start-box-link-classes')
        data.links = links
    end

    return data
end

function p.renderStartBox(data)
    -- Renders the start box html.
    -- @data - a table of data generated by p.makeStartBoxData.
    local sbox = mw.html.create('div')
    sbox
    -- 'documentation-startbox'
            :addClass(message('start-box-class'))
            :newline()
            :tag('span')
            :addClass(data.headingClass)
            :attr('id', 'documentation-heading')
            :cssText(data.headingStyleText)
            :wikitext(data.heading)
    local links = data.links
    if links then
        sbox:tag('span')
            :addClass(data.linksClass)
            :attr('id', data.linksId)
            :wikitext(links)
    end
    return tostring(sbox)
end

----------------------------------------------------------------------------
-- Documentation content
----------------------------------------------------------------------------

p.content = makeInvokeFunc('_content')

function p._content(args, env)
    -- Displays the documentation contents
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    env = env or p.getEnvironment(args)
    local docTitle = env.docTitle
    local content = args.content
    if not content and docTitle and docTitle.exists then
        content = args._content or mw.getCurrentFrame():expandTemplate{title = docTitle.prefixedText}
    end
    -- The line breaks below are necessary so that "=== Headings ===" at the start and end
    -- of docs are interpreted correctly.
    return '\n' .. (content or '') .. '\n'
end

p.contentTitle = makeInvokeFunc('_contentTitle')

function p._contentTitle(args, env)
    env = env or p.getEnvironment(args)
    local docTitle = env.docTitle
    if not args.content and docTitle and docTitle.exists then
        return docTitle.prefixedText
    else
        return ''
    end
end

----------------------------------------------------------------------------
-- End box
----------------------------------------------------------------------------

p.endBox = makeInvokeFunc('_endBox')

function p._endBox(args, env)
    --[=[
    -- This function generates the end box (also known as the link box).
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    --]=]

    -- Get environment data.
    env = env or p.getEnvironment(args)
    local subjectSpace = env.subjectSpace
    local docTitle = env.docTitle
    if not subjectSpace or not docTitle then
        return nil
    end

    -- Check whether we should output the end box at all. Add the end
    -- box by default if the documentation exists or if we are in the
    -- user, module or template namespaces.
    local linkBox = args['link box']
    if linkBox == 'off'
            or not (
            docTitle.exists
                    or subjectSpace == 2
                    or subjectSpace == 828
                    or subjectSpace == 10
    )
    then
        return nil
    end

    -- Assemble the link box.
    local text = ''
    if linkBox then
        text = text .. linkBox
    else
        text = text .. (p.makeDocPageBlurb(args, env) or '') -- "This documentation is transcluded from [[Foo]]."
        if subjectSpace == 2 or subjectSpace == 10 or subjectSpace == 828 then
            -- We are in the user, template or module namespaces.
            -- Add sandbox and testcases links.
            -- "Editors can experiment in this template's sandbox and testcases pages."
            text = text .. (p.makeExperimentBlurb(args, env) or '') .. '<br />'
            if not args.content and not args[1] then
                -- "Please add categories to the /doc subpage."
                -- Don't show this message with inline docs or with an explicitly specified doc page,
                -- as then it is unclear where to add the categories.
                text = text .. (p.makeCategoriesBlurb(args, env) or '')
            end
            text = text .. ' ' .. (p.makeSubpagesBlurb(args, env) or '') --"Subpages of this template"
        end
    end

    local box = mw.html.create('div')
    -- 'documentation-metadata'
    box:attr('role', 'note')
       :addClass(message('end-box-class'))
    -- 'plainlinks'
       :addClass(message('end-box-plainlinks'))
       :wikitext(text)
       :done()

    return '\n' .. tostring(box)
end

function p.makeDocPageBlurb(args, env)
    --[=[
    -- Makes the blurb "This documentation is transcluded from [[Template:Foo]] (edit, history)".
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    -- Messages:
    -- 'edit-link-display' --> 'edit'
    -- 'history-link-display' --> 'history'
    -- 'transcluded-from-blurb' -->
    -- 'The above [[Wikipedia:Template documentation|documentation]]
    -- is [[Help:Transclusion|transcluded]] from $1.'
    -- 'module-preload' --> 'Template:Documentation/preload-module-doc'
    -- 'create-link-display' --> 'create'
    -- 'create-module-doc-blurb' -->
    -- 'You might want to $1 a documentation page for this [[Wikipedia:Lua|Scribunto module]].'
    --]=]
    local docTitle = env.docTitle
    if not docTitle then
        return nil
    end
    if docTitle.exists then
        -- /doc exists; link to it.
        local docLink = makeWikilink(docTitle.prefixedText)
        local editDisplay = message('edit-link-display')
        local editLink = makeWikilink("Special:EditPage/" .. docTitle.prefixedText, editDisplay)
        local historyDisplay = message('history-link-display')
        local historyLink = makeWikilink("Special:PageHistory/" .. docTitle.prefixedText, historyDisplay)
        return message('transcluded-from-blurb', {docLink})
                .. ' '
                .. makeToolbar(editLink, historyLink)
                .. '<br />'
    elseif env.subjectSpace == 828 then
        -- /doc does not exist; ask to create it.
        local createUrl = docTitle:canonicalUrl{action = 'edit', preload = message('module-preload')}
        local createDisplay = message('create-link-display')
        local createLink = makeUrlLink(createUrl, createDisplay)
        return message('create-module-doc-blurb', {createLink})
                .. '<br />'
    end
end

function p.makeExperimentBlurb(args, env)
    --[[
    -- Renders the text "Editors can experiment in this template's sandbox (edit | diff) and testcases (edit) pages."
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    --
    -- Messages:
    -- 'sandbox-link-display' --> 'sandbox'
    -- 'sandbox-edit-link-display' --> 'edit'
    -- 'compare-link-display' --> 'diff'
    -- 'module-sandbox-preload' --> 'Template:Documentation/preload-module-sandbox'
    -- 'template-sandbox-preload' --> 'Template:Documentation/preload-sandbox'
    -- 'sandbox-create-link-display' --> 'create'
    -- 'mirror-edit-summary' --> 'Create sandbox version of $1'
    -- 'mirror-link-display' --> 'mirror'
    -- 'mirror-link-preload' --> 'Template:Documentation/mirror'
    -- 'sandbox-link-display' --> 'sandbox'
    -- 'testcases-link-display' --> 'testcases'
    -- 'testcases-edit-link-display'--> 'edit'
    -- 'template-sandbox-preload' --> 'Template:Documentation/preload-sandbox'
    -- 'testcases-create-link-display' --> 'create'
    -- 'testcases-link-display' --> 'testcases'
    -- 'testcases-edit-link-display' --> 'edit'
    -- 'module-testcases-preload' --> 'Template:Documentation/preload-module-testcases'
    -- 'template-testcases-preload' --> 'Template:Documentation/preload-testcases'
    -- 'experiment-blurb-module' --> 'Editors can experiment in this module's $1 and $2 pages.'
    -- 'experiment-blurb-template' --> 'Editors can experiment in this template's $1 and $2 pages.'
    --]]
    local subjectSpace = env.subjectSpace
    local templateTitle = env.templateTitle
    local sandboxTitle = env.sandboxTitle
    local testcasesTitle = env.testcasesTitle
    local templatePage = templateTitle.prefixedText
    if not subjectSpace or not templateTitle or not sandboxTitle or not testcasesTitle then
        return nil
    end
    -- Make links.
    local sandboxLinks, testcasesLinks
    if sandboxTitle.exists then
        local sandboxPage = sandboxTitle.prefixedText
        local sandboxDisplay = message('sandbox-link-display')
        local sandboxLink = makeWikilink(sandboxPage, sandboxDisplay)
        local sandboxEditDisplay = message('sandbox-edit-link-display')
        local sandboxEditLink = makeWikilink("Special:EditPage/" .. sandboxPage, sandboxEditDisplay)
        local compareUrl = env.compareUrl
        local compareLink
        if compareUrl then
            local compareDisplay = message('compare-link-display')
            compareLink = makeUrlLink(compareUrl, compareDisplay)
        end
        sandboxLinks = sandboxLink .. ' ' .. makeToolbar(sandboxEditLink, compareLink)
    else
        local sandboxPreload
        if subjectSpace == 828 then
            sandboxPreload = message('module-sandbox-preload')
        else
            sandboxPreload = message('template-sandbox-preload')
        end
        local sandboxCreateUrl = sandboxTitle:canonicalUrl{action = 'edit', preload = sandboxPreload}
        local sandboxCreateDisplay = message('sandbox-create-link-display')
        local sandboxCreateLink = makeUrlLink(sandboxCreateUrl, sandboxCreateDisplay)
        local mirrorSummary = message('mirror-edit-summary', {makeWikilink(templatePage)})
        local mirrorPreload = message('mirror-link-preload')
        local mirrorUrl = sandboxTitle:canonicalUrl{action = 'edit', preload = mirrorPreload, summary = mirrorSummary}
        if subjectSpace == 828 then
            mirrorUrl = sandboxTitle:canonicalUrl{action = 'edit', preload = templateTitle.prefixedText, summary = mirrorSummary}
        end
        local mirrorDisplay = message('mirror-link-display')
        local mirrorLink = makeUrlLink(mirrorUrl, mirrorDisplay)
        sandboxLinks = message('sandbox-link-display') .. ' ' .. makeToolbar(sandboxCreateLink, mirrorLink)
    end
    if testcasesTitle.exists then
        local testcasesPage = testcasesTitle.prefixedText
        local testcasesDisplay = message('testcases-link-display')
        local testcasesLink = makeWikilink(testcasesPage, testcasesDisplay)
        local testcasesEditUrl = testcasesTitle:canonicalUrl{action = 'edit'}
        local testcasesEditDisplay = message('testcases-edit-link-display')
        local testcasesEditLink = makeWikilink("Special:EditPage/" .. testcasesPage, testcasesEditDisplay)
        -- for Modules, add testcases run link if exists
        if testcasesTitle.contentModel == "Scribunto"  and testcasesTitle.talkPageTitle and testcasesTitle.talkPageTitle.exists then
            local testcasesRunLinkDisplay = message('testcases-run-link-display')
            local testcasesRunLink = makeWikilink(testcasesTitle.talkPageTitle.prefixedText, testcasesRunLinkDisplay)
            testcasesLinks = testcasesLink .. ' ' .. makeToolbar(testcasesEditLink, testcasesRunLink)
        else
            testcasesLinks = testcasesLink .. ' ' .. makeToolbar(testcasesEditLink)
        end
    else
        local testcasesPreload
        if subjectSpace == 828 then
            testcasesPreload = message('module-testcases-preload')
        else
            testcasesPreload = message('template-testcases-preload')
        end
        local testcasesCreateUrl = testcasesTitle:canonicalUrl{action = 'edit', preload = testcasesPreload}
        local testcasesCreateDisplay = message('testcases-create-link-display')
        local testcasesCreateLink = makeUrlLink(testcasesCreateUrl, testcasesCreateDisplay)
        testcasesLinks = message('testcases-link-display') .. ' ' .. makeToolbar(testcasesCreateLink)
    end
    local messageName
    if subjectSpace == 828 then
        messageName = 'experiment-blurb-module'
    else
        messageName = 'experiment-blurb-template'
    end
    return message(messageName, {sandboxLinks, testcasesLinks})
end

function p.makeCategoriesBlurb(args, env)
    --[[
    -- Generates the text "Please add categories to the /doc subpage."
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment
    -- Messages:
    -- 'doc-link-display' --> '/doc'
    -- 'add-categories-blurb' --> 'Please add categories to the $1 subpage.'
    --]]
    local docTitle = env.docTitle
    if not docTitle then
        return nil
    end
    local docPathLink = makeWikilink(docTitle.prefixedText, message('doc-link-display'))
    return message('add-categories-blurb', {docPathLink})
end

function p.makeSubpagesBlurb(args, env)
    --[[
    -- Generates the "Subpages of this template" link.
    -- @args - a table of arguments passed by the user
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment

    -- Messages:
    -- 'template-pagetype' --> 'template'
    -- 'module-pagetype' --> 'module'
    -- 'default-pagetype' --> 'page'
    -- 'subpages-link-display' --> 'Subpages of this $1'
    --]]
    local subjectSpace = env.subjectSpace
    local templateTitle = env.templateTitle
    if not subjectSpace or not templateTitle then
        return nil
    end
    local pagetype
    if subjectSpace == 10 then
        pagetype = message('template-pagetype')
    elseif subjectSpace == 828 then
        pagetype = message('module-pagetype')
    else
        pagetype = message('default-pagetype')
    end
    local subpagesLink = makeWikilink(
            'Special:PrefixIndex/' .. templateTitle.prefixedText .. '/',
            message('subpages-link-display', {pagetype})
    )
    return message('subpages-blurb', {subpagesLink})
end

----------------------------------------------------------------------------
-- Tracking categories
----------------------------------------------------------------------------

function p.addTrackingCategories(env)
    --[[
    -- Check if {{documentation}} is transcluded on a /doc or /testcases page.
    -- @env - environment table containing title objects, etc., generated with p.getEnvironment

    -- Messages:
    -- 'display-strange-usage-category' --> true
    -- 'doc-subpage' --> 'doc'
    -- 'testcases-subpage' --> 'testcases'
    -- 'strange-usage-category' --> 'Wikipedia pages with strange ((documentation)) usage'
    --
    -- /testcases pages in the module namespace are not categorised, as they may have
    -- {{documentation}} transcluded automatically.
    --]]
    local title = env.title
    local subjectSpace = env.subjectSpace
    if not title or not subjectSpace then
        return nil
    end
    local subpage = title.subpageText
    if message('display-strange-usage-category', nil, 'boolean')
            and (
            subpage == message('doc-subpage')
                    or subjectSpace ~= 828 and subpage == message('testcases-subpage')
    )
    then
        return makeCategoryLink(message('strange-usage-category'))
    end
    return ''
end

return p