-- Note: Originally written on English Wikipedia as [[w:en:Module:Attached_KML]]
-- ##### Localisation (L10n) settings #####
local L10n = {
	-- Template parameter names
	-- (replace values in quotes with local parameter names)
	para = {
		display = "display",
		from = "from",
		header = "header",
		title = "title",
		wikidata = "wikidata",
		demo = "demo",
	},
	-- Other configuration settings
	config = {
		-- controls the format used for inline display, can be set to "box" (default) or "line"
		-- "box" example: https://en.wikipedia.org/wiki/Template:Attached_KML
		-- "line" example: https://sv.wikipedia.org/wiki/Mall:KML
		inline_format = "box",
	},
	-- Other strings
	str = {
		inline = "inline", -- used with display parameter: (|display=inline) or (|display=title) or (|display=inline,title) or (|display=title,inline)
		title = "title", -- (as above)
		dsep = ",", -- separator between inline and title (comma in the example above)
		kml_prefix = "Template:Attached KML/", -- local KML files are stored as subpages of this location
		default_title = "Route map", -- default title for links at top of page, when title parameter not used in transclusion
		default_header = "", -- default header for links in inline box, when header parameter not used in transclusion
		kml_file = "KML file", -- text to display for link to raw KML file
		edit = "edit", -- text to display for link to edit KML file
		help = "help", -- text to display for help page link
		help_location	= "Help:Attached KML", -- page to link to for help page link
		err_prepend	= "Attached KML", -- text to prepend to the error messages, when shown at top of page (display=title)
		cat	= { -- tracking categories: full wikimarkup required, or set to the empty string ("") to not to track the condition
			wikidata_kml = "[[Category:Articles using KML from Wikidata]]", -- tracks mainspace articles using KML from Wikidata
			local_kml = "[[Category:Articles using KML not from Wikidata]]", -- tracks mainspace articles not using KML from Wikidata
			error_mqid = "[[Category:Attached KML errors|M]]", -- tracks malformed_qid error
			error_badqid = "[[Category:Attached KML errors|W]]", -- tracks bad_qid error
			error_noitem = "[[Category:Attached KML errors|N]]", -- tracks no_item error
			error_from = "[[Category:Attached KML errors|F]]", -- tracks bad_from error
			error_nokml = "[[Category:Attached KML errors|K]]", -- tracks no_kml error
		},
		line = { -- these strings are only needed if using 'inline_format = "line"' configuration
			start = "", -- wikitext to display at start of line, may include image markup, should start with a space
			separator = "", -- text to display between links to external mapping providers, should include spaces
		},
	}
}

L10n.str.err = { -- error messages
	malformed_qid	= "Error: malformed  item id in <code><nowiki>|" .. L10n.para.wikidata .. "=</nowiki></code>",	-- item id doesn't match pattern (number with Q prefix)
	bad_qid		= "Error: item specified on Wikidata, or in <code><nowiki>|" .. L10n.para.wikidata .. "=</nowiki></code>, is not a KML file <small>(P31→Q26267864 not found)</small>",	-- item doesn't have a P31→Q26267864 statement
	no_item		= "Error: item specified in <code><nowiki>|" .. L10n.para.wikidata .. "=</nowiki></code> not found on Wikidata",	-- item not found on wikidata
	bad_from	= "Error: KML file not found, check <code><nowiki>|" .. L10n.para.from .. "=</nowiki></code>",	-- KML specified by from parameter doesn't exist
	no_kml		= "Error: KML file not found",	-- no KML file found
}

-- Masks for external mapping providers, in the form:
--   externalLinkMasks[index-number] = { short = "short-label", long = "long-label", link = "url" }'
-- The short label is used for the title links; the long label is used for the inline links
-- Links in the output will be ordered by index-number
-- Instead of kml file's raw url or encoded raw url, use  __KML_URL__  or  __KML_URL_E__
local externalLinks = {}
externalLinks[1] = { 
	short = "Bing",
	long  = "Display on Bing Maps",
	link  = "http://www.bing.com/maps/?mapurl=__KML_URL__"
}

-- #### End of L10n settings ####

-- Table of available wikis, in the order that they are to be searched for kml files
-- (once a kml file is found, further sites are not checked)
local sites = {
	{
		mw.ustring.match( mw.site.server, "%w+" )  ..  mw.ustring.gsub( mw.ustring.lower(mw.site.siteName), "[mp]edia", ""), 
		mw.ustring.sub(mw.site.server, 3),
		""
	}, -- local wiki (listed first so local files can override files on other wikis)
	{ "commonswiki", "commons.wikimedia.org", "c:" }, -- Commons would be a logical central repository for KML files (but has no files as of August 2016)
	{ "enwiki", "en.wikipedia.org", "w:en:" }, -- largest source of KML files (as of August 2016)
	{ "bnwiki", "bn.wikipedia.org", "w:bn:" }, -- other sites with a KML template, listed in alphabetical order
	{ "cswiki", "cs.wikipedia.org", "w:cs:" },
	{ "fawiki", "fa.wikipedia.org", "w:fa:" },
	{ "frwiki", "fr.wikipedia.org", "w:fr:" },
	{ "jawiki", "ja.wikipedia.org", "w:ja:" },
	{ "mlwiki", "ml.wikipedia.org", "w:ml:" },
	{ "svwiki", "sv.wikipedia.org", "w:sv:" },
	{ "zhwiki", "zh.wikipedia.org", "w:zh:" },
}

local p, q = {}, {}

local function setCleanArgs(argsTable)
	local cleanArgs = {}
	for key, val in pairs(argsTable) do
		if type(val) == 'string' then
			val = val:match('^%s*(.-)%s*$')
			if val ~= '' then
				cleanArgs[key] = val
			end
		else
			cleanArgs[key] = val
		end
	end
	return cleanArgs
end

local function safeReplace(string, pattern, replacement)
	-- avoids "Lua error: invalid capture index" that occurs with string.gsub when the replacement contains one or more literal % character
	local nonpattern_parts = mw.text.split( string, pattern )
	return table.concat(nonpattern_parts, replacement)
end

local function makeTitleWikitext(titletext, err)
	if err and L10n.str.err_prepend then
		err =  mw.ustring.gsub( err, ">", ">" .. L10n.str.err_prepend .. " ", 1 )
	end

	local titleLinks = {}
	for i, v in ipairs( externalLinks ) do
		titleLinks[i] =  mw.ustring.format( "[%s %s]", v.link , v.short)
	end
	return mw.getCurrentFrame():extensionTag{
				name = 'indicator',
				args = { name = 'attached-kml' },
				content = mw.ustring.format(
					"<span id=\"coordinates\">\'\'\'%s\'\'\': %s</span>",
					titletext,
					err or table.concat(titleLinks, " / ")
				)
			}
end

local function makeInlineWikitext(headertext, url, err)
	local inlineLinks = {}
	for i, v in ipairs( externalLinks ) do
		inlineLinks[i] =  mw.ustring.format("[%s %s]", v.link , v.long)
	end
	local editUrl =  mw.ustring.gsub( url, "action=raw", "action=edit" )
	local wiki_link_class
	if  mw.ustring.find( editUrl, mw.site.server, 1, true ) then
		wiki_link_class = "plainlinks"
	else
		wiki_link_class = ""
	end

	if L10n.config.inline_format == "line" then
		return  mw.ustring.format(
			"<li>%s%s%s (<span class=\"%s\">[%s %s] <span style=\"font-size:85%%;\">([%s %s] • [[%s|%s]])</span></span>)</li>",
			headertext, L10n.str.line.start,
			err or table.concat(inlineLinks, L10n.str.line.separator),
			wiki_link_class, url, L10n.str.kml_file, editUrl, L10n.str.edit,
			L10n.str.help_location, L10n.str.help
		)
	end
	
	local text = mw.ustring.format(
		'%s<span class="%s">\'\'\'[%s %s]\'\'\' ([%s %s] • [[%s|%s]])</span>',
		headertext, wiki_link_class, url, L10n.str.kml_file, editUrl,
		L10n.str.edit, L10n.str.help_location, L10n.str.help
	)
	
	if err or #inlineLinks > 0 then
		text = mw.ustring.format(
			"%s<ul><li>%s</li></ul>",
			text,
			err or table.concat(inlineLinks, "</li><li>")
		)
	end
	
	return require('Module:Side box')._main({
		class = 'attached-kml',
		text = text
	})
end

local function makeKmldataDiv(link, s_index)
	return mw.ustring.format(
		'<div class="kmldata" data-server="%s" title="%s">[[%s%s]]</div>',
		sites[s_index][2], link, sites[s_index][3], link
	)
end

local function makeError(msg, cat)
	return  mw.ustring.format(
		'<strong class="attached-kml-error">%s</strong>%s',
		msg,
		mw.title.getCurrentTitle():inNamespaces(0, 118) and cat or ''
	)
end

local function getUrlFromQid( kml_qid )
	local pcall_result, kml_entity = pcall(mw.wikibase.getEntity, kml_qid)
	if not pcall_result then return nil, nil, nil, makeError(L10n.str.err.no_item, L10n.str.cat.error_noitem) end -- Error if entity doesn't exist

	local p31_claim = kml_entity:getBestStatements("P31") -- P31 is property "instance of"
	local has_good_p31
	for k, v in pairs( p31_claim ) do
		if (p31_claim[k] and p31_claim[k].mainsnak.snaktype == "value" and
			p31_claim[k].mainsnak.datavalue.type == "wikibase-entityid" and
			p31_claim[k].mainsnak.datavalue.value["numeric-id"] == 26267864) then
			has_good_p31 = true
		end
	end
	if not (has_good_p31) then -- Error if item isn't a kml file
		return nil, nil, nil, makeError(L10n.str.err.bad_qid, L10n.str.cat.error_badqid)
	end 

	local kml_sitelink
	local kml_siteindex
	local kml_url
	for i, v in ipairs( sites ) do
		kml_sitelink = kml_entity:getSitelink( v[1] )
		if kml_sitelink then
			kml_url = "https://" .. v[2] .. "/w/index.php?title=" .. mw.uri.encode( kml_sitelink, "WIKI" ) .. "&action=raw"
			kml_siteindex = i
		end
		if kml_url then break end
	end
	return kml_url or nil, kml_sitelink or nil, kml_siteindex or nil, nil
end

-- Attempts to get url from linked wikidata items, will return nil if it can't
local function getUrlFromWikidata()
	local entity = mw.wikibase.getEntityObject()
	if not entity then return nil end			

	local kml_claim = entity:getBestStatements("P3096")	-- P3096 is property "KML file"
	
	if kml_claim then
		-- get the QID of the first value of the property
		if (kml_claim[1] and kml_claim[1].mainsnak.snaktype == "value" and kml_claim[1].mainsnak.datavalue.type == "wikibase-entityid") then
			local kml_qid = "Q" .. kml_claim[1].mainsnak.datavalue.value["numeric-id"]
			return getUrlFromQid( kml_qid )
		else
			return nil	-- TODO: error message
		end
	else
		return nil	-- TODO: error message
	end
end

function p.main(frame)
	local parent = frame
	local Args = setCleanArgs(frame.args)

	local qid = Args[L10n.para.wikidata] or nil

	-- get KML file url
	local wikiUrl, wikiTitle, wikiLink, trackingWikitext, kmlError
	if not (Args[L10n.para.from]) then
		if not qid then
			wikiUrl, wikiLink, siteindex, kmlError = getUrlFromWikidata()
		elseif  mw.ustring.find( qid, "^Q%d+" ) then
			wikiUrl, wikiLink, siteindex, kmlError = getUrlFromQid(qid)
		else
			kmlError = makeError(L10n.str.err.malformed_qid, L10n.str.cat.error_mqid)
		end
	end
	
	if not (wikiUrl) then
		-- FIXME? this smells bad. shouldn't need to make a new title of a to_string
		-- from the current title and then turn it into text form
		wikiLink = Args[L10n.para.from] or mw.title.new(tostring(mw.title.getCurrentTitle())).text
		wikiLink = L10n.str.kml_prefix .. wikiLink
		wikiTitle = mw.title.new( wikiLink )

		if not (wikiTitle.exists) and not (kmlError) then
			if Args[L10n.para.from] then
				kmlError = makeError(L10n.str.err.bad_from, L10n.str.cat.error_from)
			else
				kmlError = makeError(L10n.str.err.no_kml, L10n.str.cat.error_nokml)
			end
		end
		wikiUrl = wikiTitle:fullUrl("action=raw", "https")
		siteindex = 1
		trackingWikitext =  mw.ustring.format(
			'<div title="KML & Wikidata" class="attached-kml-wikidata">KML is not from Wikidata</div>%s',
			mw.title.getCurrentTitle():inNamespace(0) and L10n.str.cat.local_kml or ''
		)
	else
		trackingWikitext =  mw.ustring.format(
			'<div title="KML & Wikidata" class="attached-kml-wikidata">KML is from Wikidata</div>%s',
			mw.title.getCurrentTitle():inNamespace(0) and L10n.str.cat.wikidata_kml or ''
		)
	end
	
	wikiTitle = mw.title.new( wikiLink )
	if wikiTitle.exists then
		local transclusion = wikiTitle:getContent() -- hack to register the template as transcluded.
	end
		
	-- replace __KML_URL__ or __KML_URL_E__ with actual values
	local encodedWikiUrl = mw.uri.encode(wikiUrl, "PATH")
	for i, v in ipairs( externalLinks ) do
		local el1 = safeReplace( v.link, "__KML_URL__", wikiUrl )
		local el2 = safeReplace( el1, "__KML_URL_E__", encodedWikiUrl )
		externalLinks[i]["link"] = el2
	end

	-- suppress errors and categories if demo parameter is set
	if Args[L10n.para.demo] then
		kmlError = nil
		trackingWikitext = ""
	end

	local wikitext = ""
	if Args[L10n.para.display] then
		local display = mw.text.split(Args[L10n.para.display], '%s*' .. L10n.str.dsep .. '%s*')
		if display[1] == L10n.str.title or display[2] == L10n.str.title then
			wikitext = makeTitleWikitext(Args[L10n.para.title] or L10n.str.default_title, kmlError)
		end
		if display[1] == L10n.str.inline or display[2] == L10n.str.inline or (display[1] ~= L10n.str.title and display[2] ~= L10n.str.title) then
			local inlineWikitext = makeInlineWikitext(Args[L10n.para.header] or L10n.str.default_header, wikiUrl, kmlError)
			wikitext = wikitext .. inlineWikitext
		end
	else
		wikitext = makeInlineWikitext(Args[L10n.para.header] or L10n.str.default_header, wikiUrl, kmlError)
	end
	wikitext = wikitext .. makeKmldataDiv(wikiLink, siteindex) .. trackingWikitext

	return frame:extensionTag{
		name = 'templatestyles', args = { src = 'Module:Attached KML/styles.css' }
	} .. frame:preprocess( wikitext )

end

function q.main(frame)
   local entity = mw.wikibase.getEntity(frame.args.Q)
   local entity = mw.wikibase.getEntity()

   local kml = entity:getBestStatements("P3096")

   if entity==nil then
      return frame:preprocess("Hello".."Bye")
   else
      return frame:preprocess("Hello"..tostring(kml[1]).."Bye")
   end
end

return q