require("strict")
local p = {}

local function resolveqid(label)
	local resolveEntity = require("Module:ResolveEntityId")._id
	local qid
	local rawlabel
	if label then
		rawlabel = string.match(label,'%[%[([^%|%]]+)%|') or string.match(label,'%[%[([^%|%]]+)%]%]')
		if rawlabel then
			qid = resolveEntity(rawlabel)
		else
			rawlabel = label
		end
	end
	return qid,rawlabel
end

local function tidystring(string)
	local tidy = mw.ustring.gsub(string,"%<ref.+%<%/ref%>","") -- remove any references with <ref .. </ref>
	tidy = mw.ustring.gsub(tidy,"%<ref.+%/%>","") -- remove any references with <ref .. />
	tidy = mw.text.trim(tidy) -- trim spaces
	return tidy
end

function p.import(frame)
	local tab = "|"
	local wikiqid = "Q328" -- QID for English Wikipedia
	local eol = "<br>" -- end of line string
	local coord2text = require("Module:Coordinates/sandbox")._coord2text
	local args = frame.args or frame:getParent().args
	if not args.page then
		return "No page specified."
	end
	if not args.config then
		return "No configuation."
	end
	local config = {}
	for c1,col in ipairs(mw.text.split(args.config,",")) do
		config[c1] = mw.text.split(col,"-")
	end
	local common = {}
	if args.common then
		for c1,prop in ipairs(mw.text.split(args.common,",")) do
			common[c1] = mw.text.split(prop,"-")
			common[common[c1][1]] = common[c1][2] -- create index, e.g. common["P31"]=Q39715
		end
	end
	local content = mw.title.new(args.page):getContent() -- read page specified
	content = string.match(content,"%{%|(.+)%|%}") -- keep table only
	content = string.gsub(content,"||","\n|") -- use \n| for column breaks
	local rows = mw.text.split(content,"|-\n",true) -- split table into rows
	table.remove(rows,1) -- remove table definition
	table.remove(rows,1) -- remove heading row
	local output = ""
	local v2 = ""
	for rn,row in ipairs(rows) do
		local columns = mw.text.split(row,"\n|") -- split table rom into columns
		table.remove(columns,1) -- remove content before the first \n| character
		local label = columns[1]
		if label then
			label = tidystring(label)
			local qid
			qid,label = resolveqid(label) -- resolve qid if first column is link
			if not qid then
				qid = string.match(label,"Q%d+") -- check if QID is specified in first column
			end
			local entity
			if qid then
				entity = mw.wikibase.getEntity(qid)
			else
				v2 = v2 .. "CREATE" .. eol
				qid = "LAST" -- creating new item, so use LAST
				v2 = v2 .. qid .. tab .. 'Len' .. tab .. '"' .. label .. '"' .. eol
				if common["P31"] then -- create auto-description
					v2 = v2 .. qid .. tab .. 'Den' .. tab .. '"' .. mw.wikibase.getLabel(common["P31"])
					if common["P17"] then -- add country
						v2 = v2 .. ' in '
						if common["P131"] then
							v2 = v2 .. mw.wikibase.getLabel(common["P131"]) .. ", "
						end
						v2 = v2 .. mw.wikibase.getLabel(common["P17"])
					end
					v2 = v2  .. '"' .. eol
				end
				for c = 1,#common do
					v2 = v2 .. qid .. tab .. common[c][1] .. tab .. common[c][2] .. eol
				end
			end
			local function addtov2(prop,val)
				v2 = v2 .. qid .. tab .. prop .. tab .. val .. tab .. "S143" .. tab .. wikiqid .. eol
				return v2
			end
			for cn,col in ipairs(columns) do
				if config[cn] then
					local import = true
					if entity then
						if config[cn][2] then
							if entity:getAllStatements(config[cn][2])[1] then -- statement already present for this property
								import = false
							end
						else -- no property specified to import to
							import = false
						end
					end
					if import then
						col = tidystring(col)
						if  config[cn][1] == "wikilink" then
							local val = resolveqid(col)
							if val then
								v2 = addtov2(config[cn][2],val)
							end
						elseif config[cn][1] == "year" then
							local val = string.match(col,"%d%d%d%d")
							if val then
								v2 = addtov2(config[cn][2],"+" ..val .. "-00-00T00:00:00Z/9")
							end
						elseif config[cn][1] == "quantity" then
							local val = string.gsub(col,",","") -- remove any commas
							val = string.match(val,"%d+%.?%d*") -- extract value, possibly from inside convert template
							if val then
								if string.upper(string.sub(config[cn][3],1,1)) == "Q" then
									config[cn][3] = string.sub(config[cn][3],2)
								end
								v2 = addtov2(config[cn][2],val .. "U" .. config[cn][3])
							end
						elseif config[cn][1] == "text" then
							if col ~= "" then
								v2 = addtov2(config[cn][2],'"' .. col .. '"')
							end
						elseif config[cn][1] == "coord" then
							if col ~= "" then
								local val = mw.getCurrentFrame():preprocess(col)
								v2 = addtov2(config[cn][2],"@" .. coord2text(val,"lat") .. "/" .. coord2text(val,"long"))
							end
						end
					end
				end
			end
		end
	end
	return v2
end

return p