local MessageBox = require("Module:Message box")
local yesno = require("Module:Yesno")

local p = {}

local function demoCheck(args)
	return yesno(args["demo"]) or yesno(args["nocat"])
end

local function showWarning(text, nocat)
	mw.addWarning(text)
	return nocat and "" or "[[Category:Pages with backwards copy warnings]]"
end

local function delink(text)
	if text == nil then
		return nil
	end
	return string.gsub(string.gsub(require("Module:Delink")._delink{text}, "%[%[", ""), "%]%]", "")
end

local function showError(text, nocat)
	return string.format(
		"%s%s %s",
		nocat and "" or "[[Category:Pages with backwards copy errors]] ",
		tostring(
			mw.html.create("span")
				:css("color", "var(--color-error)")
				:css("font-weight", "bold")
				:wikitext("Error:")
		),
		text
	)
end

local function row(args, i)
	return mw.html.create("li"):wikitext(rowText)
end

local function bannerText(frame, args)
	local text = ""
	
	local id = args["id"] or args["revid"]
	if id ~= nil then
		text = string.format("Revisions succeeding [[Special:Diff/%s|this version]] of this", id)
	else
		text = "This"
	end
	
	local citations = {}
	local i = 1
	while (
		args[tostring(i)] or 
			(args["articlename" .. i] or (i == 1 and args["articlename"])) or 
			(args["title" .. i] or (i == 1 and args["title"]))
	) do
		if args[tostring(i)] then
			table.insert(citations, args[tostring(i)])
		else
			local author = args["author" .. i] or (i == 1 and args["author"])
			local date = (args["date" .. i] or (i == 1 and args["date"])) or
				-- legacy way of providing dates
				string.format(
					"%s %s",
					args["monthday" .. i] or (i == 1 and args["monthday"]) or "",
					args["year" .. i] or (i == 1 and args["year"]) or ""
				)
				
			if mw.text.trim(date or "") == "" then
				if string.match(author or "", "(%d%d%d[%d]+)") then
					text = text .. " " .. showWarning(string.format(
						"A <code>year%s</code> or <code>date%s</code> parameter was not found, but a parenthesized year was found in the " ..
						"<code>author%s</code> parameter. Move the provided year to the correct parameter.",
						i, i, i
					), demoCheck(args))
				else
					text = text .. " " .. showWarning(string.format(
						"Provided <code>title%s</code> must also have a respective <code>year%s</code> or <code>date%s</code> parameter.",
						i, i, i
					))
				end
			end

			local display_authors = args["display-authors" .. i] or (i == 1 and args["display-authors"]);	-- get |display-authors= parameter value for this reference
			if tonumber (display_authors) and (0 ~= tonumber (display_authors)) then		-- for {{backwards copy}} only allowed number is 0 to suppress author name list
				display_authors = 'etal';										-- any other number gets 'etal'; any other text will be rejected by cs1|2
			end
			
			table.insert(citations, frame:expandTemplate{ title = "Citation", args = {
				ref = "none",
				author = author,
				["display-authors"] = display_authors,
				date = date,
				url = args["url" .. i] or (i == 1 and args["url"]),
				title = (args["articlename" .. i] or (i == 1 and args["articlename"]))
					or args["title" .. i] or (i == 1 and args["title"]),
				publisher = (args["org" .. i] or (i == 1 and args["org"]))
					or args["publisher" .. i] or (i == 1 and args["publisher"])
			} })
		end
		
		i = i + 1
	end

	text = string.format(
		"%s article is substantially duplicated in one or more external publications. " ..
		"Since these publication(s) copied Wikipedia, rather than the reverse, please do not flag this article as a copyright violation of the following source",
		text
	)
	local citationCount = #citations
	if citationCount == 0 then
		return showError(
			"No citations were provided. Provide at least one citation using <code>title</code>.", 
			demoCheck(args)
		)
	elseif citationCount > 1 then
		text = string.format("%ss:", text)
	else
		text = string.format("%s:", text)
	end
	
	local ul = mw.html.create("ul")
	for k, v in pairs(citations) do
		ul:node(mw.html.create("li"):wikitext(v))
	end
	
	text = string.format(
		"%s %s %s",
		text,
		tostring(ul),
		args["comments"] and tostring(
			mw.html.create("table")
				:attr("class", "mw-collapsible mw-collapsed")
				:attr("style", "width:100%; background-color: var(--background-color-warning-subtle);color:var(--color-base);")
				:node(mw.html.create("tr")
					:node(mw.html.create("th")
						:wikitext("Additional comments")
					)
				)
				:node(mw.html.create("tr"):node(mw.html.create("td")
					:attr("style", "background-color: var(--background-color-base); color:var(--color-base); border: 1px solid #c0c090; padding: 0.25em 0.5em;")
					:wikitext(
						args["comments"]
					)
				))
		) or ""
	)
	
	return text
end

function p.renderBanner(frame, args)
	return MessageBox.main('tmbox', {
		name = "backwards-copy",
		small = yesno(args["small"]),
		image = '[[File:Newspaper Cover.svg|50px]]',
		text = bannerText(frame, args)
	}) .. ((demoCheck(args) or mw.title.getCurrentTitle().namespace == 10) and
		"" or "[[Category:Wikipedia article talk pages incorporating the backwards copy template]]"
	)
end

function p.main(frame)
	local getArgs = require('Module:Arguments').getArgs
	local args = getArgs(frame, {
		trim = true,
		removeBlanks = true
	})
	return p.renderBanner(frame, args)
end

return p