local p = {}
local mArguments = require('Module:Arguments')
local TableTools = require('Module:TableTools')

local function stripToNil(text)
	-- If text is a non-empty string, return its trimmed content.
	-- Otherwise, return nothing (text is an empty string or is not a string).
	if type(text) == 'string' then
		return text:match('(%S.-)%s*$')
	end
end

local function getDoiArgs(args)
	-- Return a list of |doiN=xxx parameter values, omitting blanks and skipped N's.
	-- LATER Should expand this to work with each exported function.
	local indices = {}
	for k, v in pairs(args) do
		if stripToNil(v) and type(k) == 'string' then
			local n = tonumber(k:match('^doi(%d+)$'))
			if n then
				table.insert(indices, n)
			end
		end
	end
	table.sort(indices)
	local parms = {}
	if stripToNil(args.doi) then
		if args.doi1 then
			error('Use doi or doi1, not both', 0)
		end
		parms[1] = args.doi
	end
	for _, n in ipairs(indices) do
		table.insert(parms, args['doi' .. n])
	end
	return parms
end

local Searcher
Searcher = {
	link = function (self, doi)
		return
			'<code>&#123;{' ..
			self.doiText ..
			'|[https://en.wikipedia.org/w/index.php?' ..
			-- 'sort=relevance&title=Special%3ASearch&profile=advanced&fulltext=1&advancedSearch-current={}&' ..  -- not needed; can include this for compatibility
			'ns0=1&ns118=1&search=insource%3A' ..
			doi:gsub('10%.', '/10\\.') ..
			'%5C%2F%20*%2F ' ..  -- '%20*' seems redundant but is needed for Special:Search to work ('x*' also works)
			doi ..
			']}&#125;</code>'
	end,
	new = function (options)
		options = options or {}
		local doiText = options.linkdoi and '[[Digital object identifier#Prefix|doi]]' or 'doi'
		return setmetatable({doiText = doiText}, Searcher)
	end
}
Searcher.__index = Searcher

function p.selected(frame)
	local n = mArguments.getArgs(frame, {parentOnly = true})
	local note = n.note
	local wantSource = {
		['User:JL-Bot/Questionable.cfg'] = true,
	}
	--local abbrev = {BLJ = '[https://beallslist.weebly.com/standalone-journals.html BLJ]', BLJU='[https://beallslist.weebly.com/standalone-journals.html BLJU]', BLP='[https://beallslist.weebly.com/ BLP]', BLPU='[https://beallslist.weebly.com/ BLPU]', SPJJ = '[https://predatoryjournals.com/journals/ SPJJ]', SPJP = '[https://predatoryjournals.com/publishers/ SPJP]', DOAJ='[https://blog.doaj.org/2014/08/28/some-journals-say-they-are-in-doaj-when-they-are-not/ Lying about DOAJ]', UCG='[https://www.ugc.ac.in/journallist/4305_Journals.pdf Removed from UGC]' QW ='[https://www.quackwatch.org/04ConsumerEducation/nonrecperiodicals.html QW]',	DEPS ='[[WP:DEPS|DEPS]]', URF ='[[#Unreliable fields|URF]]'}
	local abbrev = {Bohannon = 'Bohannon', BLJ = 'BLJ', BLJU= 'BLJU', BLP = 'BLP', BLPU = 'BLPU', SPJJ ='SPJJ', SPJP ='SPJP', DOAJ = 'DOAJ', QW='QW', DEPS ='DEPS', UCG = 'UCG', URF = 'URF', Unknown = 'Unknown'}
	local source
	if wantSource[mw.title.getCurrentTitle().fullText] then
		source = n.source or 'Unknown'
		source = abbrev[source] or source
	end
	local sourcenote
	if note and source then
		sourcenote = string.format('&nbsp;(%s) &#91;%s&#93;', source, note)
	elseif source then
		sourcenote = string.format('&nbsp;(%s)', source)
	elseif note then
		sourcenote = string.format('&nbsp;&#91;%s&#93;', note)
	else
		sourcenote = ''
	end
	local listDoi, nrDoi = {}, 0
	local function addDoi(doi, i)
		if doi then
			nrDoi = nrDoi + 1
			if i and listDoi[i] then
				table.insert(listDoi, i, doi)
			else
				listDoi[nrDoi] = doi
			end
		end
	end
	local rows = {}
	for i, v in ipairs(TableTools.compressSparseArray(n)) do
		if i == 1 then
			rows[1] = { string.format('*[[:%s]]%s', v, sourcenote) }
		elseif v:match('^10%.%d+$') then
			addDoi(v)
		else
			table.insert(rows, string.format('**[[:%s]]', v))
		end
	end
	if not rows[1] then
		error('Need at least one target parameter', 0)
	end
	for _, param in ipairs({ 'imprint', 'parent' }) do
		for i = 1, 10 do
			local arg = n[param .. i]
			if arg then
				table.insert(rows[1], string.format("''[[%s]]''", arg))
			end
		end
	end
	if n.doi and n.doi1 then
		error('Use doi or doi1, not both', 0)
	end
	for i = 1, 10 do
		local doi
		if i == 1 then
			doi = n.doi or n.doi1
		else
			doi = n['doi' .. i]
		end
		addDoi(doi, i)
	end
	local search = Searcher.new()
	for i = 1, nrDoi do
		local doi = listDoi[i]
		table.insert(rows,
			'**' .. search:link(doi)
		)
	end
	rows[1] = table.concat(rows[1], ' / ')
	return table.concat(rows, '\n')
end

function p.doilist(frame)
	local doiList = getDoiArgs(frame:getParent().args)
	if not doiList[1] then
		return ''
	end
	local search = Searcher.new({linkdoi = true})
	for i, doi in ipairs(doiList) do
		doiList[i] = search:link(doi)
	end
	return
		"&nbsp;| <b><span class=plainlinks>" ..
		table.concat(doiList, '&nbsp;<b>&middot;</b> ') ..  -- middot is double bold
		"</span></b>"
end

function p.exclude(frame)
	local n = mArguments.getArgs(frame, {parentOnly = true})
	local length = TableTools.length(n)
	local text = string.format('*[[:%s]]', n[1] or '')
	n[1] = nil
	for _, v in ipairs(TableTools.compressSparseArray(n)) do
		if length > 1 then
			text = text .. string.format(" ≠ [[:%s]]", v)
		end
	end
	return text
end

function p.pattern(frame)
	local rows = {}
	for i, v in ipairs(frame:getParent().args) do
		v = mw.text.trim(v)
		if v == '' then
			rows[i] = ''
		elseif i == 1 then
			rows[i] = string.format('*[[%s]]', v)
		else
			rows[i] = string.format("\n**<code>%s</code>", v
				:gsub("%.%*", "<b><span style=color:#006400;>.*</span></b>")
				:gsub("!", "<b><span style=color:#8B0000;>!</span></b>")
				:gsub("'", "&rsquo;")
			)
		end
	end
	if not rows[1] then
		error('pattern requires parameter 1', 0)
	end
	return table.concat(rows)
end

return p