local p = {}

local yn = require('Module:Yesno')

local getArgs = require('Module:Arguments').getArgs

-- simple module that takes in an input and displays the input and output of a wikitext

-- helper function which gets all the locations of all the matches of a ustring

function p._getAllMatchIndices(text, pattern)

	local output = {}

	local i = 0

	while i ~= nil do

		i = mw.ustring.find(text, pattern, i + 1)

		if i ~= nil then table.insert(output, i) end

	end

	return output

end



-- replaces all usages of \[, \], \<, \> \\, \{, and \} with [, ], <, >, \, {,  and }

-- also replaces line breaks, carriage returns, and tabs with their appropriate character

function p._escapeAllCharacters(text)

	local indices = p._getAllMatchIndices(text, "\\")

	local splitText = mw.text.split(text, '')

	local skip = false

	for k,v in ipairs(indices) do

		if not skip then

			splitTextv = ''

			local nc = splitTextv + 1

			splitTextv + 1 = (

				nc == "e" and '=' or

				nc == "p" and '|' or

				nc == '[' and mw.getCurrentFrame():preprocess('<nowiki>[</nowiki>') or

				nc == ']' and mw.getCurrentFrame():preprocess('<nowiki>]</nowiki>') or

				nc == '{' and mw.getCurrentFrame():preprocess('<nowiki>{</nowiki>') or

				nc == '}' and mw.getCurrentFrame():preprocess('<nowiki>}</nowiki>') or

				nc == '<' and mw.getCurrentFrame():preprocess('<nowiki><</nowiki>') or

				nc == '>' and mw.getCurrentFrame():preprocess('<nowiki>></nowiki>') or

				nc == '&' and mw.getCurrentFrame():preprocess('<nowiki>&amp;</nowiki>') or

				splitTextv + 1

			)

			mw.log(splitTextv + 1])

			if nc == '\\' then

				skip = true	

			end

		else

			skip = false	

		end

	end

	return table.concat(splitText)

end



function p._escapeHTMLCharCodes(str)

	local function replaceHTMLCharCodes(entity)

		mw.log(entity)

		local charCode = mw.ustring.match(entity, "%d+") and tonumber(mw.ustring.match(entity, "%d+")) or mw.ustring.match(entity, "%w+;")

		mw.log(charCode)

		if type(charCode) == 'number' then

			return mw.ustring.char(charCode)

		else

			local HTMLCharCodes = {

				"amp;" = "&",

				"gt;" = ">",

				"lt;" = "<"

			}

			local replacementChar = HTMLCharCodescharCode or entity

			return replacementChar

		end

	end

	return mw.ustring.gsub(str, "%&%S-;", replaceHTMLCharCodes)

end



function p._removeAllLinks(text)

	-- find all [ and ] characters and remove them

	local splitText = mw.text.split(text, '')

	local numberOfBrackets = 0

	local endCharacter = false

	for k,v in ipairs(splitText) do

		if splitTextk == '[' then

			numberOfBrackets = numberOfBrackets + 1

			endCharacter = false

			if numberOfBrackets > 2 then numberOfBrackets = 2 else splitTextk = '' end

		elseif splitTextk == ']' then

			numberOfBrackets = numberOfBrackets - 1

			endCharacter = false

			if numberOfBrackets < 0 then numberOfBrackets = 0 else splitTextk = '' end

		else

			if numberOfBrackets == 2 then

				if not endCharacter then

					endCharacter = splitTextk == '|'

					splitTextk = ''

				end

			elseif numberOfBrackets == 1 then

				if not endCharacter then

					endCharacter = splitTextk == ' '

					splitTextk = ''

				end

			end

		end

	end

	return table.concat(splitText)

end



function p._removeXML(text)

	-- finds all xml tags and remove them

	local splitText = mw.text.split(text, '')

	local numberOfBrackets = 0

	local numberOfDoubleQuotes = 0

	local numberOfSingleQuotes = 0

	for k,v in ipairs(splitText) do

		if splitTextk == '<' then

			numberOfBrackets = numberOfBrackets + 1

			if numberOfBrackets > 1 then numberOfBrackets = 1 else splitTextk = '' end

		elseif splitTextk == '>' then

			numberOfBrackets = numberOfBrackets - 1

			if numberOfBrackets < 0 then numberOfBrackets = 0 else splitTextk = '' end

		else

			if numberOfBrackets == 1 then

				splitTextk = ''

			end

		end

	end

	return table.concat(splitText)

end



-- from Wikipedia

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 pfuncName](args)

	end

end



p.main = makeInvokeFunc("_main")

function p._main(args)

	local nowiki = yn(args'nowiki']) or false

	local format = args'format' or 'block'

	local code = p._code(args)

	local result = p._result(args)

	if format == 'inline' then

		return 'Using this code: ' .. code .. ' yields: ' .. result

	else

		return '<dl><dt>Using this code:</dt><dd>'

			.. code

			.. '</dd><dt>yields: </dt><dd>'

			.. result

			.. '</dd></dl>'--output the result

	end

end



p.code = makeInvokeFunc("_code")

function p._code(args)

	local nowiki = yn(args'nowiki']) or false

	local text = p._raw(args)

	local format = args'format' or 'block'

	local syntaxhighlight = yn(args"syntaxhighlight"]) or false

	if not syntaxhighlight then

		local code = format == 'inline'

			and mw.getCurrentFrame():preprocess("<code>" .. text .. "</code>")

			or mw.getCurrentFrame():preprocess("<code style=\"display:inline-block;\">" .. text .. "</code>")

		return code

	else

		local code = format == "inline"

			and mw.getCurrentFrame():preprocess("<syntaxhighlight inline lang=\"wikitext\">" .. text .. "</syntaxhighlight>")

			or mw.getCurrentFrame():preprocess("<syntaxhighlight lang=\"wikitext\">" .. text .. "</syntaxhighlight>")

		return code

	end

end



p.raw = makeInvokeFunc("_raw")

function p._raw(args)

	local nowiki = yn(args'nowiki']) or false

	local syntaxhighlight = yn(args"syntaxhighlight"]) or false

	local text = (nowiki or syntaxhighlight) and args1 or p._escapeAllCharacters(args1])

	mw.log(text)

	return text

end



p.result = makeInvokeFunc("_result")

function p._result(args)

	local nowiki = yn(args'nowiki']) or false

	local text = p._raw(args)

	mw.log(p._removeXML(

		p._removeAllLinks(text)

	))

	local result = (yn(args'nowiki']) or yn(args'syntaxhighlight']))

		and mw.getCurrentFrame():preprocess(mw.text.unstripNoWiki(text))

			or mw.getCurrentFrame():preprocess(

				p._escapeHTMLCharCodes(

					mw.text.unstripNoWiki(

						p._removeXML(

							p._removeAllLinks(text)

						)

					)

				)

			)

		or ''

	mw.log(result)

	return result

end

return p