local p = {}

local data = mw.loadData( 'Module:Interlinear/data' )

local gloss_override = {} -- for custom gloss abbreviations

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

local yesno = require('Module:Yesno')

local lang_data = mw.loadData( 'Module:Lang/data' )



--------------------------

-- Almost-global variables

--------------------------

local glossing_type, displaying_messages, free_translation, msg, buffer



-------------------

-- General settings

-------------------

local conf = { --settings

	WordSeparator = " \n\r\t", -- Don't replace with %s as this would include non-breaking spaces

	GlossAbbrPattern = "^([Ø0-9A-Z]+)$", -- this isn't a full regex, but a Lua pattern

	-- NOTE: The following characters must be formatted for use in a pattern set.

	GlossAbbrBoundary = "-.,;:<>‹›/\\~+=%?%s%[%]()%_\127'",

	GlossExcludeTable = {I = true,}, --strings not be treated as glossing abbreviations

	GlossExcludePattern = '^[0-9][0-9]+$', -- excludes strings consisting entirely of digits

	GlossSmallCapsExclude = "^[AOPS]$", -- glossing abbreviations matching this pattern will not be rendered in small caps

	GlossingType = "label", -- if set to "label" gloss abbreviations are formatted as an <abbr> with the "label" appearing in a tooltip

						-- if set to "wikilink" the abbreviation is formatted as a wikilink to the relevant wikipedia article

						-- if set to "none" abbreviations aren't formatted at all

	ErrorCategory = "[[Category:Pages with errors in interlinear text]]",

	AmbiguousGlossCategory = "[[Category:Articles with ambiguous glossing abbreviations]]",

	MessageGlossingError = "Error(s) in interlinear glossing",

	combining_gender_numbers = "[0-9][0-9]?$", --e.g. G4 '4th gender' or CL7 'class 7'

	combining_gender_prefixes = {G = "gender", CL = "class"},

	combining_person = {["1" = "first person", "2" = "second person", "3" = "third person"},

	combining_number = {S = "singular", SG = "singular", P = "plural", PL = "plural", D = "dual", DU = "dual", TRI = "trial"},

	combining_gender = {F = "feminine", M = "masculine", N = "neuter"},

	LowerCaseGlosses = {["1sg" = true, "2sg" = true, "3sg" = true, "1du" = true, "2du" = true, "3du" = true, "1pl" = true, "2pl" = true,

		"3pl" = true, "Fsg" = true, "Fpl" = true, "Msg" = true, "Mpl" = true,}, -- these are the non-all-upper-case strings that will be recognised as glossing abbreviations

	ErrorHelpLocation = "Template:Interlinear",

}



---------------------

-- CSS styles and classes

---------------------

conf.style = { --CSS styles

	WordDiv = "float: left; margin-bottom: 0.3em;",

	WordMargin = "margin-right: 1em;",

	WordP = "margin: 0px;", -- the style for the word <p> elements

	GlossAbbr = "font-variant: small-caps; font-variant-numeric: oldstyle-nums; text-transform: lowercase; ", -- won't be applied to gloss abbreviations containing lower-case characters

	HiddenText = "display: none;",

	EndDiv = "clear: left; display: block;", -- style of the <div> element at the end of the interlinear display

	ErrorMessage = "font-size: inherit",

}

conf.class = { --CSS classes

	Interlinear = "interlinear",

	GlossAbbr  = "gloss-abbr",

	GlossAbbrAmb = "gloss-abbr-ambiguous",

	GlossAbbrError = "gloss-abbr-error",

	ErrorMessage = "error",

}

---------------------

-- Section transclusion

---------------------

local page_content = nil -- lazy initilization

local function get_section(frame, section_name)

	if page_content == nil then

		local current_title = mw.title.getCurrentTitle()

		page_content = current_title:getContent()

	end

	if page_content then

		if mw.ustring.find(page_content, section_name, 1, true) then

			return frame:preprocess('{{#section:{{FULLPAGENAME}}|' .. section_name .. '}}')

		end

	end

	return ''

end

---------------------

-- Sundry small functions

---------------------

local function normalise(str)

	return mw.ustring.gsub(str,"[" .. conf.WordSeparator .. "]+"," ")

end



local function tidyCss(str)

	str = mw.ustring.gsub(str, '^[\"\']*(.-)[\"\']*$', "%1") -- trims quotation marks

	if mw.ustring.sub(str, -1) ~= ";" then str = str .. ";" end -- appends ";" if missing

	return str

end



local function highlight(text)

	if text then

		return '<span style="color:#C00;font-weight:bold;">' .. text .. '</span>'

	else return "" end

end



local function tone_sup(str)

	return mw.ustring.gsub(str, "([^%p%s0-9])([0-9]+)", "%1<sup>%2</sup>")

end



local function is_empty(str) -- returns "false" if its argument is a string containing chars other than spaces &c.

	if not str then return true end

	if mw.ustring.find(str, "[^" .. conf.WordSeparator .. "]")

		then return false

	else return true end

end



local function help_link (anchor)

	if anchor then

		return " ([[" .. conf.ErrorHelpLocation .. "#" .. anchor .. "|help]])"

	else return "" end

end



-- the following is part of a trial implementation of automatic transliteration:

local function transliterate (str, lang_from, lang_to,  scheme)

	local lookup = {grc = {module = 'Module:Ancient Greek', funct = "transliterate", } }

	if not lang_from then

		msg:add("error", "Source language for transliteration is not set")

	else

		local t = lookuplang_from

		if t then

			local module = require(t.module)

			return modulet.funct](str)

		else msg:add("error", "Can't find transliterator for language '" .. lang_from .. "'")

		end

	end

	return ""

end -- end of trial block



--------------------

-- The following two functions update the glossing settings based on the received

-- template arguments. set_global_glossing_settings() updates the global settings

-- that are valid for all gloss abbreviations. set_glossing_type()

-- returns the glossing type, which can vary between the different lines.

--------------------

local function set_global_glossing_settings(a)

	local style = ""

	if a.style then style = tidyCss(a.style) end

	if a.underline == "no" then

		style = style .. "text-decoration: none;" end

	if a.small_caps == "no" then

		style = style .. "font-variant:normal; text-transform: none;" end

	if style ~= "" then conf.style.GlossAbbr = conf.style.GlossAbbr .. style end

end



local function set_glossing_type(glossing)

	if glossing then

		local GlossingType

		glossing = mw.ustring.lower(mw.text.trim(glossing))

		if mw.ustring.find(glossing, 'link') then

			GlossingType = "wikilink"

		elseif mw.ustring.find(glossing, 'label')

			or  mw.ustring.find(glossing, 'no link') then

			GlossingType = 'label'

		elseif mw.ustring.find(glossing, 'no abbr') then

			GlossingType = "no abbr"

		elseif yesno(glossing) == false then

			GlossingType = nil

		elseif yesno(glossing) then

			GlossingType = conf.GlossingType

		else

			msg:add('error', 'Glossing type "' .. glossing .. '" not recognised') end

		return GlossingType

	else error("set_glossing_type: 'glossing' is nil or false", 2)

	end

end



local function set_custom_glosses(list)

	local abbs = mw.text.split(list, '[;\n\t]')

	for _,v in pairs(abbs) do

		local gloss = mw.text.split(v, ':')

		local a = mw.text.trim(gloss1])

		if a and a ~= "" then

			gloss_overridea = {}

			gloss_overridea].expansion = gloss2

			gloss_overridea].wikipage = gloss3

		end

	end

end



---------------------

-- The UserMessages object contains and processes error messages and warnings

---------------------

local UserMessages = {errors = {}, warnings = {}, gloss_messages = {}}

function UserMessages:add(msgtype, text, gloss)

	if msgtype == "gloss_message" then

		self.gloss_messagesgloss = text

	elseif msgtype == "warning" then

		table.insert(self.warnings, text)

	elseif msgtype == "non-repeating error" then

		self.errors.nre = text

	elseif msgtype == "ambiguous gloss" then

		self.if_ambiguous_glosses = true

	elseif msgtype == "error" then

		table.insert(self.errors, text)

	else return error("UserMessages:add(): unknown message type", 2)

	end

end

function UserMessages:print_errors()

	local out = ""

	local namespace = mw.title.getCurrentTitle().namespace

	if next(self.errors) or self.warnings1 then

		local err_span = mw.html.create("span")

		err_span:attr("style", conf.style.ErrorMessage)

		err_span:addClass(conf.class.ErrorMessage)

		for _,v in pairs(self.errors) do

			err_span:wikitext(" " .. v .. ";") end

		if namespace % 2 == 0 and namespace ~= 2 -- non-talk namespaces, excluding user pages; if modifying please update the description on the category page

			then err_span:wikitext(conf.ErrorCategory)

		end

		out = tostring(err_span)

		mw.addWarning(conf.MessageGlossingError)

	end

	if self.if_ambiguous_glosses then

		if namespace == 0 -- article namespace

			then out = out .. conf.AmbiguousGlossCategory -- this category will only track articles

		end

	end

	return out

end

function UserMessages:print_warnings()

	local out = ""

	-- Messages and warnings get displayed only if the page is being viewed in "preview" mode:

	if displaying_messages and (next(self.gloss_messages) or next(self.warnings)) then

		local div = mw.html.create("div")

		div:addClass("interlinear-preview-warning")

			:cssText('border: 1px solid #a2a9b1; background-color: #f8f9fa; width: 80%; padding: 0.2em;')

			:wikitext("<i>This message box is shown only in preview:</i>")

			:newline()

		for _,v in ipairs(self.warnings) do

			local p = div:tag("p")

			p:addClass(conf.class.ErrorMessage)

			p:attr("style", conf.style.ErrorMessage)

			p:wikitext(v)

		end

		if self.gloss_messages then

			div:wikitext("<p>  To change any of the following default expansions, see [[Template:Interlinear/doc#Custom abbreviations|the template's documentation]]:</p>")

			end

		for _,v in pairs(self.gloss_messages) do

			div:wikitext("<p>" .. v .. "</p>")

		end

		out = out .. "\n\n" .. tostring(div)

	end

	return out

end



---------------------

-- gloss_lookup() receives a gloss abbreviation and tries to uncover its meaning.

---------------------

local function gloss_lookup(a, label, wikilink)

	local _label, _wikilink, _lookup, source = nil, nil, nil, nil

	if gloss_overridea then

		_lookup = gloss_overridea

		source = "local"

	elseif data.abbreviationsa then _lookup = data.abbreviationsa end

	if _lookup and _lookup.expansion ~= "" then

		_label, _wikilink = _lookup.expansion, _lookup.wikipage

	else

		local prefix = mw.ustring.sub(a,1,1)

		local suffix = mw.ustring.sub(a,2)

		if conf.combining_personprefix then -- is it of the form 1PL or 3FS?

			_label = conf.combining_personprefix

		local _suffix = conf.combining_numbersuffix or conf.combining_gendersuffix

			if _suffix then

				_label = _label .. ", " .. _suffix

			else

				local suffix1 = mw.ustring.sub(suffix,1,1)

				local suffix2 = mw.ustring.sub(suffix,2)

					if conf.combining_gendersuffix1

					and  conf.combining_numbersuffix2 then

						_label = _label .. ", " .. conf.combining_gendersuffix1 .. ", " .. conf.combining_numbersuffix2

					else _label = nil end

			end

	elseif mw.ustring.match(suffix,conf.combining_gender_numbers) then -- cases like G4 = gender 4

		local _i,_j = mw.ustring.find(a, conf.combining_gender_numbers)

		local _pre = mw.ustring.sub(a, 1, _i - 1)

		local _suff = mw.ustring.sub(a, _i)

		if conf.combining_gender_prefixes_pre then

			_label = conf.combining_gender_prefixes_pre .. " " .. _suff

		end

	elseif prefix == "N" then -- dealing with cases like NPST = non-past

		local s = gloss_overridesuffix or data.abbreviationssuffix

			if s ~= nil and not s.ExcludeNegation then

				_label = "non-" .. s.expansion

				_wikilink = s.wikipage

			end

			s = nil

		end

	end

	if _label == "" then _label = nil end

	if _wikilink == "" then _wikilink = nil end

	if not label then label = _label end

	if not wikilink then wikilink = _wikilink end

	return label, wikilink, source

end



---------------------

-- format_gloss() calls gloss_lookup() to find the meaning of a gloss

-- abbreviation, which it then proceeds to format

---------------------

local function format_gloss(gloss, label, wikilink)

	if string.sub(gloss,1,3) == "000" then -- checks for a common component of exposed strip markers (see [[:mw:Strip marker]])

		return gloss

	end

	local gloss2 = mw.ustring.gsub(gloss,"<.->","") -- remove any html fluff

	gloss2 = mw.ustring.gsub(gloss2, "%'%'+", "") -- remove wiki bold/italic formatting

	gloss2 = mw.text.trim(mw.ustring.upper(gloss2))

	if not (label or wikilink)

		or (not label and glossing_type == "label")

		or (not wikilink  and glossing_type == "wikilink")

		then

			if glossing_type ~= "no abbr"

				then label, wikilink, source = gloss_lookup(gloss2, label, wikilink)

			end

	end

	local gloss_node

	if glossing_type == "no abbr"

		then gloss_node = mw.html.create("span")

	else gloss_node = mw.html.create("abbr") end

	gloss_node:addClass(conf.class.GlossAbbr)

	if label or wikilink then

		if not mw.ustring.match(gloss, "%l") -- excluding glosses that contain lower-case characters

			and not mw.ustring.match(gloss,conf.GlossSmallCapsExclude) -- and also excluding A, O etc. from rendering in small caps

			then gloss_node:attr("style", conf.style.GlossAbbr)

		end

		local abbr_label

		if label then abbr_label = label

			else abbr_label = wikilink end

		gloss_node:attr("title", abbr_label)

		if source ~= "local" and data.abbreviationsgloss2 then

			if data.abbreviationsgloss2].ambiguous then

				gloss_node:addClass(conf.class.GlossAbbrAmb)

					msg:add("ambiguous gloss")

				end

		end

		if glossing_type == "wikilink" and wikilink

			then gloss_node:wikitext("[[", wikilink, "|" , gloss, "]]")

			else gloss_node:wikitext(gloss) end

		if source ~= "local" and displaying_messages then -- logging gloss lookups:

			local message = ""

			if label then

				message = "assuming " .. gloss2 .. " means \"" .. abbr_label .. "\";" end

			if glossing_type == "wikilink" and wikilink then

				message = message .. " linking to [[" .. wikilink .. "]];"

			end

			msg:add("gloss_message", message, gloss)

		end

	elseif glossing_type == "no abbr"

		then gloss_node

				:attr("style", conf.style.GlossAbbr)

				:wikitext(gloss)

	else

		if displaying_messages then

			msg:add("warning", "Gloss abbreviation " .. highlight(gloss2) .. "  not recognised" .. help_link("gloss abbr"))

		end

		msg:add("non-repeating error", "Unknown glossing abbreviation(s)" .. help_link("gloss abbr"))

		gloss_node

			:addClass(conf.class.GlossAbbrError)

			:addClass("error")

			:css("font-size", "100%")

			:attr("title", gloss2 .. ": glossing abbreviation not found")

			:attr("style", conf.style.ErrorMessage)

			:wikitext(gloss)

	end

	return tostring(gloss_node)

end



---------------------

-- find_gloss() parses a word into morphemes, and it calls format_gloss()

-- for anything that looks like a glossing abbreviation.

---------------------

local function find_gloss(word)

	local function scan_gloss(boundary, gloss_abbr) -- checks a morpheme if it is a gloss abbreviation

		if (mw.ustring.match(gloss_abbr, conf.GlossAbbrPattern)

			or conf.LowerCaseGlossesgloss_abbr])

			and not (conf.GlossExcludeTablegloss_abbr

				or mw.ustring.match(gloss_abbr, conf.GlossExcludePattern))

			then gloss_abbr = format_gloss(gloss_abbr)

		end

		return boundary .. gloss_abbr

	end

	local word = mw.text.decode(word, true)

	if word == "I" -- for the case of the English word "I", the 1SG pronoun

		then return word end

	local pattern = "([" .. conf.GlossAbbrBoundary .. "]?)([^" .. conf.GlossAbbrBoundary .. "]+)"

	word = mw.ustring.gsub(word, pattern, scan_gloss) -- splits into morphemes

	return word

end



---------------------

-- The main purpose of the bletcherous parse() is to split a line into words and and then for each eligible word

-- to call find_gloss(). The parser outputs the individual words (with any gloss abbreviation formatting applied).

-- The simple job of splitting at whitespaces has been made complicated by a) the fact that the input can contain

-- whitespaces inside the various html elements that are the result of the application of various formatting templates;

-- and b) the need to be able to recognise the output of the template that formats custom gloss abbreviations

-- (and hence skip passing it on to find_gloss). See talk for a suggestion about its future.

---------------------

local function parse(cline, i, tags_found,ifglossing)



	local function issue_error(message, culprit)

		UserMessages:add("error",  message .. ": ''" .. mw.ustring.sub(cline.whole, 1, i-1) .. "'''" .. culprit  .. "'''''")

	end

	if i > cline.length then return i end --this will only be triggered if the current line has less words than line 1

	local next_step, j, _, chunk

	local probe = mw.ustring.sub(cline.whole,i,i)

	if mw.ustring.match(probe,"[" .. conf.WordSeparator .. "]") and tags_found == 0

		then next_step =  i-1

	elseif probe == "[" then --Wikilink?

		if mw.ustring.sub(cline.whole,i+1,i+1) == "[" then

			_,j,chunk = mw.ustring.find(cline.whole,"(%[%[.-%]%])", i)

		else chunk = "["; j = i end --not a wikilink then

		buffer = buffer .. chunk

		next_step =  parse(cline, j+1,tags_found,ifglossing)

	elseif probe == "{"  and tags_found == 0 then --curly brackets enclose a sequence of words to be treated as a single unit

		_,j,chunk = mw.ustring.find(cline.whole,"(.-)(})", i+1)

		if not chunk then

			issue_error("Unclosed curly bracket", "{")

			chunk = highlight("{"); j = i

		elseif ifglossing==true then

			chunk = find_gloss(chunk)

		else

			if cline.tone_sup then chunk = tone_sup(chunk) end

		end

		buffer = buffer .. chunk

		next_step =  parse(cline, j+1,tags_found,ifglossing)

	elseif probe == "<" then -- We've encountered an HTML tag. What do we do now?

		local _,j,chunk = mw.ustring.find(cline.whole,"(<.->)",i)

		if not chunk then

			issue_error("Unclosed angle bracket", "<")

			chunk = highlight("<"); j = i

		elseif mw.ustring.sub(cline.whole,i,i+1) == "</" then -- It's a CLOSING tag

			if cline.glossing

				and ifglossing==false

				and mw.ustring.match(chunk,"</abbr>")

				then ifglossing=true end

			tags_found = tags_found - 1

		elseif not mw.ustring.match(chunk, "/>$") -- It's an OPENING tag, unless it opens a self-closing element (in which case the element is ignored)

			then if ifglossing == true -- the following checks for the output of {{ggl}}:

					and mw.ustring.find(chunk, conf.class.GlossAbbr, 1, true) -- it's important that the "find" function uses literal strings and not patterns

						then ifglossing = false end

			tags_found = tags_found + 1

		end

		buffer = buffer .. chunk

		next_step = parse(cline, j+1,tags_found,ifglossing)

	else -- No HTML tags, so we only need to find where the word ends

		local _,k,chunk = mw.ustring.find(cline.whole,"(..-)([ <[])",i)

		if k then --ordinary text

			if ifglossing==true then

				buffer = buffer .. find_gloss(chunk)

			else

				if cline.tone_sup then chunk = tone_sup(chunk) end

				buffer = buffer .. chunk

			end

			next_step = parse(cline, k, tags_found, ifglossing)

		else -- reached end of string

			if ifglossing == true then

				chunk = find_gloss(mw.ustring.sub(cline.whole,i))

			else

				chunk = mw.ustring.sub(cline.whole,i)

				if cline.tone_sup then chunk = tone_sup(chunk) end

			end

			buffer = buffer .. chunk

			next_step = cline.length

		end

	end

	return next_step

end

--------------------

-- The following function is called by Template:gcl and is used for formatting an individual glossing abbreviation

--------------------

function p.gcl(frame)

	local args = getArgs(frame,{

		trim = true,

		removeBlanks = false,

		parentOnly = true,

		wrappers = {'Template:Gcl'},

	})

	msg = UserMessages

	set_global_glossing_settings{style = args.style, underline = args.underline, small_caps = args'small-caps']}

	if not args.glossing then

		glossing_type = conf.GlossingType -- a global variable

	else glossing_type = set_glossing_type(args.glossing)

	end

	local gloss, label, wikilink = args1], args2], args3

	if not gloss then UserMessages:add("error", "No gloss supplied")

		return UserMessages:print() end

	if wikilink and not args.glossing then -- if a wikilink is supplied and glossing isn't set to 'label'...

		glossing_type = 'wikilink' end --     .. then the wikilink will be formatted as such

	if label == "" then label = nil end

	if wikilink == "" then wikilink = nil end

	local result = format_gloss(gloss, label, wikilink)

	return result

end



--------------------

-- The following is the function called by Template:Interlinear.

-- It processes the template arguments, then calls parse() to split the input lines into words

-- and it then builds the output html.

--------------------

function p.interlinearise(frame)

---------------------

-- Prepare arguments

---------------------

	local if_auto_translit = false

	local args = getArgs(frame, { -- configuration for Module:Arguments

		trim = true,

		removeBlanks = false,

		parentFirst = true,

		wrappers = {'Template:Interlinear', 'Template:Fs interlinear'},

	})

	local template_name = frame:getParent():getTitle()

	if template_name == 'Template:Fs interlinear' then

		args.italics1 = args.italics1 or "no"

		args.italics2 = args.italics2 or "yes"

		args.glossing3 = args.glossing3 or "yes"

		if args.lang and not args.lang2 then args.lang2 = args.lang .."-Latn" end

		if args.transl and not args.transl2 then args.transl2 = args.transl end

		if_auto_translit = true



	end

	local revid = frame:preprocess( "{{REVISIONID}}" )

	if  revid == "" then

		if not args'display-messages' or yesno(args'display-messages']) then

		displaying_messages = true end-- messages will be displayed only in preview mode

	end

	msg = UserMessages

	local line = {}



	local function set_italics(n)

		linen].attr.style = linen].attr.style .. "font-style: italic;"

		linen].tone_sup = true -- single digits are assumed to be tone markers and will hence be superscripted

		if args'tone-superscripting' and not yesno(args'tone-superscripting'])

			then linen].tone_sup = false end

	end



	if args.glossing then -- the glossing= parameter sets the default glossing type

		local _gl = set_glossing_type(args.glossing)

		if _gl then conf.GlossingType = _gl end

	end

	--this looks for a list of glossing abbreviations on the page that transcludes the template:

	local _ablist_section = get_section(frame, 'list-of-glossing-abbreviations')

	if _ablist_section and _ablist_section ~= "" then

		local _a = mw.ustring.gsub(_ablist_section, '</?div [^\n]*>', '') -- strips off the div tags

		set_custom_glosses(_a)

	end

	--and this looks looks for a list of abbreviations set within the template:

	local _ablist = args.abbreviations

	if _ablist and _ablist ~= ""

		then set_custom_glosses(_ablist) end

	local _ablist = args.ablist

	if _ablist and _ablist ~= ""

		then set_custom_glosses(_ablist) end



	local _spacing = tonumber(args.spacing)

	if _spacing and _spacing <= 20

		then conf.style.WordDiv = conf.style.WordDiv .. 'margin-right: ' .. _spacing .. 'em;'

	else conf.style.WordDiv = conf.style.WordDiv .. conf.style.WordMargin

	end



	-- right-to-left script

	if yesno(args.rtl) == true then

		conf.style.WordDiv = string.gsub(conf.style.WordDiv, " left", " right")

	end



	local offset, last_line = 0, 0

	for j,v in ipairs(args) do -- iterates over the unnamed parameters from the template

		last_line = last_line +1

		if is_empty(v)

			then offset = offset + 1

		else

		local i = j - offset

		linei = {}

		v = normalise(v)



		-- the following is part of a trial implementation of automatic transliteration:

		if if_auto_translit and v == "auto" and i > 1 then

			local source_line = linei-1

			local src_lang = source_line.lang

			if not src_lang then src_lang = args.lang end

			if src_lang then

					v = transliterate(source_line.whole, src_lang)

			else v = ""; msg:add("error", "No language specified for automatic transliteration")

			end

		end  -- end of trial block



		linei].whole = v

		linei].length = mw.ustring.len(v)



		local _c = args"c" .. i

		if _c and _c ~= "" then

			line.hasComments = true

			linei].c = _c

		end



		---prepare style arguments----

		linei].class = ""

		local _style = args"style" .. i

		if not _style then _style = ""

		else _style = tidyCss(_style) end

		--line[i].attr holds the attributes for the <p> elements that enclose the words in line i

		linei].attr = {

			style = conf.style.WordP .. _style,

			dir = (yesno(args.rtl) == true and "rtl" or "ltr") --"auto"

		}



		local _lang = args"lang" .. i

		if _lang and #_lang > 1 then

			linei].lang = _lang

		else _lang = args.lang

			if _lang and #_lang > 1 and i == 1 then -- if a lang= parameter is supplied, it's assumed to apply to line 1

				linei].lang = _lang

			end

		end

		linei].attr.lang = linei].lang

		--the following emulates the behaviour of {{Bo-textonly}} (see Template talk:Fs interlinear#Tibetan):

		if template_name == 'Template:Fs interlinear' then

			if _lang == "bo" and i == 1 then

				line1].class = line1].class .. " uchen"

				line1].attr.style = line1].attr.style .. "font-size:1.25em; word-wrap:break-word;"

			end

		end



		if yesno(args"italics" .. i]) then

			set_italics(i)

		end



		local _transl = args"transl" .. i

		if _transl and #_transl > 1 then

			_transl = mw.ustring.lower(_transl)

			local _lookup = lang_data.translit_title_table_transl

			if _lookup then

				if _lang and  _lookup_lang then

					_transl = _lookup_lang

				else _transl = _lookup.default

				end

				if _transl then

					linei].attr.title = _transl

				end

			else  msg:add("error", "Transliteration scheme '" .. _transl .. "' not recognised")

			end

		end



		local _glossing = args"glossing" .. i

		if _glossing then

			linei].glossing = set_glossing_type(_glossing)

			-- Do not treat default glossing settings as custom.

			if not ((i == 1 and not yesno(_glossing)) or (i == 2 and yesno(_glossing))) then

				line.HasCustomGlossing = true

			end

		end



		local _ipa = args'ipa' .. i

		if yesno(_ipa) then

			linei].class = "IPA"

		end



		local _class = args'class' .. i

		if _class then

			linei].class = linei].class .. " " .. _class

		end



		if linei].class == ""

			then linei].class = nil end

		end -- ends the first if-statement in the loop

	end -- ends the FOR cycle



	local line_count = #line

	if line_count == 0 then

		msg:add("error", template_name .. ": no lines supplied.")

		return msg:print_errors()

	end



	if line_count > 1 then

		local _italics = args.italics

		local n = tonumber(_italics)

		if n and n > 0 then

			set_italics(n)

		elseif not (_italics and not yesno(_italics)) and not (args"italics1" and not yesno(args"italics1"])) then

			set_italics(1) -- by default, the first line will get italicised, unless italics=no or italics1=no

		end

		-- the last unnamed parameter is assumed to be the free translation:

		free_translation = argslast_line

		if not is_empty(free_translation) then

			line line_count = nil   end  --... and is thus excluded from interlinearising

	end



-- If glossing isn't specified for any line, then it's chosen by default to occur

-- in the second line, unless only a single line has been supplied, in which case

-- the assumption is that it is the one containing grammatical glosses

	if yesno(args.glossing) == false then

		line.HasCustomGlossing = true

	end

	if not line.HasCustomGlossing then

		if line_count == 1 then

			line1].glossing = conf.GlossingType

		elseif line2 then

			line2].glossing = conf.GlossingType

		end

	end

	set_global_glossing_settings{style = args'glossing-style'], underline = args.underline, small_caps = args'small-caps']}



---------------------

-- Segment lines into words

---------------------

	for i,v in ipairs(line) do

		local ifglossing = false

		if linei].glossing then

			ifglossing = true -- if true the parser will attempt to format gloss abbreviations in the current line

			glossing_type = linei].glossing -- neccessarily a global variable

		end

		local wc, n = 1, 1

		linei].words = {}

		while n <= linei].length do

			buffer = ""

			n = parse(linei], n, 0, ifglossing)+2

			linei].wordswc = buffer

			wc = wc + 1

		end

	end



	----Check for mismatches in number of words across lines----

	local number_of_words, mismatch_found = 0, false

	for i,v in ipairs(line) do -- find the maximum number of words in any line

		local wc = #linei].words

		if wc ~= number_of_words then

			if i ~= 1 and wc ~= 0 then

				mismatch_found = true

			end

			if wc > number_of_words then

				number_of_words = wc

			end

		end

	end

	----Deal with mismatches---

	if mismatch_found then

		local error_text = "Mismatch in the number of words between lines: "

		for i,v in ipairs(line) do

			local wc = #linei].words

			error_text = error_text .. wc .. " word(s) in line " .. i .. ", "

			if wc ~= number_of_words then

				for current_word = wc+1, number_of_words do

					linei].wordscurrent_word = "&nbsp;"

				end

			end

		end

		if string.sub(error_text, -2) == ", "

			then error_text = string.sub(error_text, 1, #error_text - 2) .. " "

		end

		error_text = error_text .. help_link("mismatch")

		UserMessages:add("error", error_text)

	end



---------------------

-- Build the HTML

---------------------

	---- If just a single line was supplied, format it as inline text

	if line_count == 1 then

		local span = mw.html.create('span')

		span:attr(line1].attr)

		for wi = 1, number_of_words do

			local space

			if wi < number_of_words then space = " " else space = "" end

			span:wikitext(line1].wordswi .. space)

		end

		return tostring(span)

	end



	---- More than one line supplied, so we'll produce interlinear display

	local div = mw.html.create("div")

	div:addClass(conf.class.Interlinear)



	-- For stuff to be displayed in the left margin, like example numbering

	local number, indent = nil, nil

	if args.number and args.number ~= ""

		then number = args.number end

	if args.indent and args.indent ~=""

		then indent = args.indent end

	if indent or number then

		if not indent then indent = "4" end --default value

		div:css("margin-left", indent .. 'em')

		if number then

			div:tag("div")

				:css("position", "absolute")

				:css("left", "1em")

				:wikitext(args.number)

		end

	end



	if args.box and args.box ~= "" then

		div:css("background-color", "#f8f9fa")

			:css("border", "1px solid #eaecf0")

			:css("padding", "1em") end

	if args.top and args.top ~= "" then --lines to display above the interlinear block

		div:tag("div")

			:wikitext(args.top)

	end



	-- Producing the interlinear block

	for wi = 1, number_of_words do

		local div2 = div:tag("div")

					:attr("style", conf.style.WordDiv)

		for i,_ in ipairs (line) do

			if linei].whole ~= "" then -- skipping empty lines

				local p = div2:tag("p")

				p:attr(linei].attr)

				if linei].class then

					p:addClass(linei].class)

				end

				local _text = linei].wordswi

				if _text == "" or _text == " "

					then _text = "&nbsp;" end -- <p> elements without content mess up the interlinear display

				p:wikitext(_text)

			end

		end

	end



	--- If any "comments" have been specified, add them at the end of each line

	if line.hasComments then

		local divc = div:tag("div")

					:attr("style", conf.style.WordDiv)

		for i,_ in ipairs (line) do

			local p = divc:tag("p")

			p:attr("style", conf.style.WordP)

			if linei].c then

				p:wikitext(linei].c)

			else p:wikitext("&nbsp;")

			end

		end

	end



	--Add hidden lines containing the content of each line of interlinear text: this is for accessibility

	for i,v in ipairs(line) do

		local hidden_line = div:tag("p")

		hidden_line:attr("style", conf.style.HiddenText)

					:wikitext(v.whole)

	end



	-- Format the free translation

	local ft_line = div:tag("p")

	if free_translation and free_translation ~= "" then

		ft_line:attr("style", "clear: left;")

		ft_line:wikitext(free_translation)

	end

	-- right-to-left script

	if yesno(args.rtl) == true then

		ft_line:attr("style", "clear: right;")

	end

	if args.bottom and args.bottom ~= ""

		then local bottom = div:tag('p')

		bottom:css('margin-top', '0')

		bottom:wikitext(args.bottom)

	end

	ft_line:node(msg:print_errors()) -- for error messages



	local end_div = div:tag("div")

		end_div:attr("style", conf.style.EndDiv)

	div:newline()

	local temp_track = ""

	if last_line == 2

		then temp_track = "[[Category:Pages with interlinear glosses using two unnamed parameters]]"

	end

	if last_line > 3 and template_name ~= 'Template:Fs interlinear'

		then  temp_track = "[[Category:Pages with interlinear glosses using more than three unnamed parameters]]"

	end

	return tostring(div) .. temp_track .. msg:print_warnings()

end



return p