-- Implement [[Template:Football manager history]] to avoid articles being

-- added to [[:Category:Pages where template include size is exceeded]]

-- when the template is used many times.



local function clean(text, default)

	-- Return text, if not empty, after trimming leading/trailing whitespace.

	-- Otherwise return default which is nil unless set by caller.

	if text then

		text = text:match("^%s*(.-)%s*$")

		if text ~= '' then

			return text

		end

	end

	return default

end



local function yes(parameter)

	-- Return true if parameter should be interpreted as "yes".

	-- Do not want to accept mixed upper/lowercase.

	return ({ Y = true, y = true, yes = true, T = true, 'true' = true })[parameter

end



local function collection()

	-- Return a table to hold items.

	return {

		n = 0,

		add = function (self, item)

			self.n = self.n + 1

			selfself.n = item

		end,

		addif = function (self, item, fmt)

			if item then

				self.n = self.n + 1

				selfself.n = fmt and string.gsub(fmt, '%%s', item) or item

			end

		end,

		join = function (self, sep)

			return table.concat(self, sep)

		end,

	}

end



local function message(msg, caller, nocat)

	-- Return formatted message text for an error.

	-- Can append "#FormattingError" to URL of a page with a problem to find it.

	-- If given, caller is the title of the navbox which has the error.

	local anchor = '<span id="FormattingError"></span>'

	local category

	if not nocat and mw.title.getCurrentTitle():inNamespaces(0, 10) then

		-- Category only in namespaces: 0=article, 10=template.

		category = '[[Category:Football template errors]]'

	else

		category = ''

	end

	return anchor ..

		'<strong class="error">Error: ' ..

		msg ..

		(caller and (' at [[Template:' .. caller .. ']]') or '') ..

		'</strong>' ..

		category .. '\n'

end



local function make_entry(name, from, to, islast)

	local result =

		'*<span class="vevent">' ..

		'<span class="agent attendee vcard">' ..

		'<span class="fn org summary">' ..

		name ..

		'</span></span>&nbsp;(<span class="dtstart">' ..

		from ..

		'</span>'

	if to then

		result = result .. '–' .. to

	elseif islast then

		result = result .. '–'

	end

	result = result .. ')</span>'

	return result

end



local function make_list(text, note, dissolved)

	-- Return a list of formatted items.

	-- Input is a string of multiple lines, one item per line.

	-- Each item is 'NAME FROM to TO' or 'NAME FROM', where

	--   NAME = manager name (any text)

	--   FROM = four digits (from year)

	--     TO = 1, 2, 3 or 4 digits (to year), or empty

	-- Alternatively, an item can use syntax (TEXT is any text, possibly empty):

	--   NAME from=TEXT

	--   NAME from=TEXT to=TEXT

	-- The code detects the end of NAME from the start of FROM.

	-- A dash is added to the last line (to show the manager is continuing) if

	-- no 'to' year is given, but no dash is added if the club is dissolved.

	text = text or ''

	if text:find('<span class=', 1, true) then

		-- To allow a transition period where some navboxes use the old syntax, the

		-- given text is used if it appears to have come from the old subtemplates.

		return text

	end

	-- Get the non-blank lines first so can tell when am processing the last line.

	-- Each line is left- and right-trimmed.

	local lines = collection()

	for line in string.gmatch(text .. '\n', '[\t ]*(.-)[\t\r ]*\n') do

		if line ~= '' then

			lines:add(line)

		end

	end

	if lines.n <= 0 then

		return ''

	end

	local ilast = dissolved and -1 or lines.n

	local entries = collection()

	entries:add('<div>')

	for i, line in ipairs(lines) do

		-- Need to detect lines like "Name from=1930 & 1935" (probably should

		-- not be like that, but that is not up to the template to enforce).

		local name, from, to = line:match('^([^=]-)%s+(%d%d%d%d)%s+to%s+(%d%d?%d?%d?)$')

		if not name then

			name, from = line:match('^([^=]-)%s+(%d%d%d%d)$')

			if not name then

				name, from, to = line:match('^(.-) from=(.-) to=(.*)')

				if not name then

					name, from = line:match('^(.-) from=(.*)')

				end

			end

		end

		name = clean(name)

		from = clean(from, '')

		to = clean(to)

		if ((name or '=') .. (from or '=') .. (to or '')):find('=', 1, true) then

			-- name and from must be defined (from can be ''); to is optional.

			-- Reject '=' to avoid typos in items like 'to=x' or 'from=xto=y'

			-- from being displayed.

			error('Invalid line "' .. mw.text.nowiki(line) .. '"', 0)

		end

		entries:add(make_entry(name, from, to, i == ilast))

	end

	entries:add('</div>')

	entries:addif(note)

	return entries:join('\n')

end



local function arg_style(bgcolor, textcolor, bordercolor)

	local result = collection()

	result:addif(clean(bgcolor), 'background:%s;')

	result:addif(clean(textcolor), 'color:%s;')

	result:addif(clean(bordercolor), 

		'box-shadow: inset 1px 1px 0 %s,' ..

		'inset -1px -1px 0 %s;')

	result:add('width: 87%;')

	return result:join(' ')

end



local function arg_title(title, teamname, managerlist, textcolor, american_english)

	title = clean(title)

	teamname = clean(teamname, 'MISSING "teamname"')

	managerlist = clean(managerlist)

	textcolor = clean(textcolor)

	american_english = clean(american_english)

	local spancolor = textcolor and ('<span style="color:' .. textcolor .. ';">') or '<span>'

	local mgr = spancolor .. (american_english and 'Head coaches' or 'managers') .. '</span>'

	return

		'<span class="fn org">[[' .. teamname .. '|' ..

		spancolor ..

		(title or teamname) .. '</span>]]</span> – ' ..

		(managerlist and ('[[' .. managerlist .. '|' .. mgr .. ']]') or mgr)

end



local function _main(args)

	-- Return wikitext for a navbox.

	-- Code does not do much checking of inputs but will throw an error

	-- if input is found to be invalid.

	local style = arg_style(args.bgcolor, args.textcolor, args.bordercolor)

	local dissolved = args.dissolved

	if dissolved then

		-- May be a number of two or more digits (year club was dissolved; compatible

		-- with {{Infobox football club}}), or an alias for 'yes'.

		dissolved = dissolved:match('^%d%d+$') and true or yes(args.dissolved)

	end

	local navargs = {

		bodyclass = 'vcard',

		name = clean(args.name),

		state = clean(args.state, 'autocollapse'),

		titlestyle = style,

		title = arg_title(args.title, args.teamname, args.managerlist, args.textcolor, args.american_english),

		listclass = 'hlist',

		nowrapitems = 'yes',

		list1 = make_list(args.list, clean(args.note), dissolved),

		belowstyle = style,

		below = clean(args.below),

	}

	local navbox = require('Module:Navbox')._navbox

	return navbox(navargs)

end



local function main(frame)

	-- Return wikitext for a navbox or an error message.

	local args = frame:getParent().args

	-- Read arguments in order of output (Module:Navbox says this puts

	-- reference numbers in the right order).

	local _

	_ = args.title

	_ = args.list

	_ = args.below

	if not args.teamname then

		args = frame.args

		_ = args.title

		_ = args.list

		_ = args.below

	end

	local success, result = pcall(_main, args)

	if success then

		return result

	end

	return message(result, clean(args.name), clean(args.nocat))

end



return { main = main, _main = _main }