--- Formats multiple numbered arguments and outputs them in order, etc.
--
-- @module multiformat
-- @alias p
-- @require Module:Escape_input
-- @release alpha

local p = {}
local yn = require("Module:Yesno")

--- Main entrypoint for formatting output string
--
-- @param {table} pargs The arguments from the template call
-- @param {table} cargs The arguments from the module call
-- @param {string} cargs.startAll the beginning formatting string sequence
-- @param {string} cargs.endAll the ending formatting string sequence
-- @param {string} cargs.format the format string
-- @param {number} cargs.firstArg the first numbered argument to begin formatting
-- @param {string} cargs.prefix the argument prefix
-- @param {string} cargs.suffix the argument suffix
-- @param {boolean} cargs.nowiki Whether the module is encased in nowiki tags
-- @param {string} cargs.empty The message to give if no arguments are specified
-- @return Output to preprocess
function p._main(pargs, cargs)
	local nowiki = yn(cargs.nowiki) or false
	local escape
	if nowiki then
		escape = function( s ) return mw.text.unstripNoWiki( s ) end
	else
		escape = require("Module:Escape input").escape
	end
	local startAll = escape(cargs.startAll or '')
	local endAll = escape(cargs.endAll or '')
	local formatString = escape(cargs.format)
	local currArg = tonumber(cargs.firstArg) or 1
	local argPrefix = escape(cargs.prefix or '')
	local argSuffix = escape(cargs.suffix or '')
	local outArr = {}
	if pargs[argPrefix .. currArg .. argSuffix] == nil then return escape(cargs.empty or '') end
	table.insert(outArr, startAll)
	while pargs[argPrefix .. currArg .. argSuffix] ~= nil do
		table.insert(outArr, tostring(mw.ustring.gsub(mw.ustring.gsub(mw.ustring.gsub(formatString, '%%ARGNUM%%', currArg), '%%ARG%%', pargs[argPrefix .. currArg .. argSuffix]), '\\%%', '%')))
		currArg = currArg + 1
	end
	table.insert(outArr, endAll)
	return table.concat(outArr)
end

--- Template call
--
-- @param {Frame} frame calling frame
-- @return Output wikitext
-- @usage {{#invoke:Multiformat|main|startAll=start|endAll=end|formatString=String with %ARG% to replace with current arguments|firstArg=number of first arg}}
function p.main(frame)
	local pargs = frame:getParent() ~= nil and frame:getParent().args or error("Error occurred while fetching wrapping template arguments for multiformat", 0)
	local cargs = frame.args
	return frame:preprocess(p._main(pargs, cargs))
end

--- Counts the number of arguments which match a particular format
--
-- @param {table} pargs The arguments from the template call
-- @param {table} cargs The arguments from the module call
-- @param {number} cargs.firstArg the first numbered argument to begin formatting
-- @param {string} cargs.prefix the argument prefix
-- @param {string} cargs.prefix the argument suffix
-- @return Number of numbered parameters supplied
function p._nArgs(pargs, cargs)
	local currArg = tonumber(cargs.firstArg) or 1
	local nowiki = yn(cargs.nowiki) or false
	local escape
	if nowiki then
		escape = function( s ) return mw.text.unstripNoWiki( s ) end
	else
		escape = require("Module:Escape input").escape
	end
	local argPrefix = escape(cargs.prefix or '')
	local argSuffix = escape(cargs.suffix or '')
	local count = 0
	while pargs[argPrefix .. currArg .. argSuffix] ~= nil do
		count = count + 1
		currArg = currArg + 1
	end
	return count
end

--- Template call
--
-- @param {Frame} frame calling frame
-- @return Output wikitext
-- @usage {{#invoke:Multiformat|nArgs}}
function p.nArgs(frame)
	local pargs = frame:getParent() ~= nil and frame:getParent().args or error("Error occurred while fetching wrapping template arguments for multiformat", 0)
	local cargs = frame.args
	return p._nArgs(pargs, cargs)
end

return p