local export = {}

local escape
do
	local escapes = {
		["\a"] = "a", ["\b"] = "b", ["\f"] = "f", ["\n"] = "n", ["\r"] = "r",
		["\t"] = "t", ["\v"] = "v", ["\\"] = "\\", ["\""] = '"', ["'"] = "'",
	}
	
	local function helper(char)
		return escapes[char] and "\\" .. escapes[char]
			or ("\\%03d"):format(char:byte())
	end
	
	-- Escape control characters, backslash, double quote, and bytes that aren't
	-- used in UTF-8.
	-- Escape stuff that can't be saved in a MediaWiki page, like invalid UTF-8
	-- and NFD character sequences? Hard.
	-- Similar to string.format("%q", str), which does not use C-like simple
	-- escapes and does not escape bytes that are not used in UTF-8.
	escape = function (str)
		return (str:gsub("[%z\1-\31\\\"\127\192\193\245-\255]", helper))
	end
end

export.escape = escape

-- Convert a value to a string
function export.dump(value, prefix, tsort)
	local t = type(value)
	
	prefix = prefix or ""
	
	if t == "string" then
		return '"' .. escape(value) .. '"'
	elseif t == "table" then
		local str_table = {}
		
		table.insert(str_table, " {")
		
		for key, val in require("Module:table").sortedPairs(value, tsort) do
			table.insert(str_table, " " .. prefix .. "\t[" .. export.dump(key, prefix .. "\t") .. "] = " .. export.dump(val, prefix .. "\t"):gsub("^ ", "") .. ",")
		end
		
		table.insert(str_table, " " .. prefix .. "}")
		
		return table.concat(str_table, "\n")
	else
		return tostring(value)
	end
end


function export.highlight_dump(value, prefix, tsort, options)
	options = options or {}
	
	local func = options.modified and "modified_dump" or "dump"
	
	local dump = export[func](value, prefix, tsort)
	
	-- Remove spaces at beginnings of lines (which are simply to force a <pre></pre> tag).
	dump = dump:gsub("^ ", "")
	dump = dump:gsub("\n ", "\n")
	
	return export.highlight(dump)
end


-- Returns true if table contains a table as one of its values
local function containsTable(t)
	for key, value in pairs(t) do
		if type(value) == "table" then
			return true
		end
	end
	return false
end


local function containsTablesWithSize(t, size)
	for key, value in pairs(t) do
		if type(value) == "table" and require("Module:table").size(value) ~= size then
			return false
		end
	end
	return true
end	


--[=[
	Convert a value to a string.
	Like dump below, but if a table has consecutive numbered keys and does not
	have a table as one of its values, it will be placed on a single line.
	Used by [[Module:User:Erutuon/script recognition]].
]=]
function export.modified_dump(value, prefix, tsort)
	local t = type(value)
	
	prefix = prefix or ""
	
	if t == "string" then
		return '"' .. value .. '"'
	elseif t == "table" then
		local str_table = {}
		
		local containsTable = containsTable(value)
		local consecutive = require("Module:table").isArray(value)
		if consecutive and not containsTable or containsTable and containsTablesWithSize(value, 3) then
			table.insert(str_table, "{")
			
			for key, val in require("Module:table").sortedPairs(value, tsort) do
				if containsTable then
					table.insert(str_table, "\n\t" .. prefix)
				else
					table.insert(str_table, " ")
				end
				
				if type(key) == "string" then
					table.insert(str_table, "[" .. export.modified_dump(key) .. "] = ")
				end
				
				table.insert(str_table, type(key) == "number" and type(val) == "number" and string.format("0x%05X", val) or export.modified_dump(val))
				
				if not (consecutive and #value == 3) or type(key) == "number" and value[key + 1] then
					table.insert(str_table, ",")
				end
			end
			
			if containsTable then
				table.insert(str_table, "\n" .. prefix)
			else
				table.insert(str_table, " ")
			end
			
			table.insert(str_table, "}")
			return table.concat(str_table)
		end
		
		table.insert(str_table, " {")
		
		for key, val in require("Module:table").sortedPairs(value, tsort) do
			table.insert(str_table, " " .. prefix .. "\t[" .. export.modified_dump(key, prefix .. "\t") .. "] = " .. export.modified_dump(val, prefix .. "\t"):gsub("^ ", "") .. ",")
		end
		
		table.insert(str_table, " " .. prefix .. "}")
		
		return table.concat(str_table, "\n")
	elseif t == "number" and value > 46 then
		return string.format("0x%05X", value)
	else
		return tostring(value)
	end
end
	

function export.track(key)
	local frame = mw.getCurrentFrame()
	if key then
		if type(key) ~= "table" then
			key = { key }
		end
		
		for i, value in pairs(key) do
			pcall(frame.expandTemplate, frame, { title = 'tracking/' .. value })
		end
	else
		error('No tracking key supplied to the function "' .. track .. '".')
	end
end


-- Trigger a script error from a template
function export.error(frame)
	error(frame.args[1] or "(no message specified)")
end

--[[
	Convenience function for generating syntaxhighlight tags.
	Display defaults to block.
	Options is a table. To display inline text with HTML highlighting:
		{ inline = true, lang = "html" }
]]
function export.highlight(content, options)
	if type(content) == "table" then
		options = content
		options = {
			lang = options.lang or "lua",
			inline = options.inline and true
		}
		return function(content)
			return mw.getCurrentFrame():extensionTag{
				name = "syntaxhighlight",
				content = content,
				args = options
			}
		end
	else
		return mw.getCurrentFrame():extensionTag{
			name = "syntaxhighlight",
			content = content,
			args = {
				lang = options and options.lang or "lua",
				inline = options and options.inline and true or nil
			}
		}
	end
end

function export.track_unrecognized_args(args, template_name)
	local function track(code)
		export.track(template_name .. "/" .. code)
	end
	
    track("unrecognized arg")
	
	local arg_list = {}
	for arg, value in pairs(args) do
		track("unrecognized arg/" .. arg)
		table.insert(arg_list, ("|%s=%s"):format(arg, value))
	end
	
	mw.log(
		("Unrecognized parameter%s in {{%s}}: %s."):format(
			arg_list[2] and "s" or "",
			template_name,
			table.concat(arg_list, ", ")))
end

return export