-- Variables ending with these names will not

-- have their values printed ('password' includes

-- 'new_password', etc.)

local censored_names = {

	password = true;

	passwd = true;

	pass = true;

	pwd = true;

};

local optimal_line_length = 65;

local termcolours = require "util.termcolours";

local getstring = termcolours.getstring;

local styles;

do

	_ = termcolours.getstyle;

	styles = {

		boundary_padding = _("bright");

		filename         = _("bright", "blue");

		level_num        = _("green");

		funcname         = _("yellow");

		location         = _("yellow");

	};

end

module("debugx", package.seeall);

function get_locals_table(level)

	level = level + 1; -- Skip this function itself

	local locals = {};

	for local_num = 1, math.huge do

		local name, value = debug.getlocal(level, local_num);

		if not name then break; end

		table.insert(locals, { name = name, value = value });

	end

	return locals;

end

function get_upvalues_table(func)

	local upvalues = {};

	if func then

		for upvalue_num = 1, math.huge do

			local name, value = debug.getupvalue(func, upvalue_num);

			if not name then break; end

			table.insert(upvalues, { name = name, value = value });

		end

	end

	return upvalues;

end

function string_from_var_table(var_table, max_line_len, indent_str)

	local var_string = {};

	local col_pos = 0;

	max_line_len = max_line_len or math.huge;

	indent_str = "\n"..(indent_str or "");

	for _, var in ipairs(var_table) do

		local name, value = var.name, var.value;

		if name:sub(1,1) ~= "(" then

			if type(value) == "string" then

				if censored_names[name:match("%a+$")] then

					value = "<hidden>";

				else

					value = ("%q"):format(value);

				end

			else

				value = tostring(value);

			end

			if #value > max_line_len then

				value = value:sub(1, max_line_len-3).."…";

			end

			local str = ("%s = %s"):format(name, tostring(value));

			col_pos = col_pos + #str;

			if col_pos > max_line_len then

				table.insert(var_string, indent_str);

				col_pos = 0;

			end

			table.insert(var_string, str);

		end

	end

	if #var_string == 0 then

		return nil;

	else

		return "{ "..table.concat(var_string, ", "):gsub(indent_str..", ", indent_str).." }";

	end

end

function get_traceback_table(thread, start_level)

	local levels = {};

	for level = start_level, math.huge do

		local info;

		if thread then

			info = debug.getinfo(thread, level+1);

		else

			info = debug.getinfo(level+1);

		end

		if not info then break; end

		levels[(level-start_level)+1] = {

			level = level;

			info = info;

			locals = get_locals_table(level+1);

			upvalues = get_upvalues_table(info.func);

		};

	end	

	return levels;

end

function traceback(...)

	local ok, ret = pcall(_traceback, ...);

	if not ok then

		return "Error in error handling: "..ret;

	end

	return ret;

end

local function build_source_boundary_marker(last_source_desc)

	local padding = string.rep("-", math.floor(((optimal_line_length - 6) - #last_source_desc)/2));

	return getstring(styles.boundary_padding, "v"..padding).." "..getstring(styles.filename, last_source_desc).." "..getstring(styles.boundary_padding, padding..(#last_source_desc%2==0 and "-v" or "v "));

end

function _traceback(thread, message, level)

	-- Lua manual says: debug.traceback ([thread,] [message [, level]])

	-- I fathom this to mean one of:

	-- ()

	-- (thread)

	-- (message, level)

	-- (thread, message, level)

	if thread == nil then -- Defaults

		thread, message, level = coroutine.running(), message, level;

	elseif type(thread) == "string" then

		thread, message, level = coroutine.running(), thread, message;

	elseif type(thread) ~= "thread" then

		return nil; -- debug.traceback() does this

	end

	level = level or 1;

	message = message and (message.."\n") or "";

	-- +3 counts for this function, and the pcall() and wrapper above us

	local levels = get_traceback_table(thread, level+3);

	local last_source_desc;

	local lines = {};

	for nlevel, level in ipairs(levels) do

		local info = level.info;

		local line = "...";

		local func_type = info.namewhat.." ";

		local source_desc = (info.short_src == "[C]" and "C code") or info.short_src or "Unknown";

		if func_type == " " then func_type = ""; end;

		if info.short_src == "[C]" then

			line = "[ C ] "..func_type.."C function "..getstring(styles.location, (info.name and ("%q"):format(info.name) or "(unknown name)"));

		elseif info.what == "main" then

			line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline);

		else

			local name = info.name or " ";

			if name ~= " " then

				name = ("%q"):format(name);

			end

			if func_type == "global " or func_type == "local " then

				func_type = func_type.."function ";

			end

			line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline).." in "..func_type..getstring(styles.funcname, name).." (defined on line "..info.linedefined..")";

		end

		if source_desc ~= last_source_desc then -- Venturing into a new source, add marker for previous

			last_source_desc = source_desc;

			table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));

		end

		nlevel = nlevel-1;

		table.insert(lines, "\t"..(nlevel==0 and ">" or " ")..getstring(styles.level_num, "("..nlevel..") ")..line);

		local npadding = (" "):rep(#tostring(nlevel));

		local locals_str = string_from_var_table(level.locals, optimal_line_length, "\t            "..npadding);

		if locals_str then

			table.insert(lines, "\t    "..npadding.."Locals: "..locals_str);

		end

		local upvalues_str = string_from_var_table(level.upvalues, optimal_line_length, "\t            "..npadding);

		if upvalues_str then

			table.insert(lines, "\t    "..npadding.."Upvals: "..upvalues_str);

		end

	end

--	table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));

	return message.."stack traceback:\n"..table.concat(lines, "\n");

end

function use()

	debug.traceback = traceback;

end

return _M;