Editing Module:Sandbox/VergirGive feedback

-- TEMPORARY diagnostic.
-- Renders heroes through the LIVE Module:InfoboxHero twice each and compares the
-- two outputs, to establish whether rendering is deterministic at all.
-- {{#invoke:Sandbox/Vergir|selfdiff}}
local p = {}

local infobox = require('Module:InfoboxHero')

local SAMPLE_HEROES = {
	'hero_atlas',
	'hero_viscous',
	'hero_haze',
	'hero_werewolf',
	'hero_targetdummy',
}

-- Byte offset of the first difference, or nil when the strings are equal.
local function first_diff(a, b)
	local limit = math.min(#a, #b)
	for i = 1, limit do
		if a:sub(i, i) ~= b:sub(i, i) then return i end
	end
	if #a ~= #b then return limit + 1 end
	return nil
end

function p.selfdiff(frame)
	local keys = {}
	if frame.args[1] and frame.args[1] ~= '' then
		for key in string.gmatch(frame.args[1], '[^,%s]+') do
			table.insert(keys, key)
		end
	else
		keys = SAMPLE_HEROES
	end

	local out = {}
	local mismatches = 0

	for _, hero_key in ipairs(keys) do
		local child = frame:newChild{ args = { key = hero_key } }
		local a = tostring(infobox.render(child))
		local b = tostring(infobox.render(child))
		local at = first_diff(a, b)
		if at ~= nil then
			mismatches = mismatches + 1
			local from = math.max(1, at - 50)
			local to = at + 50
			table.insert(out, '* <code>' .. hero_key .. '</code> differs at byte ' .. at ..
				' (len ' .. #a .. ' vs ' .. #b .. ')')
			table.insert(out, '** A: <code>' .. mw.text.nowiki(a:sub(from, to)) .. '</code>')
			table.insert(out, '** B: <code>' .. mw.text.nowiki(b:sub(from, to)) .. '</code>')
		end
	end

	return 'Same module rendered twice per hero, heroes: ' .. #keys ..
		'\n\nNon-deterministic: ' .. mismatches .. '\n' .. table.concat(out, '\n')
end

return p