textwrap.lua

local _sep_chars, sep_chars = {
	" ", "-", "\t"
}, {}

for _, c in pairs(_sep_chars) do
	sep_chars[string.byte(c)] = true
end

local function wrap_text(text, width)
	if surface.GetTextSize(text) <= width then
		-- no wrapping required
		return {text}
	end

	local lines = {}

	local current_line = ""

	local function commit_line()
		if string.byte(current_line, #current_line) == 32 then
			current_line = string.sub(current_line, 1, -2)
		end

		lines[#lines + 1] = current_line
		current_line = ""
	end

	local current_word_start = 1

	for i = 1, #text do
		if sep_chars[string.byte(text, i)] or i == #text then
			local word = string.sub(text, current_word_start, i - 1)
			local word_with_separator = string.sub(text, current_word_start, i)

			if i == #text then
				word = word_with_separator
			end

			-- special case: hyphen. todo: hyphen at start of next line
			if string.byte(text, i) == string.byte("-") then
				word_with_separator = word .. " "
			end

			current_word_start = i + 1 -- todo: go to next non-space

			if surface.GetTextSize(current_line .. word) <= width then
				-- it fits on this line, so add it
				current_line = current_line .. word_with_separator
			else
				-- start a new line
				if current_line ~= "" then
					commit_line()
				end

				if surface.GetTextSize(word) <= width then
					-- start the new line with the word
					current_line = word
				else
					-- split the word onto multiple lines, joined by hyphens
					local current_char_i = 0

					while current_char_i < #word do
						-- append one character at a time until it is too large
						while surface.GetTextSize(current_line) < width do
							current_char_i = current_char_i + 1
							if current_char_i > #word then break end
							current_line = current_line .. string.sub(word, current_char_i, current_char_i)
						end

						if current_char_i >= #word then
							-- last line, don't hyphenate
							commit_line()
						else
							-- replace last character with hyphen
							current_line = string.sub(current_line, 1, -2) .. "-"
							current_char_i = current_char_i - 1

							commit_line()
						end
					end
				end
			end
		end
	end

	if current_line ~= "" then
		commit_line()
	end

	return lines
end

return wrap_text