private class ManPage
	var mmodule: MModule
	var name: nullable String is noinit
	var synopsis: nullable String is noinit
	var options = new HashMap[Array[String], String]

	init from_file(mmodule: MModule, file: String) do
		from_lines(mmodule, file.to_path.read_lines)
	end

	init from_string(mmodule: MModule, string: String) do
		from_lines(mmodule, string.split("\n"))
	end

	init from_lines(mmodule: MModule, lines: Array[String]) do
		init mmodule

		var section = null
		for i in [0..lines.length[ do
			var line = lines[i]
			if line.is_empty then continue

			if line == "# NAME" then
				section = "name"
				continue
			end
			if line == "# SYNOPSIS" then
				section = "synopsis"
				continue
			end
			if line == "# OPTIONS" then
				section = "options"
				continue
			end

			if section == "name" and name == null then
				name = line.trim
			end
			if section == "synopsis" and synopsis == null then
				synopsis = line.trim
			end
			if section == "options" and line.has_prefix("###") then
				var opts = new Array[String]
				for opt in line.substring(3, line.length).trim.replace("`", "").split(",") do
					opts.add opt.trim
				end
				var desc = ""
				if i < lines.length - 1 then
					desc = lines[i + 1].trim
				end
				options[opts] = desc
			end
		end
	end

	fun diff(toolcontext: ToolContext, ref: ManPage) do
		if name != ref.name then
			toolcontext.warning(mmodule.location, "diff-man",
				"Warning: outdated man description. " +
				"Expected `{ref.name or else ""}` got `{name or else ""}`.")
		end
		if synopsis != ref.synopsis then
			toolcontext.warning(mmodule.location, "diff-man",
				"Warning: outdated man synopsis. " +
				"Expected `{ref.synopsis or else ""}` got `{synopsis or else ""}`.")
		end
		for name, desc in options do
			if not ref.options.has_key(name) then
				toolcontext.warning(mmodule.location, "diff-man",
					"Warning: unknown man option `{name}`.`")
				continue
			end
			var ref_desc = ref.options[name]
			if desc != ref_desc then
				toolcontext.warning(mmodule.location, "diff-man",
					"Warning: outdated man option description. Expected `{ref_desc}` got `{desc}`.")
			end
		end
		for ref_name, ref_desc in ref.options do
			if not options.has_key(ref_name) then
				toolcontext.warning(mmodule.location, "diff-man",
					"Warning: missing man option `{ref_name}`.`")
			end
		end
	end

	redef fun to_s do
		var tpl = new Template
		tpl.addn "# NAME"
		tpl.addn name or else ""
		tpl.addn "# SYNOPSIS"
		tpl.addn synopsis or else ""
		tpl.addn "# OPTIONS"
		for name, desc in options do
			tpl.addn " * {name}: {desc}"
		end
		return tpl.write_to_string
	end
end