local lfs = require"lfs";

local hg = { };

function hg.check_id(path)

	if lfs.attributes(path, 'mode') ~= "directory" then

		return nil, "not a directory";

	end

	local hg_dirstate = io.open(path.."/.hg/dirstate");

	local hgid, hgrepo

	if hg_dirstate then

		hgid = ("%02x%02x%02x%02x%02x%02x"):format(hg_dirstate:read(6):byte(1, 6));

		hg_dirstate:close();

		local hg_changelog = io.open(path.."/.hg/store/00changelog.i");

		if hg_changelog then

			hg_changelog:seek("set", 0x20);

			hgrepo = ("%02x%02x%02x%02x%02x%02x"):format(hg_changelog:read(6):byte(1, 6));

			hg_changelog:close();

		end

	else

		local hg_archival,e = io.open(path.."/.hg_archival.txt");

		if hg_archival then

			local repo = hg_archival:read("*l");

			local node = hg_archival:read("*l");

			hg_archival:close()

			hgid = node and node:match("^node: (%x%x%x%x%x%x%x%x%x%x%x%x)")

			hgrepo = repo and repo:match("^repo: (%x%x%x%x%x%x%x%x%x%x%x%x)")

		end

	end

	return hgid, hgrepo;

end

return hg;