local test_keys = require "spec.inputs.test_keys";

describe("util.crypto", function ()

	local crypto = require "util.crypto";

	local random = require "util.random";

	describe("generate_ed25519_keypair", function ()

		local keypair = crypto.generate_ed25519_keypair();

		assert.is_not_nil(keypair);

		assert.equal("ED25519", keypair:get_type());

	end)

	describe("import_private_pem", function ()

		it("can import ECDSA keys", function ()

			local ecdsa_key = crypto.import_private_pem(test_keys.ecdsa_private_pem);

			assert.equal("id-ecPublicKey", ecdsa_key:get_type());

		end);

		it("can import EdDSA (Ed25519) keys", function ()

			local ed25519_key = crypto.import_private_pem(crypto.generate_ed25519_keypair():private_pem());

			assert.equal("ED25519", ed25519_key:get_type());

		end);

		it("can import RSA keys", function ()

			-- TODO

		end);

		it("rejects invalid keys", function ()

			assert.is_nil(crypto.import_private_pem(test_keys.eddsa_public_pem));

			assert.is_nil(crypto.import_private_pem(test_keys.ecdsa_public_pem));

			assert.is_nil(crypto.import_private_pem("foo"));

			assert.is_nil(crypto.import_private_pem(""));

		end);

	end);

	describe("import_public_pem", function ()

		it("can import ECDSA public keys", function ()

			local ecdsa_key = crypto.import_public_pem(test_keys.ecdsa_public_pem);

			assert.equal("id-ecPublicKey", ecdsa_key:get_type());

		end);

		it("can import EdDSA (Ed25519) public keys", function ()

			local ed25519_key = crypto.import_public_pem(test_keys.eddsa_public_pem);

			assert.equal("ED25519", ed25519_key:get_type());

		end);

		it("can import RSA public keys", function ()

			-- TODO

		end);

	end);

	describe("PEM export", function ()

		it("works", function ()

			local ecdsa_key = crypto.import_public_pem(test_keys.ecdsa_public_pem);

			assert.equal("id-ecPublicKey", ecdsa_key:get_type());

			assert.equal(test_keys.ecdsa_public_pem, ecdsa_key:public_pem());

			assert.has_error(function ()

				-- Fails because private key is not available

				ecdsa_key:private_pem();

			end);

			local ecdsa_private_key = crypto.import_private_pem(test_keys.ecdsa_private_pem);

			assert.equal(test_keys.ecdsa_private_pem, ecdsa_private_key:private_pem());

		end);

	end);

	describe("sign/verify with", function ()

		local test_cases = {

			ed25519 = {

				crypto.ed25519_sign, crypto.ed25519_verify;

				key = crypto.import_private_pem(test_keys.eddsa_private_pem);

				sig_length = 64;

			};

			ecdsa = {

				crypto.ecdsa_sha256_sign, crypto.ecdsa_sha256_verify;

				key = crypto.import_private_pem(test_keys.ecdsa_private_pem);

			};

		};

		for test_name, test in pairs(test_cases) do

			local key = test.key;

			describe(test_name, function ()

				it("works", function ()

					local sign, verify = test[1], test[2];

					local sig = assert(sign(key, "Hello world"));

					assert.is_string(sig);

					if test.sig_length then

						assert.equal(test.sig_length, #sig);

					end

					do

						local ok = verify(key, "Hello world", sig);

						assert.is_truthy(ok);

					end

					do -- Incorrect signature

						local ok = verify(key, "Hello world", sig:sub(1, -2)..string.char((sig:byte(-1)+1)%255));

						assert.is_falsy(ok);

					end

					do -- Incorrect message

						local ok = verify(key, "Hello earth", sig);

						assert.is_falsy(ok);

					end

					do -- Incorrect message (embedded NUL)

						local ok = verify(key, "Hello world\0foo", sig);

						assert.is_falsy(ok);

					end

				end);

			end);

		end

	end);

	describe("ECDSA signatures", function ()

		local hex = require "util.hex";

		local sig = hex.decode((([[

			304402203e936e7b0bc62887e0e9d675afd08531a930384cfcf301

			f25d13053a2ebf141d02205a5a7c7b7ac5878d004cb79b17b39346

			6b0cd1043718ffc31c153b971d213a8e

		]]):gsub("%s+", "")));

		it("can be parsed", function ()

			local r, s = crypto.parse_ecdsa_signature(sig, 32);

			assert.is_string(r);

			assert.is_string(s);

			assert.equal(32, #r);

			assert.equal(32, #s);

		end);

		it("fails to parse invalid signatures", function ()

			local invalid_sigs = {

				"";

				"\000";

				string.rep("\000", 64);

				string.rep("\000", 72);

				string.rep("\000", 256);

				string.rep("\255", 72);

				string.rep("\255", 3);

			};

			for _, invalid_sig in ipairs(invalid_sigs) do

				local r, s = crypto.parse_ecdsa_signature(invalid_sig, 32);

				assert.is_nil(r);

				assert.is_nil(s);

			end

		end);

		it("can be built", function ()

			local r, s = crypto.parse_ecdsa_signature(sig, 32);

			local rebuilt_sig = crypto.build_ecdsa_signature(r, s);

			assert.equal(sig, rebuilt_sig);

		end);

	end);

	describe("AES-GCM encryption", function ()

		it("works", function ()

			local message = "foo\0bar";

			local key_128_bit = random.bytes(16);

			local key_256_bit = random.bytes(32);

			local test_cases = {

				{ crypto.aes_128_gcm_encrypt, crypto.aes_128_gcm_decrypt, key = key_128_bit };

				{ crypto.aes_256_gcm_encrypt, crypto.aes_256_gcm_decrypt, key = key_256_bit };

			};

			for _, params in pairs(test_cases) do

				local iv = params.iv or random.bytes(12);

				local encrypted = params[1](params.key, iv, message);

				assert.not_equal(message, encrypted);

				local decrypted = params[2](params.key, iv, encrypted);

				assert.equal(message, decrypted);

			end

		end);

	end);

	describe("AES-CTR encryption", function ()

		it("works", function ()

			local message = "foo\0bar hello world";

			local key_256_bit = random.bytes(32);

			local test_cases = {

				{ crypto.aes_256_ctr_decrypt, crypto.aes_256_ctr_decrypt, key = key_256_bit };

			};

			for _, params in pairs(test_cases) do

				local iv = params.iv or random.bytes(16);

				local encrypted = params[1](params.key, iv, message);

				assert.not_equal(message, encrypted);

				local decrypted = params[2](params.key, iv, encrypted);

				assert.equal(message, decrypted);

			end

		end);

	end);

end);