/*
* (C) 2009,2015,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include "tests.h"

#if defined(BOTAN_HAS_NUMBERTHEORY)
  #include <botan/bigint.h>
  #include <botan/numthry.h>
  #include <botan/reducer.h>
  #include <cmath>
#endif

namespace Botan_Tests {

namespace {

#if defined(BOTAN_HAS_NUMBERTHEORY)

using Botan::BigInt;

class BigInt_Unit_Tests : public Test
   {
   public:
      std::vector<Test::Result> run() override
         {
         std::vector<Test::Result> results;

         results.push_back(test_bigint_sizes());
         results.push_back(test_random_integer());
         results.push_back(test_random_prime());
         results.push_back(test_encode());
         results.push_back(test_bigint_io());

         return results;
         }
   private:
      Test::Result test_bigint_sizes()
         {
         Test::Result result("BigInt size functions");

         for(size_t bit : { 1, 8, 16, 31, 32, 64, 97, 128, 179, 192, 512, 521 })
            {
            BigInt a;

            a.set_bit(bit);

            // Test 2^n and 2^n-1
            for(size_t i = 0; i != 2; ++i)
               {
               const size_t exp_bits = bit + 1 - i;
               result.test_eq("BigInt::bits", a.bits(), exp_bits);
               result.test_eq("BigInt::bytes", a.bytes(),
                              (exp_bits % 8 == 0) ? (exp_bits / 8) : (exp_bits + 8 - exp_bits % 8) / 8);

               if(bit == 1 && i == 1)
                  {
                  result.test_is_eq("BigInt::to_u32bit zero", a.to_u32bit(), static_cast<uint32_t>(1));
                  }
               else if(bit <= 31 || (bit == 32 && i == 1))
                  {
                  result.test_is_eq("BigInt::to_u32bit", a.to_u32bit(), static_cast<uint32_t>((uint64_t(1) << bit) - i));
                  }
               else
                  {
                  try {
                     a.to_u32bit();
                     result.test_failure("BigInt::to_u32bit roundtripped out of range value");
                  }
                  catch(std::exception&)
                     {
                     result.test_success("BigInt::to_u32bit rejected out of range");
                     }
                  }

               a--;
               }
            }

         return result;
         }

      Test::Result test_random_prime()
         {
         Test::Result result("BigInt prime generation");

         result.test_throws("Invalid arg", []{ Botan::random_prime(Test::rng(), 0); });
         result.test_throws("Invalid arg", []{ Botan::random_prime(Test::rng(), 1); });
         result.test_throws("Invalid arg", []{ Botan::random_prime(Test::rng(), 2, 0); });
         result.test_throws("Invalid arg", []{ Botan::random_prime(Test::rng(), 2, 1, 1, 3); });
         result.test_throws("Invalid arg", []{ Botan::random_prime(Test::rng(), 2, 1, 0, 2); });

         BigInt p = Botan::random_prime(Test::rng(), 2);
         result.confirm("Only two 2-bit primes", p == 2 || p == 3);

         p = Botan::random_prime(Test::rng(), 3);
         result.confirm("Only two 3-bit primes", p == 5 || p == 7);

         p = Botan::random_prime(Test::rng(), 4);
         result.confirm("Only two 4-bit primes", p == 11 || p == 13);

         for(size_t bits = 5; bits <= 32; ++bits)
            {
            p = Botan::random_prime(Test::rng(), bits);
            result.test_eq("Expected bit size", p.bits(), bits);
            result.test_eq("P is prime", Botan::is_prime(p, Test::rng()), true);
            }

         for(size_t bits = 5; bits <= 32; ++bits)
            {
            const BigInt last_p = p;
            p = Botan::random_prime(Test::rng(), bits, last_p);

            result.test_eq("Relatively prime", Botan::gcd(last_p, p), 1);
            result.test_eq("Expected bit size", p.bits(), bits);
            result.test_eq("P is prime", Botan::is_prime(p, Test::rng()), true);
            }

         const size_t safe_prime_bits = 65;
         const BigInt safe_prime = Botan::random_safe_prime(Test::rng(), safe_prime_bits);
         result.test_eq("Safe prime size", safe_prime.bits(), safe_prime_bits);
         result.confirm("P is prime", Botan::is_prime(safe_prime, Test::rng()));
         result.confirm("(P-1)/2 is prime", Botan::is_prime((safe_prime-1)/2, Test::rng()));

         return result;
         }

      Test::Result test_random_integer()
         {
         Test::Result result("BigInt::random_integer");

         result.start_timer();

         // A value of 500 caused a non-negligible amount of test failures
         const size_t ITERATIONS_PER_POSSIBLE_VALUE = 750;

         std::vector<size_t> min_ranges{ 0 };
         std::vector<size_t> max_ranges{ 10 };

         if(Test::run_long_tests())
            {
            // This gets slow quickly:
            min_ranges.push_back(7);
            max_ranges.push_back(113);
            }

         for(size_t range_min : min_ranges)
            {
            for(size_t range_max : max_ranges)
               {
               if(range_min >= range_max)
                  continue;

               std::vector<size_t> counts(range_max - range_min);

               for(size_t i = 0; i != counts.size() * ITERATIONS_PER_POSSIBLE_VALUE; ++i)
                  {
                  uint32_t r = BigInt::random_integer(Test::rng(), range_min, range_max).to_u32bit();
                  result.test_gte("random_integer", r, range_min);
                  result.test_lt("random_integer", r, range_max);
                  counts[r - range_min] += 1;
                  }

               for(const auto count : counts)
                  {
                  double ratio = static_cast<double>(count) / ITERATIONS_PER_POSSIBLE_VALUE;

                  if(ratio >= 0.85 && ratio <= 1.15) // +/-15 %
                     {
                     result.test_success("distribution within expected range");
                     }
                  else
                     {
                     result.test_failure("distribution ratio outside expected range (+/-15 %): " +
                                         std::to_string(ratio));
                     }
                  }
               }
            }

         result.end_timer();

         return result;
         }

      Test::Result test_encode()
         {
         Test::Result result("BigInt encoding functions");

         const BigInt n1(0xffff);
         const BigInt n2(1023);

         Botan::secure_vector<uint8_t> encoded_n1 = BigInt::encode_1363(n1, 256);
         Botan::secure_vector<uint8_t> encoded_n2 = BigInt::encode_1363(n2, 256);
         Botan::secure_vector<uint8_t> expected = encoded_n1;
         expected += encoded_n2;

         Botan::secure_vector<uint8_t> encoded_n1_n2 = BigInt::encode_fixed_length_int_pair(n1, n2, 256);
         result.test_eq("encode_fixed_length_int_pair", encoded_n1_n2, expected);

         for (size_t i = 0; i < 256 - n1.bytes(); ++i)
            {
               if ( encoded_n1[i] != 0 )
                  {
                  result.test_failure("encode_1363", "no zero byte");
                  }
            }

         return result;
         }

      Test::Result test_bigint_io()
         {
         Test::Result result("BigInt IO operators");

         const std::map<std::string, Botan::BigInt> str_to_val = {
            { "-13", -Botan::BigInt(13) },
            { "0", Botan::BigInt(0) },
            { "0x13", Botan::BigInt(0x13) },
            { "1", Botan::BigInt(1) },
            { "4294967297", Botan::BigInt(2147483648)*2 + 1 }
         };

         for(auto vec : str_to_val)
            {
            Botan::BigInt n;
            std::istringstream iss;

            iss.str(vec.first);
            iss >> n;
            result.test_eq("input '" + vec.first + "'", n, vec.second);
            }

         BigInt n = 33;

         std::ostringstream oss;
         oss << n;
         result.test_eq("output 33 dec", oss.str(), "33");

         oss.str("");
         oss << std::hex << n;
         result.test_eq("output 33 hex", oss.str(), "21");

         result.test_throws("octal output not supported",
                            [&]{ oss << std::oct << n; });

         return result;
         }
   };

BOTAN_REGISTER_TEST("bigint_unit", BigInt_Unit_Tests);

class BigInt_Add_Test : public Text_Based_Test
   {
   public:
      BigInt_Add_Test() : Text_Based_Test("bn/add.vec", "In1,In2,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Addition");

         using Botan::BigInt;

         const BigInt a = get_req_bn(vars, "In1");
         const BigInt b = get_req_bn(vars, "In2");
         const BigInt c = get_req_bn(vars, "Output");
         BigInt d = a + b;

         result.test_eq("a + b", a + b, c);
         result.test_eq("b + a", b + a, c);

         BigInt e = a;
         e += b;
         result.test_eq("a += b", e, c);

         e = b;
         e += a;
         result.test_eq("b += a", e, c);

         return result;
         }

   };

BOTAN_REGISTER_TEST("bn_add", BigInt_Add_Test);

class BigInt_Sub_Test : public Text_Based_Test
   {
   public:
      BigInt_Sub_Test() : Text_Based_Test("bn/sub.vec", "In1,In2,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Subtraction");

         const BigInt a = get_req_bn(vars, "In1");
         const BigInt b = get_req_bn(vars, "In2");
         const BigInt c = get_req_bn(vars, "Output");

         BigInt d = a - b;

         result.test_eq("a - b", a - b, c);

         BigInt e = a;
         e -= b;
         result.test_eq("a -= b", e, c);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_sub", BigInt_Sub_Test);

class BigInt_Mul_Test : public Text_Based_Test
   {
   public:
      BigInt_Mul_Test() : Text_Based_Test("bn/mul.vec", "In1,In2,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Multiply");

         const BigInt a = get_req_bn(vars, "In1");
         const BigInt b = get_req_bn(vars, "In2");
         const BigInt c = get_req_bn(vars, "Output");

         result.test_eq("a * b", a * b, c);
         result.test_eq("b * a", b * a, c);

         BigInt e = a;
         e *= b;
         result.test_eq("a *= b", e, c);

         e = b;
         e *= a;
         result.test_eq("b *= a", e, c);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_mul", BigInt_Mul_Test);

class BigInt_Sqr_Test : public Text_Based_Test
   {
   public:
      BigInt_Sqr_Test() : Text_Based_Test("bn/sqr.vec", "Input,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Square");

         const BigInt input = get_req_bn(vars, "Input");
         const BigInt output = get_req_bn(vars, "Output");

         result.test_eq("a * a", input * input, output);
         result.test_eq("sqr(a)", square(input), output);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_sqr", BigInt_Sqr_Test);

class BigInt_Div_Test : public Text_Based_Test
   {
   public:
      BigInt_Div_Test() : Text_Based_Test("bn/divide.vec", "In1,In2,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Divide");

         const BigInt a = get_req_bn(vars, "In1");
         const BigInt b = get_req_bn(vars, "In2");
         const BigInt c = get_req_bn(vars, "Output");

         result.test_eq("a / b", a / b, c);

         BigInt e = a;
         e /= b;
         result.test_eq("a /= b", e, c);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_div", BigInt_Div_Test);

class BigInt_Mod_Test : public Text_Based_Test
   {
   public:
      BigInt_Mod_Test() : Text_Based_Test("bn/mod.vec", "In1,In2,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Mod");

         const BigInt a = get_req_bn(vars, "In1");
         const BigInt b = get_req_bn(vars, "In2");
         const BigInt c = get_req_bn(vars, "Output");

         result.test_eq("a % b", a % b, c);

         BigInt e = a;
         e %= b;
         result.test_eq("a %= b", e, c);

         // if b fits into a Botan::word test %= operator for words
         if(b.bytes() <= sizeof(Botan::word))
            {
            Botan::word b_word = b.word_at( 0 );
            e = a;
            e %= b_word;
            result.test_eq("a %= b (as word)", e, c);
            }

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_mod", BigInt_Mod_Test);

class BigInt_Lshift_Test : public Text_Based_Test
   {
   public:
      BigInt_Lshift_Test() : Text_Based_Test("bn/lshift.vec", "Value,Shift,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Lshift");

         const BigInt value = get_req_bn(vars, "Value");
         const size_t shift = get_req_bn(vars, "Shift").to_u32bit();
         const BigInt output = get_req_bn(vars, "Output");

         result.test_eq("a << s", value << shift, output);

         BigInt e = value;
         e <<= shift;
         result.test_eq("a <<= s", e, output);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_lshift", BigInt_Lshift_Test);

class BigInt_Rshift_Test : public Text_Based_Test
   {
   public:
      BigInt_Rshift_Test() : Text_Based_Test("bn/rshift.vec", "Value,Shift,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Rshift");

         const BigInt value = get_req_bn(vars, "Value");
         const size_t shift = get_req_bn(vars, "Shift").to_u32bit();
         const BigInt output = get_req_bn(vars, "Output");

         result.test_eq("a >> s", value >> shift, output);

         BigInt e = value;
         e >>= shift;
         result.test_eq("a >>= s", e, output);

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_rshift", BigInt_Rshift_Test);

class BigInt_Powmod_Test : public Text_Based_Test
   {
   public:
      BigInt_Powmod_Test() : Text_Based_Test("bn/powmod.vec", "Base,Exponent,Modulus,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Powmod");

         const BigInt base = get_req_bn(vars, "Base");
         const BigInt exponent = get_req_bn(vars, "Exponent");
         const BigInt modulus = get_req_bn(vars, "Modulus");
         const BigInt expected = get_req_bn(vars, "Output");

         result.test_eq("power_mod", Botan::power_mod(base, exponent, modulus), expected);

         Botan::Power_Mod pow_mod1(modulus);

         pow_mod1.set_base(base);
         pow_mod1.set_exponent(exponent);
         result.test_eq("pow_mod1", pow_mod1.execute(), expected);

         Botan::Power_Mod pow_mod2(modulus);

         // Reverses ordering which affects window size
         pow_mod2.set_exponent(exponent);
         pow_mod2.set_base(base);
         result.test_eq("pow_mod2", pow_mod2.execute(), expected);
         result.test_eq("pow_mod2 #2", pow_mod2.execute(), expected);

         if(modulus.is_odd())
            {
            // TODO: test different hints
            // also TODO: remove bogus hinting arguments :)
            Botan::Power_Mod pow_mod3(modulus, Botan::Power_Mod::NO_HINTS, /*disable_montgomery=*/true);

            pow_mod3.set_exponent(exponent);
            pow_mod3.set_base(base);
            result.test_eq("pow_mod_fixed_window", pow_mod3.execute(), expected);
            }

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_powmod", BigInt_Powmod_Test);

class BigInt_IsPrime_Test : public Text_Based_Test
   {
   public:
      BigInt_IsPrime_Test() : Text_Based_Test("bn/isprime.vec", "X") {}

      Test::Result run_one_test(const std::string& header, const VarMap& vars) override
         {
         if(header != "Prime" && header != "NonPrime")
            throw Test_Error("Bad header for prime test " + header);

         const BigInt value = get_req_bn(vars, "X");
         const bool is_prime = (header == "Prime");

         Test::Result result("BigInt Test " + header);
         result.test_eq("is_prime", Botan::is_prime(value, Test::rng()), is_prime);
         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_isprime", BigInt_IsPrime_Test);

class BigInt_Ressol_Test : public Text_Based_Test
   {
   public:
      BigInt_Ressol_Test() : Text_Based_Test("bn/ressol.vec", "Input,Modulus,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt Ressol");

         const Botan::BigInt a = get_req_bn(vars, "Input");
         const Botan::BigInt p = get_req_bn(vars, "Modulus");
         const Botan::BigInt exp = get_req_bn(vars, "Output");

         const Botan::BigInt a_sqrt = Botan::ressol(a, p);

         result.test_eq("ressol", a_sqrt, exp);

         if(a_sqrt > 1)
            {
            const Botan::BigInt a_sqrt2 = (a_sqrt*a_sqrt) % p;
            result.test_eq("square correct", a_sqrt2, a);
            }

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_ressol", BigInt_Ressol_Test);

class BigInt_InvMod_Test : public Text_Based_Test
   {
   public:
      BigInt_InvMod_Test() : Text_Based_Test("bn/invmod.vec", "Input,Modulus,Output") {}

      Test::Result run_one_test(const std::string&, const VarMap& vars) override
         {
         Test::Result result("BigInt InvMod");

         const Botan::BigInt a = get_req_bn(vars, "Input");
         const Botan::BigInt mod = get_req_bn(vars, "Modulus");
         const Botan::BigInt expected = get_req_bn(vars, "Output");

         const Botan::BigInt a_inv = Botan::inverse_mod(a, mod);

         result.test_eq("inverse_mod", a_inv, expected);

         if(a_inv > 1)
            {
            result.test_eq("inverse ok", (a * a_inv) % mod, 1);
            }

         if(mod.is_odd())
            {
            result.test_eq("ct_inverse_odd_modulus",
                           ct_inverse_mod_odd_modulus(a, mod),
                           expected);
            }

         if(mod.is_odd() && a_inv != 0)
            {
            result.test_eq("normalized_montgomery_inverse",
                           normalized_montgomery_inverse(a, mod),
                           expected);
            }

         return result;
         }
   };

BOTAN_REGISTER_TEST("bn_invmod", BigInt_InvMod_Test);

class DSA_ParamGen_Test : public Text_Based_Test
   {
   public:
      DSA_ParamGen_Test() : Text_Based_Test("bn/dsa_gen.vec", "P,Q,Counter,Seed") {}

      Test::Result run_one_test(const std::string& header, const VarMap& vars) override
         {
         const std::vector<uint8_t> seed = get_req_bin(vars, "Seed");
         const size_t offset = get_req_sz(vars, "Counter");

         const Botan::BigInt exp_P = get_req_bn(vars, "P");
         const Botan::BigInt exp_Q = get_req_bn(vars, "Q");

         const std::vector<std::string> header_parts = Botan::split_on(header, ',');

         if(header_parts.size() != 2)
            throw Test_Error("Unexpected header '" + header + "' in DSA param gen test");

         const size_t p_bits = Botan::to_u32bit(header_parts[1]);
         const size_t q_bits = Botan::to_u32bit(header_parts[0]);

         Test::Result result("DSA Parameter Generation");

         // These tests are very slow so skip in normal runs
         if(p_bits > 1024 && Test::run_long_tests() == false)
            return result;

         try {
            Botan::BigInt gen_P, gen_Q;
            if(Botan::generate_dsa_primes(Test::rng(), gen_P, gen_Q, p_bits, q_bits, seed, offset))
               {
               result.test_eq("P", gen_P, exp_P);
               result.test_eq("Q", gen_Q, exp_Q);
               }
            else
               {
               result.test_failure("Seed did not generate a DSA parameter");
               }
         }
         catch(Botan::Lookup_Error&)
            {
            }

         return result;
         }
   };

BOTAN_REGISTER_TEST("dsa_param", DSA_ParamGen_Test);

#endif

}

}