// Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <openssl/evp.h>

#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/dsa.h>
#include <openssl/ec.h>
#include <openssl/ec_key.h>
#include <openssl/mem.h>
#include <openssl/rsa.h>

#include "../internal.h"


using namespace bssl;

static int print_hex(BIO *bp, const uint8_t *data, size_t len, int off) {
  for (size_t i = 0; i < len; i++) {
    if ((i % 15) == 0) {
      if (BIO_puts(bp, "\n") <= 0 ||  //
          !BIO_indent(bp, off + 4, 128)) {
        return 0;
      }
    }
    if (BIO_printf(bp, "%02x%s", data[i], (i + 1 == len) ? "" : ":") <= 0) {
      return 0;
    }
  }
  if (BIO_write(bp, "\n", 1) <= 0) {
    return 0;
  }
  return 1;
}

static int bn_print(BIO *bp, const char *name, const BIGNUM *num, int off) {
  if (num == nullptr) {
    return 1;
  }

  if (!BIO_indent(bp, off, 128)) {
    return 0;
  }
  if (BN_is_zero(num)) {
    if (BIO_printf(bp, "%s 0\n", name) <= 0) {
      return 0;
    }
    return 1;
  }

  uint64_t u64;
  if (BN_get_u64(num, &u64)) {
    const char *neg = BN_is_negative(num) ? "-" : "";
    return BIO_printf(bp, "%s %s%" PRIu64 " (%s0x%" PRIx64 ")\n", name, neg,
                      u64, neg, u64) > 0;
  }

  if (BIO_printf(bp, "%s%s", name,
                 (BN_is_negative(num)) ? " (Negative)" : "") <= 0) {
    return 0;
  }

  // Print `num` in hex, adding a leading zero, as in ASN.1, if the high bit
  // is set.
  //
  // TODO(davidben): Do we need to do this? We already print "(Negative)" above
  // and negative values are never valid in keys anyway.
  size_t len = BN_num_bytes(num);
  uint8_t *buf = reinterpret_cast<uint8_t *>(OPENSSL_malloc(len + 1));
  if (buf == nullptr) {
    return 0;
  }

  buf[0] = 0;
  BN_bn2bin(num, buf + 1);
  int ret;
  if (len > 0 && (buf[1] & 0x80) != 0) {
    // Print the whole buffer.
    ret = print_hex(bp, buf, len + 1, off);
  } else {
    // Skip the leading zero.
    ret = print_hex(bp, buf + 1, len, off);
  }
  OPENSSL_free(buf);
  return ret;
}

// RSA keys.

static int do_rsa_print(BIO *out, const RSA *rsa, int off,
                        int include_private) {
  int mod_len = 0;
  if (RSA_get0_n(rsa) != nullptr) {
    mod_len = RSA_bits(rsa);
  }

  if (!BIO_indent(out, off, 128)) {
    return 0;
  }

  const char *s, *str;
  if (include_private && RSA_get0_d(rsa) != nullptr) {
    if (BIO_printf(out, "Private-Key: (%d bit)\n", mod_len) <= 0) {
      return 0;
    }
    str = "modulus:";
    s = "publicExponent:";
  } else {
    if (BIO_printf(out, "Public-Key: (%d bit)\n", mod_len) <= 0) {
      return 0;
    }
    str = "Modulus:";
    s = "Exponent:";
  }
  if (!bn_print(out, str, RSA_get0_n(rsa), off) ||
      !bn_print(out, s, RSA_get0_e(rsa), off)) {
    return 0;
  }

  if (include_private) {
    if (!bn_print(out, "privateExponent:", RSA_get0_d(rsa), off) ||
        !bn_print(out, "prime1:", RSA_get0_p(rsa), off) ||
        !bn_print(out, "prime2:", RSA_get0_q(rsa), off) ||
        !bn_print(out, "exponent1:", RSA_get0_dmp1(rsa), off) ||
        !bn_print(out, "exponent2:", RSA_get0_dmq1(rsa), off) ||
        !bn_print(out, "coefficient:", RSA_get0_iqmp(rsa), off)) {
      return 0;
    }
  }

  return 1;
}

static int rsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent) {
  return do_rsa_print(bp, EVP_PKEY_get0_RSA(pkey), indent, 0);
}

static int rsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent) {
  return do_rsa_print(bp, EVP_PKEY_get0_RSA(pkey), indent, 1);
}


// EC keys.

static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, int ktype) {
  const EC_GROUP *group;
  if (x == nullptr || (group = EC_KEY_get0_group(x)) == nullptr) {
    OPENSSL_PUT_ERROR(EVP, ERR_R_PASSED_NULL_PARAMETER);
    return 0;
  }

  const char *ecstr;
  if (ktype == 2) {
    ecstr = "Private-Key";
  } else if (ktype == 1) {
    ecstr = "Public-Key";
  } else {
    ecstr = "ECDSA-Parameters";
  }

  if (!BIO_indent(bp, off, 128)) {
    return 0;
  }
  int curve_name = EC_GROUP_get_curve_name(group);
  if (BIO_printf(bp, "%s: (%s)\n", ecstr,
                 curve_name == NID_undef
                     ? "unknown curve"
                     : EC_curve_nid2nist(curve_name)) <= 0) {
    return 0;
  }

  if (ktype == 2) {
    const BIGNUM *priv_key = EC_KEY_get0_private_key(x);
    if (priv_key != nullptr &&  //
        !bn_print(bp, "priv:", priv_key, off)) {
      return 0;
    }
  }

  if (ktype > 0 && EC_KEY_get0_public_key(x) != nullptr) {
    uint8_t *pub = nullptr;
    size_t pub_len = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, nullptr);
    if (pub_len == 0) {
      return 0;
    }
    int ret = BIO_indent(bp, off, 128) &&  //
              BIO_puts(bp, "pub:") > 0 &&  //
              print_hex(bp, pub, pub_len, off);
    OPENSSL_free(pub);
    if (!ret) {
      return 0;
    }
  }

  return 1;
}

static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent) {
  return do_EC_KEY_print(bp, EVP_PKEY_get0_EC_KEY(pkey), indent, 0);
}

static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent) {
  return do_EC_KEY_print(bp, EVP_PKEY_get0_EC_KEY(pkey), indent, 1);
}


static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent) {
  return do_EC_KEY_print(bp, EVP_PKEY_get0_EC_KEY(pkey), indent, 2);
}


typedef struct {
  int type;
  int (*pub_print)(BIO *out, const EVP_PKEY *pkey, int indent);
  int (*priv_print)(BIO *out, const EVP_PKEY *pkey, int indent);
  int (*param_print)(BIO *out, const EVP_PKEY *pkey, int indent);
} EVP_PKEY_PRINT_METHOD;

static const EVP_PKEY_PRINT_METHOD kPrintMethods[] = {
    {
        EVP_PKEY_RSA,
        rsa_pub_print,
        rsa_priv_print,
        /*param_print=*/nullptr,
    },
    {
        EVP_PKEY_EC,
        eckey_pub_print,
        eckey_priv_print,
        eckey_param_print,
    },
};

static const EVP_PKEY_PRINT_METHOD *find_method(int type) {
  for (const auto &p : kPrintMethods) {
    if (p.type == type) {
      return &p;
    }
  }
  return nullptr;
}

static int print_unsupported(BIO *out, const EVP_PKEY *pkey, int indent,
                             const char *kstr) {
  BIO_indent(out, indent, 128);
  BIO_printf(out, "%s algorithm unsupported\n", kstr);
  return 1;
}

int EVP_PKEY_print_public(BIO *out, const EVP_PKEY *pkey, int indent,
                          ASN1_PCTX *pctx) {
  const EVP_PKEY_PRINT_METHOD *method = find_method(EVP_PKEY_id(pkey));
  if (method != nullptr && method->pub_print != nullptr) {
    return method->pub_print(out, pkey, indent);
  }
  return print_unsupported(out, pkey, indent, "Public Key");
}

int EVP_PKEY_print_private(BIO *out, const EVP_PKEY *pkey, int indent,
                           ASN1_PCTX *pctx) {
  const EVP_PKEY_PRINT_METHOD *method = find_method(EVP_PKEY_id(pkey));
  if (method != nullptr && method->priv_print != nullptr) {
    return method->priv_print(out, pkey, indent);
  }
  return print_unsupported(out, pkey, indent, "Private Key");
}

int EVP_PKEY_print_params(BIO *out, const EVP_PKEY *pkey, int indent,
                          ASN1_PCTX *pctx) {
  const EVP_PKEY_PRINT_METHOD *method = find_method(EVP_PKEY_id(pkey));
  if (method != nullptr && method->param_print != nullptr) {
    return method->param_print(out, pkey, indent);
  }
  return print_unsupported(out, pkey, indent, "Parameters");
}