// Copyright 2020 Google LLC
//
// 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.

#ifndef PLATFORM_API_CRYPTO_H_
#define PLATFORM_API_CRYPTO_H_

#include <stddef.h>
#include <stdint.h>

#include "absl/strings/string_view.h"
#include "absl/types/span.h"
#include "internal/platform/byte_array.h"

namespace nearby {

// A provider of standard hashing algorithms.
class Crypto {
 public:
  // Initialize global crypto state.
  static void Init();
  // Return MD5 hash of input.
  static ByteArray Md5(absl::string_view input);
  // Return SHA256 hash of input.
  static ByteArray Sha256(absl::string_view input);
};

// Fills the given buffer with |length| random bytes of cryptographically
// secure random numbers.
// |length| must be positive.
//
// TODO(crbug.com/40284755): Convert all callers in Nearby to use spans
// and remove this RandBytes overload.
void RandBytes(void *bytes, size_t length);

// Fills |bytes| with cryptographically-secure random bits.
void RandBytes(absl::Span<uint8_t> bytes);

// Creates an object of type T initialized with random data.
// This template should be used for simple data types: int, char, etc.
template <typename T>
T RandData() {
  T data;
  RandBytes(&data, sizeof(data));
  return data;
}

}  // namespace nearby

#endif  // PLATFORM_API_CRYPTO_H_