#include "../include/Hash.hpp"
#include "../include/bin2hex.hpp"
#include <sodium/crypto_generichash_blake2b.h>
#include <sodium/core.h>
#include <cstring>

namespace odhtdb
{
    struct SodiumInitializer
    {
        SodiumInitializer()
        {
            if(sodium_init() < 0)
                throw std::runtime_error("Failed to initialize libsodium");
        }
    };
    
    static SodiumInitializer __sodiumInitializer;
    
    // Source: https://stackoverflow.com/a/11414104 (public license)
    static size_t fnvHash(const unsigned char *key, int len)
    {
        size_t h = 2166136261;
        for (int i = 0; i < len; i++)
            h = (h * 16777619) ^ key[i];
        return h;
    }
    
    Hash::Hash()
    {
        memset(data, 0, HASH_BYTE_SIZE);
    }
    
    Hash::Hash(const void *input, const size_t inputSize)
    {
        int result = crypto_generichash_blake2b((unsigned char*)data, HASH_BYTE_SIZE, (const unsigned char*)input, inputSize, nullptr, 0);
        if(result < 0)
            throw HashException("Failed to hash data using blake2b");
    }
    
    size_t Hash::operator()() const
    {
        return fnvHash((const unsigned char*)data, HASH_BYTE_SIZE);
    }
    
    bool Hash::operator==(const Hash &other) const
    {
        return memcmp(data, other.data, HASH_BYTE_SIZE) == 0;
    }
    
    std::string Hash::toString() const
    {
        return bin2hex(data, HASH_BYTE_SIZE);
    }
}