#pragma once

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

struct BLAKE2s_param {
  uint8_t outlen; /* digest length */
  uint8_t keylen; /* key length */
  uint8_t fanout;
  uint8_t depth;
  uint32_t leaf_length;
  uint32_t node_offset;
  uint16_t node_offset_ex;
  uint8_t node_depth;
  uint8_t inner_length;
  uint64_t salt;
  uint64_t personalization;
};

struct BLAKE2s_ctx {
  uint8_t b[64];              /* input buffer */
  size_t c;                   /* pointer for b[] */
  uint32_t h[8];              /* chained state vector h */
  uint32_t t[2];              /* total number of bytes */
  struct BLAKE2s_param param; /* parameter block */
};

/**
 * 3.1 Mixing Function G
 */
void G(uint32_t V[16], unsigned a, unsigned b, unsigned c, unsigned d, uint32_t x, uint32_t y);

/**
 * 3.2 Compression Function F
 * @param t: 2w-bit offset counter t
 * @param f: final block indicator flag f
 */
void F(struct BLAKE2s_ctx *context, uint32_t m[16], uint32_t f);

int BLAKE2s_init(struct BLAKE2s_ctx *ctx, uint8_t outlen, const void *key, uint8_t keylen);
void BLAKE2s_update(struct BLAKE2s_ctx *ctx, const void *d, size_t dd);
void BLAKE2s_final(struct BLAKE2s_ctx *ctx, void *out);

/* All-in-one convenience function. */
static __inline__ int
BLAKE2s(void *out, uint8_t outlen,       /* return buffer for digest */
        const void *key, uint8_t keylen, /* optional secret key */
        const void *in, size_t inlen)    /* data to be hashed */
{
  struct BLAKE2s_ctx ctx;
  if (BLAKE2s_init(&ctx, outlen, key, keylen)) return -1;
  BLAKE2s_update(&ctx, in, inlen);
  BLAKE2s_final(&ctx, out);

  return 0;
}