#include "hash.h"

#include <blue/core/hash.h>
#include <blue/core/rope.h>
#include <inttypes.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>

#define FNV1_OFFSET_BASIS 0xcbf29ce484222325
#define FNV1_PRIME        0x100000001b3

extern struct b_hash_function_ops z__b_md4_ops;
extern struct b_hash_function_ops z__b_md5_ops;
extern struct b_hash_function_ops z__b_sha1_ops;
extern struct b_hash_function_ops z__b_sha2_224_ops;
extern struct b_hash_function_ops z__b_sha2_256_ops;
extern struct b_hash_function_ops z__b_sha2_384_ops;
extern struct b_hash_function_ops z__b_sha2_512_ops;
extern struct b_hash_function_ops z__b_sha3_224_ops;
extern struct b_hash_function_ops z__b_sha3_256_ops;
extern struct b_hash_function_ops z__b_sha3_384_ops;
extern struct b_hash_function_ops z__b_sha3_512_ops;
extern struct b_hash_function_ops z__b_shake128_ops;
extern struct b_hash_function_ops z__b_shake256_ops;

static const struct b_hash_function_ops *hash_functions[] = {
	[B_HASH_NONE] = NULL,
	[B_HASH_MD4] = &z__b_md4_ops,
	[B_HASH_MD5] = &z__b_md5_ops,
	[B_HASH_SHA1] = &z__b_sha1_ops,
	[B_HASH_SHA2_224] = &z__b_sha2_224_ops,
	[B_HASH_SHA2_256] = &z__b_sha2_256_ops,
	[B_HASH_SHA2_384] = &z__b_sha2_384_ops,
	[B_HASH_SHA2_512] = &z__b_sha2_512_ops,
	[B_HASH_SHA3_224] = &z__b_sha3_224_ops,
	[B_HASH_SHA3_256] = &z__b_sha3_256_ops,
	[B_HASH_SHA3_384] = &z__b_sha3_384_ops,
	[B_HASH_SHA3_512] = &z__b_sha3_512_ops,
	[B_HASH_SHAKE128] = &z__b_shake128_ops,
	[B_HASH_SHAKE256] = &z__b_shake256_ops,
};
static const size_t nr_hash_functions
	= sizeof hash_functions / sizeof hash_functions[0];

uint64_t b_hash_cstr(const char *s)
{
	size_t x = 0;
	return b_hash_cstr_ex(s, &x);
}

uint64_t b_hash_cstr_ex(const char *s, size_t *len)
{
	uint64_t hash = FNV1_OFFSET_BASIS;
	size_t i = 0;

	for (i = 0; s[i]; i++) {
		hash ^= s[i];
		hash *= FNV1_PRIME;
	}

	if (len) {
		*len = i;
	}

	return hash;
}

enum b_status b_hash_ctx_init(struct b_hash_ctx *ctx, enum b_hash_function func)
{
	if (func < 0 || func >= nr_hash_functions) {
		return B_ERR_NOT_SUPPORTED;
	}

	const struct b_hash_function_ops *hash_function = hash_functions[func];
	if (!hash_function) {
		return B_ERR_NOT_SUPPORTED;
	}

	memset(ctx, 0x0, sizeof *ctx);

	ctx->ctx_func = func;
	ctx->ctx_ops = hash_function;

	if (hash_function->hash_init) {
		hash_function->hash_init(ctx);
	}

	return B_SUCCESS;
}

enum b_status b_hash_ctx_reset(struct b_hash_ctx *ctx)
{
	if (ctx->ctx_func == B_HASH_NONE || !ctx->ctx_ops) {
		return B_ERR_BAD_STATE;
	}

	memset(&ctx->ctx_state, 0x0, sizeof ctx->ctx_state);

	if (ctx->ctx_ops->hash_init) {
		ctx->ctx_ops->hash_init(ctx);
	}

	return B_SUCCESS;
}

enum b_status b_hash_ctx_update(struct b_hash_ctx *ctx, const void *p, size_t len)
{
	if (!ctx->ctx_ops) {
		return B_ERR_BAD_STATE;
	}

	if (!ctx->ctx_ops->hash_update) {
		return B_ERR_NOT_SUPPORTED;
	}

	ctx->ctx_ops->hash_update(ctx, p, len);
	return B_SUCCESS;
}

static void update_rope(const b_rope *rope, void *arg)
{
	struct b_hash_ctx *ctx = arg;
	unsigned int type = B_ROPE_TYPE(rope->r_flags);
	char tmp[64];
	size_t len = 0;

	switch (type) {
	case B_ROPE_F_CHAR:
		b_hash_ctx_update(ctx, &rope->r_v.v_char, sizeof rope->r_v.v_char);
		break;
	case B_ROPE_F_CSTR:
	case B_ROPE_F_CSTR_BORROWED:
	case B_ROPE_F_CSTR_STATIC:
		b_hash_ctx_update(
			ctx, rope->r_v.v_cstr.s, strlen(rope->r_v.v_cstr.s));
		break;
	case B_ROPE_F_INT:
		len = snprintf(tmp, sizeof tmp, "%" PRIdPTR, rope->r_v.v_int);
		b_hash_ctx_update(ctx, tmp, len);
		break;
	case B_ROPE_F_UINT:
		len = snprintf(tmp, sizeof tmp, "%" PRIuPTR, rope->r_v.v_uint);
		b_hash_ctx_update(ctx, tmp, len);
		break;
	default:
		break;
	}
}

enum b_status b_hash_ctx_update_rope(
	struct b_hash_ctx *ctx, const struct b_rope *rope)
{
	b_rope_iterate(rope, update_rope, ctx);
	return B_SUCCESS;
}

enum b_status b_hash_ctx_finish(
	struct b_hash_ctx *ctx, void *out_digest, size_t out_max)
{
	if (!ctx->ctx_ops) {
		return B_ERR_BAD_STATE;
	}

	if (!ctx->ctx_ops->hash_finish) {
		return B_ERR_NOT_SUPPORTED;
	}

	ctx->ctx_ops->hash_finish(ctx, out_digest, out_max);

	memset(&ctx->ctx_state, 0x0, sizeof ctx->ctx_state);

	if (ctx->ctx_ops->hash_init) {
		ctx->ctx_ops->hash_init(ctx);
	}

	return B_SUCCESS;
}