/* Converted to C by Rusty Russell, based on bitcoin source: */
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin Developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "address.h"
#include "base58.h"
#include "privkey.h"
#include "pubkey.h"
#include "shadouble.h"
#include <assert.h>
#include <ccan/build_assert/build_assert.h>
#include <ccan/tal/str/str.h>
#include <common/utils.h>
#include <libbase58.h>
#include <secp256k1.h>
#include <string.h>

static bool my_sha256(void *digest, const void *data, size_t datasz)
{
	sha256(digest, data, datasz);
	return true;
}

static char *to_base58(const tal_t *ctx, u8 version,
		       const struct ripemd160 *rmd)
{
	char out[BASE58_ADDR_MAX_LEN + 1];
	size_t outlen = sizeof(out);

	b58_sha256_impl = my_sha256;
	if (!b58check_enc(out, &outlen, version, rmd, sizeof(*rmd))) {
		return NULL;
	}else{
		return tal_strdup(ctx, out);
	}
}

char *bitcoin_to_base58(const tal_t *ctx, bool test_net,
			const struct bitcoin_address *addr)
{
	return to_base58(ctx, test_net ? 111 : 0, &addr->addr);
}

char *p2sh_to_base58(const tal_t *ctx, bool test_net,
		     const struct ripemd160 *p2sh)
{
	return to_base58(ctx, test_net ? 196 : 5, p2sh);
}

static bool from_base58(u8 *version,
			struct ripemd160 *rmd,
			const char *base58, size_t base58_len)
{
	u8 buf[1 + sizeof(*rmd) + 4];
	/* Avoid memcheck complaining if decoding resulted in a short value */
	memset(buf, 0, sizeof(buf));
	b58_sha256_impl = my_sha256;

	size_t buflen = sizeof(buf);
	b58tobin(buf, &buflen, base58, base58_len);

	int r = b58check(buf, buflen, base58, base58_len);
	*version = buf[0];
	memcpy(rmd, buf + 1, sizeof(*rmd));
	return r >= 0;
}

bool bitcoin_from_base58(bool *test_net,
			 struct bitcoin_address *addr,
			 const char *base58, size_t len)
{
	u8 version;

	if (!from_base58(&version, &addr->addr, base58, len))
		return false;

	if (version == 111)
		*test_net = true;
	else if (version == 0)
		*test_net = false;
	else
		return false;
	return true;
}

bool p2sh_from_base58(bool *test_net,
		      struct ripemd160 *p2sh,
		      const char *base58, size_t len)
{
	u8 version;

	if (!from_base58(&version, p2sh, base58, len))
		return false;

	if (version == 196)
		*test_net = true;
	else if (version == 5)
		*test_net = false;
	else
		return false;
	return true;
}

bool ripemd_from_base58(u8 *version,
			struct ripemd160 *ripemd160,
			const char *base58)
{
	return from_base58(version, ripemd160, base58, strlen(base58));
}

char *key_to_base58(const tal_t *ctx, bool test_net, const struct privkey *key)
{
	u8 buf[32 + 1];
	char out[BASE58_KEY_MAX_LEN + 2];
	u8 version = test_net ? 239 : 128;
	size_t outlen = sizeof(out);

	memcpy(buf, key->secret.data, sizeof(key->secret.data));
	/* Mark this as a compressed key. */
	buf[32] = 1;

	b58_sha256_impl = my_sha256;
	b58check_enc(out, &outlen, version, buf, sizeof(buf));
	return tal_strdup(ctx, out);
}

bool key_from_base58(const char *base58, size_t base58_len,
		     bool *test_net, struct privkey *priv, struct pubkey *key)
{
	// 1 byte version, 32 byte private key, 1 byte compressed, 4 byte checksum
	u8 keybuf[1 + 32 + 1 + 4];
	size_t keybuflen = sizeof(keybuf);

	b58_sha256_impl = my_sha256;

	b58tobin(keybuf, &keybuflen, base58, base58_len);
	if (b58check(keybuf, sizeof(keybuf), base58, base58_len) < 0)
		return false;

	/* Byte after key should be 1 to represent a compressed key. */
	if (keybuf[1 + 32] != 1)
		return false;

	if (keybuf[0] == 128)
		*test_net = false;
	else if (keybuf[0] == 239)
		*test_net = true;
	else
		return false;

	/* Copy out secret. */
	memcpy(priv->secret.data, keybuf + 1, sizeof(priv->secret.data));

	if (!secp256k1_ec_seckey_verify(secp256k1_ctx, priv->secret.data))
		return false;

	/* Get public key, too. */
	if (!pubkey_from_privkey(priv, key))
		return false;

	return true;
}