/*
 * Copyright 2010 Jeff Garzik
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option) 
 * any later version.  See COPYING for more details.
 */

#define _GNU_SOURCE
#include "cpuminer-config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <jansson.h>
#include <curl/curl.h>
#include "miner.h"

struct data_buffer {
	void		*buf;
	size_t		len;
};

struct upload_buffer {
	const void	*buf;
	size_t		len;
};

static void databuf_free(struct data_buffer *db)
{
	if (!db)
		return;
	
	free(db->buf);

	memset(db, 0, sizeof(*db));
}

static size_t all_data_cb(const void *ptr, size_t size, size_t nmemb,
			  void *user_data)
{
	struct data_buffer *db = user_data;
	size_t len = size * nmemb;
	size_t oldlen, newlen;
	void *newmem;
	static const unsigned char zero;

	oldlen = db->len;
	newlen = oldlen + len;

	newmem = realloc(db->buf, newlen + 1);
	if (!newmem)
		return 0;

	db->buf = newmem;
	db->len = newlen;
	memcpy(db->buf + oldlen, ptr, len);
	memcpy(db->buf + newlen, &zero, 1);	/* null terminate */

	return len;
}

static size_t upload_data_cb(void *ptr, size_t size, size_t nmemb,
			     void *user_data)
{
	struct upload_buffer *ub = user_data;
	int len = size * nmemb;

	if (len > ub->len)
		len = ub->len;

	if (len) {
		memcpy(ptr, ub->buf, len);
		ub->buf += len;
		ub->len -= len;
	}

	return len;
}

json_t *json_rpc_call(CURL *curl, const char *url,
		      const char *userpass, const char *rpc_req)
{
	json_t *val, *err_val, *res_val;
	int rc;
	struct data_buffer all_data = { };
	struct upload_buffer upload_data;
	json_error_t err = { };
	struct curl_slist *headers = NULL;
	char len_hdr[64];
	char curl_err_str[CURL_ERROR_SIZE];

	/* it is assumed that 'curl' is freshly [re]initialized at this pt */

	if (opt_protocol)
		curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_ENCODING, "");
	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
	curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 1);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, all_data_cb);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &all_data);
	curl_easy_setopt(curl, CURLOPT_READFUNCTION, upload_data_cb);
	curl_easy_setopt(curl, CURLOPT_READDATA, &upload_data);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curl_err_str);
	if (userpass) {
		curl_easy_setopt(curl, CURLOPT_USERPWD, userpass);
		curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
	}
	curl_easy_setopt(curl, CURLOPT_POST, 1);

	if (opt_protocol)
		printf("JSON protocol request:\n%s\n", rpc_req);

	upload_data.buf = rpc_req;
	upload_data.len = strlen(rpc_req);
	sprintf(len_hdr, "Content-Length: %lu",
		(unsigned long) upload_data.len);

	headers = curl_slist_append(headers,
		"Content-type: application/json");
	headers = curl_slist_append(headers, len_hdr);
	headers = curl_slist_append(headers, "Expect:"); /* disable Expect hdr*/

	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

	rc = curl_easy_perform(curl);
	if (rc) {
		fprintf(stderr, "HTTP request failed: %s\n", curl_err_str);
		goto err_out;
	}

	val = json_loads(all_data.buf, &err);
	if (!val) {
		fprintf(stderr, "JSON decode failed(%d): %s\n", err.line, err.text);
		goto err_out;
	}

	if (opt_protocol) {
		char *s = json_dumps(val, JSON_INDENT(3));
		printf("JSON protocol response:\n%s\n", s);
		free(s);
	}

	/* JSON-RPC valid response returns a non-null 'result',
	 * and a null 'error'.
	 */
	res_val = json_object_get(val, "result");
	err_val = json_object_get(val, "error");

	if (!res_val || json_is_null(res_val) ||
	    (err_val && !json_is_null(err_val))) {
		char *s;

		if (err_val)
			s = json_dumps(err_val, JSON_INDENT(3));
		else
			s = strdup("(unknown reason)");

		fprintf(stderr, "JSON-RPC call failed: %s\n", s);

		free(s);
			
		goto err_out;
	}

	databuf_free(&all_data);
	curl_slist_free_all(headers);
	curl_easy_reset(curl);
	return val;

err_out:
	databuf_free(&all_data);
	curl_slist_free_all(headers);
	curl_easy_reset(curl);
	return NULL;
}

char *bin2hex(unsigned char *p, size_t len)
{
	int i;
	char *s = malloc((len * 2) + 1);
	if (!s)
		return NULL;
	
	for (i = 0; i < len; i++)
		sprintf(s + (i * 2), "%02x", (unsigned int) p[i]);

	return s;
}

bool hex2bin(unsigned char *p, const char *hexstr, size_t len)
{
	while (*hexstr && len) {
		char hex_byte[3];
		unsigned int v;

		if (!hexstr[1]) {
			fprintf(stderr, "hex2bin str truncated\n");
			return false;
		}

		hex_byte[0] = hexstr[0];
		hex_byte[1] = hexstr[1];
		hex_byte[2] = 0;

		if (sscanf(hex_byte, "%x", &v) != 1) {
			fprintf(stderr, "hex2bin sscanf '%s' failed\n",
				hex_byte);
			return false;
		}

		*p = (unsigned char) v;

		p++;
		hexstr += 2;
		len--;
	}

	return (len == 0 && *hexstr == 0) ? true : false;
}

/* Subtract the `struct timeval' values X and Y,
   storing the result in RESULT.
   Return 1 if the difference is negative, otherwise 0.  */

int
timeval_subtract (
     struct timeval *result, struct timeval *x, struct timeval *y)
{
  /* Perform the carry for the later subtraction by updating Y. */
  if (x->tv_usec < y->tv_usec) {
    int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
    y->tv_usec -= 1000000 * nsec;
    y->tv_sec += nsec;
  }
  if (x->tv_usec - y->tv_usec > 1000000) {
    int nsec = (x->tv_usec - y->tv_usec) / 1000000;
    y->tv_usec += 1000000 * nsec;
    y->tv_sec -= nsec;
  }

  /* Compute the time remaining to wait.
     `tv_usec' is certainly positive. */
  result->tv_sec = x->tv_sec - y->tv_sec;
  result->tv_usec = x->tv_usec - y->tv_usec;

  /* Return 1 if result is negative. */
  return x->tv_sec < y->tv_sec;
}

bool fulltest(const unsigned char *hash, const unsigned char *target)
{
	unsigned char hash_swap[32], target_swap[32];
	uint32_t *hash32 = (uint32_t *) hash_swap;
	uint32_t *target32 = (uint32_t *) target_swap;
	int i;
	bool rc = true;
	char *hash_str, *target_str;

	swap256(hash_swap, hash);
	swap256(target_swap, target);

	for (i = 0; i < 32/4; i++) {
		uint32_t h32tmp = swab32(hash32[i]);
		uint32_t t32tmp = target32[i];

		target32[i] = swab32(target32[i]);	/* for printing */

		if (h32tmp > t32tmp) {
			rc = false;
			break;
		}
		if (h32tmp < t32tmp) {
			rc = true;
			break;
		}
	}

	if (opt_debug) {
		hash_str = bin2hex(hash_swap, 32);
		target_str = bin2hex(target_swap, 32);

		fprintf(stderr, " Proof: %s\nTarget: %s\nTrgVal? %s\n",
			hash_str,
			target_str,
			rc ? "YES (hash < target)" :
			     "no (false positive; hash > target)");

		free(hash_str);
		free(target_str);
	}

	return rc;
}