/*
 * 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 <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;
}

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

	curl = curl_easy_init();
	if (!curl)
		return NULL;

	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);
	if (userpass) {
		curl_easy_setopt(curl, CURLOPT_USERPWD, userpass);
		curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
	}
	curl_easy_setopt(curl, CURLOPT_POST, 1);
	curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, strlen (rpc_req));
    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, rpc_req);

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

	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)
		goto err_out;

	val = json_loads(all_data.buf, 0, &err);
	if (!val) {
		fprintf(stderr, "JSON 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);
	}

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

err_out:
	databuf_free(&all_data);
	curl_slist_free_all(headers);
	curl_easy_cleanup(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;
}

int 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 0;
		}

		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 0;
		}

		*p = (unsigned char) v;

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

	return len == 0 && *hexstr == 0;
}

/* 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;
}

uint32_t swap32(uint32_t value)
{
#if defined(__x86_64__) || defined(__i386__)
	__asm__
	(
		"bswap %0"
		: "=r"(value) 
		: "0"(value)
		:
	);
	return value;
#else
    value = ((value & 0xFF00FF00) >> 8) | ((value & 0x00FF00FF) << 8);
    return (value<<16) | (value>>16);
#endif
}