/*
 * 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 <ctype.h>
#include <string.h>
#include <jansson.h>
#include <curl/curl.h>
#include "miner.h"
#include "elist.h"

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

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

struct header_info {
	char		*lp_path;
};

struct tq_ent {
	void			*data;
	struct list_head	q_node;
};

struct thread_q {
	struct list_head	q;

	bool frozen;

	pthread_mutex_t		mutex;
	pthread_cond_t		cond;
};

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;
}

static size_t resp_hdr_cb(void *ptr, size_t size, size_t nmemb, void *user_data)
{
	struct header_info *hi = user_data;
	size_t remlen, slen, ptrlen = size * nmemb;
	char *rem, *val = NULL, *key = NULL;
	void *tmp;

	if (opt_protocol)
		printf("In resp_hdr_cb\n");

	val = calloc(1, ptrlen);
	key = calloc(1, ptrlen);
	if (!key || !val)
		goto out;

	tmp = memchr(ptr, ':', ptrlen);
	if (!tmp || (tmp == ptr))	/* skip empty keys / blanks */
		goto out;
	slen = tmp - ptr;
	if ((slen + 1) == ptrlen)	/* skip key w/ no value */
		goto out;
	memcpy(key, ptr, slen);		/* store & nul term key */
	key[slen] = 0;

	rem = ptr + slen + 1;		/* trim value's leading whitespace */
	remlen = ptrlen - slen - 1;
	while ((remlen > 0) && (isspace(*rem))) {
		remlen--;
		rem++;
	}

	memcpy(val, rem, remlen);	/* store value, trim trailing ws */
	val[remlen] = 0;
	while ((*val) && (isspace(val[strlen(val) - 1]))) {
		val[strlen(val) - 1] = 0;
	}
	if (!*val)			/* skip blank value */
		goto out;

	if (opt_protocol)
		printf("HTTP hdr(%s): %s\n", key, val);

	if (!strcasecmp("X-Long-Polling", key)) {
		hi->lp_path = val;	/* steal memory reference */
		val = NULL;
	}

out:
	free(key);
	free(val);
	return ptrlen;
}

json_t *json_rpc_call(CURL *curl, const char *url,
		      const char *userpass, const char *rpc_req,
		      bool longpoll_scan, bool longpoll)
{
	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];
	long timeout = longpoll ? (60 * 60) : (60 * 10);
	struct header_info hi = { };
	bool lp_scanning = false;

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

	if (longpoll_scan)
		lp_scanning = want_longpoll && !have_longpoll;

	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);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout);
	if (lp_scanning) {
		curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, resp_hdr_cb);
		curl_easy_setopt(curl, CURLOPT_HEADERDATA, &hi);
	}
	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;
	}

	/* If X-Long-Polling was found, activate long polling */
	if (hi.lp_path) {
		have_longpoll = true;
		opt_scantime = 60;
		tq_push(thr_info[longpoll_thr_id].q, hi.lp_path);
	} else
		free(hi.lp_path);
	hi.lp_path = NULL;

	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(const 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 true;	/* FIXME: return rc; */
}

struct thread_q *tq_new(void)
{
	struct thread_q *tq;

	tq = calloc(1, sizeof(*tq));
	if (!tq)
		return NULL;

	INIT_LIST_HEAD(&tq->q);
	pthread_mutex_init(&tq->mutex, NULL);
	pthread_cond_init(&tq->cond, NULL);

	return tq;
}

void tq_free(struct thread_q *tq)
{
	struct tq_ent *ent, *iter;

	if (!tq)
		return;

	list_for_each_entry_safe(ent, iter, &tq->q, q_node) {
		list_del(&ent->q_node);
		free(ent);
	}

	pthread_cond_destroy(&tq->cond);
	pthread_mutex_destroy(&tq->mutex);

	memset(tq, 0, sizeof(*tq));	/* poison */
	free(tq);
}

static void tq_freezethaw(struct thread_q *tq, bool frozen)
{
	pthread_mutex_lock(&tq->mutex);

	tq->frozen = frozen;

	pthread_cond_signal(&tq->cond);
	pthread_mutex_unlock(&tq->mutex);
}

void tq_freeze(struct thread_q *tq)
{
	tq_freezethaw(tq, true);
}

void tq_thaw(struct thread_q *tq)
{
	tq_freezethaw(tq, false);
}

bool tq_push(struct thread_q *tq, void *data)
{
	struct tq_ent *ent;
	bool rc = true;

	ent = calloc(1, sizeof(*ent));
	if (!ent)
		return false;

	ent->data = data;
	INIT_LIST_HEAD(&ent->q_node);

	pthread_mutex_lock(&tq->mutex);

	if (!tq->frozen) {
		list_add_tail(&ent->q_node, &tq->q);
	} else {
		free(ent);
		rc = false;
	}

	pthread_cond_signal(&tq->cond);
	pthread_mutex_unlock(&tq->mutex);

	return rc;
}

void *tq_pop(struct thread_q *tq, const struct timespec *abstime)
{
	struct tq_ent *ent;
	void *rval = NULL;
	int rc;

	pthread_mutex_lock(&tq->mutex);

	if (!list_empty(&tq->q))
		goto pop;

	if (abstime)
		rc = pthread_cond_timedwait(&tq->cond, &tq->mutex, abstime);
	else
		rc = pthread_cond_wait(&tq->cond, &tq->mutex);
	if (rc)
		goto out;
	if (list_empty(&tq->q))
		goto out;

pop:
	ent = list_entry(tq->q.next, struct tq_ent, q_node);
	rval = ent->data;

	list_del(&ent->q_node);
	free(ent);

out:
	pthread_mutex_unlock(&tq->mutex);
	return rval;
}