/* This file is part of libbrandt.
 * Copyright (C) 2022 GNUnet e.V.
 *
 * libbrandt 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 3 of the License, or (at your option) any later
 * version.
 *
 * libbrandt is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * libbrandt.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file replay.c
 * @brief Replay a auction, given as transcript in json form on stdin
 * @author Özgür Kesim
 */

#include "platform.h"

#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <taler/taler_amount_lib.h>
#include <jansson.h>

#include "brandt.h"
#include "crypto.h"
#include "util.h"

struct msg
{
	uint16_t sender;
	void     *buf;
	size_t buf_len;
};

/* This is basically BRANDT_Result with an extra string field */
struct result
{
	uint16_t bidder;
	uint16_t price_idx;
	const char    *price;
};

struct transcript
{
	// All fields from json come here.
	uint16_t n; // #bidders + 1
	uint16_t k; // #prices
	uint16_t m; // type of auction
	struct GNUNET_TIME_Absolute time_start;
	struct GNUNET_TIME_Relative time_round;
	bool public;
	char **prices; // Must be of length k. We do not parse those
	struct msg *msgs; // Array must be of length 4*n

	struct BRANDT_Auction *auction;

	struct result *results;
	size_t results_len;
	struct result *expected;
	size_t expected_len;
	uint16_t id;
	struct GNUNET_CRYPTO_EccDlogContext *edc;
};

static struct transcript tr;


static void
print_result (struct transcript *tr,
              char *error)
{
	json_t *output;
	json_t *results;

	if (NULL != error)
	{
		output = json_pack ("{s:s}", "error", error);
		GNUNET_assert (output);

		json_dumpfd (output, 1, JSON_INDENT (2));
		return;
	}

	GNUNET_assert (NULL != tr);

	output = json_object ();
	results = json_array ();
	GNUNET_assert (output);
	GNUNET_assert (results);

	for (size_t i = 0; i < tr->results_len; i++)
	{
		json_t *result = json_pack ("{s:i, s:s}",
		                            "bidder", tr->results[i].bidder,
		                            "price", tr->results[i].price);
		GNUNET_assert (result);

		GNUNET_assert (-1 !=
		               json_array_append_new (results, result));
	}

	GNUNET_assert (-1 !=
	               json_object_set_new (output,
	                                    "winners",
	                                    results));

	{
		FILE *f = fdopen (1, "w");
		GNUNET_assert(f);

		json_dumpf (output, f, JSON_INDENT (2));
		fflush (f);
	}

	json_decref (output);
}


static void
cb_result (void                 *arg,
           struct BRANDT_Result results[],
           uint16_t results_len)
{
	struct transcript *tr = (struct transcript *) arg;
	tr->results = GNUNET_new_array (results_len, struct result);
	tr->results_len = results_len;

	for (uint16_t i = 0; i < results_len; i++)
	{
		GNUNET_log (
			GNUNET_ERROR_TYPE_INFO,
			"REPLAY [seller] computed result is: bidder %d got status %d with price %d (%s)\n",
			results[i].bidder,
			results[i].status,
			results[i].price,
			tr->prices[results[i].price]);

		tr->results[i].bidder = results[i].bidder;
		tr->results[i].price_idx = results[i].price;
		tr->results[i].price = tr->prices[results[i].price];
	}

	for (uint16_t i = 0; i < tr->expected_len; i++)
	{
		GNUNET_log (
			GNUNET_ERROR_TYPE_INFO,
			"REPLAY [seller] expected result is: bidder %d wins with price %d (%s)\n",
			tr->expected[i].bidder,
			tr->expected[i].price_idx,
			tr->expected[i].price);
	}

	print_result (tr, NULL);
	// TODO: compare computed and expected results!
}


static uint16_t
cb_start (void *auction_closure)
{
	struct transcript *tr = (struct transcript *) auction_closure;
	struct cls
	{
		size_t i;
		struct transcript *tr;
	};

	void
	resend (void *x)
	{
		struct cls c = *(struct cls *) x;
		struct msg m = c.tr->msgs[c.i];
		GNUNET_log (GNUNET_ERROR_TYPE_INFO,
		            "REPLAY sending msg no. %ld, length %ld\n", c.i, m.buf_len);
		BRANDT_got_message (c.tr->auction, m.sender, m.buf, m.buf_len);
	}


	GNUNET_log (GNUNET_ERROR_TYPE_INFO, "REPLAY start replay auction\n");
	for (size_t i = 0; i < 4 * tr->n; i++)
	{
		struct cls *c = GNUNET_new (struct cls);
		c->i = i;
		c->tr = tr;
		GNUNET_SCHEDULER_add_now (&resend, (void *) c);
	}

	return tr->n;
}


static void
replay_transcript (void *arg)
{
	struct transcript *tr = (struct transcript *) arg;
	void   *desc;
	size_t desc_len;

	GNUNET_log (GNUNET_ERROR_TYPE_INFO,
	            "REPLAY calling BRANDT_new with %s outcome.\n",
	            tr->public ? "public" : "private");

	tr->auction = BRANDT_new (&cb_result,
	                          NULL,
	                          &cb_start,
	                          tr,
	                          &desc,
	                          &desc_len,
	                          GNUNET_TIME_absolute_get (),
	                          tr->time_round,
	                          tr->k, /* number of prizes */
	                          tr->m, /* m */
	                          tr->public, /* outcome public */
	                          tr->public ? tr->edc : NULL);
	if (!tr->auction)
	{
		print_result (NULL,  "REPLAY BRANDT_new() failed.");
		_exit (1);
	}
}


void
parse_json_stdin (struct transcript *tr)
{
	json_error_t jerror;
	json_t *jtr;
	struct GNUNET_CRYPTO_EddsaSignature sig;

	jtr = json_loadfd (0,
	                   JSON_REJECT_DUPLICATES,
	                   &jerror);

	if (!jtr)
	{
		char err[4096];
		snprintf (err,
		          sizeof(err),
		          "failed to parse json: %s in line %d, column %d (pos %d)",
		          jerror.text, jerror.line, jerror.column, jerror.position);
		print_result (NULL, err);
		_exit (1);
	}


	{
		json_t *auc;
		char *perr;
		unsigned int eline;
		struct GNUNET_JSON_Specification au_spec[] = {
			GNUNET_JSON_spec_bool ("public", &tr->public),
			GNUNET_JSON_spec_uint16 ("type", &tr->m),
			GNUNET_JSON_spec_end ()
		};

		auc = json_object_get (jtr, "auction");
		if (NULL == auc)
		{
			print_result (NULL,
			              "no auction found in input");
			_exit (1);
		}

		GNUNET_assert (GNUNET_OK ==
		               GNUNET_JSON_parse (auc,
		                                  au_spec,
		                                  (const char **) &perr,
		                                  &eline));

		// Prices...
		{
			json_t *prices = json_object_get (auc, "prices");
			size_t idx;
			json_t *val;


			if (!json_is_array (prices))
			{
				print_result (NULL,
				              "no prices found in input");
				_exit (1);
			}

			tr->k = json_array_size (prices);
			tr->prices = GNUNET_new_array (tr->k, char *);
			json_array_foreach (prices, idx, val)
			{
				if (!json_is_string (val))
				{
					char err[256];
					snprintf (err,
					          sizeof(err),
					          "price %ld is not a string\n", idx);
					print_result (NULL,
					              err);
					_exit (1);
				}
				tr->prices[idx] = (char *) json_string_value (val);
			}

		}

	}

	// Bidders
	{
		json_t *bidders;

		bidders = json_object_get (jtr, "bidders");
		if (!bidders || !json_is_array (bidders))
		{
			GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
			            "bidders missing or not an array\n");
			print_result (NULL, "bidders missing or not an array");
			_exit (1);
		}

		tr->n = json_array_size (bidders);
	}


	// Messages
	{
		json_t *messages;
		size_t nm;
		size_t idx;
		json_t *val;

		messages = json_object_get (jtr, "transcript");
		if (!json_is_array (messages))
		{
			print_result (NULL, "transcript missing or not an array");
			_exit (1);
		}

		nm = json_array_size (messages);

		if (nm != (4 * tr->n))
		{
			print_result (NULL, "wrong number of messages in transript");
			_exit (1);
		}

		tr->msgs = GNUNET_new_array (nm, struct msg);

		json_array_foreach (messages, idx, val) {
			char *error;
			uint16_t sender;
			void *msg;
			size_t size;
			struct GNUNET_JSON_Specification spec[] = {
				GNUNET_JSON_spec_uint16 ("bidder",
				                         &sender),
				GNUNET_JSON_spec_varsize ("msg",
				                          &msg,
				                          &size),
				GNUNET_JSON_spec_end ()
			};

			if (GNUNET_OK !=
			    GNUNET_JSON_parse (val,
			                       spec,
			                       (const char**) &error,
			                       NULL))
			{
				char err[4096];
				snprintf (err,
				          sizeof(err),
				          "error parsing message[%ld] in transcript: %s",
				          idx,
				          error);
				print_result (NULL, err);
				_exit (1);
			}

			tr->msgs[idx].sender = sender;
			tr->msgs[idx].buf = msg;
			tr->msgs[idx].buf_len = size;
		}

	}

	// Winners
	{
		json_t *winners;
		size_t idx;
		json_t *val;

		winners = json_object_get (jtr, "winners");

		if (!json_is_array (winners))
		{
			GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
			            "winners not provided, continuing without\n");
			goto CONT;
		}

		tr->expected_len = json_array_size (winners);
		tr->expected = GNUNET_new_array (tr->expected_len,
		                                 struct result);

		json_array_foreach (winners, idx, val) {
			char *error;

			struct GNUNET_JSON_Specification spec[] = {
				GNUNET_JSON_spec_uint16 ("bidder",
				                         &(tr->expected[idx].bidder)),
				GNUNET_JSON_spec_uint16 ("price_idx",
				                         &(tr->expected[idx].price_idx)),
				GNUNET_JSON_spec_string ("price",
				                         &(tr->expected[idx].price)),
				GNUNET_JSON_spec_end ()
			};

			if (GNUNET_OK !=
			    GNUNET_JSON_parse (val,
			                       spec,
			                       (const char**) &error,
			                       NULL))
			{
				char err[4096];
				snprintf (err,
				          sizeof(err),
				          "error parsing winners[%ld] in transcript: %s",
				          idx,
				          error);

				_exit (1);
			}

		}

CONT:
	}
}


int
main (int argc, char *argv[])
{
	int ret = 0;
	struct transcript tr = {0};

	if (GNUNET_OK != GNUNET_log_setup ("replay", "INFO", NULL))
		return 1;

	BRANDT_init ();

	parse_json_stdin (&tr);
	tr.edc = GNUNET_CRYPTO_ecc_dlog_prepare (1024 * 1024 * 40, 1024);
	GNUNET_SCHEDULER_run (&replay_transcript, &tr);
	GNUNET_CRYPTO_ecc_dlog_release (tr.edc);
	GNUNET_free (tr.msgs);

	return ret;
}