/**
 * This file is part of Hercules.
 * http://herc.ws - http://github.com/HerculesWS/Hercules
 *
 * Copyright (C) 2012-2018  Hercules Dev Team
 * Copyright (C)  Athena Dev Teams
 *
 * Hercules 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#define HERCULES_CORE

#include "trade.h"

#include "map/atcommand.h"
#include "map/battle.h"
#include "map/chrif.h"
#include "map/clif.h"
#include "map/intif.h"
#include "map/itemdb.h"
#include "map/log.h"
#include "map/map.h"
#include "map/npc.h"
#include "map/path.h"
#include "map/pc.h"
#include "map/storage.h"
#include "common/nullpo.h"
#include "common/socket.h"

#include <stdio.h>
#include <string.h>

static struct trade_interface trade_s;
struct trade_interface *trade;

/*==========================================
 * Initiates a trade request.
 *------------------------------------------*/
static void trade_traderequest(struct map_session_data *sd, struct map_session_data *target_sd)
{
	nullpo_retv(sd);

	if (map->list[sd->bl.m].flag.notrade) {
		clif->message (sd->fd, msg_sd(sd,272)); // You can't trade in this map
		return;
	}

	if (target_sd == NULL || sd == target_sd) {
		clif->tradestart(sd, 1); // character does not exist
		return;
	}

	if (target_sd->npc_id) {
		//Trade fails if you are using an NPC.
		clif->tradestart(sd, 2);
		return;
	}

	if (!battle_config.invite_request_check) {
		if (target_sd->guild_invite > 0 || target_sd->party_invite > 0 || target_sd->adopt_invite) {
			clif->tradestart(sd, 2);
			return;
		}
	}

	if ( sd->trade_partner != 0 ) { // If a character tries to trade to another one then cancel the previous one
		struct map_session_data *previous_sd = map->id2sd(sd->trade_partner);
		if( previous_sd ){
			previous_sd->trade_partner = 0;
			clif->tradecancelled(previous_sd);
		} // Once canceled then continue to the new one.
		sd->trade_partner = 0;
		clif->tradecancelled(sd);
	}

	if (target_sd->trade_partner != 0) {
		clif->tradestart(sd, 2); // person is in another trade
		return;
	}

	if (!pc_can_give_items(sd) || !pc_can_give_items(target_sd)) //check if both GMs are allowed to trade
	{
		clif->message(sd->fd, msg_sd(sd,246)); // Your GM level doesn't authorize you to perform this action.
		clif->tradestart(sd, 2); // GM is not allowed to trade
		return;
	}

	// Players can not request trade from far away, unless they are allowed to use @trade.
	if (!pc->can_use_command(sd, "@trade") &&
	    (sd->bl.m != target_sd->bl.m || !check_distance_bl(&sd->bl, &target_sd->bl, TRADE_DISTANCE))) {
		clif->tradestart(sd, 0); // too far
		return ;
	}

	target_sd->trade_partner = sd->status.account_id;
	sd->trade_partner = target_sd->status.account_id;
	clif->traderequest(target_sd, sd->status.name);
}

/*==========================================
 * Reply to a trade-request.
 * Type values:
 * 0: Char is too far
 * 1: Character does not exist
 * 2: Trade failed
 * 3: Accept
 * 4: Cancel
 * Weird enough, the client should only send 3/4
 * and the server is the one that can reply 0~2
 *------------------------------------------*/
static void trade_tradeack(struct map_session_data *sd, int type)
{
	struct map_session_data *tsd;
	nullpo_retv(sd);

	if (sd->state.trading || !sd->trade_partner)
		return; //Already trading or no partner set.

	if ((tsd = map->id2sd(sd->trade_partner)) == NULL) {
		clif->tradestart(sd, 1); // character does not exist
		sd->trade_partner=0;
		return;
	}

	if (tsd->state.trading || tsd->trade_partner != sd->bl.id)
	{
		clif->tradestart(sd, 2);
		sd->trade_partner=0;
		return; //Already trading or wrong partner.
	}

	if (type == 4) { // Cancel
		clif->tradestart(tsd, type);
		clif->tradestart(sd, type);
		sd->state.deal_locked = 0;
		sd->trade_partner = 0;
		tsd->state.deal_locked = 0;
		tsd->trade_partner = 0;
		return;
	}

	if (type != 3)
		return; //If client didn't send accept, it's a broken packet?

	// Players can not request trade from far away, unless they are allowed to use @trade.
	// Check here as well since the original character could had warped.
	if (!pc->can_use_command(sd, "@trade") &&
	    (sd->bl.m != tsd->bl.m || !check_distance_bl(&sd->bl, &tsd->bl, TRADE_DISTANCE))) {
		clif->tradestart(sd, 0); // too far
		sd->trade_partner=0;
		tsd->trade_partner = 0;
		return;
	}

	//Check if you can start trade.
	if (sd->npc_id || sd->state.vending || sd->state.buyingstore || sd->state.storage_flag != STORAGE_FLAG_CLOSED
	 || tsd->npc_id || tsd->state.vending || tsd->state.buyingstore || tsd->state.storage_flag != STORAGE_FLAG_CLOSED
	) {
		//Fail
		clif->tradestart(sd, 2);
		clif->tradestart(tsd, 2);
		sd->state.deal_locked = 0;
		sd->trade_partner = 0;
		tsd->state.deal_locked = 0;
		tsd->trade_partner = 0;
		return;
	}

	//Initiate trade
	sd->state.trading = 1;
	tsd->state.trading = 1;
	memset(&sd->deal, 0, sizeof(sd->deal));
	memset(&tsd->deal, 0, sizeof(tsd->deal));
	clif->tradestart(tsd, type);
	clif->tradestart(sd, type);
}

/**
 * Checks if an impossible trade will occur
 *  Normal clients refuse to have 2 items of the same type (except equipment) in the same trade window
 *  Normal clients authorize only no equipped items and only items from inventory
 * @retval 0 The trade can continue
 * @retval 1 Hack attempt
 **/
static int impossible_trade_check(struct map_session_data *sd)
{
	struct item inventory[MAX_INVENTORY];
	char message_to_gm[200];
	int i, index;

	nullpo_retr(1, sd);

	if( sd->deal.zeny > sd->status.zeny )
		return 1;

	// get inventory of player
	memcpy(&inventory, &sd->status.inventory, sizeof(struct item) * MAX_INVENTORY);

	// remove this part: arrows can be trade and equipped
	// re-added! [celest]
	// remove equipped items (they can not be trade)
	for (i = 0; i < sd->status.inventorySize; i++)
		if (inventory[i].nameid > 0 && inventory[i].equip && !(inventory[i].equip & EQP_AMMO))
			memset(&inventory[i], 0, sizeof(struct item));

	// check items in player inventory
	for(i = 0; i < 10; i++) {
		if (!sd->deal.item[i].amount)
			continue;
		index = sd->deal.item[i].index;
		if (index < 0 || index >= sd->status.inventorySize)
			return 1;
		if (inventory[index].amount < sd->deal.item[i].amount) {
			// if more than the player have -> hack
			snprintf(message_to_gm, sizeof(message_to_gm), msg_txt(538), sd->status.name, sd->status.account_id); // Hack on trade: character '%s' (account: %d) try to trade more items that he has.
			intif->wis_message_to_gm(map->wisp_server_name, PC_PERM_RECEIVE_HACK_INFO, message_to_gm);
			snprintf(message_to_gm, sizeof(message_to_gm), msg_txt(539), inventory[index].amount, inventory[index].nameid, sd->deal.item[i].amount); // This player has %d of a kind of item (id: %d), and try to trade %d of them.
			intif->wis_message_to_gm(map->wisp_server_name, PC_PERM_RECEIVE_HACK_INFO, message_to_gm);
			// if we block people
			if (battle_config.ban_hack_trade < 0) {
				chrif->char_ask_name(-1, sd->status.name, CHAR_ASK_NAME_BLOCK, 0, 0, 0, 0, 0, 0);
				sockt->eof(sd->fd); // forced to disconnect because of the hack
				// message about the ban
				safestrncpy(message_to_gm, msg_txt(540), sizeof(message_to_gm)); //  This player has been definitively blocked.
			// if we ban people
			} else if (battle_config.ban_hack_trade > 0) {
				chrif->char_ask_name(-1, sd->status.name, CHAR_ASK_NAME_BAN, 0, 0, 0, 0, battle_config.ban_hack_trade, 0); // type: 2 - ban (year, month, day, hour, minute, second)
				sockt->eof(sd->fd); // forced to disconnect because of the hack
				// message about the ban
				sprintf(message_to_gm, msg_txt(507), battle_config.ban_hack_trade); //  This player has been banned for %d minute(s).
			} else
				// message about the ban
				safestrncpy(message_to_gm, msg_txt(508), sizeof(message_to_gm)); //  This player hasn't been banned (Ban option is disabled).

			intif->wis_message_to_gm(map->wisp_server_name, PC_PERM_RECEIVE_HACK_INFO, message_to_gm);
			return 1;
		}
		inventory[index].amount -= sd->deal.item[i].amount; // remove item from inventory
	}
	return 0;
}

/*==========================================
 * Checks if trade is possible (against zeny limits, inventory limits, etc)
 *------------------------------------------*/
static int trade_check(struct map_session_data *sd, struct map_session_data *tsd)
{
	struct item inventory[MAX_INVENTORY];
	struct item inventory2[MAX_INVENTORY];
	struct item_data *data;
	int trade_i, i, n;

	nullpo_ret(sd);
	nullpo_ret(tsd);
	// check zenys value against hackers (Zeny was already checked on time of adding, but you never know when you lost some zeny since then.
	if(sd->deal.zeny > sd->status.zeny || (tsd->status.zeny > MAX_ZENY - sd->deal.zeny))
		return 0;
	if(tsd->deal.zeny > tsd->status.zeny || (sd->status.zeny > MAX_ZENY - tsd->deal.zeny))
		return 0;

	// get inventory of player
	memcpy(&inventory, &sd->status.inventory, sizeof(struct item) * MAX_INVENTORY);
	memcpy(&inventory2, &tsd->status.inventory, sizeof(struct item) * MAX_INVENTORY);

	// check free slot in both inventory
	for (trade_i = 0; trade_i < 10; trade_i++) {
		short amount = sd->deal.item[trade_i].amount;
		if (amount) {
			n = sd->deal.item[trade_i].index;
			if (amount > inventory[n].amount)
				return 0; //qty Exploit?

			data = itemdb->search(inventory[n].nameid);
			i = tsd->status.inventorySize;
			if (itemdb->isstackable2(data)) { //Stackable item.
				for(i = 0; i < tsd->status.inventorySize; i++)
					if (inventory2[i].nameid == inventory[n].nameid &&
						inventory2[i].card[0] == inventory[n].card[0] && inventory2[i].card[1] == inventory[n].card[1] &&
						inventory2[i].card[2] == inventory[n].card[2] && inventory2[i].card[3] == inventory[n].card[3]) {
						if (inventory2[i].amount + amount > MAX_AMOUNT)
							return 0;
						inventory2[i].amount += amount;
						inventory[n].amount -= amount;
						break;
					}
			}

			if (i == tsd->status.inventorySize) {// look for an empty slot.
				for (i = 0; i < tsd->status.inventorySize && inventory2[i].nameid; i++);
				if (i == tsd->status.inventorySize)
					return 0;
				memcpy(&inventory2[i], &inventory[n], sizeof(struct item));
				inventory2[i].amount = amount;
				inventory[n].amount -= amount;
			}
		}
		amount = tsd->deal.item[trade_i].amount;
		if (!amount)
			continue;
		n = tsd->deal.item[trade_i].index;
		if (n < 0 || n >= tsd->status.inventorySize)
			return 0;
		if (amount > inventory2[n].amount)
			return 0;
		// search if it's possible to add item (for full inventory)
		data = itemdb->search(inventory2[n].nameid);
		i = sd->status.inventorySize;
		if (itemdb->isstackable2(data)) {
			for(i = 0; i < sd->status.inventorySize; i++)
				if (inventory[i].nameid == inventory2[n].nameid &&
					inventory[i].card[0] == inventory2[n].card[0] && inventory[i].card[1] == inventory2[n].card[1] &&
					inventory[i].card[2] == inventory2[n].card[2] && inventory[i].card[3] == inventory2[n].card[3]) {
					if (inventory[i].amount + amount > MAX_AMOUNT)
						return 0;
					inventory[i].amount += amount;
					inventory2[n].amount -= amount;
					break;
				}
		}
		if (i == sd->status.inventorySize) {
			for(i = 0; i < sd->status.inventorySize && inventory[i].nameid; i++);
			if (i == sd->status.inventorySize)
				return 0;
			memcpy(&inventory[i], &inventory2[n], sizeof(struct item));
			inventory[i].amount = amount;
			inventory2[n].amount -= amount;
		}
	}

	return 1;
}

/*==========================================
 * Adds an item/qty to the trade window
 *------------------------------------------*/
static void trade_tradeadditem(struct map_session_data *sd, short index, short amount)
{
	struct map_session_data *target_sd;
	struct item *item;
	int trade_i, trade_weight;
	int src_lv, dst_lv;

	nullpo_retv(sd);
	if( !sd->state.trading || sd->state.deal_locked > 0 )
		return; //Can't add stuff.

	if( (target_sd = map->id2sd(sd->trade_partner)) == NULL )
	{
		trade->cancel(sd);
		return;
	}

	if (amount == 0) {
		//Why do this.. ~.~ just send an ack, the item won't display on the trade window.
		clif->tradeitemok(sd, index, TIO_SUCCESS);
		return;
	}

	index -= 2; // 0 is for zeny, 1 is unknown. Gravity, go figure...

	//Item checks...
	if (index < 0 || index >= sd->status.inventorySize)
		return;
	if( amount < 0 || amount > sd->status.inventory[index].amount )
		return;

	item = &sd->status.inventory[index];
	src_lv = pc_get_group_level(sd);
	dst_lv = pc_get_group_level(target_sd);
	if( !itemdb_cantrade(item, src_lv, dst_lv) && //Can't trade
		(pc->get_partner(sd) != target_sd || !itemdb_canpartnertrade(item, src_lv, dst_lv)) ) //Can't partner-trade
	{
		clif->message (sd->fd, msg_sd(sd,260)); // This item cannot be traded.
		clif->tradeitemok(sd, index+2, TIO_INDROCKS);
		return;
	}

	if( item->expire_time )
	{ // Rental System
		clif->message (sd->fd, msg_sd(sd,260)); // This item cannot be traded.
		clif->tradeitemok(sd, index+2, TIO_INDROCKS);
		return;
	}

	if( item->bound &&
			!( item->bound == IBT_GUILD && sd->status.guild_id == target_sd->status.guild_id ) &&
			!( item->bound == IBT_PARTY && sd->status.party_id == target_sd->status.party_id )
					&& !pc_can_give_bound_items(sd) ) {
		clif->message(sd->fd, msg_sd(sd,293)); // This bound item cannot be traded to that character.
		clif->tradeitemok(sd, index+2, TIO_INDROCKS);
		return;
	}

	//Locate a trade position
	ARR_FIND( 0, 10, trade_i, sd->deal.item[trade_i].index == index || sd->deal.item[trade_i].amount == 0 );
	if( trade_i == 10 ) //No space left
	{
		clif->tradeitemok(sd, index+2, TIO_OVERWEIGHT);
		return;
	}

	trade_weight = sd->inventory_data[index]->weight * amount;
	if (target_sd->weight + sd->deal.weight + trade_weight > target_sd->max_weight) {
		//fail to add item -- the player was over weighted.
		clif->tradeitemok(sd, index+2, TIO_OVERWEIGHT);
		return;
	}

	if (sd->deal.item[trade_i].index == index) {
		//The same item as before is being readjusted.
		if (sd->deal.item[trade_i].amount + amount > sd->status.inventory[index].amount) {
			//packet deal exploit check
			amount = sd->status.inventory[index].amount - sd->deal.item[trade_i].amount;
			trade_weight = sd->inventory_data[index]->weight * amount;
		}
		sd->deal.item[trade_i].amount += amount;
	} else {
		//New deal item
		sd->deal.item[trade_i].index = index;
		sd->deal.item[trade_i].amount = amount;
	}
	sd->deal.weight += trade_weight;

	clif->tradeitemok(sd, index+2, TIO_SUCCESS); // Return the index as it was received
	clif->tradeadditem(sd, target_sd, index+2, amount);
}

/*==========================================
 * Adds the specified amount of zeny to the trade window
 *------------------------------------------*/
static void trade_tradeaddzeny(struct map_session_data *sd, int amount)
{
	struct map_session_data* target_sd;
	nullpo_retv(sd);

	if( !sd->state.trading || sd->state.deal_locked > 0 )
		return; //Can't add stuff.

	if( (target_sd = map->id2sd(sd->trade_partner)) == NULL ) {
		trade->cancel(sd);
		return;
	}

	if (amount < 0 || amount > sd->status.zeny || amount > MAX_ZENY - target_sd->status.zeny) {
		// invalid values, no appropriate packet for it => abort
		trade->cancel(sd);
		return;
	}

	sd->deal.zeny = amount;
	clif->tradeadditem(sd, target_sd, 0, amount);
}

/*==========================================
 * 'Ok' button on the trade window is pressed.
 *------------------------------------------*/
static void trade_tradeok(struct map_session_data *sd)
{
	struct map_session_data *target_sd;

	nullpo_retv(sd);
	if(sd->state.deal_locked || !sd->state.trading)
		return;

	if ((target_sd = map->id2sd(sd->trade_partner)) == NULL) {
		trade->cancel(sd);
		return;
	}
	sd->state.deal_locked = 1;
	clif->tradeitemok(sd, 0, TIO_SUCCESS);
	clif->tradedeal_lock(sd, 0);
	clif->tradedeal_lock(target_sd, 1);
}

/*==========================================
 * 'Cancel' is pressed. (or trade was force-canceled by the code)
 *------------------------------------------*/
static void trade_tradecancel(struct map_session_data *sd)
{
	struct map_session_data *target_sd;
	int trade_i;

	nullpo_retv(sd);
	target_sd = map->id2sd(sd->trade_partner);

	if(!sd->state.trading)
	{ // Not trade accepted
		if( target_sd ) {
			target_sd->trade_partner = 0;
			clif->tradecancelled(target_sd);
		}
		sd->trade_partner = 0;
		clif->tradecancelled(sd);
		return;
	}

	for(trade_i = 0; trade_i < 10; trade_i++) { // give items back (only virtual)
		if (!sd->deal.item[trade_i].amount)
			continue;
		clif->additem(sd, sd->deal.item[trade_i].index, sd->deal.item[trade_i].amount, 0);
		sd->deal.item[trade_i].index = 0;
		sd->deal.item[trade_i].amount = 0;
	}
	if (sd->deal.zeny) {
		clif->updatestatus(sd, SP_ZENY);
		sd->deal.zeny = 0;
	}

	sd->state.deal_locked = 0;
	sd->state.trading = 0;
	sd->trade_partner = 0;
	clif->tradecancelled(sd);

	if (!target_sd)
		return;

	for(trade_i = 0; trade_i < 10; trade_i++) { // give items back (only virtual)
		if (!target_sd->deal.item[trade_i].amount)
			continue;
		clif->additem(target_sd, target_sd->deal.item[trade_i].index, target_sd->deal.item[trade_i].amount, 0);
		target_sd->deal.item[trade_i].index = 0;
		target_sd->deal.item[trade_i].amount = 0;
	}

	if (target_sd->deal.zeny) {
		clif->updatestatus(target_sd, SP_ZENY);
		target_sd->deal.zeny = 0;
	}
	target_sd->state.deal_locked = 0;
	target_sd->trade_partner = 0;
	target_sd->state.trading = 0;
	clif->tradecancelled(target_sd);
}

/*==========================================
 * lock sd and tsd trade data, execute the trade, clear, then save players
 *------------------------------------------*/
static void trade_tradecommit(struct map_session_data *sd)
{
	struct map_session_data *tsd;
	int trade_i;
	int flag;

	nullpo_retv(sd);
	if (!sd->state.trading || !sd->state.deal_locked) //Locked should be 1 (pressed ok) before you can press trade.
		return;

	if ((tsd = map->id2sd(sd->trade_partner)) == NULL) {
		trade->cancel(sd);
		return;
	}

	sd->state.deal_locked = 2;

	if (tsd->state.deal_locked < 2)
		return; //Not yet time for trading.

	//Now is a good time (to save on resources) to check that the trade can indeed be made and it's not exploitable.
	// check exploit (trade more items that you have)
	if (trade->check_impossible(sd)) {
		trade->cancel(sd);
		return;
	}
	// check exploit (trade more items that you have)
	if (trade->check_impossible(tsd)) {
		trade->cancel(tsd);
		return;
	}
	// check for full inventory (can not add traded items)
	if (!trade->check(sd,tsd)) { // check the both players
		trade->cancel(sd);
		return;
	}

	// trade is accepted and correct.
	for( trade_i = 0; trade_i < 10; trade_i++ )
	{
		int n;
		if (sd->deal.item[trade_i].amount)
		{
			n = sd->deal.item[trade_i].index;

			flag = pc->additem(tsd, &sd->status.inventory[n], sd->deal.item[trade_i].amount,LOG_TYPE_TRADE);
			if (flag == 0)
				pc->delitem(sd, n, sd->deal.item[trade_i].amount, 1, DELITEM_SOLD, LOG_TYPE_TRADE);
			else
				clif->additem(sd, n, sd->deal.item[trade_i].amount, 0);
			sd->deal.item[trade_i].index = 0;
			sd->deal.item[trade_i].amount = 0;
		}
		if (tsd->deal.item[trade_i].amount)
		{
			n = tsd->deal.item[trade_i].index;

			flag = pc->additem(sd, &tsd->status.inventory[n], tsd->deal.item[trade_i].amount,LOG_TYPE_TRADE);
			if (flag == 0)
				pc->delitem(tsd, n, tsd->deal.item[trade_i].amount, 1, DELITEM_SOLD, LOG_TYPE_TRADE);
			else
				clif->additem(tsd, n, tsd->deal.item[trade_i].amount, 0);
			tsd->deal.item[trade_i].index = 0;
			tsd->deal.item[trade_i].amount = 0;
		}
	}

	if( sd->deal.zeny ) {
		pc->payzeny(sd ,sd->deal.zeny, LOG_TYPE_TRADE, tsd);
		pc->getzeny(tsd,sd->deal.zeny,LOG_TYPE_TRADE, sd);
		sd->deal.zeny = 0;

	}
	if ( tsd->deal.zeny) {
		pc->payzeny(tsd,tsd->deal.zeny,LOG_TYPE_TRADE, sd);
		pc->getzeny(sd ,tsd->deal.zeny,LOG_TYPE_TRADE, tsd);
		tsd->deal.zeny = 0;
	}

	sd->state.deal_locked = 0;
	sd->trade_partner = 0;
	sd->state.trading = 0;

	tsd->state.deal_locked = 0;
	tsd->trade_partner = 0;
	tsd->state.trading = 0;

	clif->tradecompleted(sd, 0);
	clif->tradecompleted(tsd, 0);

	// save both player to avoid crash: they always have no advantage/disadvantage between the 2 players
	if (map->save_settings&1) {
		chrif->save(sd,0);
		chrif->save(tsd,0);
	}
}

void trade_defaults(void)
{
	trade = &trade_s;

	trade->request = trade_traderequest;
	trade->ack = trade_tradeack;
	trade->check_impossible = impossible_trade_check;
	trade->check = trade_check;
	trade->additem = trade_tradeadditem;
	trade->addzeny = trade_tradeaddzeny;
	trade->ok = trade_tradeok;
	trade->cancel = trade_tradecancel;
	trade->commit = trade_tradecommit;
}
