/*
	This file is part of Warzone 2100.
	Copyright (C) 1999-2004  Eidos Interactive
	Copyright (C) 2005-2009  Warzone Resurrection Project

	Warzone 2100 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.

	Warzone 2100 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 Warzone 2100; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "lib/framework/frame.h"
#include "map.h"
#include "hci.h"
#include "mapdisplay.h"
#include "display3d.h"
#include "lib/ivis_common/ivisdef.h" //ivis matrix code
#include "lib/ivis_common/piedef.h" //pie render
#include "lib/ivis_opengl/piematrix.h"
#include "lib/ivis_common/piepalette.h"
#include "miscimd.h"
#include "effects.h"
#include "bridge.h"

/**
 * @file bridge.c
 * Bridges - currently unused.
 *
 * Handles rendering and placement of bridging sections for
 * traversing water and ravines?! My guess is this won't make it into
 * the final game, but we'll see...
 * Alex McLean, Pumpkin Studios EIDOS Interactive, 1998.
 *
 * He was right. It did not make the final game. The code below
 * is unused. Can it be reused? - Per, 2007
 */

/*
Returns true or false as to whether a bridge is valid.
For it to be true - all intervening points must be lower than the start
and end points. We can also check other stuff here like what it's going
over. Also, it has to be between a minimum and maximum length and
one of the axes must share the same values.
*/
BOOL	bridgeValid(UDWORD startX, UDWORD startY, UDWORD endX, UDWORD endY)
{
	BOOL	xBridge, yBridge;
	UDWORD	bridgeLength;
	UDWORD	startHeight, endHeight, sectionHeight;
	UDWORD	i;

	/* Establish axes allignment */
	xBridge = ((startX == endX) ? true : false);
	yBridge = ((startY == endY) ? true : false);

	/* At least one axis must be constant */
	if (!xBridge && !yBridge)
	{
		/*	Bridge isn't straight - this shouldn't have been passed
			in, but better safe than sorry! */
		return false;
	}

	/* Get the bridge length */
	bridgeLength = (xBridge ? abs(startY - endY) : abs(startX - endX));

	/* check it's not too long or short */
	if (bridgeLength < MINIMUM_BRIDGE_SPAN || bridgeLength > MAXIMUM_BRIDGE_SPAN)
	{
		/* Cry out */
		return false;
	}

	/*	Check intervening tiles to see if they're lower
	so first get the start and end heights */
	startHeight = mapTile(startX, startY)->height;
	endHeight = mapTile(endX, endY)->height;

	/*
		Don't whinge about this piece of code please! It's nice and short
		and is called very infrequently. Could be made slightly faster.
	*/
	for (i = (xBridge ? MIN(startY, endY) : MIN(startX, endX));
	        i < (xBridge ? MAX(startY, endY) : MAX(startX, endX)); i++)
	{
		/* Get the height of a bridge section */
		sectionHeight = mapTile((xBridge ? startX : startY), i)->height;
		/* Is it higher than BOTH end points? */
		if (sectionHeight > MAX(startHeight, endHeight))
		{
			/* Cry out */
			return false;
		}
	}
	/* Everything's just fine */
	return(true);
}


/*
	This function will actually draw a wall section
	Slightly different from yer basic structure draw in that
	it's not alligned to the terrain as bridge sections sit
	at a height stored in their structure - as they're above the ground
	and wouldn't be much use if they weren't, bridge wise.
*/
BOOL	renderBridgeSection(STRUCTURE *psStructure)
{
	SDWORD			rx, rz;
	Vector3i dv;

	/* Bomb out if it's not visible */
	if (!psStructure->visible[selectedPlayer])
	{
		return false;
	}

	/* Establish where it is in the world */
	dv.x = (psStructure->pos.x - player.p.x) - terrainMidX * TILE_UNITS;
	dv.z = terrainMidY * TILE_UNITS - (psStructure->pos.y - player.p.z);
	dv.y = psStructure->pos.z;

	/* Push the indentity matrix */
	pie_MatBegin();

	/* Translate */
	pie_TRANSLATE(dv.x, dv.y, dv.z);

	/* Get the x,z translation components */
	rx = map_round(player.p.x);
	rz = map_round(player.p.z);

	/* Translate */
	pie_TRANSLATE(rx, 0, -rz);

	pie_Draw3DShape(psStructure->sDisplay.imd, 0, 0, WZCOL_WHITE, WZCOL_BLACK, 0, 0);

	pie_MatEnd();
	return(true);
}

/*
	This will work out all the info you need about the bridge including
	length - height to set sections at in order to allign to terrain and
	what you need to alter start and end terrain heights by to establish to
	connection.
*/
void	getBridgeInfo(UDWORD startX, UDWORD startY, UDWORD endX, UDWORD endY, BRIDGE_INFO *info)
{
	BOOL	xBridge, yBridge;
	UDWORD	startHeight, endHeight;
	BOOL	startHigher;

	/* Copy over the location coordinates */
	info->startX = startX;
	info->startY = startY;
	info->endX = endX;
	info->endY = endY;

	/* Get the heights of the start and end positions */
	startHeight = map_TileHeight(startX, startY);
	endHeight = map_TileHeight(endX, endY);

	/* Find out which is higher */
	startHigher = (startHeight >= endHeight ? true : false);

	/* If the start position is higher */
	if (startHigher)
	{
		/* Inform structure */
		info->startHighest = true;

		/* And the end position needs raising */
		info->heightChange = startHeight - endHeight;
	}
	/* Otherwise, the end position is lower */
	else
	{
		/* Inform structure */
		info->startHighest = false;
		/* So we need to raise the start position */
		info->heightChange = endHeight - startHeight;
	}

	/* Establish axes allignment */
	/* Only one of these can occur otherwise
	bridge is one square big */
	xBridge = ((startX == endX) ? true : false);
	yBridge = ((startY == endY) ? true : false);

	/*
		Set the bridge's height.
		Note that when the bridge is built BOTH tile heights need
		to be set to the agreed value on their bridge trailing edge
		(x,y) and (x,y+1) is constant X and (x,y) and (x+1,y) if constant
		Y
	*/
	if (startHigher)
	{
		info->bridgeHeight = map_TileHeight(startX, startY);
	}
	else
	{
		info->bridgeHeight = map_TileHeight(endX, endY);
	}

	/* We've got a bridge of constant X */
	if (xBridge)
	{
		info->bConstantX = true;
		info->bridgeLength = abs(startY - endY);
	}
	/* We've got a bridge of constant Y */
	else if (yBridge)
	{
		info->bConstantX = false;
		info->bridgeLength = abs(startX - endX);
	}
	else
	{
		debug( LOG_FATAL, "Weirdy Bridge requested - no axes allignment" );
		abort();
	}
}

void testBuildBridge(UDWORD startX, UDWORD startY, UDWORD endX, UDWORD endY)
{
	BRIDGE_INFO	bridge;
	UDWORD	i;
	Vector3i dv;

	if (bridgeValid(startX, startY, endX, endY))
	{
		getBridgeInfo(startX, startY, endX, endY, &bridge);
		if (bridge.bConstantX)
		{

			for (i = MIN(bridge.startY, bridge.endY); i < (MAX(bridge.startY, bridge.endY) + 1); i++)
			{
				dv.x = ((bridge.startX * 128) + 64);
				dv.z = ((i * 128) + 64);
				dv.y = bridge.bridgeHeight;
				addEffect(&dv, EFFECT_SMOKE, SMOKE_TYPE_DRIFTING, false, NULL, 0);
//				addExplosion(&dv, TYPE_EXPLOSION_SMOKE_CLOUD, NULL);
			}
		}
		else
		{
			for (i = MIN(bridge.startX, bridge.endX); i < (MAX(bridge.startX, bridge.endX) + 1); i++)
			{
				dv.x = ((i * 128) + 64);
				dv.z = ((bridge.startY * 128) + 64);
				dv.y = bridge.bridgeHeight;
				addEffect(&dv, EFFECT_SMOKE, SMOKE_TYPE_DRIFTING, false, NULL, 0);
//				addExplosion(&dv, TYPE_EXPLOSION_SMOKE_CLOUD, NULL);
			}
		}
		/* Flatten the start tile */
		setTileHeight(bridge.startX, bridge.startY, bridge.bridgeHeight);
		setTileHeight(bridge.startX, bridge.startY + 1, bridge.bridgeHeight);
		setTileHeight(bridge.startX + 1, bridge.startY, bridge.bridgeHeight);
		setTileHeight(bridge.startX + 1, bridge.startY + 1, bridge.bridgeHeight);

		/* Flatten the end tile */
		setTileHeight(bridge.endX, bridge.endY, bridge.bridgeHeight);
		setTileHeight(bridge.endX, bridge.endY + 1, bridge.bridgeHeight);
		setTileHeight(bridge.endX + 1, bridge.endY, bridge.bridgeHeight);
		setTileHeight(bridge.endX + 1, bridge.endY + 1, bridge.bridgeHeight);
	}
	else
	{
		getBridgeInfo(startX, startY, endX, endY, &bridge);
		if (bridge.bConstantX)
		{
			for (i = MIN(bridge.startY, bridge.endY); i < (MAX(bridge.startY, bridge.endY) + 1); i++)
			{
				dv.x = ((bridge.startX * 128) + 64);
				dv.z = ((i * 128) + 64);
				dv.y = bridge.bridgeHeight;
				addEffect(&dv, EFFECT_EXPLOSION, EXPLOSION_TYPE_SMALL, false, NULL, 0);
//				addExplosion(&dv, TYPE_EXPLOSION_MED, NULL);
			}
		}
		else
		{
			for (i = MIN(bridge.startX, bridge.endX); i < (MAX(bridge.startX, bridge.endX) + 1); i++)
			{
				dv.x = ((i * 128) + 64);
				dv.z = ((bridge.startY * 128) + 64);
				dv.y = bridge.bridgeHeight;
				addEffect(&dv, EFFECT_EXPLOSION, EXPLOSION_TYPE_SMALL, false, NULL, 0);
//				addExplosion(&dv, TYPE_EXPLOSION_MED, NULL);
			}
		}

	}
}