/* Copyright (C) 2009 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "precompiled.h"

#include "Brushes.h"

#include "ps/Game.h"
#include "ps/Shapes.h"
#include "ps/World.h"
#include "graphics/Terrain.h"
#include "lib/ogl.h"
#include "maths/MathUtil.h"
#include "renderer/TerrainOverlay.h"
#include "simulation2/Simulation2.h"
#include "simulation2/system/SimContext.h"

using namespace AtlasMessage;

class BrushTerrainOverlay : public TerrainOverlay
{
public:
	BrushTerrainOverlay(const Brush* brush)
		: TerrainOverlay(g_Game->GetSimulation2()->GetSimContext(), 300), m_Brush(brush)
	{
	}

	void GetTileExtents(
		ssize_t& min_i_inclusive, ssize_t& min_j_inclusive,
		ssize_t& max_i_inclusive, ssize_t& max_j_inclusive)
	{
		m_Brush->GetBottomLeft(min_i_inclusive, min_j_inclusive);
		m_Brush->GetTopRight(max_i_inclusive, max_j_inclusive);

		// But since brushes deal with vertices instead of tiles,
		// we don't want to include the top/right row
		--max_i_inclusive;
		--max_j_inclusive;
	}

	void ProcessTile(ssize_t i, ssize_t j)
	{
		ssize_t i0, j0;
		m_Brush->GetBottomLeft(i0, j0);
		// Color this tile based on the average of the surrounding vertices
		float avg = (
			m_Brush->Get(i-i0, j-j0)   + m_Brush->Get(i-i0+1, j-j0) +
			m_Brush->Get(i-i0, j-j0+1) + m_Brush->Get(i-i0+1, j-j0+1)
		) / 4.f;
		RenderTile(CColor(0, 1, 0, avg*0.8f), false);
		if (avg > 0.1f)
			RenderTileOutline(CColor(1, 1, 1, std::min(0.4f, avg-0.1f)), 1, true);
	}

	const AtlasMessage::Brush* m_Brush;
};

Brush::Brush()
: m_W(0), m_H(0), m_TerrainOverlay(NULL)
{
}

Brush::~Brush()
{
	delete m_TerrainOverlay;
}

void Brush::SetData(ssize_t w, ssize_t h, const std::vector<float>& data)
{
	m_W = w;
	m_H = h;

	m_Data = data;
	
	ENSURE(data.size() == (size_t)(w*h));
}

void Brush::GetCentre(ssize_t& x, ssize_t& y) const
{
	CVector3D c = m_Centre;
	if (m_W % 2) c.X += TERRAIN_TILE_SIZE/2.f;
	if (m_H % 2) c.Z += TERRAIN_TILE_SIZE/2.f;
	ssize_t cx, cy;
	CTerrain::CalcFromPosition(c, cx, cy);

	x = cx;
	y = cy;
}

void Brush::GetBottomLeft(ssize_t& x, ssize_t& y) const
{
	GetCentre(x, y);
	x -= (m_W-1)/2;
	y -= (m_H-1)/2;
}

void Brush::GetTopRight(ssize_t& x, ssize_t& y) const
{
	GetBottomLeft(x, y);
	x += m_W-1;
	y += m_H-1;
}

void Brush::SetRenderEnabled(bool enabled)
{
	if (enabled && !m_TerrainOverlay)
	{
		m_TerrainOverlay = new BrushTerrainOverlay(this);
	}
	else if (!enabled && m_TerrainOverlay)
	{
		delete m_TerrainOverlay;
		m_TerrainOverlay = NULL;
	}
}

Brush AtlasMessage::g_CurrentBrush;