/*
    Copyright 2005-2015 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks 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 Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#include "../../common/gui/video.h"
#include <cmath>
#include "tbb/blocked_range.h"
#include "tbb/parallel_for.h"


using namespace std;

#ifdef _MSC_VER
// warning C4068: unknown pragma
#pragma warning(disable: 4068)
// warning C4351: new behavior: elements of array 'array' will be default initialized
#pragma warning(disable: 4351)
#endif

#include "universe.h"

const colorcomp_t MaterialColor[4][3] = { // BGR
    {96,0,0},     // WATER
    {0,48,48},    // SANDSTONE
    {32,32,23}    // SHALE
};

void Universe::InitializeUniverse(video const& colorizer) {

    pulseCounter = pulseTime = 100;
    pulseX = UniverseWidth/3;
    pulseY = UniverseHeight/4;
    // Initialize V, S, and T to slightly non-zero values, in order to avoid denormal waves.
    for( int i=0; i<UniverseHeight; ++i )
#pragma ivdep
        for( int j=0; j<UniverseWidth; ++j ) {
            T[i][j] = S[i][j] = V[i][j] = ValueType(1.0E-6);
        }
    for( int i=1; i<UniverseHeight-1; ++i ) {
        for( int j=1; j<UniverseWidth-1; ++j ) {
            float x = float(j-UniverseWidth/2)/(UniverseWidth/2);
            ValueType t = (ValueType)i/UniverseHeight;
            MaterialType m;
            D[i][j] = 1.0;
            // Coefficient values are fictitious, and chosen to visually exaggerate
            // physical effects such as Rayleigh waves.  The fabs/exp line generates
            // a shale layer with a gentle upwards slope and an anticline.
            if( t<0.3f ) {
                m = WATER;
                M[i][j] = 0.125;
                L[i][j] = 0.125;
            } else if( fabs(t-0.7+0.2*exp(-8*x*x)+0.025*x)<=0.1 ) {
                m = SHALE;
                M[i][j] = 0.5;
                L[i][j] = 0.6;
            } else {
                m = SANDSTONE;
                M[i][j] = 0.3;
                L[i][j] = 0.4;
            }
            material[i][j] = m;
        }
    }
    ValueType scale = 2.0f/ColorMapSize;
    for( int k=0; k<4; ++k ) {
        for( int i=0; i<ColorMapSize; ++i ) {
            colorcomp_t c[3];
            ValueType t = (i-ColorMapSize/2)*scale;
            ValueType r = t>0 ? t : 0;
            ValueType b = t<0 ? -t : 0;
            ValueType g = 0.5f*fabs(t);
            memcpy(c, MaterialColor[k], sizeof(c));
            c[2] = colorcomp_t(r*(255-c[2])+c[2]);
            c[1] = colorcomp_t(g*(255-c[1])+c[1]);
            c[0] = colorcomp_t(b*(255-c[0])+c[0]);
            ColorMap[k][i] = colorizer.get_color(c[2], c[1], c[0]);
        }
    }
    // Set damping coefficients around border to reduce reflections from boundaries.
    ValueType d = 1.0;
    for( int k=DamperSize-1; k>0; --k ) {
        d *= 1-1.0f/(DamperSize*DamperSize);
        for( int j=1; j<UniverseWidth-1; ++j ) {
            D[k][j] *= d;
            D[UniverseHeight-1-k][j] *= d;
        }
        for( int i=1; i<UniverseHeight-1; ++i ) {
            D[i][k] *= d;
            D[i][UniverseWidth-1-k] *= d;
        }
    }
    drawingMemory = colorizer.get_drawing_memory();
}
void Universe::UpdatePulse() {
    if( pulseCounter>0 ) {
        ValueType t = (pulseCounter-pulseTime/2)*0.05f;
        V[pulseY][pulseX] += 64*sqrt(M[pulseY][pulseX])*exp(-t*t);
        --pulseCounter;
    }
}

struct Universe::Rectangle {
    struct std::pair<int,int> xRange;
    struct std::pair<int,int> yRange;
    Rectangle (int startX, int startY, int width, int height):xRange(startX,width),yRange(startY,height){}
    int StartX() const {return xRange.first;}
    int StartY() const {return yRange.first;}
    int Width()   const {return xRange.second;}
    int Height()  const {return yRange.second;}
    int EndX() const {return xRange.first + xRange.second;}
    int EndY() const {return yRange.first + yRange.second;}

};

void Universe::UpdateStress(Rectangle const& r ) {
    drawing_area  drawing(r.StartX(),r.StartY(),r.Width(),r.Height(),drawingMemory);
    for( int i=r.StartY(); i<r.EndY() ; ++i ) {
        drawing.set_pos(1, i-r.StartY());
#pragma ivdep
        for( int j=r.StartX(); j<r.EndX() ; ++j ) {
            S[i][j] += M[i][j]*(V[i][j+1]-V[i][j]);
            T[i][j] += M[i][j]*(V[i+1][j]-V[i][j]);
            int index = (int)(V[i][j]*(ColorMapSize/2)) + ColorMapSize/2;
            if( index<0 ) index = 0;
            if( index>=ColorMapSize ) index = ColorMapSize-1;
            color_t* c = ColorMap[material[i][j]];
            drawing.put_pixel(c[index]);
        }
    }
}

void Universe::SerialUpdateStress() {
    Rectangle  area(0, 0, UniverseWidth-1, UniverseHeight-1);
    UpdateStress(area);
}

struct UpdateStressBody {
    Universe & u_;
    UpdateStressBody(Universe & u):u_(u){}
    void operator()( const tbb::blocked_range<int>& range ) const {
        Universe::Rectangle area(0, range.begin(), u_.UniverseWidth-1, range.size());
        u_.UpdateStress(area);
    }
};

void Universe::ParallelUpdateStress(tbb::affinity_partitioner &affinity) {
    tbb::parallel_for( tbb::blocked_range<int>( 0, UniverseHeight-1 ), // Index space for loop
                       UpdateStressBody(*this),                             // Body of loop
                       affinity );                                     // Affinity hint
}

void Universe::UpdateVelocity(Rectangle const& r) {
    for( int i=r.StartY(); i<r.EndY(); ++i )
#pragma ivdep
        for( int j=r.StartX(); j<r.EndX(); ++j )
            V[i][j] = D[i][j]*(V[i][j] + L[i][j]*(S[i][j] - S[i][j-1] + T[i][j] - T[i-1][j]));
}

void Universe::SerialUpdateVelocity() {
    UpdateVelocity(Rectangle(1,1,UniverseWidth-1,UniverseHeight-1));
}

struct UpdateVelocityBody {
    Universe & u_;
    UpdateVelocityBody(Universe & u):u_(u){}
    void operator()( const tbb::blocked_range<int>& y_range ) const {
        u_.UpdateVelocity(Universe::Rectangle(1,y_range.begin(),u_.UniverseWidth-1,y_range.size()));
    }
};

void Universe::ParallelUpdateVelocity(tbb::affinity_partitioner &affinity) {
    tbb::parallel_for( tbb::blocked_range<int>( 1, UniverseHeight ), // Index space for loop
                       UpdateVelocityBody(*this),                    // Body of loop
                       affinity );                                   // Affinity hint
}

void Universe::SerialUpdateUniverse() {
    UpdatePulse();
    SerialUpdateStress();
    SerialUpdateVelocity();
}

void Universe::ParallelUpdateUniverse() {
    /** Affinity is an argument to parallel_for to hint that an iteration of a loop
    is best replayed on the same processor for each execution of the loop.
    It is a static object because it must remember where the iterations happened
    in previous executions. */
    static tbb::affinity_partitioner affinity;
    UpdatePulse();
    ParallelUpdateStress(affinity);
    ParallelUpdateVelocity(affinity);
}

bool Universe::TryPutNewPulseSource(int x, int y){
    if(pulseCounter == 0) {
        pulseCounter = pulseTime;
        pulseX = x; pulseY = y;
        return true;
    }
    return false;
}

void Universe::SetDrawingMemory(const drawing_memory &dmem) {
    drawingMemory = dmem;
}
