#include <stdio.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include "erosion_particle.h"
//include "suzie_maths.h"




/*********************************************************************
 * Initialize the openGL viewing area as a two dimensional orthogonal
 * viewing window.
 ********************************************************************/
void initialize( void )
{
  //Set the background colour to white
  glClearColor( 1.0, 1.0, 1.0, 1.0 );
  //Default drawing colour set to red
  glColor3f( 1.0, 0.0, 0.0 );

  //Set up viewing area for a projection viewing area, (frustum)
  glMatrixMode( GL_PROJECTION );
  glLoadIdentity();
  gluOrtho2D( 0.0, SCREEN, 0.0, SCREEN );
  glMatrixMode( GL_MODELVIEW );
}



/*******************************************************************
 * OpenGL display function 
 ******************************************************************/
void display( void )
{
  int base = BASE, count = 0, count2 = 0, countX, collide;
  float originX = 0, originY = 0, particleX = 0, particleY;
  float heightField[NUM_STEPS];
  float random, testVariable;
  int height, total_particles = 0;
  Particle particle;

  /* Create the openGL list for a box */
  createBox();

  glClear( GL_COLOR_BUFFER_BIT );

  srand( time(NULL) );

  /* Initialize the terrain structure */
  createTerrain( heightField );
  //fprintf(stderr, "directly after createTerrain: %.2f\n", heightField[20]);

  //fprintf(stderr, "no. of steps: %d\n", NUM_STEPS);
  /* Count the total number of particles in the heap */
  for( count = 0; count < NUM_STEPS; count++ )
    {
      //fprintf(stderr, "count = %d\n", count );
      //fprintf(stderr, "x: %d, y: %.2f\n", count, heightField[count] );
      total_particles += heightField[count]/(RADIUS*2);
      //fprintf(stderr, "total particles at %d is %d\n", count, total_particles );
    }

  glutSwapBuffers();
  //printf("still finished with creating terrain\n");
  /* While there are still particle left in the pile */
  while( total_particles > 0 )
    {
      for( count = 0; count < NUM_STEPS; count++ )
	{
	  fprintf(stderr, "looking at column %d\n", count );
	  /* If the current column has no particles, move to the next */
	  if( heightField[count] > 0 )
	    {
	      /* Determine where the particle moves to, if it moves at all */
	      move_particle( count, heightField, &total_particles );
	    }
	  glClear( GL_COLOR_BUFFER_BIT );
	  redrawTerrain( heightField );
	  //fprintf(stderr, "just redrawn terrain\n");
	  glutSwapBuffers();
	}
    }
}


/************************************************************************
 * main()
 ***********************************************************************/
int main( int argc, char** argv )
{
  FILE* input;

  if( argc < 2 )
    {
      NUM_STEPS = (int)SCREEN/(RADIUS*2);
      VELOCITY_X = RADIUS*2;
      fprintf(stderr, "No input file given, using defaults\n");
    }
  else if( strcmp( argv[1], "help" )== 0 ) 
    {
      printf("Input file requires an indication of wind strength, given as an integer\n");
      printf("between 0 and 10, with 10 being the maximum strength.  Probability of an\n");
      printf("unprotected particle being shifted is calculated as wind strength over\n");
      printf("21 times the radius.  This means there will always be some chance that the\n");
      printf("particle will not move even in the strongest wind.\n");
      printf("Input file is as follows:\n");
      printf("radius(float), wind strength(float between 0 and 20)\n");
      exit(1);
    }
  else
    {
      input = fopen( argv[1], "r" );
      if( !input )
	  fprintf(stderr, "input file did not open, using defaults\n");
      else
	{
	  fscanf( input, "%f, %f\n", &RADIUS, &WIND_STRENGTH ); 
	  fclose( input );
	  NUM_STEPS = (int)SCREEN/(RADIUS*2);
	  WIND_STRENGTH *= RADIUS;
	}
    }
  glutInit( &argc, argv );
  glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB );
  glutInitWindowSize( SCREEN, SCREEN );
  glutInitWindowPosition( 0, 0);
  glutCreateWindow("Deposition simulation");
  glutDisplayFunc( display );
  initialize();
  glutMainLoop();
}