#include<string>
#include<SDL.h>
#include <conio.h>

using namespace std;

//declare surfaces.
SDL_Surface* floor = NULL; //background tile.
SDL_Surface* player = NULL; //player tile
SDL_Surface* zombie = NULL; //enemy tile
SDL_Surface* colonist = NULL; //friendly tile
SDL_Surface* screen = NULL; //display layer.

//declare attributes of the screen
const int SCREEN_HEIGHT = 500;
const int SCREEN_WIDTH = 1000;
const int SCREEN_BPP = 32;

bool quit;

//array containing the coordinates for all entities.
SDL_Rect object[50];
//array containing type of unit
int type[50]; // player = 1, colonists = 2, zombies = 3

//amount of baddies
int enemyAmount = 4;
//whether colliding
bool isCol[50];

int amount;
bool collide;



//event
SDL_Event move;

//function for conversion of 24 bit bmps into 32 bit bmps
SDL_Surface *load_image( std::string filename ) //load bmp
{
    //loaded 24 bit bmp is placed here:
    SDL_Surface* loadedImage = NULL;
    //optimized 32 bit bmp is placed here:
    SDL_Surface* optimizedImage = NULL;

    //the bmp is loaded as "filename"
    loadedImage = SDL_LoadBMP( filename.c_str() );
    
    //if the image loads without errors:
    if( loadedImage != NULL )
    {
        //convert to 32 bit bmp
        optimizedImage = SDL_DisplayFormat( loadedImage );
        //clear RAM of 24 bit image
        SDL_FreeSurface( loadedImage );
    }
    
    if( optimizedImage != NULL )
    {
        //Map the color key
        Uint32 colorkey = SDL_MapRGB( optimizedImage->format, 0xFF, 0, 0xFF );
        
        //Set all pixels of colour transparent
        SDL_SetColorKey( optimizedImage, SDL_SRCCOLORKEY, colorkey );
    }
    
    //send the new 32 bit file back to the program
    return optimizedImage;
}

//Function to blit the surface
void apply_surface( int x, int y, SDL_Surface* source, SDL_Surface* destination )
{
    //temporary rectangle is created to hold offset values. 
    //SDL_Rect declares a rectangle with four attributes: offsets( x, y ) and dimensions( h, w )
    SDL_Rect offset;    
    //declare rectangle offsets:
    offset.x = x;
    offset.y = y;
    
    //blit the surface. ( surface used in function, ?, surface that is blitted to, offsets ) 
    SDL_BlitSurface ( source, NULL, destination, &offset );    
}

void drawFloor()
{
    int n = 1;
    int nl = 1; 
    int xl = 20;
    int yl = 40; 

       while( nl < 23 )
       {
           if( n == 37 )
           {
                xl = 20;
                yl += 20;
                n = 1;
                nl++;
           }
           else
           {
                apply_surface( xl, yl, floor, screen );
                n++;                
                xl += 20;               
           }           

       }

}

bool start()
{
    //Start SDL and end program if errors are encountered.
    if( SDL_Init( SDL_INIT_EVERYTHING ) == -1)
    {
        return -1;
    }
    
    //sets up screen, ends program if issues.
    screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE );
    if( screen == NULL )
    {
        return -1;
    }
    
    //Title of the window
    SDL_WM_SetCaption( "ROOM MOVER", NULL );
    
    
    //start position
    object[1].x = 240;
    object[1].y = 240;
    //declare player as player
    type[1] = 3;
    
    //test sci
    object[2].x = 240;
    object[2].y = 100;
    type[2] = 2;
    
    //test zamb
    object[3].x = 240;
    object[3].y = 340;
    type[3] = 1;
    
    return true;
}

bool stop()
{    
    //clear the RAM
    SDL_FreeSurface( floor );    
    
    //end SDL
    SDL_Quit();
    //end program
    return 0;
    
}

//function that blits the objects onto the screen
int drawGuys()
{

    int objCount = 1;
    
    while( objCount < enemyAmount )
    {
        if( type[objCount] == 1 ) //if its the player
        {
        apply_surface( object[objCount].x, object[objCount].y, player, screen ); //draw as player
        objCount ++;//check next thing
        }
        else if( type[objCount] == 2 )  //if its a colonist
        {
        apply_surface( object[objCount].x, object[objCount].y, colonist, screen ); //draw as colonist
        objCount ++;//check next thing
        }
        else if( type[objCount] == 3 )  //if its a zombie
        {
        apply_surface( object[objCount].x, object[objCount].y, zombie, screen ); //draw as zombie
        objCount ++;//check next thing
        }
        else  //if its none of the above
        {
        objCount ++;//check next thing
        }
        
    }

}


int draw()
{
    drawFloor();
    drawGuys();
    SDL_Flip( screen );    
}

//checks two objects colliding and determines zombification and game loss.
int actCollision( SDL_Rect offender, SDL_Rect defender, int offenderType, int defenderType )
{

    //if the one moving into the space is a zombie
    if ( offender.y == defender.y && offender.x == defender.x && offenderType == 3 && defenderType == 2 )
    {
        defenderType = 3;// the one occupying the space is now a zombie
        return (defenderType);
    }
    // if player
    else if ( offender.y == defender.y && offender.x == defender.x && offenderType == 3 && defenderType == 1 ) 
    {
        stop(); // game over
    }

}

int checkCollision()
{
    int compare1 = 1;
    int compare2 = 1;
    
    while( compare1 < 49 )
    {
        if( compare2 == 49 )
        {
            compare1 ++;
            compare2 = 1;
        }
        else
        {
        if( compare1 != compare2 )
        {
            actCollision( object[compare1], object[compare2], type[compare1], type[compare2] );
            compare2 ++;
        }
        else
        {
            compare2 ++;
        }
        }
    }

}



int main( int argc, char* args[] )
{
    start(); 

    
    //Load Images to surfaces
    floor = load_image( "tile.bmp" );
    player = load_image( "man.bmp" );
    colonist = load_image( "sci.bmp" );
    zombie = load_image( "zomb.bmp" );
    

    
    while( quit == false )        
        {
                while( SDL_PollEvent( &move ) )
                {
            
                        if (move.type == SDL_KEYDOWN)
                        {
                
                                if (move.key.keysym.sym == SDLK_w)
                                {
                                    object[1].y -= 20;
                                    checkCollision();
                                    draw();

                                }
                                else if (move.key.keysym.sym == SDLK_s)
                                {
                                    object[1].y += 20;
                                    checkCollision();
                                    draw();

                                }
                                else if (move.key.keysym.sym == SDLK_d)
                                {
                                    object[1].x += 20;
                                    checkCollision();
                                    draw();

                                }
                                else if (move.key.keysym.sym == SDLK_a)
                                {
                                    object[1].x -= 20;
                                    checkCollision();
                                    draw();

                                }
                        }
                            //looks for the 'x' of the window to be closed, the acts accordingly

                        else if (move.type == SDL_QUIT)
                        {
                                    quit = true;
                        } 
                }
        }
    
    stop();
    
}