//
// Here I tried to learn more about how to not let moving units go through each other when moving
// on the map.
//
// Note : I think when just checking for collide between units they should just both stop and plan
// a new path (for one?) towards the original destination.


#include "raylib.h"
#include <math.h>

typedef struct unit{
    float x,y;    
    int asidex,asidey;
    int wait;
    bool moveaside;    
    int pathloc;
    int pathlen;
}unit;

int path1x[10]={10,11,12,13,14,15,16,17,18,19};
int path1y[10]={5,5,5,5,5,5,5,5,5,5};

int path2x[10]={19,18,17,16,15,14,13,12,11,10};
int path2y[10]={5,5,5,5,5,5,5,5,5,5};

unit unit1={0};
unit unit2={0};
float tileWidth,tileHeight;

void iniunits();

int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib example.");

    tileWidth = 24.0f;
    tileHeight = 24.0f;
    iniunits();
 
    SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        
        // Move unit 1
        if(unit1.wait>0)unit1.wait-=1;
        if(unit1.pathloc<unit1.pathlen && unit1.wait<=0){
            // get the next location in the path
            float x=path1x[unit1.pathloc]*tileWidth;
            float y=path1y[unit1.pathloc]*tileHeight;
            // If we are not moving aside currently
            if(unit1.moveaside==false){
                // see if our next position is colliding with unit2
                int ax = path2x[unit2.pathloc+1];
                int ay = path2y[unit2.pathloc+1];
                int bx = path1x[unit1.pathloc];
                int by = path1y[unit1.pathloc];
                if(ax==bx && ay==by){
                    // We will collide 
                    unit1.moveaside=true;

                    // Get a position on the map to move aside to
                    bool found=false;
                    while(found==false){  
                        unit1.asidex=bx+GetRandomValue(-1,1);
                        unit1.asidey=by+GetRandomValue(-1,1);
                        found=true;
                        // if new position not on path of unit 1
                        for(int i=unit1.pathloc-1;i<unit1.pathloc+1;i++){
                            if(unit1.asidex==path1x[i] && unit1.asidey==path1y[i])found=false;
                        }
                        // if new position not on path of unit 2
                        for(int i=unit2.pathloc-1;i<unit2.pathloc+1;i++){
                            if(unit1.asidex==path2x[i] && unit1.asidey==path2y[i])found=false;
                        }
                        // Add checks for obstacles here...

                    }

                }
            }
            // if we are moving aside currently then adjust were we are moving to.
            if(unit1.moveaside){
                x=unit1.asidex*tileWidth;
                y=unit1.asidey*tileHeight;
            }

            // Move our unit1
            if(unit1.x<x)unit1.x+=1;
            if(unit1.y<y)unit1.y+=1;
            if(unit1.x>x)unit1.x-=1;
            if(unit1.y>y)unit1.y-=1;
            
            // If we are at the destination..
            if( unit1.x==x && 
                unit1.y==y){
                // If we are moving aside then disable this mode and increase our location on the path.
                if(unit1.moveaside){
                    unit1.moveaside=false;
                    unit1.pathloc+=3;
                    unit1.wait=60;
                //  If we are on the destination and not moving aside then increase our path location.
                }else{
                    unit1.pathloc++;                
                }
            }
        }

        // Move unit 2
        if(unit2.pathloc<unit2.pathlen){
            float x=path2x[unit2.pathloc]*tileWidth;
            float y=path2y[unit2.pathloc]*tileHeight;
            
            if(unit2.x<x)unit2.x+=1;
            if(unit2.y<y)unit2.y+=1;
            if(unit2.x>x)unit2.x-=1;
            if(unit2.y>y)unit2.y-=1;
            
            if( unit2.x==x && 
                unit2.y==y){
                unit2.pathloc++;                
            }
        }else{
            iniunits();
        }
        
        //----------------------------------------------------------------------------------
        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(RAYWHITE);
                
            DrawRectangle(unit1.x,unit1.y,tileWidth,tileHeight,RED);    
            DrawRectangle(unit2.x,unit2.y,tileWidth,tileHeight,BLUE);


        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    CloseWindow();        // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;


}

void iniunits(){
    unit1.pathloc = 0;
    unit1.pathlen = 10;
    unit1.x = path1x[unit1.pathloc]*tileWidth;
    unit1.y = path1y[unit1.pathloc]*tileHeight;    
    unit1.moveaside=false;
    unit2.pathloc = 0;
    unit2.pathlen = 10;
    unit2.x = path2x[unit2.pathloc]*tileWidth;
    unit2.y = path2y[unit2.pathloc]*tileHeight;
    unit2.moveaside=false;
    return;
}