//////////////////////////////////////////////
//      Chart creation code goes here       //
//////////////////////////////////////////////
var sampleData = [
    { "x":   1,     "y":  5 }, 
    { "x":  20,     "y": 20 }, 
    { "x":  40,     "y": 10 }, 
    { "x":  60,     "y": 40 },
    { "x":  80,     "y":  5 }, 
    { "x": 100,     "y": 60 }
    ];
function drawLine () {

    /* ================= settings ======================= */
    var vis = d3.select("#graph");
    var xRange = d3.scale.linear()
                    .range([40, 400])
                    .domain([
                        d3.min(sampleData, function (d) {return (d.x);}),
                        d3.max(sampleData, function (d) {return d.x;})
                        ]);
    var yRange = d3.scale.linear()
                    .range([400, 40])
                    .domain([
                        d3.min(sampleData, function (d) {return d.y;}),
                        d3.max(sampleData, function (d) {return d.y;})
                        ]);
    var xAxis = d3.svg.axis().scale(xRange);
    var yAxis = d3.svg.axis().scale(yRange).orient("left");
    vis.append("svg:g").call(xAxis).attr("transform", "translate(0,400)");
    vis.append("svg:g").call(yAxis).attr("transform", "translate(40,0)");

    /*@url: 
    http://code.tutsplus.com/tutorials/building-a-multi-line-chart-using-d3js--cms-22935*/
    var lineGen = d3.svg.line()
      .x(function(sampleData) {
        return xRange(sampleData.x);
      })
      .y(function(sampleData) {
        return yRange(sampleData.y);
      });

    vis.append('svg:path')
      .attr('d', lineGen(sampleData))
      .attr('stroke', 'green')
      .attr('stroke-width', 2)
      .attr('fill', 'none');
}



////////////////////////////////////////////////////////
//     FUNCTIONS TO MOVE AROUND THE ORIGIN            //
////////////////////////////////////////////////////////

//SETTINGS
var moves = 0;
var dir = 'r';
var coords = [{'x':0,   'y':0}];
var tmp = {'x': 0, 'y':0};

$('#generate-numbers').click(function() {
    var max = $('#max-num').val();

    //variable dir gives the position of the last movement direction to be able 
    //to determine which next direction to take. 
    /*
    *    u(up)    => move_left
    *    l(left)  => move_down
    *    d(down)  => move_right
    *    r(right) => move_up 
    ***** default is r(right) so that i can choose to go up 
    */
    

    while(moves <= max){
        switch(dir){
            case 'r': 
                up();       dir = 'u';      break;
            case 'u':
                left();     dir = 'l';      break;
            case 'l':
                down();     dir = 'd';      break;
            case 'd':
                right();    dir = 'r';      break;
            default: 
                alert("wrong option. Please, start all over");
                return ;
        }
        ++moves;
    }
    sampleData = coords;
    $('#graph').empty();
    drawLine();

})

function left (argument) {
    do{
    console.log("l_tmpXY (" + tmp.x + " " + tmp.y + ") moves " + moves)
        --tmp.x;
        ++moves;
        coords.push({
            'x': tmp.x, 
            'y': tmp.y
        });
    }while(!isPrime(moves));
}

function right (argument) {
    do{
    console.log("r_tmpXY (" + tmp.x + " " + tmp.y + ") moves " + moves)
        ++tmp.x;
        ++moves;
        coords.push({
            'x': tmp.x, 
            'y': tmp.y
        });
    }while(!isPrime(moves));
}

function up (argument) {
    do{
    console.log("u_tmpXY (" + tmp.x + " " + tmp.y + ") moves " + moves)
        ++tmp.y;
        ++moves;
        coords.push({
            'x': tmp.x, 
            'y': tmp.y
        });
    }while(!isPrime(moves));
}

function down (argument) {
    do{
    console.log("d_tmpXY (" + tmp.x + " " + tmp.y + ") moves " + moves)
        --tmp.y;
        ++moves;
        coords.push({
            'x': tmp.x, 
            'y': tmp.y
        });
    }while(!isPrime(moves));
}


function isPrime (argument) {

}
function isPrime(n) {

   // If n is less than 2 or not an integer then by definition cannot be prime.
   if (n < 2) {return false}
   if (n != Math.round(n)) {return false}

   // Now assume that n is prime, we will try to prove that it is not.
   var isPrime = true;

   // Now check every whole number from 2 to the square root of n. If any of these divides n exactly, n cannot be prime.
   for (var i = 2; i <= Math.sqrt(n); i++) {
      if (n % i == 0) {isPrime = false}
   }

   // Finally return whether n is prime or not.
   return isPrime;

}