// ************ CUSTOMIZABLE CONFIGURATION ************ //

// TODO: These should just be text boxes/color pickers

var Config = {
  minColCount: 16,
  minRowCount: 48,
  zoomRate: 4,
  gridScale: 24,
  gridWidth: 0.4,
  gridColor:'rgba(0,0,0,0.5)',
  emptyColor: 'rgb(255,255,255)'
};




// ******************* ACTUAL CODE ******************* //


//-----------------------------------------------------//
// Initial Setup                                       //
//-----------------------------------------------------//

var Page = {body:0, cvs:0, ctx:0, footer:0,
            btnZoomIn:0, btnZoomOut:0,            
            l:0, t:0, w:0, h:0, 
            u:0, minU:12, maxU:48,
            colCount: 0, rowCount: 0, isDirty:0};

var Tool = {active:0, draw:0, move:0, delete:0};

var ObjActive = 0,
    ObjStatic = [];


Load();

function Load(){
  Page.body = document.getElementsByTagName('body')[0];
  Page.cvs = document.createElement('canvas');
  Page.ctx = Page.cvs.getContext('2d');
    
  Page.body.appendChild(Page.cvs);
  Page.cvs.style.position = 'absolute';
    
  Page.footer = document.getElementById('footer');
  Page.btnZoomIn = document.getElementById('zoomIn');
  Page.btnZoomOut = document.getElementById('zoomOut');
  
  Tool.draw = document.getElementById('draw');
  Tool.move = document.getElementById('move');
  Tool.delete = document.getElementById('delete');
  Tool.active = Tool.draw;
  Tool.state = 0;
  
  Page.u = Config.gridScale;
  
  //SetInputEvents();  
  Init();
}


function Init(){
  ObjActive = 0;
  ObjStatic = [];
  Page.isDirty = 1;
  
  CheckWindowSize();
  UpdateLoop();
}


function CheckWindowSize(){
  var w = Page.body.offsetWidth,
      h = Page.body.offsetHeight - Page.footer.offsetHeight;

  if (w !== Page.w || h !== Page.h){
    Page.cvs.width = w;
    Page.cvs.height = h;
    SetScale(w,h,Page.u);
  }
}


function SetScale(w,h,u){
  Page.isDirty = 1;

  Page.w = (w !== null) ? w : Page.w;
  Page.h = (h !== null) ? h : Page.h;
  Page.u = (u !== null) ? u : Page.u;

  Page.colCount = Math.ceil(Page.w / Page.u);
  Page.rowCount = Math.ceil(Page.h / Page.u);

  Page.w;
  Page.cvs.height = Page.h;

  Page.cvs.style.left = Page.cvs.style.top = 0;
}


function TryZoom(dir){
  if (CanZoom(dir)){
    var newU = Clamp(Page.u+dir*Config.zoomRate,Page.minU,Page.maxU);
    
    if (newU === Page.minU){
      AddClass(Page.btnZoomOut,'btn-inactive');
    }
    else if (Page.u === Page.minU){
      RemoveClass(Page.btnZoomOut,'btn-inactive');
    }
    
    if (newU === Page.maxU){
      AddClass(Page.btnZoomIn,'btn-inactive');
    }
    else if (Page.u === Page.maxU){
      RemoveClass(Page.btnZoomIn,'btn-inactive');
    }
    
    SetScale(Page.w,Page.h,newU);
  }  
}


function CanZoom(dir){
  return ((Page.u>Page.minU&&dir<0) ||
          (Page.u<Page.maxU&&dir>0));
}


function TrySelectTool(thisTool){
  if (thisTool != Tool.active){
    RemoveClass(Tool.active,'btn-select');
    AddClass(thisTool,'btn-select');
    Tool.active = thisTool;
    Tool.state = GetToolState();
  }
}


function GetToolState(){
  switch (Tool.active){
    case Tool.draw: return 0;
    case Tool.move: return 1;
    case Tool.delete: return 2;
    default: return -1;
  }
}


function DrawBackground(){
  Page.ctx.fillStyle = Config.emptyColor;
  Page.ctx.fillRect(0, 0, Page.w, Page.h);
}


function DrawGrid(){
  var i, len; 

  Page.ctx.beginPath();

  for(i = 1, len = Page.colCount ; i < len ; i++){
    Page.ctx.moveTo(i * Page.u, 0);
    Page.ctx.lineTo(i * Page.u, Page.h);
  }

  for(i = 1, len = Page.rowCount ; i < len ; i++){
    Page.ctx.moveTo(0, i * Page.u);
    Page.ctx.lineTo(Page.w, i * Page.u);
  }

  Page.ctx.lineWidth = Config.gridWidth;
  Page.ctx.strokeStyle = Config.gridColor;
  Page.ctx.stroke();
}



//-----------------------------------------------------//
// User Input Events                                   //
//-----------------------------------------------------//


window.addEventListener('resize', CheckWindowSize, false);

/*
function SetInputEvents(){
  
  
  Page.isMobile = IsMobile();
  
  // TOUCH EVENTS
  if (Page.isMobile){
    
    document.getElementById('reset').addEventListener("touchstart", Init(), false);

    Page.btnZoomOut.addEventListener("touchstart", TryZoom(-1), false);
    Page.btnZoomIn.addEventListener("touchstart", TryZoom(1), false);

    Tool.draw.addEventListener("touchstart", TrySelectTool(Tool.draw), false);
    Tool.move.addEventListener("touchstart", TrySelectTool(Tool.move), false);
    Tool.delete.addEventListener("touchstart", TrySelectTool(Tool.delete), false);

    Page.cvs.addEventListener("touchstart", CheckClick(evt), false);
    Page.cvs.addEventListener("touchend", CheckUnclick(), false);
    Page.cvs.addEventListener("touchleave", CheckUnclick(), false);
    Page.cvs.addEventListener("touchmove", CheckMouseMove(evt), false);
    //Page.cvs.addEventListener("touchcancel", handleCancel, false);
  }
  
  // MOUSE EVENTS
  else{*/
    
document.getElementById('reset').onclick = function(){ Init(); };

Page.btnZoomOut.onclick = function(){ TryZoom(-1); };
Page.btnZoomIn.onclick = function(){ TryZoom(1); };

Tool.draw.onclick = function(){TrySelectTool(Tool.draw)};
Tool.move.onclick = function(){TrySelectTool(Tool.move)};
Tool.delete.onclick = function(){TrySelectTool(Tool.delete)};

Page.cvs.onmousedown = function(evt){
  CheckClick(evt);

  document.onmousemove = function(evt){
    CheckMouseMove(evt);
  };
  document.onmouseup = function(evt){
    CheckUnclick(evt);
  };
};


// INPUT FUNCTIONS

function CheckUnclick() {  
  if (Tool.state === 0){
    if (ObjActive !== 0 && ObjActive !== 1){
      if (ObjActive.curX != ObjActive.anchorX &&
          ObjActive.curY != ObjActive.anchorY){
        ObjStatic.push(ObjActive);
      }
      ObjActive = 1;
    }
  }
  else if (Tool.state === 2){
  }
}

    
function CheckClick(evt) {
  
  if (Tool.state === 0){
    var unitPos = GetMousePosUnits(evt);

    // TODO: null coords is pretty hacky, should return 3rd param
    if (unitPos.x !== null && unitPos.y !== null){
      isLooping = (ObjActive === 0 || ObjActive === 1) ? true : false;    
      ObjActive = new DrawObj(unitPos.x,unitPos.y,'rgba(96,160,192,1)');
      Page.isDirty = 1;
    }
  }
  else if (Tool.state === 2){
    TryDeleteDrawArea(evt);
  }
}


function CheckMouseMove(evt){
  if(Tool.state === 0){
    if (ObjActive !== 0 && ObjActive !== 1){
      ObjActive.UpdateCoords(evt);
    }
  }
}


function GetMousePosUnits(evt) {
  var pixelPos = GetMousePosPixels(evt);
  return PixelsToUnits(pixelPos.x,pixelPos.y);
}


function GetMousePosPixels(evt) {
  var xPos = evt.clientX - Page.l,
      yPos = evt.clientY - Page.t;
  
  xPos = Math.min(Math.max(xPos,0),Page.w);
  yPos = Math.min(Math.max(yPos,0),Page.h);
  
  return {x: xPos, y: yPos};
}


function PixelsToUnits(x, y){
  var unitX = null,
      unitY = null;
  
  if (x > -10 && x <= Page.w+10 && y >= -10 && y <= Page.h+10) {
    unitX = Math.round(x/Page.u);
    unitY = Math.round(y/Page.u);
  }
  
  return { x: unitX, y: unitY };
}


function TryDeleteDrawArea(evt){
  var point = GetMousePosPixels(evt);
  
  // Search backwards from the newest
  for(var i = ObjStatic.length - 1; i >= 0; i--){    
    if (PointInRect(point,ObjStatic[i].ToPixelRect())){
      ObjStatic.splice(i,1);
      Page.isDirty = 1;
      break;
    }
  }
}
  

var DrawObj = function(anchorX, anchorY, fillStyle){  
  this.fillStyle = fillStyle;  
  this.anchorX = anchorX;
  this.anchorY = anchorY;
  
  this.curX = anchorX;
  this.curY = anchorY;
  
  this.UpdateCoords = function(evt){
    var unitPos = GetMousePosUnits(evt);
    
    if (unitPos.x != this.curX || unitPos.y != this.curY){
      this.curX = Math.min(Math.max(unitPos.x,0),Page.colCount);
      this.curY = Math.min(Math.max(unitPos.y,0),Page.rowCount);
    }
  };
  
  this.ToPixelRect = function(){
    var l = Page.u * Math.min(this.anchorX, this.curX),
        r = Page.u * Math.max(this.anchorX, this.curX),
        t = Page.u * Math.min(this.anchorY, this.curY),
        b = Page.u * Math.max(this.anchorY, this.curY);
    return {left:l, top:t, right:r, bottom:b}
  };
  
  this.Draw = function(isActive){
    var left = this.anchorX * Page.u,
        top = this.anchorY * Page.u,
        right = this.curX * Page.u,
        bottom = this.curY * Page.u,
        width = right - left,
        height = bottom - top;       
        
    Page.ctx.fillStyle = this.fillStyle;
    Page.ctx.fillRect(left, top, width, height);
    
    // flashing effect for the active draw area
    if (isActive === 1){
      var alpha = 0.2 + Math.sin(Date.now()/80)/20;
      
      Page.ctx.fillStyle = 'rgba(255,255,255,' + alpha + ')';  
      Page.ctx.fillRect(left, top, width, height);
      
      Page.ctx.beginPath();
      Page.ctx.moveTo(left,top);
    }
    
    Page.ctx.lineWidth = 1.5;
    Page.ctx.strokeStyle = 'rgba(0,0,0,0.5)';
    Page.ctx.strokeRect(left, top, width, height);
    
    // visuals on the anchor point and current point
    if (isActive === 1){      
      Page.ctx.beginPath();
      Page.ctx.arc(left,top,Page.u/5,0,2*Math.PI,false);
      Page.ctx.arc(right,bottom,Page.u/5,0,2*Math.PI,false);  
      Page.ctx.fillStyle = this.fillStyle;
      Page.ctx.fill();
      Page.ctx.fillStyle = 'rgba(0,0,0,0.5)';
      Page.ctx.fill(); 
    }
  };
};


//-----------------------------------------------------//
// Draw Update Loop                                    //
//-----------------------------------------------------//


function UpdateLoop(){  

  if (Page.isDirty === 1){    
    DrawBackground();

    for(var i = 0, len = ObjStatic.length; i < len; i++){
      ObjStatic[i].Draw(0);
    }

    // TODO: stop being so hacky with the ObjActive 0 and 1 stuff
    if (ObjActive !== 0 && ObjActive !== 1){
      ObjActive.Draw(1); 
    }
    else{
      Page.isDirty = ObjActive = 0;
    }
    DrawGrid();
  }

  window.requestAnimationFrame(UpdateLoop);
}



//-----------------------------------------------------//
// Helper Functions                                    //
//-----------------------------------------------------//

/*
function IsMobile() {
  var check = false;
  (function(a){if(/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(a.substr(0,4)))check = true})(navigator.userAgent||navigator.vendor||window.opera);
  return check; 
}*/


function PointInRect(p, r){
  return (p.x>=r.left&&p.x<=r.right&&p.y>=r.top&&p.y<=r.bottom);
}


function Clamp(n,min,max){
  return Math.min(Math.max(n,min),max);
}


function AddClass(ele,classStr){
  ele.className = ele.className.replaceAll(' '+classStr,'')+' '+classStr;
}

function RemoveClass(ele,classStr){
  ele.className = ele.className.replaceAll(' '+classStr,'');
}

function ToggleClass(ele,classStr){
  var str = ele.className.replaceAll(' '+classStr,'');
  ele.className = (str.length===ele.className.length)?str+' '+classStr:str;
}

String.prototype.replaceAll = function (replaceThis, withThis) {
   var re = new RegExp(replaceThis,"g"); 
   return this.replace(re, withThis);
};


function onTouch(evt) {
  evt.preventDefault();
  if (evt.touches.length > 1 || (evt.type == "touchend" && evt.touches.length > 0))
    return;

  var newEvt = document.createEvent("MouseEvents");
  var type = null;
  var touch = null;
  switch (evt.type) {
    case "touchstart":    type = "mousedown";    touch = evt.changedTouches[0];break;
    case "touchmove":        type = "mousemove";    touch = evt.changedTouches[0];break;
    case "touchend":        type = "mouseup";    touch = evt.changedTouches[0];break;
  }
  newEvt.initMouseEvent(type, true, true, evt.originalTarget.ownerDocument.defaultView, 0,
    touch.screenX, touch.screenY, touch.clientX, touch.clientY,
    evt.ctrlKey, evt.altKey, evt.shirtKey, evt.metaKey, 0, null);
  evt.originalTarget.dispatchEvent(newEvt);  
}