var margin = {left: 20, right: 20, top: 40, bottom: 20}
    width  = 960 - margin.left - margin.right,
    height = 500 - margin.top  - margin.bottom,
    cols = 8,
    rows = 8,
    gS = 35   //gate size

//set up gates
var types = [
  {str: 'AND',  fn: function(a, b){ return a && b} },
  {str: 'OR',   fn: function(a, b){ return a || b} },
  {str: 'XOR',  fn: function(a, b){ return a ^ b} },
  {str: 'NAND', fn: function(a, b){ return !(a && b)} },
]

var x = d3.scale.linear().domain([0, cols - 1]).range([0, width])
var y = d3.scale.linear().domain([0, rows - 1]).range([0, height])

var gates = d3.range(cols*rows).map(function(n){
  var rv = {
    i:    n % cols,
    j:    Math.floor(n / rows),
    n:    n,
    type: types[Math.floor(Math.random()*types.length)],
    on: false
  }
  rv.x = x(rv.i)
  rv.y = y(rv.j)
  rv.inputs = [{to: rv}, {to: rv}]
  rv.outputs = []

  return rv
})

//first col of gates are off or on, not actual gates
var onType  = {str: 'ON',  fn: function(){ return true } }
var offType = {str: 'OFF', fn: function(){ return false } }
var gatesByCol = d3.nest().key(ƒ('i')).entries(gates).sort(d3.ascendingKey('key'))
gatesByCol[0].values.forEach(function(d){
  d.type = Math.random() < .5 ? onType : offType
})


//set up wires
var wires = _.flatten(gates.map(ƒ('inputs'))).filter(ƒ('to', 'i'))

var wireByCol  = d3.nest().key(ƒ('to', 'i')).entries(wires)
wireByCol.forEach(function(wireCol){
  wireCol.key = +wireCol.key

  var prevGateCol = gatesByCol[wireCol.key - 1]
  
  var gateSpace = x(1) - x(0) - gS
  var vXscale = d3.scale.linear().domain([0, wireCol.values.length]).range([10, gateSpace - 10])

  _.shuffle(wireCol.values).forEach(function(wire, i){
    wire.colI = i
  })

  _.shuffle(wireCol.values).forEach(function(wire, i){
    var gate = prevGateCol.values[Math.floor(i/2)]
    
    wire.from = gate
    gate.outputs.push(wire)

    wire.vX = vXscale(i)
  })
})

gates.forEach(function(gate){
  gate.outputs.forEach(function(d, i){
    d.fromN = i
  })
  gate.inputs.forEach(function(d, i){
    d.toN = i
  })
})

wires.forEach(function(d){
  d.pathStr = [
    'M', [d.from.x + gS/2, d.from.y + (d.fromN ? -gS/3 : -gS/5)], 
    'h', d.vX,
    'V', d.to.y + (d.toN ? gS/3 : gS/5),
    'L', [d.to.x - gS/2, d.to.y + (d.toN ? gS/3 : gS/5)]
  ].join('')
})


//add elements to the page
var svg = d3.select('body').append('svg')
    .attr({width: width + margin.left + margin.right, height: height + margin.top + margin.bottom})
  .append('g').translate([margin.left, margin.right])

var gateGs = svg.dataAppend(gates, 'g')
    .translate(function(d){ return [d.x, d.y] })
    .each(function(d){ d.sel = d3.select(this) })

gateGs.append('rect')
    .style({stroke: 'black', fill: 'darkgrey'})
    .attr({x: -gS/2, y: -gS/2, width: gS, height: gS})

gateGs.append('text')
    .text(ƒ('type', 'str'))
    .attr({'text-anchor': 'middle', dy: '.33em'})
    .style('font-size', '70%')


var wireBotEls = svg.dataAppend(wires, 'path.wire.bot').attr('d', ƒ('pathStr'))
    .style('stroke', 'lightgrey')
var wireTopEls = svg.dataAppend(wires, 'path.wire.top').attr('d', ƒ('pathStr'))
    .attr('stroke-dasharray', '100% 100%')


//update logic
function update(i){
  gatesByCol.forEach(function(gateCol){
    gateCol.values.forEach(function(gate){
      gate.lastOn = gate.on
      gate.on = gate.type.fn.apply(null, gate.inputs.map(ƒ('on')))
      gate.changedOn = gate.lastOn != gate.on

      gate.outputs.forEach(function(d){
        d.on = gate.on 
        d.changedOn = gate.changedOn
      })
    })
  })

  var uuid = Math.random()

  gateGs.selectAll('rect').filter(ƒ('changedOn'))
    .transition(uuid).delay(function(d){ return (d.i - i)*300+ 100})
      .style('fill', color)
      .style('fill-opacity', 1)
    .transition(uuid).duration(300)
      .style('fill-opacity', .5)

  wireBotEls
    .transition(uuid).delay(function(d){ return (d.from.i - i)*300 + 600 })
      .style('stroke', color)

  wireTopEls.filter(ƒ('changedOn'))
      .attr({stroke: color, 'stroke-width': 3, 'stroke-dashoffset': '100%'})
    .transition(uuid).delay(function(d){ return (d.from.i - i)*300 + 100 }).duration(1000)
      .each('start', function(){ d3.select(this).style('stroke-width', 3) })
      .attr('stroke-dashoffset', '0%')
    .transition(uuid)
      .style('stroke-width', 0)


  function color(d){ return d.on ? 'yellow' : 'darkgrey' }
}

update(0)

gateGs.on('click', function(d){
  //toggle type
  if (d.i){
    var oldType = d.type
    while (oldType == d.type) d.type = types[Math.floor(Math.random()*types.length)]
  
  } else{
    d.type = d.type == onType ? offType : onType
  }

  d3.select(this).select('text').text(d.type.str)

  update(d.i)
})


window.setInterval(function(){
  var d = gatesByCol[0].values[Math.floor(Math.random()*8)]
  d.type = d.type == onType ? offType : onType
  d.sel.select('text').text(d.type.str)
  update(0)
}, 3000)