var parseTime = d3.timeParse('%a %b %d %H:%M:%S +0000 %Y');
var formatTime = d3.timeFormat('%Y-%m-%d');
var parseFormattedTime = d3.timeParse('%Y-%m-%d');

var lineChart = function(data){
  // set the dimensions and margins of the graph
  var margin = {top: 20, right: 20, bottom: 60, left: 50},
      width = 606 - margin.left - margin.right,
      height = 181 - margin.top - margin.bottom;
  
  // NEST
  var nestedData = d3.nest()
  .key(function(d) { return formatTime(parseTime(d.created_at)); })
  .sortKeys(d3.ascending)
  .rollup(function(values) { return values.length; })
  .entries(data);
  
  console.log(nestedData);
  
  // set the ranges
  var xScale = d3.scaleTime().range([0, width]);
  var yScale = d3.scaleLinear().range([height, 0]);

  // define the line
  var line = d3.line()
   .x(function(d) { return xScale(parseFormattedTime(d.key)); })
   .y(function(d) { return yScale(d.value); });

  //add a new svg to hold the chart
  var svg = d3.select("body").append("svg")
   .attr("width", width + margin.left + margin.right)
   .attr("height", height + margin.top + margin.bottom)
   .append("g")
   .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

  // Scale the range of the data
  xScale.domain(d3.extent(nestedData, function(d) { return parseFormattedTime(d.key); }));
  yScale.domain(d3.extent(nestedData, function(d) { return d.value; }));
  
  // Add the X Axis
  svg.append("g")
  	.attr('class', 'axis x')
    .attr("transform", "translate(0," + 0 + ")")
    .call(d3.axisBottom(xScale).tickSize(height));

  // Add the Y Axis
  svg.append("g")
  	.attr('class', 'axis y')
    .attr("transform", "translate(" + width +",0)")
    .call(d3.axisLeft(yScale).ticks(3).tickSize(width));
 
  // Add the line path
  svg.selectAll("path.tweetline")
    .data([nestedData])
  	.enter().append('path')
    .attr("class", "tweetline")
    .attr("d", line);
  
  var annotation = svg.append('g')
  	.attr('class', 'annotation')
    .attr('transform', 'translate(' + xScale(parseFormattedTime('2017-01-20')) +', 0)');
  
  annotation.append('line')
    .attr('x1', 0)
    .attr('y1', 0)
    .attr('x2', 0)
    .attr('y2', height)
  
  annotation.append('text')
    .text('LABEL TEXT')
  	.attr('text-anchor', 'end')
    .attr('dx', -5)
    .attr('dy', 10)
};