var chartColors = {
	red: 'rgb(255, 99, 132)',
	orange: 'rgb(255, 159, 64)',
	yellow: 'rgb(255, 205, 86)',
	green: 'rgb(75, 192, 192)',
	blue: 'rgb(54, 162, 235)',
	purple: 'rgb(153, 102, 255)',
	grey: 'rgb(201, 203, 207)'
};

function randomScalingFactor() {
	return Math.round(Math.random() * 100);
}

var color = Chart.helpers.color;
var config = {
	type: 'polarArea',
	data: {
		labels: ['Red', 'Orange', 'Yellow', 'Green', 'Blue'],
		datasets: [{
			data: [0, 0, 0, 0, 0].map(function() {
				return randomScalingFactor();
			}),
			backgroundColor: [
				window.chartColors.red,
				window.chartColors.orange,
				window.chartColors.yellow,
				window.chartColors.green,
				window.chartColors.blue
			],
			borderColor: [
				window.chartColors.red,
				window.chartColors.orange,
				window.chartColors.yellow,
				window.chartColors.green,
				window.chartColors.blue
			]
		}]
	},
	plugins: [ChartRough],
	options: {
		title: {
			display: true,
			text: 'Polar area chart sample'
		},
		scale: {
			ticks: {
				beginAtZero: true,
				showLabelBackdrop: false
			}
		},
		animation: {
			animateScale: true,
			animateRotate: true
		}
	}
};

Chart.defaults.global.defaultFontFamily = '"Indie Flower", cursive';
Chart.defaults.global.defaultFontSize = 14;

window.onload = function() {
	var ctx = document.getElementById('myChart').getContext('2d');
	window.myChart = new Chart(ctx, config);
};

document.getElementById('randomizeData').addEventListener('click', function() {
	config.data.datasets.forEach(function(dataset) {
		dataset.data = dataset.data.map(function() {
			return randomScalingFactor();
		});
	});
	window.myChart.update();
});

var colorNames = Object.keys(chartColors);
document.getElementById('addDataset').addEventListener('click', function() {
	var colorName = colorNames[config.data.datasets.length % colorNames.length];
	var newColor = chartColors[colorName];
	var newDataset = {
		data: [],
		backgroundColor: [],
		borderColor: []
	};

	for (var index = 0; index < config.data.labels.length; ++index) {
		newDataset.data.push(randomScalingFactor());

		var colorName = colorNames[index % colorNames.length];
		var newColor = window.chartColors[colorName];
		newDataset.backgroundColor.push(newColor);
		newDataset.borderColor.push(newColor);
	}

	config.data.datasets.push(newDataset);
	window.myChart.update();
});

document.getElementById('removeDataset').addEventListener('click', function() {
	config.data.datasets.pop();
	window.myChart.update();
});

document.getElementById('addData').addEventListener('click', function() {
	if (config.data.datasets.length > 0) {
		var colorName = colorNames[config.data.datasets[0].data.length % colorNames.length];
		var newColor = window.chartColors[colorName];

		config.data.labels.push(colorName.charAt(0).toUpperCase() + colorName.slice(1));

		config.data.datasets.forEach(function(dataset) {
			dataset.data.push(randomScalingFactor());
			dataset.backgroundColor.push(newColor);
			dataset.borderColor.push(newColor);
		});

		window.myChart.update();
	}
});

document.getElementById('removeData').addEventListener('click', function() {
	config.data.labels.splice(-1, 1); // remove the label first

	config.data.datasets.forEach(function(dataset) {
		dataset.data.pop();
		dataset.backgroundColor.pop();
		dataset.borderColor.pop();
	});

	window.myChart.update();
});