const WIDTH = 800;
const HEIGHT = 600;

let instances;
const selectedInstances = [];
let xScale, yScale;
const parseTime = d3.timeParse("%B %e, %Y");
const formatTime = d3.timeFormat("%B %e, %Y");

const renderTable = () => {
	const trs = d3.select('tbody')
		.selectAll('tr')
		.data(instances.filter(d => d.highlighted), d => d.id)
		.enter()
		.append('tr')
		.selectAll('td')
		.data(d => [d.instance_id, d.course, d.graduation_date, d.total_students, d.dropped, d.graduates, d.ninety_day_outcomes])
		.enter()
		.append('td')
		.text(value => value)
}

const renderPoints = () => {
	const circles = d3.select('#points')
		.selectAll('circle')
		.data(instances, d => d.id)
		.enter()
		.append('circle');

	d3.selectAll('circle')
		.attr('cy', (datum, index) => {
			return yScale(datum.ninety_day_outcomes/datum.graduates*100);
		});

	d3.selectAll('circle')
		.attr('cx', (datum, index) => {
			return xScale(parseTime(datum.graduation_date));
		});

	d3.selectAll('circle')
		.classed('highlighted', (datum, index)=>{
			return datum.highlighted
		})

	d3.selectAll('circle').on('click', (event, datum) => {
		datum.highlighted = true;
		renderPoints()
		renderTable()
	});

}

const setupGraph = ()=>{
	d3.select('svg');
	d3.select('svg')
		.style('width', WIDTH)
		.style('height', HEIGHT);

	xScale = d3.scaleTime();
	xScale.range([0,WIDTH]);
	const xDomain = d3.extent(instances, (datum, index) => {
		return parseTime(datum.graduation_date);
	});
	xScale.domain(xDomain);

	yScale = d3.scaleLinear();
	yScale.range([HEIGHT, 0]);
	const yDomain = d3.extent(instances, (datum, index) => {
		return datum.ninety_day_outcomes/datum.graduates*100;
	})
	yScale.domain(yDomain);
}

const createAxes = () => {
	const bottomAxis = d3.axisBottom(xScale);
	d3.select('#container')
		.append('g')
		.attr('id', 'x-axis')
		.call(bottomAxis)
		.attr('transform', 'translate(0,'+HEIGHT+')');

	const leftAxis = d3.axisLeft(yScale);
	d3.select('#container')
		.append('g')
		.attr('id', 'y-axis')
		.call(leftAxis);
}

const createFormSubmissionHandler = () => {
	d3.select('form').on('submit', (event)=>{
		event.preventDefault();
		const instanceID = parseInt(d3.select('input[type="text"]').property('value'))
		const found = instances.find(i => i.instance_id === instanceID)
		found.highlighted = true;
		renderTable();
		renderPoints();
	});
}

window.onload = async ()=>{
	instances = await d3.json('/instances');
	instances.forEach(instance => instance.highlighted = false)
	setupGraph();
	createAxes();
	renderPoints();
	createFormSubmissionHandler();
}