// SARS-CoV-2-Viz
// Animated COVID case count visualization
// Copyright 2022 Edward L. Platt <ed@elplatt.com>

function UI() {

    let frames = [];
    let currentFrame = 0;
    let msPerFrame = 500;
    let playing = false;
    let onTick = null;

    let animate = function () {
	if (playing) {
	    setTimeout(animate, msPerFrame);
	}
	if (onTick) {
	    onTick(currentFrame);
	}
	currentFrame = (currentFrame + 7) % frames.length;
    };
    
    let node = document.createElement("div");
    
    let controls = document.createElement("div");
    controls.classList.add("hidden");
    node.appendChild(controls);
   
    let play = document.createElement("button");
    play.innerText = 'play';
    play.id = 'play';
    controls.appendChild(play);
    play.addEventListener(
	"click", () => {
	    if (playing) {
		play.innerText = 'play';
		playing = false;
	    } else {
		play.innerText = 'pause';
		playing = true;
		animate();
	    }
	});

    let display = document.createElement("div");
    display.id = "display";
    let mainDisplay = document.createElement("div");
    mainDisplay.id = "main-display";
    let secondaryDisplays = {};
    display.appendChild(mainDisplay);
    node.appendChild(display);

    return {
	node: node,
	display: (s, id=null) => {
	    if (id === null) {
		mainDisplay.innerText = s;
	    } else {
		secondaryDisplays[id].innerText = s;
	    }
	},
	addDisplay: (id) => {
	    let secondary = document.createElement("div");
	    secondary.id = `display-${id}`;
	    display.appendChild(secondary);
	    secondaryDisplays[id] = secondary;
	},
	showControls: (show=true) => {
	    if (show) {
		controls.classList.remove("hidden");
	    } else {
		controls.classList.add("hidden");
	    }
	},
	clearDisplays: () => {
	    mainDisplay.innerText = '';
	    for (const [id, d] of Object.entries(secondaryDisplays)) {
		d.remove();
	    }
	    secondaryDisplays = {};
	},
	onTick: (f) => { onTick = f; },
	setFrames: (newFrames, current) => {
	    frames = newFrames;
	    currentFrame = current;
	},
	setMsPerFrame: (newMsPerFrame) => { msPerFrame = newMsPerFrame; }
    }
}