"use strict";

//! {"require": ["libiframe"]}

let isClient = imports.terminal != null;
if (isClient) {
	require("libiframe").iframe({
		source: `
			document.documentElement.setAttribute("style", "width: 100%; height: 100%; margin: 0; padding: 0");
			document.body.setAttribute("style", "display: flex; flex-direction: column; height: 100%; width: 100%; margin: 0; padding: 0");
			document.body.style.color = '#fff';
			document.body.style.backgroundColor = '#000';

			var canvas = document.createElement("canvas");
			canvas.setAttribute("style", "flex: 1 1; image-rendering: pixelated");
			canvas.width = 128;
			canvas.height = 128;
			document.body.append(canvas);

			var buttonBar = document.createElement("div");
			buttonBar.setAttribute("style", "flex: 0 1 1in; display: flex; flex-direction: row");
			var buttons = ["<", "^", "v", ">", "Fire!"];
			for (var i = 0; i < buttons.length; i++) {
				var button = document.createElement("input");
				button.setAttribute("type", "button");
				button.setAttribute("style", "flex: 1 1");
				button.value = buttons[i];
				button.onclick = buttonClicked.bind(null, buttons[i]);
				buttonBar.append(button);
			}
			document.body.append(buttonBar);

			var buttonCallback;
			function buttonClicked(button) {
				if (buttonCallback) {
					buttonCallback(button);
				}
			}

			var kExportNames = [
				"beginPath",
				"fill",
				"save",
				"restore",
				"scale",
				"rotate",
				"translate",
				"transform",
				"arc",
				"moveTo",
				"lineTo",
				"fillRect",
				"fillText",
				"stroke",
			];
			var context = canvas.getContext("2d");
			var exports = {};
			for (var i = 0; i < kExportNames.length; i++) {
				exports[kExportNames[i]] = context[kExportNames[i]].bind(context);
			}
			exports.setButtonCallback = function(callback) { buttonCallback = callback; };
			exports.setFillStyle = function(style) { context.fillStyle = style; };
			exports.setStrokeStyle = function(style) { context.strokeStyle = style; };
			exports.setLineWidth = function(width) { context.lineWidth = width; };
			rpc.export(exports);
			`,
		style: `
			border: 0;
	`}).then(initialize).catch(terminal.print);

	function initialize(iframe) {
		iframe.setButtonCallback(click);
		draw(iframe);
		core.register("onMessage", onMessage.bind(null, iframe));
		core.getService("server").then(function(server) {
			server.postMessage({ready: true});
		});
	}

	async function click(button) {
		(await core.getService("server")).postMessage({button: button});
	}

	function draw(iframe) {
		iframe.setFillStyle('#222');
		iframe.fillRect(0, 0, 640, 480);
	}

	function drawTank(iframe, x, y, color, angle) {
		iframe.save();
		iframe.setLineWidth(1);
		iframe.setFillStyle(color);
		iframe.setStrokeStyle(color);
		iframe.translate(x, y);
		iframe.beginPath();
		iframe.arc(0, 0, 4, Math.PI, 2 * Math.PI);
		iframe.fill();
		iframe.beginPath();
		var radians = Math.PI + angle * Math.PI / 180.0;
		iframe.moveTo(Math.cos(radians) * 2, Math.sin(radians) * 2 - 0.5);
		iframe.lineTo(Math.cos(radians) * 10, Math.sin(radians) * 10 - 0.5);
		iframe.stroke();
		iframe.restore();
	}

	function onMessage(iframe, sender, message) {
		iframe.setFillStyle('#222');
		iframe.fillRect(0, 0, 640, 480);

		for (let i = 0; i < message.users.length; i++) {
			var tank = message.users[i];
			drawTank(iframe, tank.position.x, tank.position.y, tank.user == core.user.index ? '#f00' : '#0f0', tank.angle);
		}
		iframe.setFillStyle('#0f0');
		for (let i = 0; i < message.terrain.length; i++) {
			let h = message.terrain[i];
			iframe.fillRect(i, 128 - h, i + 1, h);
		}
	}
} else {
	let users = {};
	let terrain = new Array(128);
	let updating = false;

	function startUpdating() {
		if (!updating) {
			setTimeout(100, update);
			updating = true;
		}
	}

	function update() {
		updating = false;
		for (let u of Object.values(users)) {
			user.position.y++;
			updating = true;
		}
		broadcastUsers();
		if (updating) {
			setTimeout(100, update);
		}
	}

	function initializeTerrain() {
		for (let i = 0; i < terrain.length; i++) {
			terrain[i] = 32;
		}
	}

	function broadcastUsers() {
		core.broadcast({
			users: Object.keys(users).map(x => ({user: x, position: users[x].position, angle: users[x].angle})),
			terrain: terrain,
		});
	}

	function placeNewUser() {
		let positions = Object.keys(users).map(x => users[x].position.x);
		var best = 128 / 2;
		var bestDistance = -1;
		if (positions.length) {
			for (var i = 10; i < 118; i++) {
				var thisDistance = Math.min.apply(null, positions.map(x => Math.abs(i - x)));
				if (thisDistance > bestDistance) {
					bestDistance = thisDistance;
					best = i;
				}
			}
		}
		return {x: best, y: 10, d: bestDistance};
	}

	initializeTerrain();

	core.register("onMessage", function(sender, message) {
		if (message.ready) {
			users[sender.index] = {
				user: sender,
				angle: 0,
				velocity: 100,
				position: placeNewUser(),
			};
			broadcastUsers();
			startUpdating();
		} else if (message.button) {
			switch (message.button) {
				case "<":
					users[sender.index].angle = Math.round(Math.max(users[sender.index].angle - 5.0, 0.0));
					break;
				case ">":
					users[sender.index].angle = Math.round(Math.min(users[sender.index].angle + 5.0, 180.0));
					break;
				case "^":
					users[sender.index].velocity++;
					break;
				case "v":
					users[sender.index].velocity--;
					break;
			}
			broadcastUsers();
		}
	});

	core.register("onSessionEnd", function(user) {
		delete users[user.index];
		broadcastUsers();
	});
}