"use strict";

class Client {
	async start() {
		let self = this;
		terminal.setTitle("Emoji Push");
		terminal.setSendKeyEvents(true);
		self.send({action: "ready"});

		core.register("key", function(event) {
			if (event.type == "keydown") {
				switch (event.keyCode) {
					case 37:
						self.requestMove(-1, 0);
						break;
					case 38:
						self.requestMove(0, -1);
						break;
					case 39:
						self.requestMove(1, 0);
						break;
					case 40:
						self.requestMove(0, 1);
						break;
				}
			}
		});

		core.register("onMessage", function(sender, message) {
			if (message.action == "display") {
				terminal.cork();
				terminal.clear();
				terminal.print(message.board);
				terminal.uncork();
			}
		});
	}

	async send(message) {
		(await core.getService("server")).postMessage(message);
	}

	async requestMove(dx, dy) {
		await this.send({action: "move", delta: [dx, dy]});
	}
}

class Server {
	constructor() {
		this.rows = 17;
		this.columns = 17;
		this.players = {};
		this.objects = [];

		for (let i = 2; i < this.rows - 1; i += 2) {
			for (let j = 2; j < this.columns - 1; j += 2) {
				let block = new Entity();
				block.position = [j, i];
				block.symbol = '#';
				this.objects.push(block);
			}
		}
	}

	async start() {
		let self = this;
		core.register("onMessage", function(sender, message) {
			if (!self.players[sender.index]) {
				let player = new Entity();
				player.symbol = '@';
				player.position = self.findNewPlayerPosition();
				self.players[sender.index] = player;
				self.objects.push(player);
			}
			switch (message.action) {
				case "move":
					self.move(sender.index, message.delta);
					self.redisplay();
					break;
				case "ready":
					self.redisplay();
					break;
			}
		});
		core.register("onSessionEnd", function(session) {
			let player = self.players[session.index];
			if (player) {
				delete self.players[session.index];
				self.objects.splice(self.objects.indexOf(player), 1);
				self.redisplay();
			}
		});
	}

	occupied(position) {
		let board = this.getBoard();

		if (position[0] < 0 || position[1] < 0 || position[1] >= board.length || position[0] >= board[position[1]].length) {
			return true;
		}

		if (board[position[1]].charAt(position[0]) != ' ') {
			return true;
		}

		if (this.objects.some(x => position[0] == x.position[0] && position[1] == x.position[1])) {
			return true;
		}
	}

	move(index, delta) {
		let newPosition = [
			this.players[index].position[0] + delta[0],
			this.players[index].position[1] + delta[1],
		];
		if (!this.occupied(newPosition)) {
			this.players[index].position = newPosition;
		}
	}

	findNewPlayerPosition() {
		let best = null;
		let bestDistance = -1;
		let players = Object.values(this.players);

		for (let i = 0; i < this.rows; i++) {
			for (let j = 0; j < this.columns; j++) {
				if (!this.occupied([j, i])) {
					let distance = Math.min.apply(null, players.map(x => Math.sqrt(
						(x.position[0] - j) * (x.position[0] - j)
						+ (x.position[1] - i) * (x.position[1] - i))));
					if (distance > bestDistance) {
						best = [j, i];
						bestDistance = distance;
					}
				}
			}
		}

		return best;
	}

	redisplay() {
		let board;
		try {
			board = this.getBoardString();
		} catch (error) {
			board = error;
		}
		core.broadcast({action: "display", board: board});
	}

	getBoard() {
		let board = [];
		for (let i = 0; i < this.rows; i++) {
			let row = "";
			for (let j = 0; j < this.columns; j++) {
				if (i == 0 && j == 0) {
					row += '┌';
				} else if (i == 0 && j == this.columns - 1) {
					row += '┐';
				} else if (i == this.rows - 1 && j == 0) {
					row += '└';
				} else if (i == this.rows - 1 && j == this.columns - 1) {
					row += '┘';
				} else if (i == 0 || i == this.rows - 1) {
					row += '─';
				} else if (j == 0 || j == this.columns - 1) {
					row += '│';
				} else {
					row += ' ';
				}
			}
			board.push(row);
		}
		for (let object of this.objects) {
			board[object.position[1]] = board[object.position[1]].slice(0, object.position[0]) + object.symbol + board[object.position[1]].slice(object.position[0] + 1);
		}
		return board;
	}

	getBoardString() {
		let board = this.getBoard();
		let colors = board.map(x => x.split("").map(y => '#fff'));
		return board.map((r, row) => r.split("").map((v, column) => ({style: "color: " + colors[row][column], value: v})).concat(["\n"]));
	}
}

class Entity {
	constructor() {
		this.position = [0, 0];
		this.symbol = '?';
		this.color = '#fff';
	}
}

if (imports.terminal) {
	new Client().start().catch(terminal.print);
} else {
	new Server().start().catch(print);
}