ensl_gathers/lib/gather/gather.js

"use strict";

/*
 *	Implements Gather Model
 *
 *	Gather States
 *	- Gathering
 *	- Election (Electing leaders)
 *	- Selection (Selecting teams)
 *	- Done
 *
 */ 

var Gatherer = require("./gatherer");
var StateMachine = require("javascript-state-machine");

function Gather (options) {
	if (!(this instanceof Gather)) {
		return new Gather(options);
	}

	var noop = () => {};

	if (options && typeof options.onEvent === 'function') {
		this.onEvent = options.onEvent;
	} else {
		this.onEvent = noop;
	}

	if (options && typeof options.onDone === 'function') {
		this.onDone = options.onDone;
	} else {
		this.onDone = noop;
	}

	this.TEAM_SIZE = 6;
	this.gatherers = [];
	this.ELECTION_INTERVAL = 300000; // 5 mins
	this.electionStartTime = null;
	this.initState();
}

Gather.prototype.alienLeader = () => {
	return this.gatherers.reduce((acc, gatherer) => {
		if (gatherer.team === "alien" && gatherer.leader) acc.push(gatherer);
		return acc;
	}, []).pop();
};

Gather.prototype.marineLeader = () => {
	return this.gatherers.reduce((acc, gatherer) => {
		if (gatherer.team === "marine" && gatherer.leader) acc.push(gatherer);
		return acc;
	}, []).pop();
};

Gather.prototype.assignMarineLeader = id => {
	this.modifyGatherer({id: id}, gatherer => {
		gatherer.leader = true;
		gatherer.team = "marine";
	});
};

Gather.prototype.assignAlienLeader = id => {
	this.modifyGatherer({id: id}, gatherer => {
		gatherer.leader = true;
		gatherer.team = "alien";
	});
};

Gather.prototype.containsUser = user => {
	return this.gatherers.some(gatherer => {
		return gatherer.id === user.id;
	});
}; 

Gather.prototype.addUser = user => {
	if (this.containsUser(user)) {
		return null;
	}
	var gatherer = new Gatherer(user);
	this.gatherers.push(gatherer);
	return gatherer;
};

Gather.prototype.removeUser = user => {
	this.gatherers = this.gatherers.filter(gatherer => user.id !== gatherer.id);
};

Gather.prototype.modifyGatherer = (user, callback) => {
	this.gatherers.forEach(gatherer => {
		if (gatherer.id === user.id) callback(gatherer);
	});
}

Gather.prototype.moveToMarine = user => {
	if (this.marines().length >= this.TEAM_SIZE) return;
	this.modifyGatherer(user, gatherer => gatherer.team = "marine");
};

Gather.prototype.moveToAlien = user => {
	if (this.aliens().length >= this.TEAM_SIZE) return;
	this.modifyGatherer(user, gatherer => gatherer.team = "alien");
};

Gather.prototype.moveToLobby = user => {
	this.gatherers.forEach((gatherer, index, array) => {
		if (gatherer.id === user.id) {
			gatherer.team = "lobby";
			array[index] = gatherer;
		}
	});
};

Gather.prototype.retrieveGroup = team => {
	return this.gatherers.filter(gatherer => gatherer.team === team);
};

Gather.prototype.lobby = () => {
	return this.retrieveGroup("lobby");
};

Gather.prototype.aliens = () => {
	return this.retrieveGroup("alien");
};

Gather.prototype.marines = () => {
	return this.retrieveGroup("marine");
};

Gather.prototype.toJson = () => {
	return {
		gatherers: this.gatherers,
		state: this.current,
		election: {
			startTime: (this.electionStartTime === null) ? null : this.electionStartTime.toISOString(),
			interval: this.ELECTION_INTERVAL
		}
	}
};

Gather.prototype.voteForMap = (voter, mapId) => {
	this.gatherers.forEach((gatherer, index, array) => {
		if (gatherer.id === voter.id) {
			array[index].mapVote = mapId;
		}
	});
};

Gather.prototype.voteForServer = (voter, serverId) => {
	this.gatherers.forEach((gatherer, index, array) => {
		if (gatherer.id === voter.id) {
			array[index].serverVote = serverId;
		}
	});
};

// Returns an array of IDs representing votes for leaders
Gather.prototype.leaderVotes = () => {
	var self = this;
	return self.gatherers.map(gatherer => gatherer.leaderVote)
		.filter(leaderId => typeof leaderId === 'number')
		.filter(candidate => {
			return self.gatherers.some(gatherer => gatherer.id === candidate);
		});
};

Gather.prototype.voteForLeader = (voter, candidate) => {
	// Find voter and then assign their vote to candidate id
	this.gatherers.forEach((gatherer, index, array) => {
		if (gatherer.id === voter.id) {
			array[index].voteForLeader(candidate);
		}
	});
};

Gather.prototype.getGatherer = (user) => {
	var matchingGatherer = null;
	this.gatherers.forEach((gatherer) => {
		if (gatherer.id === user.id) matchingGatherer = gatherer;
	});
	return matchingGatherer;
};

// Gather States
// - Gathering
// - Election
// - Selection
// - Done

// gather.current - contains the current state
// gather.is(s) - return true if state s is the current state
// gather.can(e) - return true if event e can be fired in the current state
// gather.cannot(e) - return true if event e cannot be fired in the current state
// gather.transitions() - return list of events that are allowed from the current state

StateMachine.create({
	target: Gather.prototype,
	events: [
		{ name: "initState", from: "none", to: "gathering" },
		{ name: "addGatherer", from: "gathering", to: "election" },
		{ name: "selectLeader", from: "election", to: "selection" },
		{ name: "electionTimeout", from: "election", to: "selection" },
		{ name: "confirmSelection", from: "selection", to: "done" },
		{ name: "removeGatherer", from: ["gathering", "election", "selection"], to: "gathering" }
	],
	callbacks: {
		// Callbacks for events
		onafterevent: () => {
			this.onEvent.call(this);
		},

		// Gathering State
		onbeforeaddGatherer: (event, from, to, user) => {
			this.addUser(user);
			if (this.gatherers.length !== 12) {
				return false;
			}
		},

		// Election State
		onbeforeselectLeader: (event, from, to, voter, candidate) => {
			this.voteForLeader(voter, candidate);
			if (this.leaderVotes().length !== 12) {
				return false;
			}
		},

		onenterelection: () => {
			// Setup timer for elections
			var self = this;
			self.electionStartTime = new Date();
			setTimeout(() => {
				if (self.can("electionTimeout")) {
					self.electionTimeout();
				}
			}, self.ELECTION_INTERVAL);
		},

		onleaveelection: () => {
			this.electionStartTime = null;
		},

		// Selection State 
		onenterselection: () => {
			// Remove all leaders and teams
			this.gatherers.forEach(gatherer => {
				gatherer.leader = false;
				gatherer.team = "lobby";
			});

			// Assign leaders based on vote
			// 1st place alien comm
			// 2nd place marine comm
			var voteCount = {};
			this.gatherers.forEach(gatherer => { voteCount[gatherer.id] = 0 });
			this.leaderVotes().forEach(candidateId => { voteCount[candidateId]++ });
			var rank = [];
			for (var candidate in voteCount) {
				rank.push({ candidate: candidate, count: voteCount[candidate] });
			}
			rank.sort((a, b) => {
				return a.count - b.count;
			});
			this.assignAlienLeader(parseInt(rank.pop().candidate, 0));
			this.assignMarineLeader(parseInt(rank.pop().candidate, 0));
		},

		onbeforeconfirmSelection: (event, from, to, leader) => {
			return (this.aliens().length === this.TEAM_SIZE
							&& this.marines().length === this.TEAM_SIZE);
		},

		// Remove gatherer event
		onbeforeremoveGatherer: (event, from, to, user) => {
			// Cancel transition if no gatherers have been removed
			let userCount = this.gatherers.length;
			this.removeUser(user);
			return (userCount > this.gatherers.length);
		},

		// On enter done
		onenterdone: () => {
			this.onDone.call(this);
		}
	}
});

module.exports = Gather;