Very simple, dumb AI for code challenge

tank_ai.js

var api = require('./API.js');

/**
 * http://honeypot.softwareskills.se/#/contest/5587cf988a4c5edb08ffa049
 * 
 * Executes a single step of the tank's programming. The tank can only move,
 * turn, or fire its cannon once per turn. Between each update, the tank's
 * engine remains running and consumes 1 fuel. This function will be called
 * repeatedly until there are no more targets left on the grid, or the tank runs
 * out of fuel.
 */
var currentPlan;
var visited = [];
var knownInfo = {};
var orientations = ['north', 'east', 'south', 'west'];
var currentOrientation = 2;
var currentPosition = {
    x: 0,
    y: 0
};

function buildMap(distances) {
    // Based on current info and knowledge about the distance to things build
    // a map.
}

function planMovementsBasedOnLidar() {
    // We have no objective right now so
    // build a plan based off of Lidar data
    var distances = {
        front: api.lidarFront(),
        back: api.lidarBack(),
        left: api.lidarLeft(),
        right: api.lidarRight()
    };

    var movements;

    var thisPlan = [];

    // Turn in the longest direction
    if (distances.front > 1) {
        movements = distances.front;
    }
    else if (distances.right > 1) {
        thisPlan.push('turnRight');
        move = distances.right;
    }
    else if (distances.left > 1) {
        thisPlan.push('turnLeft');
        move = distances.left;
    }
    else {
        // We want to head back behind us, so turn twice
        thisPlan.push('turnRight');
        thisPlan.push('turnRight');
        move = distances.back;
    }

    for (var i = 0; i < movements - 1; i++) {
        thisPlan.push('moveForward');
        //thisPlan.push('seek');
    }

    return thisPlan;
}

exports.update = function() {
    if (!currentPlan || currentPlan.length === 0) {
        currentPlan = planMovementsBasedOnLidar();
    }
    else {
        // Check for immeadiate targets that we should shoot as this
        // always takes precedence over any movement plan.
        if (api.identifyTarget()) {
            // Cancel all plans, fire cannon then turn and recalc plans
            api.fireCannon();
            currentPlan = ['turnRight'];
        }
        else {
            // Just execute on the movement plan
            var action = currentPlan.shift();

            console.log('Currently at (' +
                currentPosition.x + ',' +
                currentPosition.y + ') facing ' +
                orientations[currentOrientation]);

            if (action == 'turnRight') {
                currentOrientation++;
                if (currentOrientation > 3) {
                    currentOrientation = 0;
                }
            }
            else if (action == 'turnRight') {
                currentOrientation--;
                if (currentOrientation < 0) {
                    currentOrientation = 3;
                }
            }
            else if (action == 'moveForward') {
                if (orientations[currentOrientation] == 'north') {
                    currentPosition.y++;
                }
                else if (orientations[currentOrientation] == 'south') {
                    currentPosition.y--;
                }
                else if (orientations[currentOrientation] == 'west') {
                    currentPosition.x--;
                }
                else if (orientations[currentOrientation] == 'east') {
                    currentPosition.x++;
                }
                visited.push(currentPosition.x+'_'+currentPosition.y);
            }

            console.log('Executing ' + action);

            api[action]();
        }
    }
};