brain.js

   1 "use strict";
   2
   3 function randrange (lo, hi) {
   4     return lo + (Math.random() * (hi - lo)) | 0;
   5 }
   6
   7 function shuffle (seq) {
   8     for (var i = seq.length - 1; i > 0; --i) {
   9         var index = randrange(0, i + 1);
  10         var temp = seq[i];
  11         seq[i] = seq[index];
  12         seq[index] = temp;
  13     }
  14     return seq;
  15 }
  16
  17 var MOVEMENT = ["fore", "fore", "fore", "fore", "fore",
  18                 "left", "left", "left",
  19                 "right", "right", "right",
  20                 null];
  21 var RAMMING = ["none", "none", "fore", "fore", "aft"];
  22 var ORDER = ["nearest", "nearest", "nearest",
  23              "threat", "strongest", "farthest"];
  24 var BREAKER = ["clockwise", "clockwise",
  25                "anti-clockwise", "anti-clockwise"];
  26 var ARC = ["fore", "fore", "fore", "aft"];
  27
  28 var FIRING = ["spread fire, engage 1-1",
  29               "spread fire, engage 1-1",
  30               "spread fire, engage 1-1",
  31               "focus fire, engage 2-1",
  32               "focus fire, engage 2-1",
  33               "concentrate all fire"];
  34 var MISSILES = [0.20, 0.10, 0.05];
  35
  36 function drop1 (seq) {
  37     return shuffle(seq.slice()).slice(1);
  38 }
  39
  40 function Brain () {
  41     var movement = drop1(MOVEMENT);
  42     var ramming = drop1(RAMMING);
  43     var order = drop1(ORDER);
  44     var breaker = drop1(BREAKER);
  45     var arc = drop1(ARC);
  46     var firing = drop1(FIRING);
  47     var missiles = choice(MISSILES)
  48
  49     this.report = function (movePoints, hasMissiles) {
  50         var ram = movePoints > 1 ? choice(ramming) : null;
  51         var move = [];
  52         for (var i = 0; i < movePoints; ++i) {
  53             do {
  54                 var m = choice(movement);
  55             } while ((m === "left" && move.indexOf("right") >= 0)
  56                      || (m === "right" && move.indexOf("left") >= 0))
  57             if (m)
  58                 move.push(m);
  59         }
  60
  61         var launch = 0;
  62         while (hasMissiles && Math.random() < Math.pow(missiles, launch + 1))
  63             ++launch;
  64
  65         var instr = [];
  66         instr.push("sensors sweeping " + choice(breaker));
  67         if (ram === "aft")
  68             instr.push("ram back if opportune");
  69         instr.push((ram === "aft" ? "otherwise " : "")
  70                    + "ahead " + move.join(", "));
  71         if (ram)
  72             instr.push("  ramming if opportune");
  73         instr.push("target " + choice(order) + ", "
  74                    + choice(arc) + " first");
  75         instr.push("  " + choice(firing));
  76         if (hasMissiles)
  77             instr.push("launch missiles at howitzers and key targets");
  78         if (launch) {
  79             instr.push("  further expend up to " + launch + " missile(s)");
  80             instr.push("    on the " + choice(order) + " vehicle target(s)");
  81         }
  82
  83         return instr.join("\n");
  84     }
  85     return this;
  86 }
  87
  88 var brain, ttl;
  89 function think () {
  90     if (!(brain && ttl-- > 0)) {
  91         brain = new Brain();
  92         ttl = Math.max(1, choice([2, 10, 18]) + randrange(-2, 3));
  93     }
  94     document.getElementById('report').textContent =
  95         brain.report(3, true, true).replace(/\w\S*/g, function (s) {
  96             return ["and", "of", "if", "at"].indexOf(s) < 0
  97                 ? s[0].toUpperCase() + s.slice(1)
  98                 : s;
  99         });
 100 }