LOL LMAO ROFL XD XD XP XP XP

doc/API.md

@@ -45,6 +45,10 @@
       - [server.playNoteBlock(world, position, pitch)](#serverplaynoteblockworld-position-pitch)
       - [server.getNote(note)](#servergetnotenote)
       - [server.emitParticle(particle, world, position, opt)](#serveremitparticleparticle-world-position-opt)
+      - [serv.getXpLevel(xp)](#servgetxplevelxp)
+      - [serv.getXpRequired(level, toLevel=level+1)](#servgetxprequiredlevel-tolevellevel1)
+      - [serv.getBaseXpFromLevel(level)](#servgetbasexpfromlevellevel)
+      - [serv.distanceToXpLevel(xp, toLevel=startLevel+1, startLevel=xp level)](#servdistancetoxplevelxp-tolevelstartlevel1-startlevelxp-level)
     - [Low level methods](#low-level-methods)
       - [server._writeAll(packetName, packetFields)](#server_writeallpacketname-packetfields)
       - [server._writeArray(packetName, packetFields, playerArray)](#server_writearraypacketname-packetfields-playerarray)
@@ -92,6 +96,9 @@
     - [Properties](#properties-2)
       - [player.username](#playerusername)
       - [player.view](#playerview)
+      - [player.xp](#playerxp)
+      - [player.displayXp](#playerdisplayxp)
+      - [player.xpLevel](#playerxplevel)
     - [Events](#events-2)
       - ["connected"](#connected)
       - ["spawned"](#spawned)
@@ -132,6 +139,10 @@
       - [player.spawnAPlayer(spawnedPlayer)](#playerspawnaplayerspawnedplayer)
       - [player.updateAndSpawnNearbyPlayers()](#playerupdateandspawnnearbyplayers)
       - [player.playSound(sound, opt)](#playerplaysoundsound-opt)
+      - [player.setXp(xp, opt)](#playersetxpxp-opt)
+      - [player.sendXp()](#playersendxp)
+      - [player.setXpLevel(level)](#playersetxplevellevel)
+      - [player.setDisplayXp(num)](#playersetdisplayxpnum)
     - [Low level properties](#low-level-properties)
       - [player._client](#player_client)
     - [Low level methods](#low-level-methods-1)
@@ -353,6 +364,28 @@ Opt:
 - size: vec3 of the size. (0,0,0) will be at an exact position, (10,10,10) will be very spread out (particles less dense)
 - count: Number of particles. 100,000,000+ will crash the client. Try not to go over 100,000 (sincerely, minecraft clients)
 
+#### serv.getXpLevel(xp)
+
+Get level given XP amount
+
+#### serv.getXpRequired(level, toLevel=level+1)
+
+Get's the amount of xp required to get from level to toLevel (or level to level+1)
+
+#### serv.getBaseXpFromLevel(level)
+
+Gets the minimum amount of xp required to be at that level (or "base xp" for that level)
+
+#### serv.distanceToXpLevel(xp, toLevel=startLevel+1, startLevel=xp level)
+
+Gets a number between 0 and 1 (used in player.displayXp as the green bar at the bottom) that is the progress of xp between startLevel and toLevel.
+
+By default, startLevel will be the xp's lowest possible level: serv.getXpLevel(xp)
+
+By default, toLevel is startLevel + 1.
+
+This means when startLevel and toLevel are at their defaults, this function returns the progress to the next level of XP (from 0.0 to 1.0)
+
 ### Low level methods
 
 #### server._writeAll(packetName, packetFields)
@@ -605,6 +638,18 @@ The username of the player
 
 The view size of the player, for example 8 for 16x16
 
+#### player.xp
+
+Total experience the player has (int). Set this using player.setXp()
+
+#### player.displayXp
+
+Number from 0 to 1.0 representing the progress bar at the bottom of the player's screen. Set this with player.setDisplayXp()
+
+#### player.xpLevel
+
+Level of xp the player has. Set this with player.setXpLevel()
+
 ### Events
 
 #### "connected" 
@@ -876,6 +921,25 @@ Spawn and despawn the correct players depending on distance for `player`.
 
 Easy way to only play a sound for one player. Same opt as serv.playSound except no `whitelist`.
 
+#### player.setXp(xp, opt)
+
+Sets the player's XP level. Options:
+- setLevel: Calculate and set player.level (default: true)
+- setDisplay: Calculate and set player.displayXp (default: true)
+- send: Send xp packet (default: true)
+
+#### player.sendXp()
+
+Updates the player's xp based on player.xp, player.displayXp, and player.xpLevel
+
+#### player.setXpLevel(level)
+
+Sets and sends the player's new level
+
+#### player.setDisplayXp(num)
+
+Sets and sends the palyer's new display amount. num should be from 0 to 1.0
+
 ### Low level properties
 
 #### player._client

src/lib/plugins/experience.js

@@ -0,0 +1,106 @@
+module.exports.player = function(player, serv) {
+  player.xp = 0;
+  player.displayXp = 0;
+  player.xpLevel = 0;
+
+  player.sendXp = () => {
+    player._client.write('experience', {
+      experienceBar: player.displayXp,
+      level: player.level,
+      totalExperience: player.xp
+    });
+  }
+
+  player.setXpLevel = (level) => {
+    player.xpLevel = level;
+    player.sendXp();
+  }
+
+  player.setDisplayXp = (num) => {
+    player.displayXp = Math.max(0, Math.min(1, player.displayXp));
+    player.sendXp();
+  }
+
+  player.setXp = (xp, { setLevel=true, setDisplay=true, send=true }={}) => {
+    player.xp = xp;
+    if (setLevel) player.level = serv.getXpLevel(xp);
+    if (setDisplay) player.displayXp = serv.distanceToXpLevel(xp);
+    if (send) player.sendXp();
+  }
+
+  player.commands.add({
+    base: 'xp',
+    info: 'Give yourself experience',
+    usage: '/xp <amount> [player] OR /xp <amount>L [player]',
+    op: true,
+    parse(str) {
+      return str.match(/(-?\d+)(L)? ?([a-zA-Z0-9_]+)?/) || false;
+    },
+    action(args) {
+      var isLevel = !!args[2];
+      var amt = parseInt(args[1]);
+      var user = args[3] ? serv.getPlayer(args[3]) : player;
+      if (!user) return args[3] + ' is not on this server!';
+
+      if (!isLevel) {
+        user.setXp(user.xp + amt);
+        player.chat('Gave ' + user.username + ' ' + amt + ' xp');
+      } else {
+        var currLevel = serv.getXpLevel(player.xp);
+        var baseCurrLevel = serv.getBaseXpFromLevel(currLevel);
+        var extraXp = player.xp - baseCurrLevel;
+        user.setXp(serv.getBaseXpFromLevel(currLevel + amt) + extraXp);
+        player.chat('Gave ' + user.username + ' ' + amt + ' levels');
+      }
+    }
+  });
+}
+
+module.exports.server = function(serv) {
+  serv.distanceToXpLevel = (xp, toLevel) => {
+    var level = serv.getXpLevel(xp);
+    if (!toLevel) toLevel = level+1;
+    var levelBaseXp = serv.getBaseXpFromLevel(level);
+    var requiredXp = serv.getXpRequired(level, toLevel);
+    return (xp - levelBaseXp) / requiredXp;
+  }
+
+  serv.getXpLevel = (xp) => {
+    // I have to use quadratic equation to reverse the equation from serv.getBaseXpFromLevel(). Ugh.
+    var a;
+    var b;
+    var c;
+    if (xp < 352) { // 352 == Experience at level 16
+      a = 1;
+      b = 6;
+      c = 0;
+    } else if (xp < 1507) { // 1507 == Experience at level 31
+      a = 2.5;
+      b = -40.5;
+      c = 360;
+    } else { // Level 32+
+      a = 4.5;
+      b = -162.5;
+      c = 2220;
+    }
+    c -= xp;
+    return Math.floor((-b + Math.sqrt(b*b - 4*a*c)) / (2 * a)); // Math class was useful I guess mmph
+  }
+
+  serv.getXpRequired = (level, toLevel) => {
+    if (!toLevel) toLevel = level + 1;
+    return serv.getBaseXpFromLevel(toLevel) - serv.getBaseXpFromLevel(level);
+  }
+
+  serv.getBaseXpFromLevel = (level) => {
+    // The equations in this function are stupid and directly from the MC Wiki
+    // http://minecraft.gamepedia.com/Experience#Leveling_up
+    if (level <= 16) {
+      return level*level + 6*level;
+    } else if (level <= 31) {
+      return 2.5*level*level - 40.5*level + 360;
+    } else { // 32+
+      return 4.5*level*level - 162.5*level + 2220;
+    }
+  }
+}