diff --git a/common/GameCommon.js b/common/GameCommon.js
new file mode 100644
index 0000000..0e886df
--- /dev/null
+++ b/common/GameCommon.js
@@ -0,0 +1,412 @@
+import Geometry from './Geometry.js'
+
+const GAMES = {}
+
+function exists(gameId) {
+  return (!!GAMES[gameId]) || false
+}
+
+function setGame(gameId, game) {
+  GAMES[gameId] = game
+}
+
+function addPlayer(gameId, playerId) {
+  GAMES[gameId].players[playerId] = {
+    id: playerId,
+    x: 0,
+    y: 0,
+    down: false
+  }
+  GAMES[gameId].evtInfos[playerId] = {
+    _last_mouse: null,
+    _last_mouse_down: null,
+  }
+}
+
+function addSocket(gameId, socket) {
+  const sockets = GAMES[gameId].sockets
+
+  if (!sockets.includes(socket)) {
+    sockets.push(socket)
+  }
+}
+
+function get(gameId) {
+  return GAMES[gameId]
+}
+
+function getSockets(gameId) {
+  return GAMES[gameId].sockets
+}
+
+function changePlayer(gameId, playerId, change) {
+  for (let k of Object.keys(change)) {
+    GAMES[gameId].players[playerId][k] = change[k]
+  }
+}
+
+function changeData(gameId, change) {
+  for (let k of Object.keys(change)) {
+    GAMES[gameId].puzzle.data[k] = change[k]
+  }
+}
+
+function changeTile(gameId, tileIdx, change) {
+  for (let k of Object.keys(change)) {
+    GAMES[gameId].puzzle.tiles[tileIdx][k] = change[k]
+  }
+}
+
+const getTile = (gameId, tileIdx) => {
+  return GAMES[gameId].puzzle.tiles[tileIdx]
+}
+
+const getTileGroup = (gameId, tileIdx) => {
+  const tile = getTile(gameId, tileIdx)
+  return tile.group
+}
+
+const getFinalTilePos = (gameId, tileIdx) => {
+  const info = GAMES[gameId].puzzle.info
+  const boardPos = {
+    x: (info.table.width - info.width) / 2,
+    y: (info.table.height - info.height) / 2
+  }
+  const srcPos = srcPosByTileIdx(gameId, tileIdx)
+  return Geometry.pointAdd(boardPos, srcPos)
+}
+
+const getTilePos = (gameId, tileIdx) => {
+  const tile = getTile(gameId, tileIdx)
+  return tile.pos
+}
+
+const getTileZIndex = (gameId, tileIdx) => {
+  const tile = getTile(gameId, tileIdx)
+  return tile.z
+}
+
+const getFirstOwnedTileIdx = (gameId, userId) => {
+  for (let t of GAMES[gameId].puzzle.tiles) {
+    if (t.owner === userId) {
+      return t.idx
+    }
+  }
+  return -1
+}
+
+const getMaxGroup = (gameId) => {
+  return GAMES[gameId].puzzle.data.maxGroup
+}
+
+const getMaxZIndex = (gameId) => {
+  return GAMES[gameId].puzzle.data.maxZ
+}
+
+const getMaxZIndexByTileIdxs = (gameId, tileIdxs) => {
+  let maxZ = 0
+  for (let tileIdx of tileIdxs) {
+    let tileZIndex = getTileZIndex(gameId, tileIdx)
+    if (tileZIndex > maxZ) {
+      maxZ = tileZIndex
+    }
+  }
+  return maxZ
+}
+
+function srcPosByTileIdx(gameId, tileIdx) {
+  const info = GAMES[gameId].puzzle.info
+
+  const c = info.coords[tileIdx]
+  const cx = c.x * info.tileSize
+  const cy = c.y * info.tileSize
+
+  return { x: cx, y: cy }
+}
+
+function getSurroundingTilesByIdx(gameId, tileIdx) {
+  const info = GAMES[gameId].puzzle.info
+
+  const _X = info.coords[tileIdx].x
+  const _Y = info.coords[tileIdx].y
+
+  return [
+    // top
+    (_Y > 0) ?               (tileIdx - info.tilesX) : -1,
+    // right
+    (_X < info.tilesX - 1) ? (tileIdx + 1)           : -1,
+    // bottom
+    (_Y < info.tilesY - 1) ? (tileIdx + info.tilesX) : -1,
+    // left
+    (_X > 0) ?               (tileIdx - 1)           : -1,
+  ]
+}
+
+const setTilesZIndex = (gameId, tileIdxs, zIndex) => {
+  for (let tilesIdx of tileIdxs) {
+    changeTile(gameId, tilesIdx, { z: zIndex })
+  }
+}
+
+const moveTileDiff = (gameId, tileIdx, diff) => {
+  const oldPos = getTilePos(gameId, tileIdx)
+  const pos = Geometry.pointAdd(oldPos, diff)
+  changeTile(gameId, tileIdx, { pos })
+}
+
+const moveTilesDiff = (gameId, tileIdxs, diff) => {
+  for (let tileIdx of tileIdxs) {
+    moveTileDiff(gameId, tileIdx, diff)
+  }
+}
+
+const finishTiles = (gameId, tileIdxs) => {
+  for (let tileIdx of tileIdxs) {
+    changeTile(gameId, tileIdx, { owner: -1, z: 1 })
+  }
+}
+
+const setTilesOwner = (gameId, tileIdxs, owner) => {
+  for (let tileIdx of tileIdxs) {
+    changeTile(gameId, tileIdx, { owner })
+  }
+}
+
+// get all grouped tiles for a tile
+function getGroupedTileIdxs(gameId, tileIdx) {
+  const tiles = GAMES[gameId].puzzle.tiles
+  const tile = tiles[tileIdx]
+
+  const grouped = []
+  if (tile.group) {
+    for (let other of tiles) {
+      if (other.group === tile.group) {
+        grouped.push(other.idx)
+      }
+    }
+  } else {
+    grouped.push(tile.idx)
+  }
+  return grouped
+}
+
+// Returns the index of the puzzle tile with the highest z index
+// that is not finished yet and that matches the position
+const freeTileIdxByPos = (gameId, pos) => {
+  let info = GAMES[gameId].puzzle.info
+  let tiles = GAMES[gameId].puzzle.tiles
+
+  let maxZ = -1
+  let tileIdx = -1
+  for (let idx = 0; idx < tiles.length; idx++) {
+    const tile = tiles[idx]
+    if (tile.owner !== 0) {
+      continue
+    }
+
+    const collisionRect = {
+      x: tile.pos.x,
+      y: tile.pos.y,
+      w: info.tileSize,
+      h: info.tileSize,
+    }
+    if (Geometry.pointInBounds(pos, collisionRect)) {
+      if (maxZ === -1 || tile.z > maxZ) {
+        maxZ = tile.z
+        tileIdx = idx
+      }
+    }
+  }
+  return tileIdx
+}
+
+// determine if two tiles are grouped together
+const areGrouped = (gameId, tileIdx1, tileIdx2) => {
+  const g1 = getTileGroup(gameId, tileIdx1)
+  const g2 = getTileGroup(gameId, tileIdx2)
+  return g1 && g1 === g2
+}
+
+function handleInput(gameId, playerId, input) {
+  let puzzle = GAMES[gameId].puzzle
+  let players = GAMES[gameId].players
+  let evtInfo = GAMES[gameId].evtInfos[playerId]
+
+  let changes = []
+
+  const _dataChange = () => {
+    changes.push(['data', puzzle.data])
+  }
+
+  const _tileChange = (tileIdx) => {
+    changes.push(['tile', getTile(gameId, tileIdx)])
+  }
+
+  const _tileChanges = (tileIdxs) => {
+    for (let tileIdx of tileIdxs) {
+      _tileChange(tileIdx)
+    }
+  }
+
+  const _playerChange = () => {
+    changes.push(['player', players[playerId]])
+  }
+
+  // put both tiles (and their grouped tiles) in the same group
+  const groupTiles = (gameId, tileIdx1, tileIdx2) => {
+    let tiles = GAMES[gameId].puzzle.tiles
+    let group1 = getTileGroup(gameId, tileIdx1)
+    let group2 = getTileGroup(gameId, tileIdx2)
+
+    let group
+    let searchGroups = []
+    if (group1) {
+      searchGroups.push(group1)
+    }
+    if (group2) {
+      searchGroups.push(group2)
+    }
+    if (group1) {
+      group = group1
+    } else if (group2) {
+      group = group2
+    } else {
+      let maxGroup = getMaxGroup(gameId) + 1
+      changeData(gameId, { maxGroup })
+      _dataChange()
+      group = getMaxGroup(gameId)
+    }
+
+    changeTile(gameId, tileIdx1, { group })
+    _tileChange(tileIdx1)
+    changeTile(gameId, tileIdx2, { group })
+    _tileChange(tileIdx2)
+
+    // TODO: strange
+    if (searchGroups.length > 0) {
+      for (let tile of tiles) {
+        if (searchGroups.includes(tile.group)) {
+          changeTile(gameId, tile.idx, { group })
+          _tileChange(tile.idx)
+        }
+      }
+    }
+  }
+
+  let [type, x, y] = input
+  let pos = {x, y}
+  if (type === 'down') {
+    changePlayer(gameId, playerId, { down: true })
+    _playerChange()
+    evtInfo._last_mouse_down = pos
+
+    const tileIdxAtPos = freeTileIdxByPos(gameId, pos)
+    if (tileIdxAtPos >= 0) {
+      console.log('tile: ', tileIdxAtPos)
+      let maxZ = getMaxZIndex(gameId) + 1
+      changeData(gameId, { maxZ })
+      _dataChange()
+      const tileIdxs = getGroupedTileIdxs(gameId, tileIdxAtPos)
+      setTilesZIndex(gameId, tileIdxs, getMaxZIndex(gameId))
+      setTilesOwner(gameId, tileIdxs, playerId)
+      _tileChanges(tileIdxs)
+    }
+
+  } else if (type === 'move') {
+    changePlayer(gameId, playerId, pos)
+    _playerChange()
+
+    if (evtInfo._last_mouse_down !== null) {
+      let tileIdx = getFirstOwnedTileIdx(gameId, playerId)
+      if (tileIdx >= 0) {
+        const diffX = x - evtInfo._last_mouse_down.x
+        const diffY = y - evtInfo._last_mouse_down.y
+        const diff = { x: diffX, y: diffY }
+        const tileIdxs = getGroupedTileIdxs(gameId, tileIdx)
+        moveTilesDiff(gameId, tileIdxs, diff)
+        _tileChanges(tileIdxs)
+      }
+
+      evtInfo._last_mouse_down = pos
+    }
+  } else if (type === 'up') {
+    changePlayer(gameId, playerId, { down: false })
+    _playerChange()
+    evtInfo._last_mouse_down = null
+
+    let tileIdx = getFirstOwnedTileIdx(gameId, playerId)
+    if (tileIdx >= 0) {
+      // drop the tile(s)
+      let tileIdxs = getGroupedTileIdxs(gameId, tileIdx)
+      setTilesOwner(gameId, tileIdxs, 0)
+      _tileChanges(tileIdxs)
+
+      // Check if the tile was dropped near the final location
+      let tilePos = getTilePos(gameId, tileIdx)
+      let finalPos = getFinalTilePos(gameId, tileIdx)
+      if (Geometry.pointDistance(finalPos, tilePos) < puzzle.info.snapDistance) {
+        let diff = Geometry.pointSub(finalPos, tilePos)
+        // Snap the tile to the final destination
+        moveTilesDiff(gameId, tileIdxs, diff)
+        finishTiles(gameId, tileIdxs)
+        _tileChanges(tileIdxs)
+      } else {
+        // Snap to other tiles
+        const check = (gameId, tileIdx, otherTileIdx, off) => {
+          let info = GAMES[gameId].puzzle.info
+          if (otherTileIdx < 0) {
+            return false
+          }
+          if (areGrouped(gameId, tileIdx, otherTileIdx)) {
+            return false
+          }
+          const tilePos = getTilePos(gameId, tileIdx)
+          const dstPos = Geometry.pointAdd(
+            getTilePos(gameId, otherTileIdx),
+            {x: off[0] * info.tileSize, y: off[1] * info.tileSize}
+          )
+          if (Geometry.pointDistance(tilePos, dstPos) < info.snapDistance) {
+            let diff = Geometry.pointSub(dstPos, tilePos)
+            let tileIdxs = getGroupedTileIdxs(gameId, tileIdx)
+            moveTilesDiff(gameId, tileIdxs, diff)
+            groupTiles(gameId, tileIdx, otherTileIdx)
+            tileIdxs = getGroupedTileIdxs(gameId, tileIdx)
+            const zIndex = getMaxZIndexByTileIdxs(gameId, tileIdxs)
+            console.log('z:' , zIndex, tileIdxs)
+            setTilesZIndex(gameId, tileIdxs, zIndex)
+            _tileChanges(tileIdxs)
+            return true
+          }
+          return false
+        }
+
+        for (let tileIdxTmp of getGroupedTileIdxs(gameId, tileIdx)) {
+          let othersIdxs = getSurroundingTilesByIdx(gameId, tileIdxTmp)
+          if (
+            check(gameId, tileIdxTmp, othersIdxs[0], [0, 1]) // top
+            || check(gameId, tileIdxTmp, othersIdxs[1], [-1, 0]) // right
+            || check(gameId, tileIdxTmp, othersIdxs[2], [0, -1]) // bottom
+            || check(gameId, tileIdxTmp, othersIdxs[3], [1, 0]) // left
+          ) {
+            break
+          }
+        }
+      }
+    }
+  }
+  // console.log(mouse)
+  evtInfo._last_mouse = pos
+
+  return changes
+}
+
+
+export default {
+  setGame,
+  exists,
+  addPlayer,
+  addSocket,
+  get,
+  getSockets,
+  handleInput,
+}
diff --git a/common/Geometry.js b/common/Geometry.js
new file mode 100644
index 0000000..9eb4323
--- /dev/null
+++ b/common/Geometry.js
@@ -0,0 +1,50 @@
+function pointSub(a, b) {
+  return { x: a.x - b.x, y: a.y - b.y }
+}
+
+function pointAdd(a, b) {
+  return { x: a.x + b.x, y: a.y + b.y }
+}
+
+function pointDistance(a, b) {
+  const diffX = a.x - b.x
+  const diffY = a.y - b.y
+  return Math.sqrt(diffX * diffX + diffY * diffY)
+}
+
+function pointInBounds(pt, rect) {
+  return pt.x >= rect.x
+    && pt.x <= rect.x + rect.w
+    && pt.y >= rect.y
+    && pt.y <= rect.y + rect.h
+}
+
+function rectCenter(rect) {
+  return {
+    x: rect.x + (rect.w / 2),
+    y: rect.y + (rect.h / 2),
+  }
+}
+
+function rectMoved(rect, x, y) {
+  return {
+    x: rect.x + x,
+    y: rect.y + y,
+    w: rect.w,
+    h: rect.h,
+  }
+}
+
+function rectCenterDistance(rectA, rectB) {
+  return pointDistance(rectCenter(rectA), rectCenter(rectB))
+}
+
+export default {
+  pointSub,
+  pointAdd,
+  pointDistance,
+  pointInBounds,
+  rectCenter,
+  rectMoved,
+  rectCenterDistance,
+}
diff --git a/common/Protocol.js b/common/Protocol.js
new file mode 100644
index 0000000..07f4ccb
--- /dev/null
+++ b/common/Protocol.js
@@ -0,0 +1,51 @@
+/*
+SERVER_CLIENT_MESSAGE_PROTOCOL
+NOTE: clients always send game id and their id
+      when creating sockets (via socket.protocol), so
+      this doesn't need to be set in each message data
+
+NOTE: first value in the array is always the type of event/message
+      when describing them below, the value each has is used
+      instead of writing EVENT_TYPE or something ismilar
+
+
+EV_CLIENT_EVENT: event triggered by clients and sent to server
+[
+  EV_CLIENT_EVENT, // constant value, type of event
+  CLIENT_SEQ, // sequence number sent by client.
+  EV_DATA, // (eg. mouse input info)
+]
+
+EV_SERVER_EVENT: event sent to clients after recieving a client
+                 event and processing it
+[
+  EV_SERVER_EVENT, // constant value, type of event
+  CLIENT_ID, // user who sent the client event
+  CLIENT_SEQ, // sequence number of the client event msg
+  CHANGES_TRIGGERED_BY_CLIENT_EVENT,
+]
+
+EV_CLIENT_INIT: event sent by client to enter a game
+[
+  EV_CLIENT_INIT, // constant value, type of event
+]
+
+EV_SERVER_INIT: event sent to one client after that client
+                connects to a game
+[
+  EV_SERVER_INIT, // constant value, type of event
+  GAME, // complete game instance required by
+        // client to build client side of the game
+]
+*/
+const EV_SERVER_EVENT = 1
+const EV_SERVER_INIT = 4
+const EV_CLIENT_EVENT = 2
+const EV_CLIENT_INIT = 3
+
+export default {
+  EV_SERVER_EVENT,
+  EV_SERVER_INIT,
+  EV_CLIENT_EVENT,
+  EV_CLIENT_INIT,
+}
diff --git a/server/util.js b/common/Util.js
similarity index 99%
rename from server/util.js
rename to common/Util.js
index 4d0293c..0d20aa1 100644
--- a/server/util.js
+++ b/common/Util.js
@@ -1,4 +1,3 @@
-
 // get a unique id
 export const uniqId = () => Date.now().toString(36) + Math.random().toString(36).substring(2)
 
diff --git a/common/package.json b/common/package.json
new file mode 100644
index 0000000..3dbc1ca
--- /dev/null
+++ b/common/package.json
@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}
diff --git a/game/Camera.js b/game/Camera.js
index b51adc5..bb92a67 100644
--- a/game/Camera.js
+++ b/game/Camera.js
@@ -28,30 +28,27 @@ export default class Camera {
         this.y += y / this.zoom
     }
 
-    zoomOut() {
-        const newzoom = Math.max(this.zoom - this.zoomStep, this.minZoom)
-        if (newzoom !== this.zoom) {
-            // centered zoom
-            this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
-            this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
-
-            this.zoom = newzoom
-            return true
-        }
+    setZoom(newzoom) {
+      const zoom = Math.min(Math.max(newzoom, this.minZoom), this.maxZoom)
+      if (zoom == this.zoom) {
         return false
+      }
+
+      // centered zoom
+      // TODO: mouse-centered-zoom
+      this.x -= Math.round(((this.width / this.zoom) - (this.width / zoom)) / 2)
+      this.y -= Math.round(((this.height / this.zoom) - (this.height / zoom)) / 2)
+
+      this.zoom = zoom
+      return true
+    }
+
+    zoomOut() {
+        return this.setZoom(this.zoom - this.zoomStep)
     }
 
     zoomIn() {
-        const newzoom = Math.min(this.zoom + this.zoomStep, this.maxZoom)
-        if (newzoom !== this.zoom) {
-            // centered zoom
-            this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
-            this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
-
-            this.zoom = newzoom
-            return true
-        }
-        return false
+        return this.setZoom(this.zoom + this.zoomStep)
     }
 
     /**
@@ -61,8 +58,8 @@ export default class Camera {
      */
     viewportToWorld(coord) {
         return {
-            x: (coord.x / this.zoom) - this.x,
-            y: (coord.y / this.zoom) - this.y,
+            x: Math.round((coord.x / this.zoom) - this.x),
+            y: Math.round((coord.y / this.zoom) - this.y),
         }
     }
 
@@ -73,15 +70,15 @@ export default class Camera {
      */
     worldToViewport(coord) {
         return {
-            x: (coord.x + this.x) * this.zoom,
-            y: (coord.y + this.y) * this.zoom,
+            x: Math.round((coord.x + this.x) * this.zoom),
+            y: Math.round((coord.y + this.y) * this.zoom),
         }
     }
 
     worldDimToViewport(dim) {
         return {
-            w: dim.w * this.zoom,
-            h: dim.h * this.zoom,
+            w: Math.round(dim.w * this.zoom),
+            h: Math.round(dim.h * this.zoom),
         }
     }
 }
diff --git a/game/Communication.js b/game/Communication.js
index fe6c1cc..0c9ea5c 100644
--- a/game/Communication.js
+++ b/game/Communication.js
@@ -1,49 +1,55 @@
 import WsClient from './WsClient.js'
+import Protocol from './../common/Protocol.js'
 
+/** @type WsClient */
 let conn
 let changesCallback = () => {}
 
-function onChanges(callback) {
+function onServerChange(callback) {
   changesCallback = callback
 }
 
-function connect(gameId, playerId) {
-  conn = new WsClient(WS_ADDRESS, playerId + '|' + gameId)
+function send(message) {
+  conn.send(JSON.stringify(message))
+}
+
+let clientSeq
+let events
+function connect(gameId, clientId) {
+  clientSeq = 0
+  events = {}
+  conn = new WsClient(WS_ADDRESS, clientId + '|' + gameId)
   return new Promise(r => {
     conn.connect()
-    conn.send(JSON.stringify({ type: 'init' }))
+    send([Protocol.EV_CLIENT_INIT])
     conn.onSocket('message', async ({ data }) => {
-      const d = JSON.parse(data)
-      if (d.type === 'init') {
-        r(d.game)
-      } else if (d.type === 'state_changed' && d.origin !== playerId) {
-        changesCallback(d.changes)
+      const msg = JSON.parse(data)
+      const msgType = msg[0]
+      if (msgType === Protocol.EV_SERVER_INIT) {
+        const game = msg[1]
+        r(game)
+      } else if (msgType === Protocol.EV_SERVER_EVENT) {
+        const msgClientId = msg[1]
+        const msgClientSeq = msg[2]
+        if (msgClientId === clientId && events[msgClientSeq]) {
+          delete events[msgClientSeq]
+        }
+        changesCallback(msg)
       }
     })
   })
 }
 
-const _STATE = {
-  changed: false,
-  changes: [],
-}
-
-function addChange(change) {
-  _STATE.changes.push(change)
-  _STATE.changed = true
-}
-
-function sendChanges() {
-  if (_STATE.changed) {
-    conn.send(JSON.stringify({ type: 'state', state: _STATE }))
-    _STATE.changes = []
-    _STATE.changed = false
-  }
+function sendClientEvent(mouse) {
+  // when sending event, increase number of sent events
+  // and add the event locally
+  clientSeq++;
+  events[clientSeq] = mouse
+  send([Protocol.EV_CLIENT_EVENT, clientSeq, events[clientSeq]])
 }
 
 export default {
   connect,
-  onChanges,
-  addChange,
-  sendChanges,
+  onServerChange,
+  sendClientEvent,
 }
diff --git a/game/EventAdapter.js b/game/EventAdapter.js
deleted file mode 100644
index 806959b..0000000
--- a/game/EventAdapter.js
+++ /dev/null
@@ -1,38 +0,0 @@
-export default class EventAdapter {
-    constructor(canvas) {
-        this._mouseEvts = []
-        canvas.addEventListener('mousedown', this._mouseDown.bind(this))
-        canvas.addEventListener('mouseup', this._mouseUp.bind(this))
-        canvas.addEventListener('mousemove', this._mouseMove.bind(this))
-        canvas.addEventListener('wheel', this._wheel.bind(this))
-    }
-
-    consumeAll() {
-        if (this._mouseEvts.length === 0) {
-            return []
-        }
-        const all = this._mouseEvts.slice()
-        this._mouseEvts = []
-        return all
-    }
-
-    _mouseDown(e) {
-        if (e.button === 0) {
-            this._mouseEvts.push({type: 'down', x: e.offsetX, y: e.offsetY})
-        }
-    }
-
-    _mouseUp(e) {
-        if (e.button === 0) {
-            this._mouseEvts.push({type: 'up', x: e.offsetX, y: e.offsetY})
-        }
-    }
-
-    _mouseMove(e) {
-        this._mouseEvts.push({type: 'move', x: e.offsetX, y: e.offsetY})
-    }
-
-    _wheel(e) {
-        this._mouseEvts.push({type: 'wheel', deltaY: e.deltaY, x: e.offsetX, y: e.offsetY})
-    }
-}
diff --git a/game/Game.js b/game/Game.js
new file mode 100644
index 0000000..93800b7
--- /dev/null
+++ b/game/Game.js
@@ -0,0 +1,6 @@
+import GameCommon from './../common/GameCommon.js'
+
+export default {
+  createGame: GameCommon.setGame,
+  handleInput: GameCommon.handleInput,
+}
diff --git a/game/Graphics.js b/game/Graphics.js
index ed09947..95b313f 100644
--- a/game/Graphics.js
+++ b/game/Graphics.js
@@ -1,5 +1,3 @@
-// import Bitmap from './Bitmap.js'
-
 function createCanvas(width = 0, height = 0) {
     const c = document.createElement('canvas')
     c.width = width === 0 ? window.innerWidth : width
diff --git a/game/PuzzleGraphics.js b/game/PuzzleGraphics.js
new file mode 100644
index 0000000..29dc7a7
--- /dev/null
+++ b/game/PuzzleGraphics.js
@@ -0,0 +1,119 @@
+import Geometry from '../common/Geometry.js'
+import Graphics from './Graphics.js'
+
+async function createPuzzleTileBitmaps(img, tiles, info) {
+  var tileSize = info.tileSize
+  var tileMarginWidth = info.tileMarginWidth
+  var tileDrawSize = info.tileDrawSize
+  var tileRatio = tileSize / 100.0
+
+  var curvyCoords = [
+    0, 0, 40, 15, 37, 5,
+    37, 5, 40, 0, 38, -5,
+    38, -5, 20, -20, 50, -20,
+    50, -20, 80, -20, 62, -5,
+    62, -5, 60, 0, 63, 5,
+    63, 5, 65, 15, 100, 0
+  ];
+
+  const bitmaps = new Array(tiles.length)
+
+  const paths = {}
+  function pathForShape(shape) {
+    const key = `${shape.top}${shape.right}${shape.left}${shape.bottom}`
+    if (paths[key]) {
+      return paths[key]
+    }
+
+    const path = new Path2D()
+    const topLeftEdge = { x: tileMarginWidth, y: tileMarginWidth }
+    path.moveTo(topLeftEdge.x, topLeftEdge.y)
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      const p1 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.top * curvyCoords[i * 6 + 1] * tileRatio })
+      const p2 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.top * curvyCoords[i * 6 + 3] * tileRatio })
+      const p3 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.top * curvyCoords[i * 6 + 5] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const topRightEdge = Geometry.pointAdd(topLeftEdge, { x: tileSize, y: 0 })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      const p1 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
+      const p2 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
+      const p3 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const bottomRightEdge = Geometry.pointAdd(topRightEdge, { x: 0, y: tileSize })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      let p1 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 1] * tileRatio })
+      let p2 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 3] * tileRatio })
+      let p3 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 5] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const bottomLeftEdge = Geometry.pointSub(bottomRightEdge, { x: tileSize, y: 0 })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      let p1 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
+      let p2 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
+      let p3 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    paths[key] = path
+    return path
+  }
+
+  for (let tile of tiles) {
+    const srcRect = srcRectByIdx(info, tile.idx)
+    const path = pathForShape(info.shapes[tile.idx])
+
+    const c = Graphics.createCanvas(tileDrawSize, tileDrawSize)
+    const ctx = c.getContext('2d')
+    // -----------------------------------------------------------
+    // -----------------------------------------------------------
+    ctx.lineWidth = 2
+    ctx.stroke(path)
+    // -----------------------------------------------------------
+    // -----------------------------------------------------------
+    ctx.save();
+    ctx.clip(path)
+    ctx.drawImage(
+      img,
+      srcRect.x - tileMarginWidth,
+      srcRect.y - tileMarginWidth,
+      tileDrawSize,
+      tileDrawSize,
+      0,
+      0,
+      tileDrawSize,
+      tileDrawSize,
+    )
+    ctx.stroke(path)
+    ctx.restore();
+
+    bitmaps[tile.idx] = await createImageBitmap(c)
+  }
+
+  return bitmaps
+}
+
+function srcRectByIdx(puzzleInfo, idx) {
+  const c = puzzleInfo.coords[idx]
+  return {
+    x: c.x * puzzleInfo.tileSize,
+    y: c.y * puzzleInfo.tileSize,
+    w: puzzleInfo.tileSize,
+    h: puzzleInfo.tileSize,
+  }
+}
+
+async function loadPuzzleBitmaps(puzzle) {
+  // load bitmap, to determine the original size of the image
+  const bmp = await Graphics.loadImageToBitmap(puzzle.info.imageUrl)
+
+  // creation of tile bitmaps
+  // then create the final puzzle bitmap
+  // NOTE: this can decrease OR increase in size!
+  const bmpResized = await Graphics.resizeBitmap(bmp, puzzle.info.width, puzzle.info.height)
+  return await createPuzzleTileBitmaps(bmpResized, puzzle.tiles, puzzle.info)
+}
+
+export default {
+  loadPuzzleBitmaps,
+}
diff --git a/game/index.js b/game/index.js
index 0b5bb27..637c39f 100644
--- a/game/index.js
+++ b/game/index.js
@@ -1,10 +1,12 @@
 "use strict"
 import {run} from './gameloop.js'
 import Camera from './Camera.js'
-import EventAdapter from './EventAdapter.js'
 import Graphics from './Graphics.js'
 import Debug from './Debug.js'
 import Communication from './Communication.js'
+import Util from './../common/Util.js'
+import PuzzleGraphics from './PuzzleGraphics.js'
+import Game from './Game.js'
 
 if (typeof GAME_ID === 'undefined') throw '[ GAME_ID not set ]'
 if (typeof WS_ADDRESS === 'undefined') throw '[ WS_ADDRESS not set ]'
@@ -16,622 +18,199 @@ function addCanvasToDom(canvas) {
     return canvas
 }
 
-function pointDistance(a, b) {
-  const diffX = a.x - b.x
-  const diffY = a.y - b.y
-  return Math.sqrt(diffX * diffX + diffY * diffY)
-}
-
-function rectMoved(rect, x, y) {
-  return {
-    x: rect.x + x,
-    y: rect.y + y,
-    w: rect.w,
-    h: rect.h,
-  }
-}
-
-const rectCenter = (rect) => {
-  return {
-    x: rect.x + (rect.w / 2),
-    y: rect.y + (rect.h / 2),
-  }
-}
-
-function rectCenterDistance(a, b) {
-  return pointDistance(rectCenter(a), rectCenter(b))
-}
-
-function pointInBounds(pt, rect) {
-  return pt.x >= rect.x
-    && pt.x <= rect.x + rect.w
-    && pt.y >= rect.y
-    && pt.y <= rect.y + rect.h
-}
-
-function getSurroundingTilesByIdx(puzzle, idx) {
-  var _X = puzzle.info.coords[idx].x
-  var _Y = puzzle.info.coords[idx].y
-
-  return [
-    // top
-    _Y === 0 ? null : puzzle.tiles[idx - puzzle.info.tiles_x],
-    // right
-    (_X === puzzle.info.tiles_x - 1) ? null : puzzle.tiles[idx + 1],
-    // bottom
-    (_Y === puzzle.info.tiles_y - 1) ? null : puzzle.tiles[idx + puzzle.info.tiles_x],
-    // left
-    _X === 0 ? null : puzzle.tiles[idx - 1]
-  ]
-}
-
-async function createPuzzleTileBitmaps(img, tiles, info) {
-  var tileSize = info.tileSize
-  var tileMarginWidth = info.tileMarginWidth
-  var tileDrawSize = info.tileDrawSize
-  var tileRatio = tileSize / 100.0
-
-  var curvyCoords = [
-    0, 0, 40, 15, 37, 5,
-    37, 5, 40, 0, 38, -5,
-    38, -5, 20, -20, 50, -20,
-    50, -20, 80, -20, 62, -5,
-    62, -5, 60, 0, 63, 5,
-    63, 5, 65, 15, 100, 0
-  ];
-
-  const bitmaps = new Array(tiles.length)
-
-  const paths = {}
-  function pathForShape(shape) {
-    const key = `${shape.top}${shape.right}${shape.left}${shape.bottom}`
-    if (paths[key]) {
-      return paths[key]
-    }
-
-    const path = new Path2D()
-    const topLeftEdge = { x: tileMarginWidth, y: tileMarginWidth }
-    path.moveTo(topLeftEdge.x, topLeftEdge.y)
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      const p1 = pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.top * curvyCoords[i * 6 + 1] * tileRatio })
-      const p2 = pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.top * curvyCoords[i * 6 + 3] * tileRatio })
-      const p3 = pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.top * curvyCoords[i * 6 + 5] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const topRightEdge = pointAdd(topLeftEdge, { x: tileSize, y: 0 })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      const p1 = pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
-      const p2 = pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
-      const p3 = pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const bottomRightEdge = pointAdd(topRightEdge, { x: 0, y: tileSize })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      let p1 = pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 1] * tileRatio })
-      let p2 = pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 3] * tileRatio })
-      let p3 = pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 5] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const bottomLeftEdge = pointSub(bottomRightEdge, { x: tileSize, y: 0 })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      let p1 = pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
-      let p2 = pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
-      let p3 = pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    paths[key] = path
-    return path
-  }
-
-  for (let tile of tiles) {
-    const srcRect = srcRectByIdx(info, tile.idx)
-    const path = pathForShape(info.shapes[tile.idx])
-
-    const c = Graphics.createCanvas(tileDrawSize, tileDrawSize)
-    const ctx = c.getContext('2d')
-    // -----------------------------------------------------------
-    // -----------------------------------------------------------
-    ctx.lineWidth = 2
-    ctx.stroke(path)
-    // -----------------------------------------------------------
-    // -----------------------------------------------------------
-    ctx.save();
-    ctx.clip(path)
-    ctx.drawImage(
-      img,
-      srcRect.x - tileMarginWidth,
-      srcRect.y - tileMarginWidth,
-      tileDrawSize,
-      tileDrawSize,
-      0,
-      0,
-      tileDrawSize,
-      tileDrawSize,
-    )
-    ctx.stroke(path)
-    ctx.restore();
-
-    bitmaps[tile.idx] = await createImageBitmap(c)
-  }
-
-  return bitmaps
-}
-
-function srcRectByIdx(puzzleInfo, idx) {
-  let c = puzzleInfo.coords[idx]
-  let cx = c.x * puzzleInfo.tileSize
-  let cy = c.y * puzzleInfo.tileSize
-  return {
-    x: cx,
-    y: cy,
-    w: puzzleInfo.tileSize,
-    h: puzzleInfo.tileSize,
-  }
-}
-
-const pointSub = (a, b) => ({ x: a.x - b.x, y: a.y - b.y })
-
-const pointAdd = (a, b) => ({x: a.x + b.x, y: a.y + b.y})
-
-// Returns the index of the puzzle tile with the highest z index
-// that is not finished yet and that matches the position
-const unfinishedTileByPos = (puzzle, pos) => {
-  let maxZ = -1
-  let tileIdx = -1
-  for (let idx = 0; idx < puzzle.tiles.length; idx++) {
-    const tile = puzzle.tiles[idx]
-    if (tile.owner === -1) {
-      continue
-    }
-
-    const collisionRect = {
-      x: tile.pos.x,
-      y: tile.pos.y,
-      w: puzzle.info.tileSize,
-      h: puzzle.info.tileSize,
-    }
-    if (pointInBounds(pos, collisionRect)) {
-      if (maxZ === -1 || tile.z > maxZ) {
-        maxZ = tile.z
-        tileIdx = idx
-      }
-    }
-  }
-  return tileIdx
-}
-
-class DirtyRect {
-  constructor() {
-    this.reset()
-  }
-  get () {
-    return this.x0 === null ? null : [
-      {x0: this.x0, x1: this.x1, y0: this.y0, y1: this.y1}
-    ]
-  }
-  add (pos, offset) {
-    const x0 = pos.x - offset
-    const x1 = pos.x + offset
-    const y0 = pos.y - offset
-    const y1 = pos.y + offset
-    this.x0 = this.x0 === null ? x0 : Math.min(this.x0, x0)
-    this.x1 = this.x1 === null ? x1 : Math.max(this.x1, x1)
-    this.y0 = this.y0 === null ? y0 : Math.min(this.y0, y0)
-    this.y1 = this.y1 === null ? y1 : Math.max(this.y1, y1)
-  }
-  reset () {
-    this.x0 = null
-    this.x1 = null
-    this.y0 = null
-    this.y1 = null
-  }
-}
-
-async function loadPuzzleBitmaps(puzzle) {
-  // load bitmap, to determine the original size of the image
-  const bmp = await Graphics.loadImageToBitmap(puzzle.info.imageUrl)
-
-  // creation of tile bitmaps
-  // then create the final puzzle bitmap
-  // NOTE: this can decrease OR increase in size!
-  const bmpResized = await Graphics.resizeBitmap(bmp, puzzle.info.width, puzzle.info.height)
-  return await createPuzzleTileBitmaps(bmpResized, puzzle.tiles, puzzle.info)
-}
-
-function uniqId() {
-  return Date.now().toString(36) + Math.random().toString(36).substring(2)
-}
-
 function initme() {
   // return uniqId()
   let ID = localStorage.getItem("ID")
   if (!ID) {
-    ID = uniqId()
+    ID = Util.uniqId()
     localStorage.setItem("ID", ID)
   }
   return ID
 }
 
-async function main () {
+const getFirstOwnedTile = (puzzle, userId) => {
+  for (let t of puzzle.tiles) {
+    if (t.owner === userId) {
+      return t
+    }
+  }
+  return null
+}
+
+export default class EventAdapter {
+  constructor(canvas, viewport) {
+    this._mouseEvts = []
+    this._viewport = viewport
+    canvas.addEventListener('mousedown', this._mouseDown.bind(this))
+    canvas.addEventListener('mouseup', this._mouseUp.bind(this))
+    canvas.addEventListener('mousemove', this._mouseMove.bind(this))
+    canvas.addEventListener('wheel', this._wheel.bind(this))
+  }
+
+  consumeAll() {
+    if (this._mouseEvts.length === 0) {
+      return []
+    }
+    const all = this._mouseEvts.slice()
+    this._mouseEvts = []
+    return all
+  }
+
+  _mouseDown(e) {
+    if (e.button === 0) {
+      const pos = this._viewport.viewportToWorld({
+        x: e.offsetX,
+        y: e.offsetY,
+      })
+      this._mouseEvts.push(['down', pos.x, pos.y])
+    }
+  }
+
+  _mouseUp(e) {
+    if (e.button === 0) {
+      const pos = this._viewport.viewportToWorld({
+        x: e.offsetX,
+        y: e.offsetY,
+      })
+      this._mouseEvts.push(['up', pos.x, pos.y])
+    }
+  }
+
+  _mouseMove(e) {
+    const pos = this._viewport.viewportToWorld({
+      x: e.offsetX,
+      y: e.offsetY,
+    })
+    this._mouseEvts.push(['move', pos.x, pos.y])
+  }
+
+  _wheel(e) {
+    const pos = this._viewport.viewportToWorld({
+      x: e.offsetX,
+      y: e.offsetY,
+    })
+    const evt = e.deltaY < 0 ? 'zoomin' : 'zoomout'
+    this._mouseEvts.push([evt, pos.x, pos.y])
+  }
+}
+
+async function main() {
   let gameId = GAME_ID
-  let me = initme()
+  let CLIENT_ID = initme()
 
   let cursorGrab = await Graphics.loadImageToBitmap('/grab.png')
   let cursorHand = await Graphics.loadImageToBitmap('/hand.png')
 
-  const game = await Communication.connect(gameId, me)
+  const game = await Communication.connect(gameId, CLIENT_ID)
+  Game.createGame(GAME_ID, game);
 
-  const bitmaps = await loadPuzzleBitmaps(game.puzzle)
+  const bitmaps = await PuzzleGraphics.loadPuzzleBitmaps(game.puzzle)
   const puzzle = game.puzzle
   const players = game.players
 
-  // information for next render cycle
-  let rectPlayer = new DirtyRect()
-  let rerenderPlayer = true
-  let rectTable = new DirtyRect()
-  let rerenderTable = true
   let rerender = true
 
   const changePlayer = (change) => {
     for (let k of Object.keys(change)) {
-      players[me][k] = change[k]
+      players[CLIENT_ID][k] = change[k]
     }
-    Communication.addChange({type: 'change_player', player: players[me]})
-  }
-  const changeData = (change) => {
-    for (let k of Object.keys(change)) {
-      puzzle.data[k] = change[k]
-    }
-    Communication.addChange({type: 'change_data', data: puzzle.data})
-  }
-  const changeTile = (t, change) => {
-    for (let k of Object.keys(change)) {
-      t[k] = change[k]
-    }
-    Communication.addChange({type: 'change_tile', tile: t})
   }
 
   // Create a dom and attach adapters to it so we can work with it
   const canvas = addCanvasToDom(Graphics.createCanvas())
   const ctx = canvas.getContext('2d')
-  const evts = new EventAdapter(canvas)
 
   // initialize some view data
   // this global data will change according to input events
   const viewport = new Camera(canvas)
+  // center viewport
+  viewport.move(
+    -(puzzle.info.table.width - viewport.width) /2,
+    -(puzzle.info.table.height - viewport.height) /2
+  )
 
-  Communication.onChanges((changes) => {
-    for (let change of changes) {
-      switch (change.type) {
-        case 'change_player': {
-          if (players[change.player.id]) {
-            rectPlayer.add(viewport.worldToViewport(players[change.player.id]), cursorGrab.width)
+  const evts = new EventAdapter(canvas, viewport)
+
+  Communication.onServerChange((msg) => {
+    const msgType = msg[0]
+    const evClientId = msg[1]
+    const evClientSeq = msg[2]
+    const evChanges = msg[3]
+    for(let [changeType, changeData] of evChanges) {
+      switch (changeType) {
+        case 'player': {
+          if (changeData.id !== CLIENT_ID) {
+            players[changeData.id] = changeData
+            rerender = true
           }
-
-          players[change.player.id] = change.player
-
-          rectPlayer.add(viewport.worldToViewport(players[change.player.id]), cursorGrab.width)
         } break;
-
-        case 'change_tile': {
-          rectTable.add(puzzle.tiles[change.tile.idx].pos, puzzle.info.tileDrawSize)
-
-          puzzle.tiles[change.tile.idx] = change.tile
-
-          rectTable.add(puzzle.tiles[change.tile.idx].pos, puzzle.info.tileDrawSize)
+        case 'tile': {
+          puzzle.tiles[changeData.idx] = changeData
+          rerender = true
         } break;
-        case 'change_data': {
-          puzzle.data = change.data
+        case 'data': {
+          puzzle.data = changeData
+          rerender = true
         } break;
       }
     }
   })
 
-  // Information about what tile is the player currently grabbing
-  let grabbingTileIdx = -1
-
-  // The actual place for the puzzle. The tiles may
-  // not be moved around infinitely, just on the (invisible)
-  // puzzle table. however, the camera may move away from the table
-  const puzzleTableColor = '#222'
-  const puzzleTable = await Graphics.createBitmap(
-    puzzle.info.table.width,
-    puzzle.info.table.height,
-    puzzleTableColor
-  )
-
   // In the middle of the table, there is a board. this is to
   // tell the player where to place the final puzzle
   const boardColor = '#505050'
-  const board = await Graphics.createBitmap(
-    puzzle.info.width,
-    puzzle.info.height,
-    boardColor
-  )
-  const boardPos = {
-    x: (puzzleTable.width - board.width) / 2,
-    y: (puzzleTable.height - board.height) / 2
-  } // relative to table.
-
-
-  // Some helper functions for working with the grabbing and snapping
-  // ---------------------------------------------------------------
-
-  // get all grouped tiles for a tile
-  function getGroupedTiles(tile) {
-    let grouped = []
-    if (tile.group) {
-      for (let other of puzzle.tiles) {
-        if (other.group === tile.group) {
-          grouped.push(other)
-        }
-      }
-    } else {
-      grouped.push(tile)
-    }
-    return grouped
-  }
-
-  // put both tiles (and their grouped tiles) in the same group
-  const groupTiles = (tile, other) => {
-    let targetGroup
-    let searchGroups = []
-    if (tile.group) {
-      searchGroups.push(tile.group)
-    }
-    if (other.group) {
-      searchGroups.push(other.group)
-    }
-    if (tile.group) {
-      targetGroup = tile.group
-    } else if (other.group) {
-      targetGroup = other.group
-    } else {
-      changeData({ maxGroup: puzzle.data.maxGroup + 1 })
-      targetGroup = puzzle.data.maxGroup
-    }
-
-    changeTile(tile, { group: targetGroup })
-    changeTile(other, { group: targetGroup })
-
-    if (searchGroups.length > 0) {
-      for (let tmp of puzzle.tiles) {
-        if (searchGroups.includes(tmp.group)) {
-          changeTile(tmp, { group: targetGroup })
-        }
-      }
-    }
-  }
-
-  // determine if two tiles are grouped together
-  const areGrouped = (t1, t2) => {
-    return t1.group && t1.group === t2.group
-  }
-
-  // get the center position of a tile
-  const tileCenterPos = (tile) => {
-
-    return rectCenter(tileRectByTile(tile))
-  }
-
-  // get the would-be visible bounding rect if a tile was
-  // in given position
-  const tileRectByPos = (pos) => {
-    return {
-      x: pos.x,
-      y: pos.y,
-      w: puzzle.info.tileSize,
-      h: puzzle.info.tileSize,
-    }
-  }
-
-  // get the current visible bounding rect for a tile
-  const tileRectByTile = (tile) => {
-    return tileRectByPos(tile.pos)
-  }
 
   const tilesSortedByZIndex = () => {
     const sorted = puzzle.tiles.slice()
     return sorted.sort((t1, t2) => t1.z - t2.z)
   }
 
-  const setGroupedZIndex = (tile, zIndex) => {
-    for (let t of getGroupedTiles(tile)) {
-      changeTile(t, { z: zIndex })
-    }
-  }
-
-  const setGroupedOwner = (tile, owner) => {
-    for (let t of getGroupedTiles(tile)) {
-      // may only change own tiles or untaken tiles
-      if (t.owner === me || t.owner === 0) {
-        changeTile(t, { owner: owner })
-      }
-    }
-  }
-
-  const moveGroupedTilesDiff = (tile, diffX, diffY) => {
-    for (let t of getGroupedTiles(tile)) {
-      changeTile(t, { pos: pointAdd(t.pos, { x: diffX, y: diffY }) })
-
-      // TODO: instead there could be a function to
-      //       get min/max x/y of a group
-      rectTable.add(tileCenterPos(t), puzzle.info.tileDrawSize)
-    }
-  }
-  const moveGroupedTiles = (tile, dst) => {
-    let diff = pointSub(tile.pos, dst)
-    moveGroupedTilesDiff(tile, -diff.x, -diff.y)
-  }
-  const finishGroupedTiles = (tile) => {
-    for (let t of getGroupedTiles(tile)) {
-      changeTile(t, { owner: -1, z: 1 })
-    }
-  }
-  // ---------------------------------------------------------------
-
-
-
-
-
-
-
-  let _last_mouse = null
   let _last_mouse_down = null
   const onUpdate = () => {
-    let last_x = null
-    let last_y = null
+    for (let evt of evts.consumeAll()) {
 
-    if (_last_mouse_down !== null) {
-      last_x = _last_mouse_down.x
-      last_y = _last_mouse_down.y
-    }
-    for (let mouse of evts.consumeAll()) {
-      const tp = viewport.viewportToWorld(mouse)
-      if (mouse.type === 'move') {
-        changePlayer({ x: tp.x, y: tp.y })
-        if (_last_mouse) {
-          rectPlayer.add(_last_mouse, cursorGrab.width)
-        }
-        rectPlayer.add(mouse, cursorGrab.width)
+      // LOCAL ONLY CHANGES
+      // -------------------------------------------------------------
+      const type = evt[0]
+      const pos = {x: evt[1], y: evt[2]}
+      if (type === 'move') {
+        rerender = true
+        changePlayer(pos)
 
-        if (_last_mouse_down !== null) {
-          _last_mouse_down = mouse
-
-          if (last_x === null || last_y === null) {
-            last_x = mouse.x
-            last_y = mouse.y
-          }
-
-          if (grabbingTileIdx >= 0) {
-            const tp_last = viewport.viewportToWorld({ x: last_x, y: last_y })
-            const diffX = tp.x - tp_last.x
-            const diffY = tp.y - tp_last.y
-
-            const t = puzzle.tiles[grabbingTileIdx]
-            moveGroupedTilesDiff(t, diffX, diffY)
-
-            // todo: dont +- tileDrawSize, we can work with less?
-            rectTable.add(tp, puzzle.info.tileDrawSize)
-            rectTable.add(tp_last, puzzle.info.tileDrawSize)
-          } else {
+        if (_last_mouse_down && !getFirstOwnedTile(puzzle, CLIENT_ID)) {
             // move the cam
-            const diffX = Math.round(mouse.x - last_x)
-            const diffY = Math.round(mouse.y - last_y)
+            const mouse = viewport.worldToViewport(pos)
+            const diffX = Math.round(mouse.x - _last_mouse_down.x)
+            const diffY = Math.round(mouse.y - _last_mouse_down.y)
             viewport.move(diffX, diffY)
-            rerender = true
-          }
-        }
-      } else if (mouse.type === 'down') {
-        changePlayer({ down: true })
-        rectPlayer.add(mouse, cursorGrab.width)
 
-        _last_mouse_down = mouse
-        if (last_x === null || last_y === null) {
-          last_x = mouse.x
-          last_y = mouse.y
+            _last_mouse_down = mouse
         }
-
-        grabbingTileIdx = unfinishedTileByPos(puzzle, tp)
-        console.log(grabbingTileIdx)
-        if (grabbingTileIdx >= 0) {
-          changeData({ maxZ: puzzle.data.maxZ + 1 })
-          setGroupedZIndex(puzzle.tiles[grabbingTileIdx], puzzle.data.maxZ)
-          setGroupedOwner(puzzle.tiles[grabbingTileIdx], me)
-        }
-
-      } else if (mouse.type === 'up') {
-        changePlayer({ down: false })
-        if (_last_mouse) {
-          rectPlayer.add(_last_mouse, cursorGrab.width)
-        }
-        rectPlayer.add(mouse, cursorGrab.width)
-
+      } else if (type === 'down') {
+        _last_mouse_down = viewport.worldToViewport(pos)
+      } else if (type === 'up') {
         _last_mouse_down = null
-        last_x = null
-        last_y === null
-
-        if (grabbingTileIdx >= 0) {
-          // Check if the tile was dropped at the correct
-          // location
-
-          let tile = puzzle.tiles[grabbingTileIdx]
-          setGroupedOwner(tile, 0)
-          let pt = pointSub(tile.pos, boardPos)
-          let dst = tileRectByPos(pt)
-          let srcRect = srcRectByIdx(puzzle.info, grabbingTileIdx)
-          if (rectCenterDistance(srcRect, dst) < puzzle.info.snapDistance) {
-            // Snap the tile to the final destination
-            moveGroupedTiles(tile, {
-              x: srcRect.x + boardPos.x,
-              y: srcRect.y + boardPos.y,
-            })
-            finishGroupedTiles(tile)
-            rectTable.add(tp, puzzle.info.tileDrawSize)
-          } else {
-            // Snap to other tiles
-            const check = (t, off, other) => {
-              if (!other || (other.owner === -1) || areGrouped(t, other)) {
-                return false
-              }
-              const trec_ = tileRectByTile(t)
-              const otrec = rectMoved(
-                tileRectByTile(other),
-                off[0] * puzzle.info.tileSize,
-                off[1] * puzzle.info.tileSize
-              )
-              if (rectCenterDistance(trec_, otrec) < puzzle.info.snapDistance) {
-                moveGroupedTiles(t, { x: otrec.x, y: otrec.y })
-                groupTiles(t, other)
-                setGroupedZIndex(t, t.z)
-                rectTable.add(tileCenterPos(t), puzzle.info.tileDrawSize)
-                return true
-              }
-              return false
-            }
-
-            for (let t of getGroupedTiles(tile)) {
-              let others = getSurroundingTilesByIdx(puzzle, t.idx)
-              if (
-                check(t, [0, 1], others[0]) // top
-                || check(t, [-1, 0], others[1]) // right
-                || check(t, [0, -1], others[2]) // bottom
-                || check(t, [1, 0], others[3]) // left
-              ) {
-                break
-              }
-            }
-          }
-        }
-        grabbingTileIdx = -1
-      } else if (mouse.type === 'wheel') {
-        if (
-          mouse.deltaY < 0 && viewport.zoomIn()
-          || mouse.deltaY > 0 && viewport.zoomOut()
-        ) {
+      } else if (type === 'zoomin') {
+        if (viewport.zoomIn()) {
           rerender = true
-          changePlayer({ x: tp.x, y: tp.y })
-          if (_last_mouse) {
-            rectPlayer.add(_last_mouse, cursorGrab.width)
-          }
-          rectPlayer.add(mouse, cursorGrab.width)
+          changePlayer(pos)
+        }
+      } else if (type === 'zoomout') {
+        if (viewport.zoomOut()) {
+          rerender = true
+          changePlayer(pos)
         }
       }
-      // console.log(mouse)
-      _last_mouse = mouse
-    }
-    if (rectTable.get()) {
-      rerenderTable = true
-    }
-    if (rectPlayer.get()) {
-      rerenderPlayer = true
-    }
 
-    Communication.sendChanges()
+      // LOCAL + SERVER CHANGES
+      // -------------------------------------------------------------
+      Game.handleInput(GAME_ID, CLIENT_ID, evt)
+      Communication.sendClientEvent(evt)
+    }
   }
 
   const onRender = () => {
-    if (!rerenderTable && !rerenderPlayer && !rerender) {
+    if (!rerender) {
       return
     }
 
@@ -640,24 +219,33 @@ async function main () {
 
     if (DEBUG) Debug.checkpoint_start(0)
 
-    ctx.fillStyle = puzzleTableColor
-    ctx.fillRect(0, 0, canvas.width, canvas.height)
+    // CLEAR CTX
+    // ---------------------------------------------------------------
+    ctx.clearRect(0, 0, canvas.width, canvas.height)
     if (DEBUG) Debug.checkpoint('clear done')
+    // ---------------------------------------------------------------
+
 
     // DRAW BOARD
     // ---------------------------------------------------------------
-    pos = viewport.worldToViewport(boardPos)
-    dim = viewport.worldDimToViewport({w: board.width, h: board.height})
-    ctx.drawImage(board,
-      0, 0, board.width, board.height,
-      pos.x, pos.y, dim.w, dim.h
-    )
+    pos = viewport.worldToViewport({
+      x: (puzzle.info.table.width - puzzle.info.width) / 2,
+      y: (puzzle.info.table.height - puzzle.info.height) / 2
+    })
+    dim = viewport.worldDimToViewport({
+      w: puzzle.info.width,
+      h: puzzle.info.height,
+    })
+    ctx.fillStyle = boardColor
+    ctx.fillRect(pos.x, pos.y, dim.w, dim.h)
     if (DEBUG) Debug.checkpoint('board done')
+    // ---------------------------------------------------------------
+
 
     // DRAW TILES
     // ---------------------------------------------------------------
     for (let tile of tilesSortedByZIndex()) {
-      let bmp = bitmaps[tile.idx]
+      const bmp = bitmaps[tile.idx]
       pos = viewport.worldToViewport({
         x: puzzle.info.tileDrawOffset + tile.pos.x,
         y: puzzle.info.tileDrawOffset + tile.pos.y,
@@ -672,6 +260,8 @@ async function main () {
       )
     }
     if (DEBUG) Debug.checkpoint('tiles done')
+    // ---------------------------------------------------------------
+
 
     // DRAW PLAYERS
     // ---------------------------------------------------------------
@@ -679,19 +269,16 @@ async function main () {
       const p = players[id]
       const cursor = p.down ? cursorGrab : cursorHand
       const pos = viewport.worldToViewport(p)
-      ctx.drawImage(cursor, pos.x, pos.y)
+      ctx.drawImage(cursor,
+        Math.round(pos.x - cursor.width/2),
+        Math.round(pos.y - cursor.height/2)
+      )
     }
-    //
     if (DEBUG) Debug.checkpoint('players done')
+    // ---------------------------------------------------------------
 
 
-    if (DEBUG) Debug.checkpoint('all done')
-
-    rerenderTable = false
-    rerenderPlayer = false
     rerender = false
-    rectTable.reset()
-    rectPlayer.reset()
   }
 
   run({
diff --git a/server/Game.js b/server/Game.js
new file mode 100644
index 0000000..5d722dc
--- /dev/null
+++ b/server/Game.js
@@ -0,0 +1,23 @@
+import { createPuzzle } from './Puzzle.js'
+import GameCommon from './../common/GameCommon.js'
+
+async function createGame(gameId, targetTiles, image) {
+  const game = {
+    puzzle: await createPuzzle(targetTiles, image),
+    players: {},
+
+    sockets: [],
+    evtInfos: {},
+  }
+  GameCommon.setGame(gameId, game)
+}
+
+export default {
+  createGame,
+  exists: GameCommon.exists,
+  addPlayer: GameCommon.addPlayer,
+  addSocket: GameCommon.addSocket,
+  get: GameCommon.get,
+  getSockets: GameCommon.getSockets,
+  handleInput: GameCommon.handleInput,
+}
diff --git a/server/puzzle.js b/server/Puzzle.js
similarity index 66%
rename from server/puzzle.js
rename to server/Puzzle.js
index 2ac4592..0a45cab 100644
--- a/server/puzzle.js
+++ b/server/Puzzle.js
@@ -1,25 +1,23 @@
 import sizeOf from 'image-size'
-import { choice, shuffle } from './util.js'
+import Util from './../common/Util.js'
 
 // cut size of each puzzle tile in the
 // final resized version of the puzzle image
 const TILE_SIZE = 64
 
 async function createPuzzle(targetTiles, image) {
-  const imgPath = './../game' + image
-  const imgUrl = image
+  const imagePath = './../game' + image
+  const imageUrl = image
 
   // load bitmap, to determine the original size of the image
-  let dim = sizeOf(imgPath)
+  const dim = sizeOf(imagePath)
 
   // determine puzzle information from the bitmap
-  let info = determinePuzzleInfo(dim.width, dim.height, targetTiles)
+  const info = determinePuzzleInfo(dim.width, dim.height, targetTiles)
 
   let tiles = new Array(info.tiles)
   for (let i = 0; i < tiles.length; i++) {
-    tiles[i] = {
-      idx: i,
-    }
+    tiles[i] = { idx: i }
   }
   const shapes = determinePuzzleTileShapes(info)
 
@@ -33,43 +31,46 @@ async function createPuzzle(targetTiles, image) {
     }
   }
 
-  let tableWidth = info.width * 3
-  let tableHeight = info.height * 3
+  const tableWidth = info.width * 3
+  const tableHeight = info.height * 3
 
-  let off = (info.tileSize * 1.5)
-  let last = {x: info.width - (1 * off), y: info.height - (2 * off) }
-  let count_x = Math.ceil(info.width / off) + 2
-  let count_y = Math.ceil(info.height / off) + 2
+  const off = info.tileSize * 1.5
+  let last = {
+    x: info.width - (1 * off),
+    y: info.height - (2 * off),
+  }
+  let countX = Math.ceil(info.width / off) + 2
+  let countY = Math.ceil(info.height / off) + 2
 
-  let diff_x = off
-  let diff_y = 0
+  let diffX = off
+  let diffY = 0
   let index = 0
   for (let pos of positions) {
     pos.x = last.x
     pos.y = last.y
-    last.x+=diff_x
-    last.y+=diff_y
+    last.x+=diffX
+    last.y+=diffY
     index++
     // did we move horizontally?
-    if (diff_x !== 0) {
-      if (index === count_x) {
-        diff_y = diff_x
-        count_y ++
-        diff_x = 0
+    if (diffX !== 0) {
+      if (index === countX) {
+        diffY = diffX
+        countY++
+        diffX = 0
         index = 0
       }
     } else {
-      if (index === count_y) {
-        diff_x = -diff_y
-        count_x ++
-        diff_y = 0
+      if (index === countY) {
+        diffX = -diffY
+        countX++
+        diffY = 0
         index = 0
       }
     }
   }
 
   // then shuffle the positions
-  positions = shuffle(positions)
+  positions = Util.shuffle(positions)
 
   tiles = tiles.map(tile => {
     return {
@@ -91,7 +92,7 @@ async function createPuzzle(targetTiles, image) {
   })
 
   // Complete puzzle object
-  const p = {
+  return {
     // tiles array
     tiles,
     // game data for puzzle, data changes during the game
@@ -109,7 +110,7 @@ async function createPuzzle(targetTiles, image) {
       },
       // information that was used to create the puzzle
       targetTiles: targetTiles,
-      imageUrl: imgUrl,
+      imageUrl,
 
       width: info.width, // actual puzzle width (same as bitmap.width)
       height: info.height, // actual puzzle height (same as bitmap.height)
@@ -122,8 +123,8 @@ async function createPuzzle(targetTiles, image) {
       // makes the tile snap to destination
       snapDistance: info.tileSize / 2,
       tiles: info.tiles, // the final number of tiles in the puzzle
-      tiles_x: info.tiles_x, // number of tiles each row
-      tiles_y: info.tiles_y, // number of tiles each col
+      tilesX: info.tilesX, // number of tiles each row
+      tilesY: info.tilesY, // number of tiles each col
       coords: info.coords, // map of tile index to its coordinates
       // ( index => {x, y} )
       // this is not the physical coordinate, but
@@ -133,7 +134,6 @@ async function createPuzzle(targetTiles, image) {
       shapes: shapes, // tile shapes
     },
   }
-  return p
 }
 
 function determinePuzzleTileShapes(info) {
@@ -142,34 +142,38 @@ function determinePuzzleTileShapes(info) {
   const shapes = new Array(info.tiles)
   for (let i = 0; i < info.tiles; i++) {
     shapes[i] = {
-      top: info.coords[i].y === 0 ? 0 : shapes[i - info.tiles_x].bottom * -1,
-      right: info.coords[i].x === info.tiles_x - 1 ? 0 : choice(tabs),
+      top: info.coords[i].y === 0 ? 0 : shapes[i - info.tilesX].bottom * -1,
+      right: info.coords[i].x === info.tilesX - 1 ? 0 : Util.choice(tabs),
       left: info.coords[i].x === 0 ? 0 : shapes[i - 1].right * -1,
-      bottom: info.coords[i].y === info.tiles_y - 1 ? 0 : choice(tabs),
+      bottom: info.coords[i].y === info.tilesY - 1 ? 0 : Util.choice(tabs),
     }
   }
   return shapes
 }
 
-const determinePuzzleInfo = (w, h, targetTiles) => {
-  let tileSize = 0
+const determineTilesXY = (w, h, targetTiles) => {
+  const w_ = w < h ? (w * h) : (w * w)
+  const h_ = w < h ? (h * h) : (w * h)
+  let size = 0
   let tiles = 0
   do {
-    tileSize++
-    tiles = tilesFit(w, h, tileSize)
+    size++
+    tiles = Math.floor(w_ / size) * Math.floor(h_ / size)
   } while (tiles >= targetTiles)
-  tileSize--
+  size--
+  return {
+    tilesX: Math.round(w_ / size),
+    tilesY: Math.round(h_ / size),
+  }
+}
 
-  tiles = tilesFit(w, h, tileSize)
-  const tiles_x = Math.round(w / tileSize)
-  const tiles_y = Math.round(h / tileSize)
-  tiles = tiles_x * tiles_y
-
-  // then resize to final TILE_SIZE (which is always the same)
-  tileSize = TILE_SIZE
-  const width = tiles_x * tileSize
-  const height = tiles_y * tileSize
-  const coords = coordsByNum({ width, height, tileSize, tiles })
+const determinePuzzleInfo = (w, h, targetTiles) => {
+  const {tilesX, tilesY} = determineTilesXY(w, h, targetTiles)
+  const tiles = tilesX * tilesY
+  const tileSize = TILE_SIZE
+  const width = tilesX * tileSize
+  const height = tilesY * tileSize
+  const coords = buildCoords({ width, height, tileSize, tiles })
 
   const tileMarginWidth = tileSize * .5;
   const tileDrawSize = Math.round(tileSize + tileMarginWidth * 2)
@@ -181,25 +185,23 @@ const determinePuzzleInfo = (w, h, targetTiles) => {
     tileMarginWidth,
     tileDrawSize,
     tiles,
-    tiles_x,
-    tiles_y,
+    tilesX,
+    tilesY,
     coords,
   }
 }
 
-const tilesFit = (w, h, size) => Math.floor(w / size) * Math.floor(h / size)
-
-const coordsByNum = (puzzleInfo) => {
-  const w_tiles = puzzleInfo.width / puzzleInfo.tileSize
+const buildCoords = (puzzleInfo) => {
+  const wTiles = puzzleInfo.width / puzzleInfo.tileSize
   const coords = new Array(puzzleInfo.tiles)
   for (let i = 0; i < puzzleInfo.tiles; i++) {
-    const y = Math.floor(i / w_tiles)
-    const x = i % w_tiles
+    const y = Math.floor(i / wTiles)
+    const x = i % wTiles
     coords[i] = { x, y }
   }
   return coords
 }
 
 export {
-  createPuzzle
+  createPuzzle,
 }
diff --git a/server/index.js b/server/index.js
index cee0dca..0c3224c 100644
--- a/server/index.js
+++ b/server/index.js
@@ -1,13 +1,14 @@
 import WebSocketServer from './WebSocketServer.js'
 
 import express from 'express'
-import { createPuzzle } from './puzzle.js'
 import config from './config.js'
-import { uniqId, choice } from './util.js'
+import Protocol from './../common/Protocol.js'
+import Util from './../common/Util.js'
+import Game from './Game.js'
 
 // desired number of tiles
 // actual calculated number can be higher
-const TARGET_TILES = 500
+const TARGET_TILES = 1000
 
 const IMAGES = [
   '/example-images/ima_86ec3fa.jpeg',
@@ -37,6 +38,7 @@ app.use('/g/:gid', (req, res, next) => {
   `)
 })
 
+app.use('/common/', express.static('./../common/'))
 app.use('/', (req, res, next) => {
   if (req.path === '/') {
     res.send(`
@@ -44,7 +46,7 @@ app.use('/', (req, res, next) => {
       html,body {margin: 0; overflow: hidden;}
       html, body, #main { background: #222 }
       </style></head><body>
-      <a href="/g/${uniqId()}">New game :P</a>
+      <a href="/g/${Util.uniqId()}">New game :P</a>
       ${Object.keys(games).map(k => {
         return `<a href="/g/${k}">Game ${k}</a>`
       })}
@@ -59,61 +61,41 @@ app.use('/', (req, res, next) => {
 const wss = new WebSocketServer(config.ws);
 
 const notify = (data, sockets) => {
-  // TODO: throttle
+  // TODO: throttle?
   for (let socket of sockets) {
     wss.notifyOne(data, socket)
   }
-  console.log('notify', data)
 }
 
 wss.on('message', async ({socket, data}) => {
   try {
     const proto = socket.protocol.split('|')
-    const uid = proto[0]
-    const gid = proto[1]
-    const parsed = JSON.parse(data)
-    switch (parsed.type) {
-      case 'init': {
-        // a new player (or previous player) joined
-        games[gid] = games[gid] || {
-          puzzle: await createPuzzle(TARGET_TILES, choice(IMAGES)),
-          players: {},
-          sockets: []
+    const clientId = proto[0]
+    const gameId = proto[1]
+    const msg = JSON.parse(data)
+    const msgType = msg[0]
+    switch (msgType) {
+      case Protocol.EV_CLIENT_INIT: {
+        if (!Game.exists(gameId)) {
+          await Game.createGame(gameId, TARGET_TILES, Util.choice(IMAGES))
         }
-        if (!games[gid].sockets.includes(socket)) {
-          games[gid].sockets.push(socket)
-        }
-        games[gid].players[uid] = {id: uid, x: 0, y: 0, down: false}
+        Game.addPlayer(gameId, clientId)
+        Game.addSocket(gameId, socket)
 
-        wss.notifyOne({
-          type: 'init',
-          game: {
-            puzzle: games[gid].puzzle,
-            players: games[gid].players,
-          },
-        }, socket)
+        notify(
+          [Protocol.EV_SERVER_INIT, Game.get(gameId)],
+          [socket]
+        )
       } break;
 
-      // somebody has changed the state
-      case 'state': {
-        for (let change of parsed.state.changes) {
-          switch (change.type) {
-            case 'change_player': {
-              games[gid].players[uid] = change.player
-            } break;
-            case 'change_tile': {
-              games[gid].puzzle.tiles[change.tile.idx] = change.tile
-            } break;
-            case 'change_data': {
-              games[gid].puzzle.data = change.data
-            } break;
-          }
-        }
-        notify({
-          type:'state_changed',
-          origin: uid,
-          changes: parsed.state.changes,
-        }, games[gid].sockets)
+      case Protocol.EV_CLIENT_EVENT: {
+        const clientSeq = msg[1]
+        const clientEvtData = msg[2]
+        const changes = Game.handleInput(gameId, clientId, clientEvtData)
+        notify(
+          [Protocol.EV_SERVER_EVENT, clientId, clientSeq, changes],
+          Game.getSockets(gameId)
+        )
       } break;
     }
   } catch (e) {