Add aggregation proxy

lib/cartodb/models/aggregation/aggregation-proxy.js

@@ -0,0 +1,43 @@
+const RasterAggregation = require('./raster-aggregation');
+const VectorAggregation = require('./vector-aggregation');
+const RASTER_AGGREGATION = 'RasterAggregation';
+const VECTOR_AGGREGATION = 'VectorAggregation';
+
+module.exports = class AggregationProxy {
+    constructor (mapconfig, resolution = 256, threshold = 10e5, placement = 'centroid') {
+        this.mapconfig = mapconfig;
+        this.resolution = resolution;
+        this.threshold = threshold;
+        this.placement = placement;
+        this.implementation = this._getAggregationImplementation();
+    }
+
+    _getAggregationImplementation () {
+        let implementation = null;
+
+        switch (this._getAggregationType()) {
+            case VECTOR_AGGREGATION:
+                implementation = new VectorAggregation(this.resolution, this.threshold, this.placement);
+                break;
+            case RASTER_AGGREGATION:
+                implementation = new RasterAggregation(this.resolution, this.threshold, this.placement);
+                break;
+            default:
+                throw new Error('Unsupported aggregation type');
+        }
+
+        return implementation;
+    }
+
+    _getAggregationType () {
+        if (this.mapconfig.isVetorLayergroup()) {
+            return VECTOR_AGGREGATION;
+        }
+
+        return RASTER_AGGREGATION;
+    }
+
+    sql () {
+        return this.implementation.sql();
+    }
+};