Very rough sketch of query library

frontend/src/metabase-query/lib/index.js

+/* @flow */
+
+class Database {
+    newQuery(): Query {}
+    newNativeQuery(): NativeQuery {}
+}
+
+class Schema {}
+
+class Table {
+    newQuery(): Query {}
+    newNativeQuery(): NativeQuery {}
+}
+
+class Field {}
+
+class Query {
+    constructor(metadata: Metadata, datasetQuery: DatasetQuery) {}
+
+    setDatabase(database: Database) {}
+    setTable(table: Table) {}
+
+    aggregations(): Aggregation[] {}
+    aggregationOptions(): AggregationOption[] {}
+    canAddAggregation(): bool {}
+
+    breakouts(): Breakout[] {}
+    breakoutOptions(unused: boolean = false): BreakoutOption[] {}
+    canAddBreakout(): bool {}
+
+    filters(): Filter[] {}
+    filterOptions(): FilterOption[] {}
+    canAddFilter(): bool {}
+
+    sorts(): Sort[] {}
+    sortOptions(): SortOption[] {}
+    canAddSort(): bool {}
+
+    // top-level actions
+    actions(): Action[] {}
+    // drill-through etc actions
+    actionsForClick(clicked: ClickObject): Action[] {}
+}
+
+// AGGREGATIONS
+
+class Aggregation {
+    displayName: string;
+    icon: string;
+
+    remove() {}
+    options(): AggregationOption[] {}
+}
+
+class AggregationOption {
+    displayName: string;
+    icon: string;
+    section: string;
+    isSelected: ?boolean;
+
+    add() {}
+}
+
+// TODO: similar for breakout, etc
+
+// ACTIONS / DRILL THROUGHS
+
+class Action {
+    perform() {}
+}