(core) New date filter with a calendar view

Summary:
Implements the new date filtering panel. Design results from long
discussion between: Alex, Anais, Cyprien and Dmitry.

Test environment: https://grist-new-date-range-filter.fly.dev/

Test Plan: Include various new tests.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3720

app/client/models/ColumnFilter.ts

@@ -1,6 +1,9 @@
 import {ColumnFilterFunc, makeFilterFunc} from "app/common/ColumnFilterFunc";
 import {CellValue} from 'app/common/DocActions';
-import {FilterSpec, FilterState, isRangeFilter, makeFilterState} from "app/common/FilterState";
+import {
+  FilterSpec, FilterState, IRelativeDateSpec, isRangeFilter, isRelativeBound, makeFilterState
+} from "app/common/FilterState";
+import {toUnixTimestamp} from "app/common/RelativeDates";
 import {nativeCompare} from 'app/common/gutil';
 import {Computed, Disposable, Observable} from 'grainjs';
 
@@ -14,8 +17,8 @@ import {Computed, Disposable, Observable} from 'grainjs';
  */
 export class ColumnFilter extends Disposable {
 
-  public min = Observable.create<number|undefined>(this, undefined);
-  public max = Observable.create<number|undefined>(this, undefined);
+  public min = Observable.create<number|undefined|IRelativeDateSpec>(this, undefined);
+  public max = Observable.create<number|undefined|IRelativeDateSpec>(this, undefined);
 
   public readonly filterFunc = Observable.create<ColumnFilterFunc>(this, () => true);
 
@@ -25,6 +28,8 @@ export class ColumnFilter extends Disposable {
   // Computed that returns the current filter state.
   public readonly state: Computed<FilterState> = Computed.create(this, this.filterFunc, () => this._getState());
 
+  public readonly isRange: Computed<boolean> = Computed.create(this, this.filterFunc, () => this._isRange());
+
   private _include: boolean;
   private _values: Set<CellValue>;
 
@@ -119,6 +124,12 @@ export class ColumnFilter extends Disposable {
     return this.makeFilterJson() !== this._initialFilterJson;
   }
 
+  public getBoundsValue(minMax: 'min' | 'max'): number | undefined {
+    const value = this[minMax].get();
+    return isRelativeBound(value) ? toUnixTimestamp(value) : value;
+  }
+
+
   private _updateState(): void {
     this.filterFunc.set(makeFilterFunc(this._getState(), this._columnType));
   }