supporting datemath for between operator

vm/datemath.go

@@ -42,10 +42,9 @@ func CalcBoundaryFns(n expr.Node) BoundaryFns {
 	return findDateMathFn(n)
 }
 
-// NewDateConverter takes a node expression
-func NewDateConverter(ctx expr.EvalIncludeContext, n expr.Node) (*DateConverter, error) {
+func NewDateConverterWithAnchorTime(ctx expr.EvalIncludeContext, n expr.Node, at time.Time) (*DateConverter, error) {
 	dc := &DateConverter{
-		at: time.Now(),
+		at: at,
 	}
 	fns := findDateMathFn(n)
 	dc.bt, dc.err = FindBoundary(dc.at, ctx, fns)
@@ -54,6 +53,11 @@ func NewDateConverter(ctx expr.EvalIncludeContext, n expr.Node) (*DateConverter,
 	}
 	return dc, dc.err
 }
+
+// NewDateConverter takes a node expression
+func NewDateConverter(ctx expr.EvalIncludeContext, n expr.Node) (*DateConverter, error) {
+	return NewDateConverterWithAnchorTime(ctx, n, time.Now())
+}
 func compareBoundaries(currBoundary, newBoundary time.Time) time.Time {
 	// Should we check for is zero on the newBoundary?
 	if currBoundary.IsZero() || newBoundary.Before(currBoundary) {
@@ -183,6 +187,16 @@ func findDateMathFn(node expr.Node) BoundaryFns {
 	case *expr.UnaryNode:
 		return findDateMathFn(n.Arg)
 	case *expr.TriNode:
+		// Only handle BETWEEN operator with specific node types
+		if n.Operator.T == lex.TokenBetween && len(n.Args) == 3 {
+			// Check if first arg is IdentityNode and other two are StringNodes
+			fn := findBoundaryForBetween(n)
+			if fn != nil {
+				fns = append(fns, fn)
+				return fns
+			}
+		}
+
 		for _, arg := range n.Args {
 			fns = append(fns, findDateMathFn(arg)...)
 		}
@@ -204,3 +218,97 @@ func findDateMathFn(node expr.Node) BoundaryFns {
 	}
 	return fns
 }
+
+// findBoundaryForBetween calculates the next time boundary for a BETWEEN expression
+// with date math boundaries. It handles expressions like:
+//
+//	time_column BETWEEN "now-3d" AND "now+3d"
+//
+// The function returns a boundary function that:
+// 1. Evaluates the comparison time (Ct) against the window boundaries
+// 2. Determines when the expression's boolean value will change
+// 3. Returns the appropriate re-evaluation time
+//
+// Example:
+//
+//	Input:  time_column BETWEEN "now-3d" AND "now+3d"
+//	When:   now = 2025-01-22
+//	Window: 2025-01-19 to 2025-01-25
+//
+//	If Ct = 2025-01-01 (left side of window):
+//	- Expression is false
+//	- Will always be false as window is moving forward
+//	- Returns zero time (no re-evaluation needed)
+//
+//	If Ct = 2025-01-30 (right side of window):
+//	- Expression is false
+//	- Will become true when window catches up (enter event)
+//	- Returns re-evaluation time when this will enter the window
+//
+//	If Ct = 2025-01-22 (inside window):
+//	- Expression is true
+//	- Will become false when Ct passes lower bound (exit event)
+//	- Returns re-evaluation time when this will be exit the window
+func findBoundaryForBetween(n *expr.TriNode) func(d *DateConverter, ctx expr.EvalIncludeContext) {
+
+	// Check if first arg is IdentityNode and other two are StringNodes
+	_, isFirstIdentity := n.Args[0].(*expr.IdentityNode)
+	_, isSecondString := n.Args[1].(*expr.StringNode)
+	_, isThirdString := n.Args[2].(*expr.StringNode)
+
+	if !isFirstIdentity || !isSecondString || !isThirdString {
+		return nil
+	}
+	arg1, arg2, arg3 := n.Args[0], n.Args[1], n.Args[2]
+
+	// datemath only if both date args are relative to an anchor time like "now-1d"
+	val2 := strings.ToLower(arg2.(*expr.StringNode).Text)
+	val3 := strings.ToLower(arg3.(*expr.StringNode).Text)
+	if !nowRegex.MatchString(val2) || !nowRegex.MatchString(val3) {
+		return nil
+	}
+
+	return func(d *DateConverter, ctx expr.EvalIncludeContext) {
+
+		lhv, ok := Eval(ctx, arg1)
+		if !ok {
+			return
+		}
+		ct, ok := value.ValueToTime(lhv)
+		if !ok {
+			d.err = fmt.Errorf("could not convert %T: %v to time.Time", lhv, lhv)
+			return
+		}
+
+		date1, err := datemath.EvalAnchor(d.at, val2)
+		if err != nil {
+			d.err = err
+			return
+		}
+
+		date2, err := datemath.EvalAnchor(d.at, val3)
+		if err != nil {
+			d.err = err
+			return
+		}
+
+		// assign lower and upper bounds
+		lower, upper := date1, date2
+		if date1.After(date2) {
+			lower, upper = date2, date1
+		}
+
+		if ct.Before(lower) {
+			// out of window's lower bound, so will always be false
+			return
+		}
+
+		if ct.After(upper) || ct.Equal(upper) {
+			// in the future or right in the border, so will enter the window later sometime in the future, do re-evaluate
+			d.bt = compareBoundaries(d.bt, d.at.Add(ct.Sub(upper)))
+			return
+		}
+		// currently in the window, so will exit the window in the future, do re-evaluate
+		d.bt = compareBoundaries(d.bt, d.at.Add(ct.Sub(lower)))
+	}
+}

vm/datemath_test.go

@@ -253,3 +253,113 @@ func TestDateMath(t *testing.T) {
 	_, err = vm.NewDateConverter(evalCtx, fs.Filter)
 	assert.Equal(t, nil, err)
 }
+
+func TestDateBoundaryForBetween(t *testing.T) {
+	today := time.Now()
+
+	type testCase struct {
+		testName             string
+		filter               string
+		match                bool
+		expectedBoundaryTime time.Time
+		lastEvtTs            time.Time
+	}
+
+	tests := []testCase{
+		{
+			testName:             "within_window_1_day_before_lower_bound",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 1), // Will exit after 1 day since lower bound is after 2 days
+			lastEvtTs:            today.AddDate(0, 0, -1),
+		},
+		{
+			testName:             "within_window_including_other_filters",
+			filter:               `FILTER AND( last_event BETWEEN "now-2d" AND "now+3d", exists subscription_expires )`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 1), // Will exit after 1 day since lower bound is after 2 days
+			lastEvtTs:            today.AddDate(0, 0, -1),
+		},
+		{
+			testName:             "exact_current_time",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 2), // Will exit after two days
+			lastEvtTs:            today,
+		},
+		{
+			testName:             "just_inside_lower",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                true,
+			expectedBoundaryTime: today.Add(time.Minute),                   // will be after a minute
+			lastEvtTs:            today.AddDate(0, 0, -2).Add(time.Minute), // 2 days ago + 1 minute
+		},
+		{
+			testName:             "just_inside_upper",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 5).Add(-time.Minute), // as window is of 5 days and this one just entered
+			lastEvtTs:            today.AddDate(0, 0, 3).Add(-time.Minute), // will exit after 2 days later
+		},
+		{
+			testName:             "exact_boundary_lower",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                false,                   // going to be false as it thinks it is out of window
+			expectedBoundaryTime: today,                   // already in the lowerbound, so should exit now
+			lastEvtTs:            today.AddDate(0, 0, -2), // Exactly 2 days ago
+		},
+		{
+			testName:             "exact_boundary_upper",
+			filter:               `FILTER last_event BETWEEN "now-2d" AND "now+3d"`,
+			match:                false,                  // not entered yet
+			expectedBoundaryTime: today,                  // should enter right now
+			lastEvtTs:            today.AddDate(0, 0, 3), // Exactly 3 days in future
+		},
+		{
+			testName:             "multiple_date_math",
+			filter:               `FILTER AND(last_event BETWEEN "now-2d" AND "now+3d", subscription_expires > "now+1d")`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 2), // Will exit after 2 days last_event is in window and subscription_expires date is 6 days later
+			lastEvtTs:            today,                  // today
+		},
+		{
+			testName:             "not_condition",
+			filter:               `FILTER NOT(last_event BETWEEN "now-2d" AND "now+3d")`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 1), // Will enter after a day as it will be inside of window
+			lastEvtTs:            today.AddDate(0, 0, 4), // 4 days in the future (right of window)
+		},
+		{
+			testName:             "multiple_between",
+			filter:               `FILTER AND( last_event BETWEEN "now-2d" AND "now+3d", subscription_expires BETWEEN "now+1d" AND "now+7d")`,
+			match:                true,
+			expectedBoundaryTime: today.AddDate(0, 0, 1),  // Will exit after 1 day due to last_event sliding out of window after 1 day
+			lastEvtTs:            today.AddDate(0, 0, -1), // 1 day ago
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.testName, func(t *testing.T) {
+			evalCtx := datasource.NewContextMapTs(map[string]interface{}{
+				"last_event":           tc.lastEvtTs,
+				"subscription_expires": today.Add(time.Hour * 24 * 6),
+				"lastevent":            map[string]time.Time{"signedup": today},
+				"first.event":          map[string]time.Time{"has.period": today},
+			}, true, today)
+
+			includeCtx := &includectx{ContextReader: evalCtx}
+
+			fs := rel.MustParseFilter(tc.filter)
+
+			dc, err := vm.NewDateConverterWithAnchorTime(includeCtx, fs.Filter, today)
+			require.NoError(t, err)
+			require.True(t, dc.HasDateMath)
+
+			matched, evalOk := vm.Matches(includeCtx, fs)
+			assert.True(t, evalOk)
+			assert.Equal(t, tc.match, matched)
+
+			assert.Equal(t, tc.expectedBoundaryTime.Unix(), dc.Boundary().Unix())
+		})
+	}
+}