Merge pull request #21 from adhocore/18-batch-check

Batch due check

README.md

@@ -45,6 +45,29 @@ gron.IsDue(expr) // true|false, nil
 gron.IsDue(expr, time.Date(2021, time.April, 1, 1, 1, 0, 0, time.UTC)) // true|false, nil
 ```
 
+### Batch Due Check
+
+If you have multiple cron expressions to check due on same reference time use `BatchDue()`:
+```go
+gron := gronx.New()
+exprs := []string{"* * * * *", "0 */5 * * * *"}
+
+// gives []gronx.Expr{} array, each item has Due flag and Err enountered.
+dues := gron.BatchDue(exprs)
+
+for _, expr := range dues {
+    if expr.Err != nil {
+        // Handle err
+    } else if expr.Due {
+        // Handle due
+    }
+}
+
+// Or with given time
+ref := time.Now()
+gron.BatchDue(exprs, ref)
+```
+
 ### Next Tick
 
 To find out when is the cron due next (onwards):

batch.go

@@ -0,0 +1,40 @@
+package gronx
+
+import (
+	"time"
+)
+
+// Expr represents an item in array for batch check
+type Expr struct {
+	Expr string
+	Due  bool
+	Err  error
+	segs []string
+}
+
+// BatchDue checks if multiple expressions are due for given time (or now).
+// It returns []Expr with filled in Due and Err values.
+func (g *Gronx) BatchDue(exprs []string, ref ...time.Time) []Expr {
+	if len(ref) > 0 {
+		g.C.SetRef(ref[0])
+	} else {
+		g.C.SetRef(time.Now())
+	}
+
+	batch := make([]Expr, len(exprs))
+	for i := range exprs {
+		if batch[i].segs, batch[i].Err = Segments(exprs[i]); batch[i].Err != nil {
+			continue
+		}
+		due := true
+		for pos, seg := range batch[i].segs {
+			if seg != "*" && seg != "?" {
+				if due, batch[i].Err = g.C.CheckDue(seg, pos); !due || batch[i].Err != nil {
+					break
+				}
+			}
+		}
+		batch[i].Due = due
+	}
+	return batch
+}

batch_test.go

@@ -0,0 +1,40 @@
+package gronx
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestBatch(t *testing.T) {
+	gron := New()
+
+	t.Run("batch no error", func(t *testing.T) {
+		ref := time.Now()
+		exprs := []string{"@everysecond", "* * * * * *", "*  *  *  *  *  *"}
+		exprs = append(exprs, fmt.Sprintf("* %d * * * * %d", ref.Minute(), ref.Year()))
+		exprs = append(exprs, fmt.Sprintf("* * * * * * %d-%d", ref.Year()-1, ref.Year()+1))
+
+		for _, expr := range gron.BatchDue(exprs) {
+			if expr.Err != nil {
+				t.Errorf("%s error: %#v", expr.Expr, expr.Err)
+			}
+			if !expr.Due {
+				t.Errorf("%s must be due", expr.Expr)
+			}
+		}
+	})
+
+	t.Run("batch error", func(t *testing.T) {
+		exprs := []string{"* * * *", "A B C D E F"}
+		ref, _ := time.Parse(FullDateFormat, "2022-02-02 02:02:02")
+		for _, expr := range gron.BatchDue(exprs, ref) {
+			if expr.Err == nil {
+				t.Errorf("%s expected error", expr.Expr)
+			}
+			if expr.Due {
+				t.Errorf("%s must not be due when there is error", expr.Expr)
+			}
+		}
+	})
+}