Switched to expression-based timestamps

cmds/timestamps/ast.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"errors"
+	"strings"
+	"time"
+)
+
+type TimeComponent struct {
+	TS *string `parser:"@Time"`
+}
+
+func (t TimeComponent) Time() (time.Time, error) {
+	if strings.HasSuffix(*t.TS, "Z") {
+		return time.ParseInLocation("15:04:05Z", *t.TS, time.UTC)
+	}
+	return time.ParseInLocation("15:04:05", *t.TS, time.Local)
+}
+
+func (t TimeComponent) RequiresRefreshing() bool {
+	return false
+}
+
+type DateWithTimeComponents struct {
+	Date      *string        `parser:"@Date"`
+	MaybeTime *TimeComponent `parser:" @@?"`
+}
+
+func (d DateWithTimeComponents) Time() (time.Time, error) {
+	t, err := time.Parse("2006-01-02", *d.Date)
+	if err != nil {
+		return time.Time{}, err
+	}
+	if d.MaybeTime != nil {
+		tt, err := d.MaybeTime.Time()
+		if err != nil {
+			return time.Time{}, err
+		}
+		t = t.Add(tt.Sub(tt.Truncate(24 * time.Hour)))
+	}
+	return t, nil
+}
+
+type Timestamp struct {
+	Full      *string                 `parser:"@Timestamp"`
+	DT        *DateWithTimeComponents `parser:"| @@"`
+	TimeToday *TimeComponent          `parser:" | @@"`
+	Int       *int                    `parser:" | @Int"`
+}
+
+func (t Timestamp) Time() (time.Time, error) {
+	switch {
+	case t.Full != nil:
+		if strings.HasSuffix(*t.Full, "Z") {
+			return time.ParseInLocation("2006-01-02T15:04:05Z", *t.Full, time.UTC)
+		}
+		return time.ParseInLocation("2006-01-02T15:04:05", *t.Full, time.Local)
+	case t.DT != nil:
+		return t.DT.Time()
+	case t.TimeToday != nil:
+		tt, err := t.TimeToday.Time()
+		if err != nil {
+			return time.Time{}, err
+		}
+		today := time.Now().In(tt.Location())
+		return time.Date(today.Year(), today.Month(), today.Day(), tt.Hour(), tt.Minute(), tt.Second(), tt.Nanosecond(), tt.Location()), nil
+	}
+	return time.Unix(int64(*t.Int), 0), nil
+}
+
+func (t Timestamp) RequiresRefreshing() bool {
+	return false
+}
+
+type Atom struct {
+	Timestamp  *Timestamp `parser:"@@"`
+	Identifier *string    `parser:" | @Identifier"`
+}
+
+func (a Atom) Time() (time.Time, error) {
+	switch {
+	case a.Timestamp != nil:
+		return a.Timestamp.Time()
+	case a.Identifier != nil:
+		if *a.Identifier == "now" {
+			return time.Now(), nil
+		}
+
+		return time.Time{}, errors.New("unknown identifier")
+	}
+	return time.Time{}, errors.New("unhandled case")
+}
+
+func (a Atom) RequiresRefreshing() bool {
+	switch {
+	case a.Timestamp != nil:
+		return a.Timestamp.RequiresRefreshing()
+	case a.Identifier != nil:
+		if *a.Identifier == "now" {
+			return true
+		}
+		return false
+	}
+	return false
+}