chore: improve legacy iso parsing (#8581)

* chore: improve legacy iso parsing

* Add parser for legacy TimeRange

* self review

Author: AdityaHegde

runtime/metricsview/executor/executor_rewrite_time.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/rilldata/rill/runtime/metricsview"
-	"github.com/rilldata/rill/runtime/pkg/duration"
 	"github.com/rilldata/rill/runtime/pkg/rilltime"
 	"github.com/rilldata/rill/runtime/pkg/timeutil"
 )
@@ -113,9 +112,12 @@ func (e *Executor) resolveTimeRange(ctx context.Context, tr *metricsview.TimeRan
 
 // resolveISOTimeRange resolves the given time range where either only start/end is specified along with ISO duration/offset, ensuring only its Start and End properties are populated.
 func (e *Executor) resolveISOTimeRange(ctx context.Context, tr *metricsview.TimeRange, tz *time.Location, executionTime *time.Time) error {
+	var ts metricsview.TimestampsResult
+	var err error
+
 	if tr.Start.IsZero() && tr.End.IsZero() {
 		if executionTime == nil {
-			ts, err := e.Timestamps(ctx, tr.TimeDimension)
+			ts, err = e.Timestamps(ctx, tr.TimeDimension)
 			if err != nil {
 				return fmt.Errorf("failed to fetch timestamps: %w", err)
 			}
@@ -125,65 +127,30 @@ func (e *Executor) resolveISOTimeRange(ctx context.Context, tr *metricsview.Time
 		tr.End = *executionTime
 	}
 
-	var isISO bool
 	if tr.IsoDuration != "" {
-		d, err := duration.ParseISO8601(tr.IsoDuration)
-		if err != nil {
-			return fmt.Errorf("invalid iso_duration %q: %w", tr.IsoDuration, err)
-		}
-
-		if !tr.Start.IsZero() && !tr.End.IsZero() {
-			return errors.New(`cannot resolve "iso_duration" for a time range with fixed "start" and "end" timestamps`)
-		} else if !tr.Start.IsZero() {
-			tr.End = d.Add(tr.Start)
-		} else if !tr.End.IsZero() {
-			tr.Start = d.Sub(tr.End)
-		} else {
-			// In practice, this shouldn't happen since we resolve a time anchor dynamically if both start and end are zero.
-			return errors.New(`cannot resolve "iso_duration" for a time range without "start" and "end" timestamps`)
-		}
-
-		isISO = true
-	}
-
-	if tr.IsoOffset != "" {
-		d, err := duration.ParseISO8601(tr.IsoOffset)
+		rt, err := rilltime.ParseLegacy(tr.IsoDuration, tr.IsoOffset, tr.RoundToGrain.ToTimeutil(), rilltime.ParseOptions{
+			DefaultTimeZone: tz,
+			SmallestGrain:   timeutil.TimeGrainFromAPI(e.metricsView.SmallestTimeGrain),
+		})
 		if err != nil {
-			return fmt.Errorf("invalid iso_offset %q: %w", tr.IsoOffset, err)
-		}
-
-		if !tr.Start.IsZero() {
-			tr.Start = d.Sub(tr.Start)
+			return err
 		}
-		if !tr.End.IsZero() {
-			tr.End = d.Sub(tr.End)
-		}
-
-		isISO = true
-	}
 
-	// Only modify the start and end if ISO duration or offset was sent.
-	// This is to maintain backwards compatibility for calls from the UI.
-	if isISO {
-		fdow := int(e.metricsView.FirstDayOfWeek)
-		if fdow > 7 || fdow <= 0 {
-			fdow = 1
-		}
-		fmoy := int(e.metricsView.FirstMonthOfYear)
-		if fmoy > 12 || fmoy <= 0 {
-			fmoy = 1
-		}
-		if !tr.RoundToGrain.Valid() {
-			return fmt.Errorf("invalid time grain %q", tr.RoundToGrain)
-		}
-		if tr.RoundToGrain != metricsview.TimeGrainUnspecified {
-			if !tr.Start.IsZero() {
-				tr.Start = timeutil.TruncateTime(tr.Start, tr.RoundToGrain.ToTimeutil(), tz, fdow, fmoy)
-			}
-			if !tr.End.IsZero() {
-				tr.End = timeutil.TruncateTime(tr.End, tr.RoundToGrain.ToTimeutil(), tz, fdow, fmoy)
+		if ts.Now.IsZero() {
+			ts, err = e.Timestamps(ctx, tr.TimeDimension)
+			if err != nil {
+				return fmt.Errorf("failed to fetch timestamps: %w", err)
 			}
 		}
+
+		tr.Start, tr.End, _ = rt.Eval(rilltime.EvalOptions{
+			Now:        ts.Now,
+			MinTime:    ts.Min,
+			MaxTime:    ts.Max,
+			Watermark:  tr.End,
+			FirstDay:   int(e.metricsView.FirstDayOfWeek),
+			FirstMonth: int(e.metricsView.FirstMonthOfYear),
+		})
 	}
 
 	// Clear all other fields than Start and End