fix: handle expiration date in regard to changed timezones (#667)

stackit/internal/utils/attributes.go

@@ -0,0 +1,46 @@
+package utils
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/path"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/core"
+)
+
+type attributeGetter interface {
+	GetAttribute(ctx context.Context, attributePath path.Path, target interface{}) diag.Diagnostics
+}
+
+func ToTime(ctx context.Context, format string, val types.String, target *time.Time) (diags diag.Diagnostics) {
+	var err error
+	text := val.ValueString()
+	*target, err = time.Parse(format, text)
+	if err != nil {
+		core.LogAndAddError(ctx, &diags, "cannot parse date", fmt.Sprintf("cannot parse date %q with format %q: %v", text, format, err))
+		return diags
+	}
+	return diags
+}
+
+// GetTimeFromStringAttribute retrieves a string attribute from e.g. a [plan.Plan], [tfsdk.Config] or a [tfsdk.State] and
+// converts it to a [time.Time] object with a given format, if possible.
+func GetTimeFromStringAttribute(ctx context.Context, attributePath path.Path, source attributeGetter, dateFormat string, target *time.Time) (diags diag.Diagnostics) {
+	var date types.String
+	diags.Append(source.GetAttribute(ctx, attributePath, &date)...)
+	if diags.HasError() {
+		return diags
+	}
+	if date.IsNull() || date.IsUnknown() {
+		return diags
+	}
+	diags.Append(ToTime(ctx, dateFormat, date, target)...)
+	if diags.HasError() {
+		return diags
+	}
+
+	return diags
+}