Module split

sort.go

@@ -0,0 +1,110 @@
+package path
+
+import (
+	"errors"
+	"reflect"
+	"sort"
+	"time"
+
+	"cloud.google.com/go/civil"
+	"github.com/gopatchy/jsrest"
+)
+
+func Sort(objs any, path string) error {
+	as := newAnySlice(objs, path)
+	sort.Stable(as)
+
+	return as.err
+}
+
+func SortReverse(objs any, path string) error {
+	as := newAnySlice(objs, path)
+	sort.Stable(sort.Reverse(as))
+
+	return as.err
+}
+
+type anySlice struct {
+	path    string
+	slice   reflect.Value
+	swapper func(i, j int)
+	err     error
+}
+
+var ErrUnsupportedSortType = errors.New("unsupported _sort type")
+
+func newAnySlice(objs any, path string) *anySlice {
+	return &anySlice{
+		path:    path,
+		slice:   reflect.ValueOf(objs),
+		swapper: reflect.Swapper(objs),
+	}
+}
+
+func (as *anySlice) Len() int {
+	return as.slice.Len()
+}
+
+func (as *anySlice) Less(i, j int) bool {
+	v1, err := Get(as.slice.Index(i).Interface(), as.path)
+	if err != nil {
+		as.err = err
+		// We have to obey the Less() contract even in error cases
+		return i < j
+	}
+
+	v2, err := Get(as.slice.Index(j).Interface(), as.path)
+	if err != nil {
+		as.err = err
+		return i < j
+	}
+
+	switch {
+	case v1 == nil && v2 == nil:
+		return false
+	case v1 == nil:
+		return true
+	case v2 == nil:
+		return false
+	}
+
+	switch t1 := v1.(type) {
+	case int:
+		return t1 < v2.(int)
+
+	case int64:
+		return t1 < v2.(int64)
+
+	case uint:
+		return t1 < v2.(uint)
+
+	case uint64:
+		return t1 < v2.(uint64)
+
+	case float32:
+		return t1 < v2.(float32)
+
+	case float64:
+		return t1 < v2.(float64)
+
+	case string:
+		return t1 < v2.(string)
+
+	case bool:
+		return !t1 && v2.(bool)
+
+	case time.Time:
+		return t1.Before(v2.(time.Time))
+
+	case civil.Date:
+		return t1.Before(v2.(civil.Date))
+
+	default:
+		as.err = jsrest.Errorf(jsrest.ErrBadRequest, "%s: %T (%w)", as.path, t1, ErrUnsupportedSortType)
+		return i < j
+	}
+}
+
+func (as *anySlice) Swap(i, j int) {
+	as.swapper(i, j)
+}