1 files changed, 51 insertions, 0 deletions
diff --git a/graphql/resolvers/pagers.go b/graphql/resolvers/pagers.go
new file mode 100644
index 00000000..378dcdbf
--- /dev/null
+++ b/graphql/resolvers/pagers.go
@@ -0,0 +1,51 @@
+//go:generate genny -in=pagers_template.go -out=pager_bug.go gen "NodeType=bug.Snapshot EdgeType=BugEdge"
+//go:generate genny -in=pagers_template.go -out=pager_operation.go gen "NodeType=bug.Operation EdgeType=OperationEdge"
+//go:generate genny -in=pagers_template.go -out=pager_comment.go gen "NodeType=bug.Comment EdgeType=CommentEdge"
+
+package resolvers
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const cursorPrefix = "cursor:"
+
+type Edge interface {
+	GetCursor() string
+}
+
+// Creates the cursor string from an offset
+func offsetToCursor(offset int) string {
+	str := fmt.Sprintf("%v%v", cursorPrefix, offset)
+	return base64.StdEncoding.EncodeToString([]byte(str))
+}
+
+// Re-derives the offset from the cursor string.
+func cursorToOffset(cursor string) (int, error) {
+	str := ""
+	b, err := base64.StdEncoding.DecodeString(cursor)
+	if err == nil {
+		str = string(b)
+	}
+	str = strings.Replace(str, cursorPrefix, "", -1)
+	offset, err := strconv.Atoi(str)
+	if err != nil {
+		return 0, fmt.Errorf("Invalid cursor")
+	}
+	return offset, nil
+}
+
+func (e OperationEdge) GetCursor() string {
+	return e.Cursor
+}
+
+func (e BugEdge) GetCursor() string {
+	return e.Cursor
+}
+
+func (e CommentEdge) GetCursor() string {
+	return e.Cursor
+}