Feature/#33 wait class function (#63)

* #33 Lib cleanup. Added WAIT_CLASS and WAIT_CLASS_ALL functions

* #33 Fixed attr update

* #33 HTMLElement.WaitForClass

* #33 Updated HTMLDocument.WaitForClass

pkg/stdlib/html/wait_class.go

@@ -0,0 +1,87 @@
+package html
+
+import (
+	"context"
+	"github.com/MontFerret/ferret/pkg/runtime/core"
+	"github.com/MontFerret/ferret/pkg/runtime/values"
+	"github.com/MontFerret/ferret/pkg/stdlib/html/driver/dynamic"
+)
+
+/*
+ * Waits for a class to appear on a given element.
+ * Stops the execution until the navigation ends or operation times out.
+ * @param docOrEl (HTMLDocument|HTMLElement) - Target document or element.
+ * @param selectorOrClass (String) - If document is passed, this param must represent an element selector.
+ * Otherwise target class.
+ * @param classOrTimeout (String|Int, optional) - If document is passed, this param must represent target class name.
+ * Otherwise timeout.
+ * @param timeout (Int, optional) - If document is passed, this param must represent timeout.
+ * Otherwise not passed.
+ */
+func WaitClass(_ context.Context, args ...core.Value) (core.Value, error) {
+	err := core.ValidateArgs(args, 2, 4)
+
+	if err != nil {
+		return values.None, err
+	}
+
+	// document or element
+	err = core.ValidateType(args[0], core.HTMLDocumentType, core.HTMLElementType)
+
+	if err != nil {
+		return values.None, err
+	}
+
+	// selector or class
+	err = core.ValidateType(args[1], core.StringType)
+
+	if err != nil {
+		return values.None, err
+	}
+
+	timeout := values.NewInt(defaultTimeout)
+
+	// lets figure out what is passed as 1st argument
+	switch args[0].(type) {
+	case *dynamic.HTMLDocument:
+		// class
+		err = core.ValidateType(args[2], core.StringType)
+
+		if err != nil {
+			return values.None, err
+		}
+
+		doc := args[0].(*dynamic.HTMLDocument)
+		selector := args[1].(values.String)
+		class := args[2].(values.String)
+
+		if len(args) == 4 {
+			err = core.ValidateType(args[3], core.IntType)
+
+			if err != nil {
+				return values.None, err
+			}
+
+			timeout = args[3].(values.Int)
+		}
+
+		return values.None, doc.WaitForClass(selector, class, timeout)
+	case *dynamic.HTMLElement:
+		el := args[0].(*dynamic.HTMLElement)
+		class := args[1].(values.String)
+
+		if len(args) == 3 {
+			err = core.ValidateType(args[2], core.IntType)
+
+			if err != nil {
+				return values.None, err
+			}
+
+			timeout = args[3].(values.Int)
+		}
+
+		return values.None, el.WaitForClass(class, timeout)
+	default:
+		return values.None, core.Errors(core.ErrInvalidType, ErrNotDynamic)
+	}
+}