package glib

// #cgo pkg-config: glib-2.0 gobject-2.0
// #include <gio/gio.h>
// #include <glib.h>
// #include <glib-object.h>
// #include "glib.go.h"
import "C"
import "unsafe"

type BindingFlags int

const (
        BINDING_DEFAULT BindingFlags = C.G_BINDING_DEFAULT
        BINDING_BIDIRECTIONAL BindingFlags = C.G_BINDING_BIDIRECTIONAL
        BINDING_SYNC_CREATE = C.G_BINDING_SYNC_CREATE
        BINDING_INVERT_BOOLEAN = C.G_BINDING_INVERT_BOOLEAN
)

type Binding struct {
        *Object
}

func (v *Binding) native() *C.GBinding {
        if v == nil || v.GObject == nil {
            return nil
        }
        return C.toGBinding(unsafe.Pointer(v.GObject))
}

func marshalBinding(p uintptr) (interface{}, error) {
        c := C.g_value_get_object((*C.GValue)(unsafe.Pointer(p)))
        return &Binding{wrapObject(unsafe.Pointer(c))}, nil
}

// Creates a binding between source property on source and target property on
// target . Whenever the source property is changed the target_property is
// updated using the same value.
func BindProperty(source *Object, sourceProperty string,
                  target *Object, targetProperty string,
                  flags BindingFlags) *Binding {
        srcStr := (*C.gchar)(C.CString(sourceProperty))
        defer C.free(unsafe.Pointer(srcStr))
        tgtStr := (*C.gchar)(C.CString(targetProperty))
        defer C.free(unsafe.Pointer(tgtStr))
        obj := C.g_object_bind_property(
            C.gpointer(source.GObject), srcStr,
            C.gpointer(target.GObject), tgtStr,
            C.GBindingFlags(flags),
        )
        if obj == nil {
            return nil
        }
        return &Binding{wrapObject(unsafe.Pointer(obj))}
}

// Explicitly releases the binding between the source and the target property
// expressed by Binding
func (v *Binding) Unbind() {
        C.g_binding_unbind(v.native())
}

// Retrieves the GObject instance used as the source of the binding
func (v *Binding) GetSource() *Object {
        obj := C.g_binding_get_source(v.native())
        if obj == nil {
            return nil
        }
        return wrapObject(unsafe.Pointer(obj))
}

// Retrieves the name of the property of “source” used as the source of
// the binding.
func (v *Binding) GetSourceProperty() string {
        s := C.g_binding_get_source_property(v.native())
        return C.GoString((*C.char)(s))
}

// Retrieves the GObject instance used as the target of the binding.
func (v *Binding) GetTarget() *Object {
        obj := C.g_binding_get_target(v.native())
        if obj == nil {
            return nil
        }
        return wrapObject(unsafe.Pointer(obj))
}

// Retrieves the name of the property of “target” used as the target of
// the binding.
func (v *Binding) GetTargetProperty() string {
        s := C.g_binding_get_target_property(v.native())
        return C.GoString((*C.char)(s))
}

// Retrieves the flags passed when constructing the GBinding.
func (v *Binding) GetFlags() BindingFlags {
        flags := C.g_binding_get_flags(v.native())
        return BindingFlags(flags)
}