// 12 december 2015

package ui

import (
	"unsafe"
)

// #include <stdlib.h>
// #include "ui.h"
// #include "util.h"
// extern void doColorButtonOnChanged(uiColorButton *, void *);
// // see golang/go#19835
// typedef void (*colorButtonCallback)(uiColorButton *, void *);
// typedef struct pkguiCColor pkguiCColor;
// struct pkguiCColor { double *r; double *g; double *b; double *a; };
// static inline pkguiCColor pkguiNewCColor(void)
// {
// 	pkguiCColor c;
// 
// 	c.r = (double *) pkguiAlloc(4 * sizeof (double));
// 	c.g = c.r + 1;
// 	c.b = c.g + 1;
// 	c.a = c.b + 1;
// 	return c;
// }
// static inline void pkguiFreeCColor(pkguiCColor c)
// {
// 	free(c.r);
// }
import "C"

// ColorButton is a Control that represents a button that the user can
// click to select a color.
type ColorButton struct {
	ControlBase
	b	*C.uiColorButton
	onChanged		func(*ColorButton)
}

// NewColorButton creates a new ColorButton.
func NewColorButton() *ColorButton {
	b := new(ColorButton)

	b.b = C.uiNewColorButton()

	C.uiColorButtonOnChanged(b.b, C.colorButtonCallback(C.doColorButtonOnChanged), nil)

	b.ControlBase = NewControlBase(b, uintptr(unsafe.Pointer(b.b)))
	return b
}

// Color returns the color currently selected in the ColorButton.
// Colors are not alpha-premultiplied.
// TODO rename b or bl
func (b *ColorButton) Color() (r, g, bl, a float64) {
	c := C.pkguiNewCColor()
	defer C.pkguiFreeCColor(c)
	C.uiColorButtonColor(b.b, c.r, c.g, c.b, c.a)
	return float64(*(c.r)), float64(*(c.g)), float64(*(c.b)), float64(*(c.a))
}

// SetColor sets the currently selected color in the ColorButton.
// Colors are not alpha-premultiplied.
// TODO rename b or bl
func (b *ColorButton) SetColor(r, g, bl, a float64) {
	C.uiColorButtonSetColor(b.b, C.double(r), C.double(g), C.double(bl), C.double(a))
}

// OnChanged registers f to be run when the user changes the
// currently selected color in the ColorButton. Only one function
// can be registered at a time.
func (b *ColorButton) OnChanged(f func(*ColorButton)) {
	b.onChanged = f
}

//export doColorButtonOnChanged
func doColorButtonOnChanged(bb *C.uiColorButton, data unsafe.Pointer) {
	b := ControlFromLibui(uintptr(unsafe.Pointer(bb))).(*ColorButton)
	if b.onChanged != nil {
		b.onChanged(b)
	}
}