package goffmpeg

/*
#include <stdlib.h>
#include "libcffmpeg.h"
*/
import "C"
import "unsafe"

const (
	// ScaleNone self add no scale raw frame data
	ScaleNone = 0
	// ScaleFastBilinear SWS_FAST_BILINEAR
	ScaleFastBilinear = 1
	// ScaleBilinear SWS_BILINEAR
	ScaleBilinear = 2
	// ScaleBicubic SWS_BICUBIC
	ScaleBicubic = 4
	// ScaleX SWS_X
	ScaleX = 8
	// ScalePoint SWS_POINT
	ScalePoint = 0x10
	// ScaleArea SWS_AREA
	ScaleArea = 0x20
	// ScaleBicublin SWS_BICUBLIN
	ScaleBicublin = 0x40
	// ScaleGauss SWS_GAUSS
	ScaleGauss = 0x80
	// ScaleSinc SWS_SINC
	ScaleSinc = 0x100
	// ScaleLancZos SWS_LANCZOS
	ScaleLancZos = 0x200
	// ScaleSpline SWS_SPLINE
	ScaleSpline = 0x400
)

// SrcFormat format
const SrcFormat = 23

// DstFormat format
const DstFormat = 3

// GoConv conv
type GoConv struct {
	SrcW int
	SrcH int
	DstW int
	DstH int

	conv C.cconv
}

// NewConv new conv
func NewConv(srcW, srcH, dstW, dstH, scaleFlag int) *GoConv {
	c := C.wrap_fn_create_conv(unsafe.Pointer(libcffmpeg), C.int(srcW), C.int(srcH), C.int(SrcFormat),
		C.int(dstW), C.int(dstH), C.int(DstFormat), C.int(scaleFlag))

	if c == nil {
		return nil
	}

	return &GoConv{
		srcW,
		srcH,
		dstW,
		dstH,
		c,
	}
}

// NewResizer resize
func NewResizer(srcW, srcH, format, dstW, dstH, scaleFlag int) *GoConv {
	c := C.wrap_fn_create_conv(unsafe.Pointer(libcffmpeg), C.int(srcW), C.int(srcH), C.int(format),
		C.int(dstW), C.int(dstH), C.int(format), C.int(scaleFlag))

	if c == nil {
		return nil
	}

	return &GoConv{
		srcW,
		srcH,
		dstW,
		dstH,
		c,
	}
}

// Free free
func (c *GoConv) Free() {
	if c.conv != nil {
		C.wrap_fn_destroy_conv(unsafe.Pointer(libcffmpeg), c.conv)
	}
}

// ConvToPicture conv to pic
func (c *GoConv) ConvToPicture(src []byte) []byte {
	if c.conv == nil {
		return nil
	}

	cin := C.CBytes(src)
	defer C.free(cin)

	bgr := C.wrap_fn_conv(unsafe.Pointer(libcffmpeg), c.conv, (*C.uchar)(cin))
	defer C.free(unsafe.Pointer(bgr))

	if bgr != nil {
		return C.GoBytes(bgr, C.int(c.DstW*c.DstH*3))
	}

	return nil
}

// Resize resize
func (c *GoConv) Resize(src []byte) []byte {
	if c.SrcW == c.DstW && c.SrcH == c.DstH {
		return src
	}
	return c.ConvToPicture(src)
}

/////////////// for conv