package frame

import (
	"errors"
	"git.gammaspectra.live/S.O.N.G/Ignite/colorspace"
	"runtime"
	"unsafe"
)

type uint16Frame struct {
	colorSpace colorspace.ColorSpace
	width      int
	height     int
	Y          []uint16
	Cb         []uint16
	Cr         []uint16
}

func NewUint16FrameFromBytes(space colorspace.ColorSpace, width, height int, data []byte) (*uint16Frame, error) {
	if frameLength, _ := space.FrameSize(width, height); frameLength != len(data) {
		return nil, errors.New("wrong length of data")
	}

	if space.BitDepth >= 16 {
		return nil, errors.New("wrong bit depth")
	}

	buf := make([]uint16, len(data)/2)
	copy(buf, unsafe.Slice((*uint16)(unsafe.Pointer(&data[0])), len(data)/2))
	runtime.KeepAlive(data)

	iY := space.PlaneLumaSamples(width, height)
	iCb := space.PlaneCbSamples(width, height)
	iCr := space.PlaneCrSamples(width, height)

	return &uint16Frame{
		colorSpace: space,
		height:     height,
		width:      width,
		Y:          buf[:iY],
		Cb:         buf[iY : iY+iCb],
		Cr:         buf[iY+iCb : iY+iCb+iCr],
	}, nil
}

func (i *uint16Frame) Get16(x, y int) (Y uint16, Cb uint16, Cr uint16) {
	cy, cb, cr := i.GetNative(x, y)

	return cy << (16 - i.colorSpace.BitDepth), cb << (16 - i.colorSpace.BitDepth), cr << (16 - i.colorSpace.BitDepth)
}

func (i *uint16Frame) Get8(x, y int) (Y uint8, Cb uint8, Cr uint8) {
	cy, cb, cr := i.GetNative(x, y)

	return uint8(cy >> (i.colorSpace.BitDepth - 8)), uint8(cb >> (i.colorSpace.BitDepth - 8)), uint8(cr >> (i.colorSpace.BitDepth - 8))
}

func (i *uint16Frame) Width() int {
	return i.width
}

func (i *uint16Frame) Height() int {
	return i.height
}

func (i *uint16Frame) ColorSpace() colorspace.ColorSpace {
	return i.colorSpace
}

func (i *uint16Frame) GetNative(x, y int) (Y uint16, Cb uint16, Cr uint16) {
	Yindex := x + y*i.width

	Cwidth := (i.width * int(i.colorSpace.Subsampling.A)) / int(i.colorSpace.Subsampling.J)
	if i.colorSpace.Subsampling.B == 0 {
		y /= 2
	}
	Cindex := (x*int(i.colorSpace.Subsampling.A))/int(i.colorSpace.Subsampling.J) + y*Cwidth
	Y = i.Y[Yindex]
	Cb = i.Cb[Cindex]
	Cr = i.Cr[Cindex]
	return
}

func (i *uint16Frame) GetNativeLuma() []uint16 {
	return i.Y
}

func (i *uint16Frame) GetNativeCb() []uint16 {
	return i.Cb
}

func (i *uint16Frame) GetNativeCr() []uint16 {
	return i.Cr
}